In the morning, well, every Friday we do have a guest presenter in the studio and this week we have Mr. Muyangua Muyangua who is the director general of NAPSA. Now, Mr. Muyangua, this week must have been very, very exciting and probably challenging for one for NAPSA, following President Hichilamas signing into law the National Patients Scheme Amendment Bill of 2023, which sought to amend the 1996 NAPSA Act. The new law allows for partial withdrawal of patients. How would you describe week one for you as NAPSA? I think it has been a very empowering week economically for our members and I think this I'll take it back from December. I think most people don't realize we have actually enacted two huge reform bills since December. On the 6th of December, the president signed on to the ZNPF and immediately the following day we started the processes, we're ready. On the 16th, he signed the one on the partial withdrawal and we're ready to go with our systems because we had been preparing for that for a long time. So really it has been a very empowering period for our members and exciting too in that we've seen something that people had been waiting for actually come to be implemented. I think now they'll stop saying give us a way. And week one for this 20% partial withdrawal, how has it been? It's been I think quite interesting, we're learning a lot of lessons that we didn't expect those numbers to turn up at our offices because the plan was that we're going to do most of that online. But definitely people have had challenges here and there and the numbers have been coming through to our offices country-wide but we are up to the task. We have a very committed and vibrant young guys and girls at NAPSA who are up to the task and they have been eating into those queues like you would not expect. We have the queues in the morning like at 6, 6.26 today there was the marquee that we have put up outside the headquarters was full. The queue was already coming out of that but I can assure you if you went there by 9 you would have all these service points around the mall and around the offices including our own car park it's now a service point and everyone is attending to everyone. We've taken in all the stuff that are available to just make sure we ride this wave because we know once people get through this process the next process they don't need to come to us they have no option they will not be able to come to us okay because all they need to do is press a button and say I've claimed and that's it okay so can you confirm that payouts have started yes 1.3 million paid as of yesterday 1.3 million yes that's that's a good start yes it is what does that translate to the 1.3 million how many members have been paid only 27 as in 27 people yes 27 people got 1.3 million okay you see by the time we are getting to a hundred people there the values that we'll be talking about but we're ready we're projecting that we'll get to about 9 10 11 billion but we're ready for that if you look at the response that you've gotten the number that of the number of payouts that you've had in week one are you moving at the pace that you want to be at or is it a bit slow on your end that is on our end I think the first process that we we design the process in such a manner that we don't want you to come back and say I'm not the one that got my money okay so that's a process you see creating the cues of actually validating who you are so you have to we don't use we use a multiple point verification process which goes to the banks it goes to the MNOs and our database and when you pass all those three we positive that you that's when you go to the process the next stage of of actual claiming so some of the issues you're seeing people coming up on the cues they're coming up with maybe queries of the names as held at the MNOs and held at the bank and held in our database are not the same but the NRC could be the same yeah so we're trying to align all those and make sure it's actually the same person we're talking about others are coming in to find out why their gaps on their on their contributions which is a very big a very big development cause before this no one was paying attention to their naps account yeah I'm sure all of you trust I wasn't paying your bank account yeah you would monitor what is happening every day no one would monitor what is happening on their on their naps account and yet it is a savings account you should know how much money you have all the time imagine the process where every month your employer detects a certain amount of money and you don't care where it goes now people are caring where it went and they're looking for it and they're getting it but why do you think that was the case before the reluctance they I think it's because of the way people are looking at NAPSA contributions I think the general feeling you get is that people think it's a tax they don't look at it as a savings so we need to transform that perception and to get people to understand that this is actually a savings account but do you feel as do you equally feel as NAPSA you've done enough in that area in terms of sensitization I think partly we took on we tried to internalize a lot of that and say it's a statutory obligation therefore it's fine we should have done a little bit more going out and saying look actually just as much as you have an app's account you have an app's account can you check what you say if you see now what what we've been doing is sending SMS to you every time you get credit even every time it doesn't get credited you get an SMS and then the statement that is just to ignite the interest in the people to check on what is happening on an app's account okay some of our listeners have you know reached out with some complaints of glitches on the system and very frustrating you know a login process or procedure what are some of the common issues your office has you know encountered since this process commenced I think one of the issues is just people navigating the process that has been quite a challenge for some people we are all our levels of being techie savvy are different so some people it might be lower others much higher but then on the lower end that's where you find they need to be to for handholding through the process and that's what our staff are doing some of it yes there could be a glitch here and there depending on the workload or the or the Lord on the system at a particular time it just slows down the process but then it picks up again and we're able to process but you you'll be you'll be happy to know that I think on the first day we had almost half of the number of people that turned up in person the other half was online they managed to do their own on-boarding without assistance from NAPSA okay now let's go back to the to the law in simpler terms who is eligible to withdraw partially and what happens at retirement age to those that partially withdrew and those that may opt out what are the key features of the law let's take a deeper look at so there are two main key features of the law one is in terms of qualifying one is a fact that you should only have 60 contributions on the account 60 contributions is equivalent five years off of contributing to NAPSA that entitles you to a 20 percent partial withdrawal or if you don't have the 60 contributions it should be 45 and above then you are able to access the 20 percent now in terms of what happens to those who access to maintain fairness and equity remember this is a NAPSA the scheme that we run is what is called a defined benefit it's a solidarity scheme it's not a defined contribution where it's one one man for each man for himself and NAPSA for all this one is a solidarity contribution so it's like all resources are put together and you pay from there that's why you find that under NAPSA you can contribute 50,000 the whole of your life you can get five million the whole of your life more than you contributed even if we factor out the issue of the interest what people are calling interest that payout is huge that's why the system is able to do that now if you withdraw and the other does not withdraw basically you are saying you cannot be treated the same you have accessed part of your 100 percent the other person needs to have to have to access the 400 percent so you only access the 80 percent that remained okay yeah at retirement that is okay for other benefits as well so all the other benefits are going to be 80 percent for anybody that opts to withdraw 20 percent now yes okay and I like the fact that you said opts because it's not mandatory you make a choice all right we've also received inquiries on you know how the interest is accrued or calculated without getting very mathematical what variables are you know taken into account when arriving at the interest to be paid on the amounts to be withdrawn so it's there's a study that early study that the Zambia statistics office undertakes what's called determining the national average waging in simple terms the wage inflation so you make sure that the savings are protected from the wage inflation so that's a factor by which NAPSA grows your contributions to make sure that you maintain that the purchasing power if you may put it that way all through your life so that's it's it's people don't know how much that value actually comes to but some people should not be surprised when they look at their statement a 20 percent contribution say 61 the payout you are getting is hundred and 21 because of that very factor we're talking about the uplifting to protect the value using what we call the national average earnings so it's quite significant I think it's one of the best paying savings account you ever have all right now some quarters fail you know you as DG rushed in to announcing that you know people could actually start getting their money 24 hours after the law was passed would you say perhaps the authority wasn't technically ready to absorb all the requests that were coming in and maybe you should have waited a bit a bit longer after the assenting of the law how do you respond to that those that fail this whole thing has not so we have no time for eating that's that's not our DNA DNA is to get things done when they are we knew all this time that the law was coming okay what people don't realize is we've been working behind the scenes developing that system from last year as the law was going through the channels of approval we're also developing a system to take care of the members so look at what happened on the Zambia national profit and fund the president signs the law today the following day we started the process that's exactly what happened was we were ready the glitches yes but if people listen to what I said I said the process of claiming starts now and the process is first of all you have to validate who you are that validation is actually the the lengthy the lengthy of the two processes because the payment once you have validated it's a click of a button you get your money then your bank account or in a mobile money account so that process yes people might say we I don't feel we rushed we have first glitches understood agreed but there was no need for us to say we wait what would we have been waiting for cause we were ready you were ready for the numbers we were ready the numbers shocked us okay because we didn't expect all of them to come through to the office and also a few issues we did on the system that we realize was maybe asking too much and we had to relax so that people can actually be on the system and be able to serve themselves so it is what would have been worse out loud want to ask those who think we rushed the president signs today and you start telling people wait till next week I wouldn't have been sitting here they would have lynched me that's just not the way we operate when you cannot there was no need for us to look surprised because we knew we were part of the process of moving the bill not really surprised obviously the concern is from you being prepared we are because we just paid because of the numbers the numbers is a factor that you could not predict even the genius is that are talking about being prepared I'd like them to tell us how just ask them how many people I think they end up they wouldn't have known that no one would have known that and that's because there is something maybe this partial destroy is going to to review to people as to where things are you didn't expect this because this was very popular when President Hagan actually proposed it when he was in opposition yes it was very very popular so you should have expected at least so popular huge 10 out of people coming to withdraw well they're not coming to withdraw they're coming to verify or to verify some of them don't qualify some of them don't qualify but they're interested in knowing because they're counting down to 60 remember you just need to meet 60 so rather when they hit 60 they don't need to come back to but you can't turn them away so we have to process them and get them ready for when they are 60 hits they get paid others are already hit 60 they'll get paid so that's just a process we can't say if you are five five contributions away don't come to the office in the scheme of things those people are not planned they are not eligible so they do not get any any partial for now but we can't turn them away so we have to treat and handle the whole clientele the whole membership but I think we've responded well a few people maybe were surprised to see what was on the account but they're working on them together with our staff whom I must say you need you need the people who are talking needs to come and see what those young guys are doing okay let's get you know broader here with our discussion for planning's perspective from an economic benefit analysis what does a 11 billion estimated total value of the payout do to our economy like ours imagine 11 billion injected into an economy whatever size 11 billion is a lot of money the stimulation of activity economic activity is you cannot even predict what is going to happen but what we know is that liquidity is going to spare a lot of economic activity and that's what we need so in terms of the impact imagine how many people will be able to say I'm going to build up my my small business where I'm sorry where I'm running this and that or someone says I'm actually going to invest this in government boards which is what I'm hearing from from people we have live test months of people coming here and say when I get my money I'm putting it in a in a government bond or I'm actually paying off making a down payment on my plot or I'm actually going to buy more animals so you can imagine what that if you are the seller of animals suddenly you have cash because someone has bought your animals if you are the one selling the plot suddenly you have cash because knapsack given some money 20% and was able to pay you the balance on you on the sale the transaction that has been hanging for a time so in terms of impact the economic impact is broad and wide and that's what we are expecting and that's what they were looking for with that with that kind of reform remember the issue behind this is access to money yeah yeah so that's a cheaper way of providing the money than waiting most of those people not afford to go to the bank and get get alone or get an overdraft yeah so what do you have to say to those that were you know trying to shoot this down obviously you you heard a lot I have a whole list not to mention names but what do you have to say I mean sentiments like this money will just be wasted you know these people that you want to give this money we're going to have a crop of you know very poor old people it's not a good idea what do you have to say I don't know well posing I don't know which country they live in fly over Lusaka and ask yourself who built those houses hmm those are the same people are saying they're responsible how many people do you know who have two two two two two lines of revenues the salary and something else how many plenty those are some people are calling it responsible now there are people who don't want to take action because the fear the fear of the unknown we are not going to be designing policy on the basis that one percent of the people two percent are going to be supply the money and then you deny the ninety eight percent to spare the economic activity in the country that's not how police design works so in all that I'll tell them is let's look for example bring the people we are we are we are looking for the people what some people have told us what they're doing we have videos of people showing us that last time I got ZNPF I actually bought so many goats now I'm going to get the partial and I'm going to increase the number of goats I own that's what we're talking about first of all there was a complaint that the money is too little 20 why not 50 that's that's objective little compare to what if we're fat guy fat cow somewhere and you're ending yourself millions and the other guy has one thousand twenty percent of one thousand the value attached to that is the same so you can't tell me that a guy who is asking for five thousand it's too little it's too little for you but it's it's not little for them because that five thousand is maybe they are yearly income or even maybe one or ten percent of the early income if you ask CCEC the amount of money that people are applying for let's let's let's go back to Village Banking I meant you heard of people looking for five thousand on Village Banking so why is it different money is money okay we're gonna go to the headlines I've got another follow-up question on that I had a conversation yesterday on the hot seat with CTPD country executive director and Mr. Isaac my people and he said he would have loved or his proposition is that maybe as the fund which you should have been loaning the money to the owners of this money maybe 10% and have them pay back in six months and still allow them to continue accessing this cheaper fund and that would have you know brought up some sort of stiffer competition for the banks that have these high lending rates but we'll hear your response after the news headlines to that proposition thank you give it a look right here we have


Welcome everyone. Thank you so much for being here with us today. We really want to share with you our passion for exploring ways that climate change is impacting our understanding of cultural landscapes, but also show how preservation practice can mitigate the effects of climate change on landscape resources that we know and cherish. Collectively, we've specialized in the preservation and stewardship of cultural landscapes for many decades. There is now an emerging shift in our focus, however, as we not only think about how we can protect cultural resources from the effects of climate change, but how we more holistically develop preservation-minded solutions that can also help mitigate climate change itself. We work to increase the resiliency of these cultural landscapes while also encouraging the preservation of their historic character. From around the United States, we're going to share case studies with our Solutions for Historic Landscapes that are affected by the rapidly changing climate. We will also explain solving complicated climate change issues through a preservation approach. Let's be clear, the reality of climate change is no longer in doubt. This is not news, but it is not only about global warming, it is about global climate change. We now expect colder winters, hotter summers, some wetter and some drier seasons, as well as extended periods of uncertainty and climate confusion. With these changes come associated impacts on the resources we value, both slowly over time or through dramatic events. The historic trends that characterize defined areas of the globe can no longer be readily expected or relied upon. Tornadoes, hurricanes and wildfires are more prevalent and not always predictable. This is not hyperbole, however, but is supported in the latest reports from the United Nations and other scientific organizations. Climate change brings special challenges to the preservation community and especially to the protection of significant and inherently dynamic cultural landscapes. These are landscapes that have always changed over time in one way or another, even within their periods of significance. But that change was understood and anticipated in a regional context of predictability. We now face a time when that predictability is in serious doubt. This requires the preservation community, all of us, to view and understand significant resources, especially significant cultural landscape resources with new filters and new perspectives. The three main effects of a change in climate that we will address in this presentation are wildfire, increased storm intensity and vegetation loss due to pests and diseases. Now how do we do this? MIG has undertaken a number of cultural landscape preservation projects in which the vegetation and plant communities play a major role in the landscape's character, significance and value. They clearly reveal the impact of climate change and require understanding these landscapes not only for their history, but for their future as well. Past and future perspectives are not uncommon in the start of preservation as we all know, but cultural landscape projects require that the consideration of known and anticipated impacts of climate change and climate impacts play a central role in treatment decisions. As with all cultural landscape projects, the first step in these case studies was to understand the landscape history, its historic condition and what it is like now. Why and how is it significant? What was it like during the period of significance and what characterizes it now? How has it changed, been modified or evolved? This step is founded in established tools developed and supported by the National Park Service and professional guidelines. With this base knowledge, the team seeks the best data on current and projected climate change, what has changed in the past 30 to 50 years, and what is projected to change. Let me be clear, these are projections not predictions, and that is an important distinction. Scientists anticipate what will change, but never know for sure what will occur. There will always be a level of uncertainty. It is also necessary to understand climate as a system, not as a single factor. For example, a warmer landscape may be associated with a drier one and often with more substantial, yet less frequent storms. As with the landscape itself, climate requires being understood comprehensively. Overlapping the understanding of the cultural landscape and climate projections, we develop a set of anticipated landscape hazards and impacts. For example, if it is drier, might this be filed by an erosion hazard when it storms, followed by an uprooting and loss of historic vegetation? Might a warmer and drier climate support a welcoming habitat for pests, such as the infestation of the Wulia del Gid in Shenandoah National Park and the northeast region of the country, as on the screen in front of you, leading to a major loss of hemlock trees throughout the area? Or will it result in a major drought, such as we now see in the western U.S., with the dramatic landscape loss, for example, in Lake Mead at Hoover Dam in Nevada? Might a wetter and longer rainy season result in dramatic flooding and loss of landscape resources and recently witnessed a Yellowstone National Park? The next step, prior to developing cultural landscape treatments, is to develop a cultural landscape feature and climate change matrix, indicating those character defining features that are most likely vulnerable to specific climate variables. This may be one variable or many, but provides critical insight into vulnerable features that need to be treated for projected climate impacts. As you can see, this is a very complicated process. We will share specific case studies and examples that illustrate how this method has had a direct effect on protecting significant cultural landscapes in the age of climate change. We will begin with general considerations from Eleanor Cox, move to detailed specifics from Rachel Edwards, and return to a broader view from Laurie Matthews. Illustrating in all cases how the climate change reality is causing us to modify our approach to cultural landscapes and to all aspects of our landscape preservation practice. Let's move now to Eleanor Cox. Thank you, Robert. I'll be taking the next five minutes to highlight two recent projects we've worked on where we framed some of our treatment recommendations within the context of the climate crisis. While one case is in East Texas and the other is in California's Central Valley, vernacular cultural landscapes like these are facing similar challenges across the country. This image shows a former pastor or field at Bassett Farms in Limestone County, Texas. The property served as an active family and tenant farm for generations first established during reconstruction and continuing until the mid-20th century. Farm activities cycled through grazing, cotton farming, and stock raising based on the economy of the era. This is a little context to show the location and scale of the property. The boundary of the property is delineated with the black dashed line and this aerial shows the character of the landscape very well. It's fairly flat and overwhelmingly under agricultural use. Here we see two barns that are associated with the Bacon Ranch Historic District, which is located within Pinnacles National Park in California. The Bacon family and their neighbors homesteaded this land and the surrounding valley floor during a period of time that is similar to Bassett Farms. Although the farm operations here were smaller and more diverse than is typical for homesteads. You can see the location on the left and on the right are historic aerials overlaid on a topographic map that illustrate the valley setting for this cluster of homesteads. Both properties are significant for their associations with the late 19th century settlement and agricultural patterns and both are remarkably intact given the changes both natural and cultural that have occurred in these regions over the last century. Our goal was to propose ecologically sound solutions that are compatible with the historic district and function of the farms while remaining flexible enough to adapt to rapidly changing climates that include more frequent storms, flood and drought events. In our view, compatible solutions for these properties respond to both the historic character of the site as well as the changing environment. We aim to plan for flexibility, whether it's flexibility in use or flexibility in temperature and precipitation. Our short term recommendations focused on collecting data so that site managers are able to monitor the impacts of climate change on historic resources and help with projections. This includes completing ecological surveys of the properties before developing a management strategy. Surveys that establish a baseline for vegetation, fauna, invertebrates, and soil and water quality will help track impacts over time and can then guide management decisions. Longer term recommendations include prioritizing restoration of the stream banks and the riparian corridors that wind their way through both properties to provide habitat and improve water quality as well as to protect the landscape from floods and erosion. We recommend inciting new construction and uses outside of the 100-year floodplain whenever possible. We also recommended opportunities to incorporate man-made stockponds at Bassett Farms used historically to provide water for cattle into new trail and recreation systems or fire suppression systems. And mitigation of invasive vegetation in the former pastures and fields through the integration of pollinator, forage, wildflower, and soil building species that are compatible with the historic crops that were grown in terms of visual texture and scale. This can be done in combination with re-establishing some of the historic crops grown at Bassett Farms or Bacon Ranch if desired, such as cotton, hay, and barley, but a wider diversity of species will allow for adaptation to unpredictable conditions. All of our recommendations focus on building changing climates into long-term planning strategies where the only consistency is change, which is in fact already characteristic of vernacular landscapes. As I mentioned earlier at Bassett Farms, the primary agricultural activity evolved with the market when the value of cotton bottomed out in the early 20th century, the Bassett family adapted by raising stock instead. And since the Bacon family were homesteaders who couldn't rely on large-scale irrigation or machinery, they were forced to adapt from season to season. Planning for designed landscapes within the context of changing climates presents a different set of challenges. And with that, I'm going to hand this over to my colleague, Rachel. Thanks, Eleanor. This case study of the South Park blocks is an example of how climate change consideration and resilience strategies are being factored in design and management of historic parks with mature tree canopies. This is a linear park comprised of 12 path blocks situated in downtown Portland, Oregon, shown here in this early panoramic illustration. In 2019-2021, MIG led a master planning effort for the South Park blocks in collaboration with consulting arborist, Morgan Hole and associates, and Portland Parks and Recreation. This park, like all landscapes, has continued to evolve and transform since it was first planted with the combination of Lombardi poplars and American Elms in 1877. Young trees were established under similar growing conditions, with equal access to sunlight, water, and air circulation. The park today, 141 years later, includes many mature trees, the most characteristic species being American Elms, Olmas Americana. There are also many young trees. Here you can see the characteristic soaring cathedral-like canopy that mature Elms provide the park blocks. Canopies of adjacent trees overlap, providing nearly continuous coverage, and shaded conditions at ground level. During the master plan process, feedback gathered from the public identified the tree canopy as the most important to the park experience, a characteristic underscored in its recent National Register nomination listing. The dense grid planting scheme originally fit up to 48 large trees and a typical 0.7 acre park block. Today's standards and best practices would not permit the style of dense planting. The bottom diagram depicts current conditions. On any block, there are awesome examples of mature Elms, but given their age, some trees have died and those replaced struggle to thrive. Many of the mature trees, those aged 100 years or more, are reaching the end of their lifespans. In 2018, the Parks and Recreation Bureau realized that a master plan was needed for this park. It had never had one before, which resulted in many decades of piecemeal decision making. They needed a plan to protect the aging cohort of trees while accounting for their future replacement. The master plan also addressed contemporary needs through a rehabilitation framework and equity lens. A tree succession plan was a major component of the master plan, necessary for sustainable stewardship of this iconic park resource. When trees died in the South Park box, they were typically replanted in the same location under deep shade next to other mature trees, denying them access to sunlight that is critical to establish a healthy structural form. These trees lean and developed unbalanced crowns. Our consulting arborists predicted that many of the park's juvenile trees would fail to become long term park amenities down the road, presenting a sobering outlook for how the next generation of Portlanders might experience the South Park box. Historic parks with mature tree canopies and crowded growing conditions are particularly vulnerable to the spread of pests and diseases, like Dutch-owned disease, and impacts of climate change. In recent years, Portland has experienced increasingly volatile weather conditions and events, such as late season ice storms, prolonged rain surges, and fallout from statewide fire events. It is not uncommon for mature trees to fail under these stressful conditions, which seemingly happens with more frequency and intensity than before. The approach to both the tree succession strategy and the master plan design went hand in hand. Notting to contemporary best practices, the team advocated for a succession strategy that would retain the characteristic tree canopy and grid layout, but do it with fewer trees, a change that will provide each tree more growing space and access to sunlight needed for healthy structural development. This was highly controversial and very difficult for the public to grasp, but reasoning for it was strongly grounded in science, best agricultural practices, and common sense. Shown here in plan is the tree succession strategy for six of the 12 park blocks. On top are the existing tree locations. Below is how each block is envisioned to transform with fewer trees over a span of what will likely be many decades. As you can see, some blocks have fewer trees, but together provide similar canopy coverage. What's more, and key to the sustainability of this endeavor, considering climate change, is the proposed diversified composition of the park's tree species. Elms are still retained in key planting locations to ensure their characteristic form and presence, and their locations reinforce other aspects of the design. A key challenge for landscape architects and designers in identifying the expanded tree species palette was the unique and rare characteristics of American Elms. These trees, which many cities would prefer not to use given their risk of disease, really have no co-equals in terms of their form, height, rate of growth, their strength, their urban resilience, and canopy characteristics. It was really quite a challenge to identify non-elm species that really fit the bill in terms of their capacity to preserve the park's character. This final slide highlights the range of tree species that share some of the qualities of characteristic South Park block elms, but also meet the city of Portland's urban forestry standards and sustainability goals. A wider range of species, a mix of native and non-natives, provides the park with more resilience against disease and die-off. Some Dutch elm disease-resistant elm varieties were also included. As the park continues to evolve and adapt to impacts of climate change in the region, it will do so with trees that have stronger structural form, more room to grow and thrive, and be able to ward off disease and other threats that will inevitably present themselves. I'm now going to hand it over to Lori Matthews. Thanks Rachel. Another devastating effect of a rapidly changing climate is wildfires. I think we've all thought they could only happen in the western United States or similar climates, and the two examples that I'm going to share are really from that part of the world. But this summer, as temperatures rose above 100 degrees Fahrenheit for the first time in England, a country known for its damp and temperate summers, they had to address wildfires that erupted in both urban and rural areas, such as this one just east of London. What this shows us is that our planning efforts need to be aware of all the effects of climate change and not just those that seem most likely at the present moment. At Point Reyes National Seashore in California, warmer and drier climate conditions have persisted for years. And combined with aging electric infrastructure, wildfires have sparked and grassy and woody vegetation. Due to the devastation of these events, coupled with the urgency of addressing them, applying narrow focus solutions is common and has led to compounded disasters like this, where utility company butchered a historic Cyprus windbreak at one of the park's historic ranches. While this is problematic from a resource protection and integrity perspective, ironically, it also removes a landscape feature that can help mitigate another effect of climate change that occurs frequently in this region, namely higher winds associated with more frequent and intense storms coming off the Pacific Ocean. Applying a myopic solution focused only on the buildings leaves historic places like this less resilient and protected from climate change impacts. Applying a more holistic approach involving the cultural landscape and cultural landscape preservation principles can provide a more effective solution, especially since that focuses on retaining the feature in a way that preserves its character and buffers it from the hazard. Burying the electric lines is one solution, but we found that's not always feasible. So another option involves replanting the next generation of trees offset from the original to separate it from the hazard of the utility lines while retaining the windbreak's form and function. This should be combined with more sensitive pruning of the mature trees, reducing the dead woody mass while also increasing access to light for the new plantings. As the windbreaks die or deteriorate, many of which are reaching the end of their life at Point Reyes, this new planting will regenerate the feature and continue to provide climate protection to the ranch's domestic cores. Another example at Hearst Castle further south along the California coast shows how taking a cultural landscape approach can help mitigate wildfire risk at the same time it restores one of the site's historic features, namely its iconic views. For many years, water from the Neptune pool was leaking down the hillside and fostering the expansion of eucalyptus groves around the base of the hilltop. As one wildfire expert graphically described one of our planning meetings, these trees are like firecrackers given the highly volatile oils inherent in the trees. Some of the eucalyptus groves had also started obstructing historic views from each of the cottages for which they were sited. Therefore, the cultural landscape reports recommendation to remove eucalyptus trees restored historic views at the same time it mitigated a threat heightened by climate change. What we've shared today are just a few examples of how utilizing a cultural landscape preservation framework provides benefits when addressing the effects of a rapidly changing climate and historic properties. It encourages a holistic approach that inherently understands the role of change and how to manage that change. A cultural landscape-centered approach broadens the conversation beyond just protection of historic fabric to retention of a property's historic character. One resource our practice references is this document authored by the University of Oregon's cultural landscape research group which is led by Robert. While preservation is often perceived as a past focus profession, we've shown how it can also be used as a future focused tool to expand our approach to not just protecting but mitigating climate change impacts. As we conclude our proportion of the presentation with some final thoughts, we've written down some guiding principles that we bring to every project. The philosophical and methodological foundation of cultural landscape preservation embraces change as part of the resource. So when we need to think about climate change, namely rapidly accelerating impacts, what better framework to use than one which is already grappled with and set forth best practices and guidelines for historic and cultural resources that inherently change. The key is flexibility within certain parameters as some historic fabric can change if the overall character is retained. Our practice often looks to ecological approaches for solutions given that cultural landscapes are as steeped in our culture as our natural world. In our experience, that encourages a broader and deeper understanding of the effects themselves, since it pushes us to see the bigger picture in both scale and time, promoting flexibility in our approaches. In essence, it gives us more tools in our toolbox, and that is something we believe will be incredibly valuable moving forward. Thank you. Hello everyone. We're so excited to be presenting as part of Pass Forward 2022 to talk about historic preservation and a changing climate and to explore how we as preservationists can work together to preserve the past while planning for the future. I'm Patti Kelleher, Historic Preservation Planner for the City of Salem, Massachusetts. I'm here today with Barbara Warren, the Executive Director of Salem Sound Coastwatch, a science-based not-for-profit, and Susan Baker, Collections Manager for the House of the Seven Gables, an historic museum complex on Salem Harbor. Next, today we will be presenting a case study on Salem, Massachusetts, a microcosm of an historic coastal community confronted with the realities of an ever-changing climate. We will explore Salem's approach to historic preservation at the local level as we work to address impacts on historic resources from sea-level rise, storm surge, and other climate impacts. We will explore the science of climate change in Salem and highlight a unique collaboration between the City of Salem and the Salem Preservation Partners, a group of local preservation and environmental organizations who are working together to raise awareness of climate change impacts to historic resources and to develop strategies for mitigation and adaptation. We will then dive deeper into what one historic site in Salem, the House of the Seven Gables, is doing to adapt to these climate change challenges. As Salem prepares to celebrate its past in 2026 in honor of its 400th anniversary, it also needs to look to its future, one of great opportunity, but one of great environmental change. We hope that at the end of our session you will leave with ideas, approaches, examples, and resources around preservation planning for climate change realities. I will now turn it over to Barbara who will talk more about Salem's changing climate. Thank you Patty. Our changing climate is already bringing challenges to Salem as we can be seen from these photos and the news article. More frequent and intense storms along with higher tides are resulting in damaged sea walls, flooded streets, and buildings. People in Salem are experiencing the changing climate and watching as our coastline changes. Next, as an environmental organization, we know the importance of examining historical maps and documents to understand that what happened on the land and the water still affects what happens today. The influence of history and human actions remains with us. As soon as colonists arrived in New England, they began changing the coastline, clearing the land that led to coastal erosion and filling the shoreline to build roads, wars, and buildings. Forests were cut down for fuel, buildings, and ships, resulting in erosion. William Bentley wrote in his diary that, I quote, a piece of land which contained about five acres was washed away into the cove and was filled up all the channels. This National Park Service map shows that the early in what the land looked like in the early 1800s. And you can see that it had already been altered from the 2016. There were 19 wars in Salem Harbor, the South River, and the Mill Pond were still running with water. But filling continued at a fast pace and by the late 1800s until we arrive at today's modern shoreline. So you see the red arrows are indicating the current shoreline of Salem. Next, here is a graph of the sea level rise from 1880 to 2008, 128 years in total. The average global sea level rise increased with eight inches globally, but Boston experienced 13 inches. Around 1880, Thai lands were converted to land for railroad tracks and that sort of ended. So what I want you to think about is how much were the low lands and the Thai lands raised? Think about the effort it took to fill land. The fill had to be dug by hand and had to be carted to the area. So if you were filling Thai lands, marsh and mudflats using manual labor and bringing the fill in by mule or horse and cart, how high would you have raised the land? Probably only as high as needed at the time. Then remember we've had at least 13 inches of sea level rise since these Thai lands were filled. Next, now let's look at the sea level rise predictions based on climate change modeling that Massachusetts has done to provide its communities with estimates for planning purposes. The blue colors in the bar chart are based on different greenhouse emissions scenarios with the light blue intermediate to dark blue, the extreme case where we do little. So you can see that the sea level rise projections in 2050 go from 1.4 feet up to 3.1 feet. And then in extreme cases, 2070 or maybe sooner, it could be even 5.4 feet with 2100 potentially up to 10.2 feet. So these were used for planning purposes. Next, to promote the preservation and changing climate conference, we got together and created the Salem climate change exhibit. This is just one of the panels illustrating the potential impact of sea level rise. On the right, you see the map from 1875. It's the U.S. Coast and Geodetic Survey map that shows the South River and downtown Salem where ships used to sail right up to the Old Town Hall. On the right is the modern day map. It shows the channelized South River and downtown and the Derby Wharf, which is the Salem Maritime National Park on the right. The area, and you can see that the South River has been buried and the mill pond. The area in yellow on the map on the right shows the tide flooding in 2070. So twice a day at high tide, that whole, all the yellow area will be covered. And this is often referred to as sunny day or blue sky flooding. It doesn't happen with a storm. It just happens twice a day because our tides have gotten that high. Next, we probably all know about storm surge now after Hurricane Ion wrecked Havoc in Florida and South Carolina. It is an abnormal rise of water from being pushed by a storm. And it comes particularly bad if it takes place at high tide. So you can see at the top one what storm surge would have looked like with the 1880 floodplain, how far it would have gone towards the land or the buildings. 2010, it's already reaching the bottom of your building. By 2050, with sea level rise, our storm should be going through those coastal buildings and it will just continue to increase. Happening more often, flooding a larger area and more inland areas and threatening resources that traditionally have not been flooded. Next, 2018 was a wake-up call for Massachusetts. Here is the picture at the top is the Derby Wharf. It's taken from the National Park, from their cupola of the Salem Maritime Customs House. And you can see that white line out in the water and that was where the beach was. The Derby Wharf is completely covered. So are the other wharfs to the right. Next, present day to flood risk of flooding from storms. So this was another exhibit from the climate exhibit we put together. These maps are from the Massachusetts Coast Flood Risk Model Inundation maps. And they were created by Woods Hole Group commissioned by the Massachusetts Coastal Zone Management for all coastal communities in Massachusetts. These maps detail coastal flood modeling and mapping under changing climatic conditions. This panel illustrates the probability of Derby Wharf and the downtown south river area being flooded from coastal storms from present through 2017. The percent chance or risk increases over time as sea level rises and storm intensities increase. So the pink is a 0.1 percent chance of flooding. So you can see that in the present day that rarely is this area flooded. But then in 2030 we start to see green. So the probability raises to 2 to 5 percent. The purple in 2050 is now we're at a 20 percent probability. When you get up to the Dark Navy, that's 100 percent probability of being flooded in 2017. Of course, all this implies the community has not made any adaptations or taken no action to prevent the sea level rise from entering the downtown next. Climate change is not uniform across the earth in the northeast Gulf of Maine. We are experiencing greater ocean warming already nine times faster than that global average sea level rise is three to four times faster than the global average. And we're seeing more chaotic weather between heat and droughts and extreme precipitation events. This infographic first was produced by the Union of Concerned Scientists in 2006 and then adapted by the Massachusetts for Massachusetts by Mass Audubon. And it shows how Massachusetts climate is changing. Our temperatures are projected to rise, rise faster than the global average and our winters have already warmed three times faster than the summers. So you can see the summer heat index from 1960 to 1999. It's the Massachusetts climate that we're used to. And currently we're already experiencing a warmer summer and just north of New Jersey's weather. And if the with the lower projections of the climate emissions between 2070 and 2090, we may, we will continue to be warmer but slow it down. But if we continue as business as usual in by 2070, Massachusetts could be experiencing a weather temperature similar to the south. You will hear from our next two speakers how not only is flooding an issue for Massachusetts and our historical preservation, but wind, extreme precipitation, heat and humidity are also impacting our historic structures. To continue our story, Patti Kelleher, Salem's preservation planner since 2016 will share how the city, its historical commission and the Salem's preservation partners are working together to mitigate and adapt to these climate challenges. Patti. Thank you, Barbara. As Barbara mentioned, Salem's waterways and coastlines have informed, have informed life in Salem for more than four centuries from the first arrival of European settlers in 1626 to the native people who call this land home for 1000 of years before. Today, Salem is a small city with a diverse population of 43,000 people. It is blessed with an abundance of historic cultural and natural resources and dedicated residents and organizations who work tirelessly to preserve the community's unique character and sense of place. Next please. For those not familiar with Salem or who only know Salem as the witch city famous for its month long Halloween celebrations, Salem is so much more. As one walks around the city, 400 years of Salem's history is visually represented in the built environment. From first period houses of Salem 17th century past to Georgian houses along the historic waterfront to its nationally renowned collection of federal era mansions and architecture to Victorian era homes and cottages, as well as monumental public architecture. Next. Today, Salem has four local historic districts protecting over 600 historic resources, as well as 10 national historic landmarks and 20 national registered districts. The Salem Historical Commission, a municipal board that serves a dual role of historical commission and historic district commission oversees a local districts and advocates for historic preservation citywide. As you can see by the maps on the screen, while only one of the city's local historic districts is located on the coastline, several of our national registered districts are positioned directly on the water. Next. As Robert described this waterfront location, which has long been critical to Salem's identity and economy is now threatening our heritage. Historic buildings structures and landscapes on the city's coastline are increasingly subject to flooding from rising sea level and storm surge. The image on the screen shows the impact to the historic Victorian era willows national registered district from one of the series of Nor'easters that hit the city in 2018. Next. It is not just coastal resources that are impacted by climate change in Salem, though inland historic buildings are threatened by ever increasing storm intensity with extreme wind and precipitation. In addition, excessive moisture, intense heat fluctuation and rising groundwater are also damaging Salem's historic building fabric. During my seven years as Salem's preservation planner, the city has witnessed unprecedented changes in the way climate is affecting our historic resources. Wind damage, overflowing gutters, leaky basement, spreading mold and flooding are quickly becoming the new normal for our historic buildings. What is perhaps most alarming is how quickly these changes are accelerating. As a preservationist, I admit that it is difficult to accept accept change sometimes. But after witnessing the irreparable damage caused by climate impacts, it is apparent that we need to change a conversation. We can no longer say no to resiliency and adaptation strategies for our historic buildings. We need to be willing to consider these changes and guide them in an historically appropriate manner. Next slide please. The Salem Historical Commission is accepting this challenge, working with property owners to find creative solutions that preserve Salem's architectural heritage while planning for the future. These solutions include the use of non-wood replacement gutters instead of traditional wood gutters to ensure longevity and to provide increased capacity, as shown in the image on the screen that was provided by the Cambridge Historical Commission. The commission is also allowing new gutters were non-existent before and adding diverters to existing gutters to capture extreme rainfall before it damages building facades. In addition, the commission is willing to accept alternative materials in some instances in place of traditional wood slate and masonry such as the use of composite railing systems brush painted to replicate the look of wood as shown in this image on the screen. Next, the commission is also balancing historic appropriateness with climate change mitigation by allowing sustainability options such as solar panels and electric heat pumps on historic buildings. The commission works with property owners to ensure that these changes have minimal impacts on the architectural character of the historic building and the district and meet the Secretary of the Interior standards. The image on the left shows solar panels placed on the upper slope of a gambrel roof with a low profile rectangular arrangement with black framing and panels. The slate on the lower portion of the gambrel roof was preserved intact. The other image shows a placement of a mini-split system with a condenser hidden by a lattice screen and exterior docks placed in the corner and painted out to match the underlying building color. Next slide please. This changing attitude is codified in the commission's recently updated design guidelines, which includes resiliency, sustainability, and adaptation strategies. Within the guidelines, call out boxes as shown on the screen, alert readers to sustainability notes indicating where a building owner can make their projects more environmentally friendly. In addition, the guidelines include information on sustainable practices in building and construction as well as sustainable material and reuse options. These guidelines serve not just the historic district. We've shared them with other municipal staff and development review boards as well as to the building department, neighborhood groups, owners of historic buildings citywide, and local contractors and architects. The link to the guidelines are shown on the screen and will be included in resources for our session. Next. The commission is not undertaking this planning effort alone. Salem is fortunate to have a diverse and passionate group of preservation-based organizations and individuals who serve as caretakers of the city's historic assets. In 2016, the Salem Preservation Partners was formed to gather these groups together to provide a forum for collaborating and sharing resources. The informal group meets quarterly and is open to anyone with an interest in the city's heritage. Today, the group is 25 plus members strong and includes traditional historic and preservation-based organizations, as well as neighborhood and friends groups, the local university and public library, and members involved with tourism and economic development. In addition to sharing resources and preservation strategies, the partners have collaborated on walking and bike tours, educational workshops, and a preservation month breakfast to engage with local and state officials on preservation interests. Next. During the partners meetings, a recurring topic of discussion was the need to address climate change impacts on historic buildings. Whether the building is owned by a private homeowner or a nonprofit organization, climate change is affecting historic buildings citywide. The group formed a committee of partners with immediate concerns relating to building adaptation, including those with buildings and structures on the shoreline. It quickly became apparent to us that understanding the science of climate change was critical to addressing current conditions as well as future predictions. The committee reached out to Barbara and Salem Sound Coast Watch to help with our effort. In 2021, the partners held the region's first annual preservation and the changing climate conference to raise awareness of and begin planning for climate change impacts on historic resources. We worked with the Keeping History Above Water Initiative and invited preservationists from other coastal communities to present their experiences with climate change planning. In addition, the partners hosted the exhibit that Barbara spoke of before that we hosted at City Hall in the lobby. So much has changed in the past two years since we started this effort. The recognition of climate change and the need for adaptation strategies is widespread now. We no longer have to talk about why we need to adapt, but how. In September, the partners held its 2022 conference with a focus on tools and strategies. The National Park Service presented the new Secretary of the Interior Standards for Flood Adaptation, which will become increasingly necessary here in Salem. We advertised the conference beyond traditional preservationists and we reached out to planners, environmentalists, sustainability managers, educators and municipal and state officials. Recordings from both the 2021 and 2022 conferences can be found on the preservingsalem.com website with a link shown on the screen. The preservation and the changing climate effort has also provided us with an opportunity to engage with local and state officials and staff who are working on sustainability and resiliency initiatives to ensure that preservation is part of the conversation. Next. Moving forward, the city and the partners will seek to gain a better understanding of the specific historic resources most at risk from climate change and to provide guidelines for adaptation, such as raising buildings above flood predictions. We're working with local GIS specialists to help overlay the flood risk model maps that Barbara showed earlier with historic resource maps. The map shown on the screen is an initial draft visually depicting sea level rise on historic properties. While moving buildings in Salem was once common practice, efforts to raise the buildings above flood levels is still rare here in Salem. The National Register listed Victorian cottage shown in these images is one example of a building elevated on a new raised foundation in Salem. This building is sighted directly on the coast with an area identified on the map for future sea level rise. In fact, this area has already witnessed repeated flooding from storm surge. Fortunately, despite a lack of design guidelines and jurisdictional oversight by the historical commission at the time this project happened, the owners of this house chose to replicate much of the original Victorian detailing such as a decorative porch in the elevated design. With rising sea levels and increased storm surge, raising historic buildings will become much more in common, much more common in Salem, and it will be critical to ensure that historic buildings are elevated in a manner that preserves their architectural character and that of the surrounding streetscape. We will continue to engage with preservationists and other coastal communities who are further ahead in their planning efforts and who have generously shared their preservation experiences and strategies at our preservation and changing climate conferences. Now we will hear from Susan who will provide a case study of one property in Salem, the House of the Seven Gables. Thank you Patty. For those of you not familiar with the House of the Seven Gables Settlement Association as we are formerly known, we are a two acre museum complex set directly on Salem Harbor and located within the city's historic Derby Street neighborhood. Next, our seaside campus of seven buildings, gardens and lawns is a national historic landmark district that includes among other historic buildings, three important first period houses. American first period houses were largely built between 1626 and 1725. There are only around 400 first period buildings left in the country today, so the historic and architectural importance of these buildings really can't be overstated. And the photograph on the left with the tree is our flagship building, the Turner-Ever Soul Mansion, commonly referred to as the House of the Seven Gables, built in 1668 and still on its original and architecturally important foundation. The photo on the right shows the other two first period buildings, the Hooper Halfway House, built in 1682 to the left, and to the right the retired Becket House, circa 1687. The red building you see peeking out of the back of the photo is Nathaniel Hawthorne's Birthplace, built in 1750. All three of these buildings were moved to the site over the course of about 50 years during the early 20th century to save them from demolition. Next, the Gables is a heavily visited historic site with over 110,000 visitors per year. We offer a constant stream of history and literary tours, educational offerings, public programs, function rentals, and our grounds and gardens play a key role in the kinds of programs we're able to offer the public. Our beautiful seaside site is one of our great assets, but it also makes us ground zero for dealing with climate change issues. Next, the effects of climate change are upon us and the Gables is particularly susceptible given our waterfront location, but rising seawater is not our only concern. I'm going to walk you through some of the challenges we've begun to face with increased frequency and higher level of impact, beginning with challenges to our seawall. We really aren't quite sure when it was built or added to, but do know that the area was first filled and walled in somewhere in the very early 1700s and continuously added to and adjusted over time. With increased storm frequency and strength and rising tide levels, we're now experiencing breaches, overwashes, and damage to the wall that had not occurred in the past. The picture on the left shows wave action on the seawall near one of our building's accounting house and that's not at extremely high tide either. In addition to seawall breaches, equally concerning now is seawater intrusion beyond the wall. Next, these photos show sinkholes that are now developing behind the seawall, something that hasn't happened before in our collective memory. The roped off section shown in the photo to the right is where a very unfortunate visitor fell up to earth high and undermined ground. This seawater intrusion and undermining is happening all along the seawall, as you can see from the pictures. Next, we're also experiencing an increased pace and humidity and moisture damage to our historic structures. The cells, clavours, and underlying historical structural elements are rotting and deteriorating at a much faster pace than in the past, requiring more frequent and expansive maintenance and repairs. And it's not just the structures themselves that are being impacted. Next, mold blooms inside of the buildings are becoming more frequent and more widely spread. All of our buildings do have HVAC and humidity is constantly monitored, but the systems in these porous old buildings cannot keep up with the increased and prolonged levels of moisture in the air. The photo at the left shows furniture brought out to be in the sun as the last step in a mold mitigation effort done last summer. All of the pieces you see in the photo were once owned by Nathaniel Hawthorne and his family. And we're on exhibit in the Hawthorne birthplace during a huge mold bloom caused by basement flooding and sustained high relative humidity levels. We also have an extensive book and archival collection that's being impacted with more frequency. You can see the mold bloom on the books, the book on the top of the pile is a rare Hawthorne first edition. Next, relative humidity levels have increased and so have rainfall and groundwater levels. Our drain and gutter systems are inadequate and overflow frequently. There's literally nowhere for the water to go. Water always seeks the lowest points, which means basements in our case. Sustained foundation seeping and rain related flooding, sometimes happening for the first time in memory, are causing rotting and mold and abundance as well as threatening the utilities located in the basements. Next, we've taken a number of steps to deal with the effects of climate change. These include an accelerated maintenance schedule and adding more staff to the preservation and maintenance team, installing sump pumps and industrial strength dehumidifiers in the basements, raising bulkheads where possible to avoid water overflow, clearing drains frequently and expanding the capacity of the gutters, increasing monitoring using among other things our integrated pest management system, which is a great trigger for identifying some types of problems. Sparing you a disgusting picture of the carpenter ants we collected in our Trapsis spring, but those collections of bugs told us that we had a moisture and rot problem in certain parts of the building that we were then able to repair. We're also working to improve the performance of our HVAC systems so the levels of humidity can be more consistently maintained even within a porous historic house. And importantly, all of the work we do has to follow the City of Salem's preservation guidelines and the Secretary of the Interior guidelines for historic preservation. Of course, all of this costs money, of which, like most museum nonprofits, we have very little. Funding these efforts also takes away from funding other mission-driven educational programs, so we are very dependent on a long, uncertain cycle of grant funding. We know our efforts are just a drop in the bucket compared to what will need to be done for the gables to survive the coming storm of climate change. Next, our list of things we need to do sounds straightforward, but nothing is ever simple or easy. We know we need to rebuild our seawall, for instance, but that will be a complex project given the inclusion of state environmental regulations and city and privately owned property budding the wall, and in the case of the city, actually running through portions of the gable seawall. In essence, we don't want to do something that will make flooding worse for our neighbors down the road and whatever is done needs to be done in an environmentally sound way and at the same time provide us with adequate protection. We know we need to move the utilities currently located in flooding basements to higher ground, but just relocating them to attic spaces, which is an obvious option, is complicated because we store our collections in many of the attics, and in the case of the term Angersaw Mansion, visitors are actually brought to the attic to explore the architectural history of the house. Although we have many buildings on the campus, storage is extremely limited and there's no obvious place on-site to put collections and off-site collection storage is prohibitively expensive. Two of our swallower buildings, the County House and the Prim House, are already experiencing storm seawater flooding and will need to be raised or moved in the near future. If it's decided to move them, where will they go and how will that impact other areas of the site? Again, it feels like we are just reacting to problems rather than anticipating them. It's become very clear the museum needs to know what our options are and come up with a comprehensive climate change adaptation plan for the site that can inform decision making and funding allocations within the near and the long term. Next, our involvement with the preservation partners and preservation and changing climate committee that Patty mentioned earlier has proved to be very fruitful when considering how the Gables can plan for adaptation to climate change. In collaboration partnership with Salem Sound Coast Watch, we've applied for and recently been awarded a two-year grant with the Massachusetts Coastal Zone Management to conduct a full assessment of the site and make recommendations for immediate, medium and long-term adaptations to climate change challenges. Various engineering companies will assess groundwater and underground water flow, the underground infrastructure on the site, the basement utilities configurations, and the efficacy of the seawall. The data collected and analyzed during this assessment will provide the underpinning for a far-reaching adaptation plan for the site that will be developed by an historic preservation architectural firm. This is a groundbreaking grant in that it will allow us to serve as a prototype for the kinds of adaptations that could be considered by other historic property owners. With the models developed at the Gables, we hope other nonprofits and individual historic property owners will be inspired to plan for their own properties while working with an historic preservation guidelines. Next, Patty mentioned that the preservation partners just held a two-day conference devoted to the topic of historic preservation and adaptations to climate change. As she mentioned, you can watch the recorded portions of the preservation and changing climate conference just held by following the link you see here to view the recorded sessions. And please plan to attend our next preservation and changing climate conference in September of 2023, where you can hear about some of the Gables Coastal Zone Management grant outcomes and learn what other historic property owners are doing to adapt to climate change. On behalf of the City of Salem preservation partners, Salem Sound Coast Watch and the House of the Seven Gables Settlement Association, thank you for listening to our presentation.


So welcome back everyone. I hope you all enjoyed your lunch and are now ready for this session on crypt analysis with algebraic structures The first talk is on non-linear approximations in crypt analysis revisited and is on a paper by Christoph Bayerle, Ancanto and Gregor Lernder And the talk is going to be by Christoph. Yeah, thanks for the introduction. Can you all hear me? So today I want to talk about non-linear approximations in crypt analysis and more More generally how how we can express those in a unified framework with linear crypt analysis And so linear crypt analysis is nowadays a standard attack methods on cryptographic primitives And the basic idea is to approximate a linear Boolean function in the output of of the primitive by a linear function in the input and One year after after linear crypt analysis was introduced in generalization to non-linear approximations was introduced and Very recently as we heard in Gregor's talk before Those were rediscovered in the context of invariant attacks Which which employ and deterministic non-linear approximations for this non-linear Boolean function that holds with Yeah, with probability one over over the block cipher And in this work we want to look at non-linear approximations a bit more generally and Try to express this it's using the framework of linear crypt analysis So first I will talk about this unified framework and Then I will talk about the case of invariance again and show How they in many cases imply the existence of highly biased linear approximations and As a third step, I will talk about how how one could go to to Utilize probability probabilistic non-linear approximations so those that do not hold with with probability one So throughout this talk we will consider a function f from m bit to n bit for example a block cipher with a fixed key and The idea of these these approximations is that we want to approximate the Boolean function h in the output by a Boolean function g in the input and We want to quantify the probability That g of x equals h of the function of x minus one-half So how much it deviates from one-half and this is quantified in the in the notion of the correlation So for these two functions g and h The correlation of the approximation by the function G in the input and h in the output Is quantified by the correlation which is defined as two times the probability that these these are equal minus one And so in that way the correlation will be a value between minus one and one As an example we can look at linear crypt analysis where these g and h are defined to be linear functions Which can be given by by a mask gamma as an n-bit vector? And then the linear function corresponding to gamma is defined as the inner product of gamma with x and Then in linear crypt analysis we exploit the existence of the input mass gamma and an output mass gamma prime for which the correlation of the fixed key instance is Is larger than two to the minus half of the block size this threshold is therefore Yeah for having having a text depending on the data complexity So this is this is higher than you you would have enough data to to eventually Use it as an attack in I will briefly go to to non-linear invariant attacks So we have seen lots a lot about this in the talk by Gregor already So in invariant attacks, we are looking at an invariant set that stays Invariant for for the application of a permutation f. So either s is mapped to itself or Or this this set s is mapped to Is mapped to the complement and This can be expressed by a by a Boolean function in on n-bit which is defined to be the indicator function on this set and Then we have exactly this property for for this this Boolean function and in the notion of of the approximation we can phrase it that way that The correlation over f with the input function g and the output function g is Either plus one or minus one depending on which case we are So we have transformed this in the notion of non-linear approximations So usually when you look at linear crypt analysis you look at linear trails and for an iterated Function there is the well-known notion notion of a linear trail composition Which means if you have a function f which is iterated by round functions fi Then you can express the correlation of the approximation of the linear approximation by the sum over all linear trails so by all intermediate masks And you sum over the correlation of the trail which is defined as the product of the correlations over the round functions And we try to generalize this to two non-linear approximations and we came out with With the notion of some kind of non-linear trail composition Which means if you look if you generalize this to arbitrary functions g and h the correlation over f can be expressed as a bunch of linear linear correlations that's all linear approximations over over the function and so you sum over over lots of them and multiply each of The terms in the sum by a correlations over the Boolean functions, which input mask Gamma and output mask one and for the output it's input mask gamma prime and output mask So this is just a simplified notion for What is this correlation here? So this is this is the idea for this framework and now I will talk about about invariance as a special case to apply this So this is this is our decomposition or trail composition a theorem and Suppose we have an invariant for for a permutation f This would mean that the absolute value of this correlation over the function is equal to 1 and Then you can express this this correlation by this this trail composition so you can express it is it as a sum of Linear approximation correlations of linear approximations times these these correlates correlations over g and So you can trivial trivially exclude those Approximations test that's lead to zero for these terms So we be some only over the mask lying in this big gamma g set Which are exactly all those all those masks such that the correlation over gamma is non-zero If you apply this to to one special case of so-called balance plateaued functions for the invariant We can come up with with this This theorem so a balanced plateau function is a balanced Boolean function such that the Walsh spectrum takes Is either zero or it takes only one absolute value L Yeah, and in this case you can express the the size of this gamma g set as a sign sum of correlations of linear approximations Where you can express the sign? Of each of these terms by a Boolean function f And from this formula you can immediately derive that there because it sums up to a high value There must be must be exist one pair of of gamma and gamma prime Which has a high correlation higher than the absolute value is higher than one over over the size of the gamma set and a Special case of a balance plateau function is the quadratic function. So those of degree two and For degree two functions. You only have exactly those two Two values in the in the Walsh spectrum. So this theorem directly applies And so for example if you look at the non-linear invariant on scream Which is published in this Asia Asia group 2016 paper We have a cypher with a block size of 128 bit and the quadratic invariant Which is balanced and it works for two to the 96 weak keys So by this theorem before this means that for each weak key K There exists such a Boolean function that takes care of the sign such that you can express the size of the gamma set with which is two to the 32 as a sign sum of linear a correlations of linear approximations and This implies that you have for each for each weak key You have at least one linear approximation in this sum Which which has a correlation higher than two to the minus 32? And this is much larger than two to the minus half of the block size so in in principle that this could be exploitable by an attack and Since this function g it is invariant for each of the rounds and you iterate this for for the rounds The existence of this approximation is independent of the actual number of rounds you use in the in the cypher But what could change is is which correlation exactly is is the higher one? So another example is the case of invariant subspaces Where this this invariant function g it is the indicator function of some affine subspace, so it's not Necessarily balanced anymore So and we have shown that if you have if you if you have an invariant affine subspace u plus plus some offset a For a permutation then for any non-zero output masks lying in the orthogonal complement of u You can find a non-zero input masks such that the absolute value of the correlation Where this this invariant function g it is the indicator function of some affine subspace, so it's not Necessarily balanced anymore So and we have shown that if you have if you if you have an invariant affine subspace u plus plus some offset a For a permutation then for any non-zero output masks lying in the orthogonal complement of u You can find a non-zero input masks such that the absolute value of the correlation is is higher than this value depending on the dimension of u and And a similar theorem was already shown in the invariant subspace paper in 2011 and They have proven the also the existence of a highly biased Approximation with a similar term, but there is some error term you have to subtract there And they only show the existence of of one specific approximation and not not many of those here Okay, so this leads to this observation leads to to some open questions So first of all can we say anything more about this highly biased linear approximations besides the mere existence? So these arguments we have here are basically exists and so arguments of existence And they don't show a particular way to construct those and to to identify those approximations and This is related to to whether we can understand more about the distribution of the actual Correlations of these linear approximations over all these masks in this gamma set gamma set so now I want to talk about Yeah, about probabilistic non-linear approximations so far. We were only in the set of the invariant attack So the goal would be to express the probabilistic Non-linear approximations in the framework of linear crypt analysis and The idea would be instead of using non-linear approximations over the over the cipher itself We transformed the cipher a bit so we use a Different representation and use linear crypt analysis over this transformed version of the cipher So the idea would work like this So we have a permutation f and the balanced Balanced function g so we really we cry here that that g is balanced And we would construct an n-bit permutation big g such that this function Small g is embedded as one component function alpha And then we would look at the transform permutation where we would first apply the inverse of g followed by f and then g again and then in this framework this transforms to Instead of looking at the the approximation By g over f we look at the linear approximation With mask alpha over the transformed version of the cipher And then we would use linear crypt analysis methods to look at the transformed version Note that we need balance function here because we want to embed this As a component in a bijection and we want to to apply the inverse here So this requires that that every component function is balanced the other component functions can be chosen arbitrarily So to pick as typical for linear crypt analysis. We will look at linear trails So suppose we have a round iterated cipher e then we can if we look at the transformed version of the cipher We can look at every transformed round by this function g because we can We can apply the inverse of g followed by g which means we have identities in between that would cancel out so we can express it in this in this variant and Then we would express the correlation over Over the transformed cipher of this linear approximation by the by the linear trail composition by summing over the correlations of all in linear trails in in this linear hull and And for our analysis we we base it on a single linear trail for now Because this is the standard analysis method So we look at the at the correlation of the trail which is defined as the product of the correlations of surround functions and In this notion we can express the invariant on on Midori 64 also from this Asia prep paper quite simply so we have our Forbit S box SB which is applied 16 times in parallel denoted by by the S box layer s and By by s sub k we denote We denote the keys keyed S box layer. So we we X or the key To the state and then apply the S box layer And then in the in the invariant attack on Midori The quadratic function of this form is used as an invariant for the S box and the weakies are exactly those that are zero in the first two coordinates of every S box and Then we would we would go on and choose a forbit permutation that embeds this invariant as one coordinate function denoted by this mask 8 so it's the fourth coordinate function in in X notion and We define our our big permutation as the parallel application of this forbit permutation and Then we can we can look at the linear trail Corresponding to to this approximation so every every S box would be active in this in this notion and Because we have this this invariant over the over the S box for the week he space this means that If we go over over this transformed S box layer The absolute value of the correlation is one for every for every weekly. So here we are restricted in this in this WK space of the key and Then the next step would be the permutation of the of the nibbles in the in the linear layer and those Dispermutation would basically Permute all this all these cells. So because every Every cell is active every cell is active after after the permutation For the transform mix columns layer We would use the the observation made by by the designer by the by the by the attackers on on Midori With which explored the orthogonal orthogonality of the layer so you can get we can show that that the correlation is equal to one and you can also look at the At the correlation matrix for every column you would get the same way experimentally Yeah, and then one round is over and then you can iterate this property for every round So Because in this notion every S box is active we try to to look at the case one where not every S box is active. Yeah, so like More general in your trades For this we looked at the four-round version of Of a transform Midori by transform We mean that not the key schedule for now and assume independent round keys in every round and We choose another balance balanced invariant for the S box now It's not quadratic anymore, but of degree 3 we denoted by G prime You cannot easily show that this is invariant for every S box and Then we choose another permutation Which embeds this G prime as one coordinate function and then we define our big permutation as For the transformation as a parallel application of the smaller Forbit permutations As I said, we omit the key schedule for now And then we can come up with this linear trail here. So now really we have inactive S boxes For every inactive S box you can basically choose any key and go over over the S box layer because nothing happens For every active S box you Can go through this transformed S box layer whenever you choose to be key Because it's an invariant for for the keyed S box layer for wiki. You have the absolute correlation of one for After the S box And then you have to look at this this permute nibble layer and now you really have to permute Permute the cells according to do the state permutation For mixed columns, it's a bit more complicated now because It's it's quite hard to find find some some provable properties there So we looked at the correlation matrix of this one column 32-bit Linear mapping so it's not linear anymore because we transformed it by this G here but you can still compute it and So in this case where you have these three Active active S boxes which go to one active S box. The correlation is 11 over 32 So it's quite high and for each active active column you have to compute it So it's it's 11 over 32 to the power of 3 And so you can go on over the rounds until you You you finish this with four rounds and you can multiply all these correlations to get the correlations of the trail and Out of these two to the 256 possible keys you can choose two to the 208 a week keys if you assume these Independent round keys and by multiplying this correlation you get the correlation of the trail Which is two to the minus 12.3 and Because it's only a trail it's it's up the or it's not clear whether the correlation of the actual Approximation so without looking at the intermediate masks would would be close to this approximation of the trail But by experimentally checking we obtained that the correlation of the actual approximation is very close to this correlation of the trail So in this case, it's the trail really gives a good approximation But What is interesting here is if you look at normal linear cryptanalysis by the white rail strategy you would You you know that there are at least 16 active S boxes in every four round So you would expect by the property of the S box that the absolute correlation is at least two to the minus 16 So by looking at this nonlinear transformation you we have shown that there are there is a Significantly smaller correlation We try to also look at probabilistic nonlinear approximations over over the S box layer because in this example so far The approximation over the S box was deterministic. So this absolute correlation one The question is can we generalize this further by using a different so in this example We use a different bijection G where we embed another permutation in the first S box layer corresponding to this cubic invariant and in this case Every key would be weak With the non trivial correlation. So for the V key space you have an absolute correlation of one over the S box layer and for the other You still have a correlation of one half and in this way you can come up with a trail again where every S box is active and the theoretical Approximation of a full round Midori would be two to the minus 29 point two eight. So it would be higher than Than it would be needed in an actual attack for the full round Midori but Unfortunately in this case this trail does not approximate the correlation of the linear hull very nicely so there are strong linear hull effects and We've made an experiment and one single column by using the same same idea on only one column of the state and We found out that for some keys where it Theoretically works the actual correlation of the approximation is exactly zero This is a very strange observation and we don't really understand why it's exactly zero. So there are some Yeah, some open questions raised So the most important one in which cases can we really approximate The approximation by a single trail and when we can't and also from another view can we maybe use the The non-linear approximations in order to quantify linear hull effects in the more general Cyphers Okay, thanks for your attention. I think I'm a bit over time. Yeah, but we do have time for one So, I think maybe I missed some of the necessary condition for your attack towards but do you need these Really trivial key schedules or could you apply this to some cyphers like for instance present where you have some strongly in attacks? So you were asking whether you need independent round keys Well, like yeah, like a trivial key schedule with the just round constants or Yeah, so so it depends what you want to do if you have this trail here What you would need is if you go to the next round that you have a weak key in every active cell So if you have a key schedule that does not allow this to have a weak key here and also we key here Then this attack would not work in this case. Okay, so it really depends on yes That's why all of your application on cyphers with weak keys somehow. Yes. Okay. Thanks. Any other questions else? Let's thank the speaker again