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Earth & Marine Sciences - On the Brink


Photo by Karl Kreutz

UMaine Climate Change Institute Director Paul Mayewski offers his perspectives on our changing climate and the science that’s getting closer to predicting its future

Paul Mayewski first set foot on the driest continent on Earth four decades ago. At that time, the world knew Antarctica has an unchanging, frozen expanse that lured adventurers like him to explore the unknown.

Since then, so much has changed.

Now in remote polar and high-elevation regions, the bellwethers for greenhouse gas warming, landscapes once considered stable and invariable are being altered. Even in Antarctica, which has not experienced the dramatic melting recently seen in the Arctic and Greenland, the effects of climate change are evident on the continent’s outer edges.

“In a matter of decades in some parts of Antarctica, we’ll probably see changes thought in the past as taking hundreds of thousands of years,” says Mayewski, who this spring returned from Antarctica having led the final leg of an 8,000-kilometer, six-season International Trans Antarctic Scientific Expedition (ITASE).

Since that first trip to Antarctica as a student researcher helping reconstruct the history of the ice sheet, Mayewski has led nearly 50 expeditions to such remote regions as the Arctic, Tibet, Himalayas, Greenland and Tierra del Fuego. As a scientist, he has pioneered the use of ice core records to reconstruct past atmospheric conditions, document changes in atmospheric chemistry produced naturally and by humans, and correlate associations between climate change and disruptions to civilizations.

It’s the current implications of human-induced climate change, particularly in the past 20 years, that have internationally renowned researchers like Mayewski speaking out.

“Since the 1980s, the warming rate has been large enough to push us to the possibility of abrupt climate change,” says Mayewski, who directs the University of Maine Climate Change Institute, a multidisciplinary research unit focused on understanding past climate and how to use a variety of research tools, like ice cores, to predict change. Primary study areas for institute researchers are Antarctica; Tibet and the Himalayas; New Zealand and North and South America; Greenland and the Arctic.

“Until now, climate change occurred by natural processes. Today, we’re overpowering the greenhouse gas system at a rate 100 times faster than nature. With stresses–from sulfate aerosols in the atmosphere to freshwater injection into the oceans from melting sea ice–the climate system can’t be expected to respond in a smooth way.”

For Mayewski, who has made 100 first descents in Antarctica and traversed more of the ice sheet than anyone else in the world, this crossroads for the planet is epitomized by his years exploring the bottom of the Earth.

“There you can experience the way nature has been for millions of years,” he says. “In Antarctica, you can see for such long distances that you can see the curvature of the Earth. It’s so quiet, the only sound is your own heartbeat. And you breathe more deeply because the air is so clean.

“That reoccurring experience is a constant reminder of what we’ve traded for our current existence. I enjoy our current existence as much as anyone, but I believe there’s a better combination of the natural system and our involvement in it.”

Before leaving this summer to join a research expedition in Greenland, Mayewski sat down with UMaine Today magazine to talk about climate change.

What is climate change?

Climate change is natural, constant and has happened for as long as the Earth has been around. A better term for what’s happening now might be human controls on climate change or perhaps destabilization of climate beyond natural levels. The question is how much of the climate change we’re introducing. Humans can’t do anything about the natural part. It’s the human-induced change that is gradually going to eat away at the way we live, both physically through sea level rise, through storms, through warming, but also through increased incidence of disease in warmer and wetter areas.

What are the biggest misconceptions about climate change?

One of the biggest is that one person can’t make a difference. The climate system is very big and it can toss us around, but we each have the capability of impacting it. Another misconception is that everything that’s happening eventually will be taken care of by the Earth’s system. It will, a few hundred to thousands of years from now, and by then, if we continue the way we are, we probably will have mutated into something different in order to survive. People also think that the current climate change is just part of a natural cycle. But this change is not natural and our impact on it is very, very great.

What is science telling us about the state of climate change?

It’s absolutely undeniable that humans have had a very dramatic impact on both physical and chemical climate throughout the world. There’s evidence of warming in the Arctic. Almost all of the mountain glaciers around the world are melting back, and even in Antarctica, despite being a very large place, there’s dramatic melting around the edges. In addition, we’re seeing very big changes in the atmosphere with increasing greenhouse gases–the cause of much of the recent warming–and increasing levels of toxic metals and acid rain. A lot of these toxic metals and chemicals in the atmosphere have very detrimental impacts on human and ecosystem health.

What are the most important factors influencing climate change?

In addition to greenhouse gases, a primary factor in climate change is the relationship between the Earth and Sun. How the Earth handles energy output from the sun changes with the Earth’s surface whiteness–expansion and contraction of everything from ice sheets and glaciers to snowpack and sea ice. It changes with ocean circulation–how long the ocean holds chemicals, affecting its capture or release of heat. Along with the ocean, atmospheric circulation transports heat and moisture. If we didn’t have a change in greenhouse gases, what we would be most concerned about is atmospheric circulation.

How do we know which climate changes are natural and which are human-induced?

To make that determination, you need records that are long enough to help you understand how the natural system operates. Records for the northern hemisphere demonstrate that temperatures for the last couple of decades are warmer than for the last thousand years at least, but there have also been times between the 1940s and the 1970s when the climate was cooler. However, the farther you go back in time, the more it’s clear that what’s happening today with greenhouse gases and changes in other chemistries in the atmosphere haven’t happened at any other time in the past few thousand years. That’s how you understand that we’re impacting climate.

From looking at the past, what have we learned about the predictability of the climate system?

We have learned that there is a lot of predictability in the climate system. If it were left alone to take its natural course for the next few hundred or thousand years, there would be a lot of predictability. On the other hand, while looking for predictability, we discovered something that we never imagined–abrupt climate change events with massive reorganizations in the ocean atmosphere system. I believe those abrupt climate change events involved a convergence of factors, with some small trigger actually pushing to make them happen. That’s why I am so concerned about where we are right now. We’re pushing ourselves way out of the natural system and we’re pushing so fast out of the natural system that even the predictions for where we’re going–the reality–could be very different to the point at which we could have significant cooling in some parts of the world that we would have never, certainly today or in the last hundred years, expected. So, we’ve learned a lot. We’ve learned that the climate system is far more dynamic than we ever thought it was, that the natural, I emphasize natural, climate system is more predictable than we thought it was, and that it can also be changed by very small things.

What is abrupt climate change?

The Climate Change Institute pioneered the understanding of abrupt climate change. It happens naturally in the environment and can be very, very large, yet triggered by very, very small changes. The climate shift that is coming because of greenhouse gas warming will clearly not be a naturally occurring event. I believe that there may be an abrupt change within coming decades, occurring over a period of possibly 2-10 years. Once it happens the change will shift climate into a new state–perhaps significantly warmer seasons with notably higher frequency of storms in a place like Maine. We can’t make 100 percent predictions, but we need to get to the point of making significantly better predictions for the future.

As an explorer, how do see the world?

My type of physical exploration takes me to very remote areas indifferent parts of the world. In my 40 years of exploration, what strikes me most is how close you can get in these remote areas to the natural climate system. You actually get to see the way humans lived up until a few short centuries ago. It was completely different than the world we live in now. The air was significantly cleaner so that you could breathe far more deeply. The only noises were the wind and animals. Experiencing that has made me much more passionate about understanding our impact on the environment. I know that we will never turn the environment around so that it will be absolutely natural. That’s unrealistic. I like being in a warm house and driving my car as much as anybody, but the closer that we can get to the way things used to be, the better off we will be. We allowed ourselves to change the atmosphere, to change the climate. But now we need to be smart enough to know that where we will have the best quality of life will under conditions as close to the natural environment as possible.

How has your understanding of climate change evolved throughout your career?

From the time I first worked in Antarctica until the early 1980s, we assumed the continent to be remote and unchangeable, particularly in our lifetimes. We assumed that if you wanted to see change, you probably would have to go back or forward hundreds, if not thousands of years. That view now has changed completely. We now realize that Antarctica, as well as the planet, for that matter, is a very fragile place and that the potential for change is far, far faster than we ever thought.

Has the role of scientists changed to include more of a public education component?

Absolutely. Twenty to 30 years ago, many of the things that we did were purely academic and experimental. Today it’s very clear that for the survival of the environment, scientists need to become better tuned in to the value of what they do and disciplines in general have begun to blend together. For example, it’s important for scientists to come closer to engineers and scientists to come closer to social scientists. Scientists need to become better at applying what they do and understanding what it is that the public needs. About 10 years ago, there was a big push by the National Science Foundation, which provides a significant portion of the funding for our research, to do more and more applied research.

Is it too late to make changes that will have any effect?

We can’t assume that we’re too late, because if we do, it’s nothing but gloom and doom ahead of us. However, the longer we wait, the more likely there will be more serious consequences. We have already begun to alter the natural climate system quite dramatically. We need to begin to respond quickly. There is giant momentum in the climate system. Even if we were to shutoff all the greenhouse gas emissions from humans right now, it would take decades to centuries, if not longer, to recover from global warming.

What can we do to begin to address climate change?

How much warming we have will be determined by how much higher we let greenhouse gases go. However, many of the toxic chemicals in the atmosphere can actually be reduced very quickly. When 9-11 occurred, they shut the aircraft flights off over the United States and the air cleaned up dramatically. It was related to a very sad situation, but it was a demonstration that, in fact, we can have a much cleaner atmosphere. We have to think about how we can reduce the emissions of toxic chemicals. Some of it is from factories; some of it is simply the way we live, using fertilizers to excess, using chemicals for cleaning. In addition, state and federal governments need to develop policies to legislate reductions and set benchmarks for greenhouse gases and toxic metals, acid rain, organic acids and humanly engineered chemicals. There also need to be incentives for individuals to become more energy self-sufficient. In the longer term, reductions of greenhouse gases will require a very big change in the way we live. We tend to think of change as being uncomfortable, but this is really going to be a change for the better–a better economy, a healthier life and a more predictable climate future.

What is the basic science underlying all the multidisciplinary research at the Climate Change Institute?

All of our researchers are interested in learning about the past. We want to know what happened from one second ago to a hundred thousand years ago–the whole continuum. The value of doing that is that it allows you, like any person studying history, to garner perspective. The Climate Change Institute provides perspective in order to make better predictions for the future.

Why are ice cores so important? What do they tell us?

Evidence of past climate change can be found in tree rings, glacial deposits, caves and corals. But ice cores are the most robust archive of past climate, providing a baseline of how the climate system has changed. The ice has actually captured atmosphere, precipitation, temperature, wind speeds, chemistry providing more data than even the best human records, which focused for decades primarily on temperature. Cores from around the world allow us to correlate data from different time periods. Year-by-year comparisons allow us to find out whether, for instance, an abrupt climate change event in Antarctica occurred before or after an event in the Arctic. That’s very important, because it helps determine what actually triggered the event, what we might call a precursor. Then if we start to see change happening in that location, it means we may expect that sequence of events to continue.

Is global warming increasing the urgency to retrieve ice cores?

Absolutely. It’s the equivalent of having a library out there and trying to scramble to get the books. It’s a library of the environment and those libraries exist in all of the high mountain and polar regions in the world. As temperatures warm they are becoming a very scarce resource. There are places that we went 20 years ago where we couldn’t collect records today. So we are trying to go to as many places as we can, collect these records, get them into the freezers, and ideally analyze and preserve them. The science of analyzing these things changes every five or 10 years. We’re hoping to develop new systems in the next couple of years that will allow us to look at smaller samples, do more measurements and disturb the ice core less allowing us to archive piece for future research.

How do you predict the world will look in half a century?

I’m an optimist. It will still be warming and climate will still be unstable because of what we’ve done, BUT I see no reason why we won’t be living primarily on renewable energy. I think we’ll be a lot smarter about recycling. I think we will be healthier. I think we will be able to travel as well as we can now or more easily, but I think we will become more self-subsistent.

What changes are in store for Maine?

The Northeast Regional Assessment suggests that in the next century, Maine will get warmer. In the last century, we have already experienced an increase of a little more than 1 degree Fahrenheit. The expectation is that there will be an increase of several degrees Fahrenheit by 2100. In the process, the state will get wetter, have less snow and probably will be stormier. The climate will become less stable because, whenever you warm up the ocean, there is the increased likelihood of storms. The analogy used in the Northeast Regional Assessment is that we should expect by 2100 a climate similar to West Virginia. We also now know that the North Atlantic is one of the most sensitive regions on the planet. Climate in the North Atlantic changes more abruptly and more dramatically in terms of magnitude than in other parts of the world.

How do you respond to climate change skeptics?

The first thing I say to them is, “thank you,” because they forced the science to be better than it would have been had they not been naysayers. The second thing I say to them is, “Now you need to get out of the way,” because they’re no longer talking about the science; they’re simply talking about things that serve as blockades. In some cases, these are the same naysayers who tried to convince people that acid rain didn’t occur, and that tobacco was not a problem. At some stage, if you’re going to be critical, you’ve got to come up with a solution and the solution can no longer be that it’s not a problem, because it is a problem.

by Margaret Nagle

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