Sunday, March 8, 2020

Sorry, climate change is not about water

"What can be effective is producing real-world changes in the short time remaining."

We are gathered here this week in Belize for the 15th annual permaculture design course at the Maya Mountain Research Farm. I have blogged in past years from this place, set upon an ancient city ruin from the Classic Maya Era, surrounded today by a multi-strata agroforestry example of the human potential for antifragile, harmonious living with élan in the uncertain and ominous Anthropocene. I’ll not do that again just now. Instead I want to mention something I delved into during our first day of class — a bit of climate science confusion that needs to be corrected and nipped in the bud.

The ecologist Walter Jehne is particularly guilty of spreading this particular point of misinformation, and while I like Jehne and his work in general, he does the world a disservice when he tries to opine on atmospheric science. 

Jehne correctly reports that humans — primarily by land use change — have altered Earth’s water cycle in some very profound ways. He also correctly observes that the single largest greenhouse gas, by a sizeable margin, is water vapor. He then draws the conclusion that by restoring hydrological health to the land surface of the planet we will rapidly restore the natural climate that existed before the industrial age. This is a logical error in which coincidence is confused with causality, something we humans have a neurological propensity towards and that leads us to all manner of ills. 

Yes, the water cycle is out of kilter. As are the nitrogen cycle, the carbon cycle, the potassium cycle, and much more. We humans are great disruptors. You could say, and I do in this permaculture class, that disturbance is our ecological niche, and we do our damage on the same scale as super-volcanoes or asteroid impacts, using mere biological means.

Searching for a metaphor to explain Jehne’s error, I have taken to comparing Earth’s atmosphere to mega rock concerts. If you look at that towering rack of amplifiers bathing an acre of audience in decibels of sound, you could call that water vapor in the atmosphere. Jehne, in my analogy, would tell us confidently that we can repair Earth’s climate by starting to remove some of those amplifiers from the tower. He is right, as far as he goes, but there are a lot of amplifiers up there, they are pretty heavy, and it is a very high tower.

Instead, we could look more closely at the electric guitar of the lead musician. Just below that jewel-studded ring on his pinky finger there is this little round knob. It is known as “gain” and maybe it has some markings on it like the numbers 1 to 5 or 1 to 10. Or 1 to 11 if the band is Spinal Tap. When the musician reaches down and gives that knob a tiny twist, the decibels in the entire amphitheater elevate (or diminish) exponentially. Gain is a control knob for volume.

In Earth’s climate system the gain knob is carbon.

In 1957, during the International Geophysical Year, the First Russian Antarctic Expedition founded Vostok Station, literally, “Station East” at the southern Pole of Cold, on the East Antarctic Ice Sheet, with the lowest reliably measured natural temperature on Earth of −89.2 °C (−128.6 °F; 184.0 K). It is also one of the driest places on earth with only 26 days of precipitation, on average. In the summer season of 1983–1984, a building was constructed by Professor Boris Kudryashov and ancient ice core samples were obtained.

I reprinted his core data chart in my 1990 book, Climate in Crisis. At that time, the chart looked back 800,000 years, and Kudryashov was able to reliably extract CO2 bubbles and to correlate the carbon content of the atmosphere across the ages to known temperatures, globally averaged, taken from various other data sources. 

It’s true that water vapor is the largest contributor to the Earth’s greenhouse effect. On average, it probably accounts for about 60% of warming. However, water vapor does not control the Earth’s temperature, but is instead controlled by the temperature. Warmer temperatures evaporate more water.

From 2002 to 2009, an infrared sounder aboard NASA’s Aqua satellite measured the atmospheric concentration of water vapor. Combined with a radiative transfer model, Gordon et al. used these observations to determine the strength of the water vapor feedback. According to their calculations, atmospheric water vapor amplifies warming by 2.2 plus or minus 0.4 watts per square meter per degree short-term and 1.9 to 2.8 watts per square meter per degree long-term. 

However, we have seen from these kinds of measurements that atmospheric water vapor concentration is not correlated to temperature rise the way carbon dioxide is.

What rightfully concerns climate scientists is what that Vostok ice core is telling us about our immediate future.

We are now at 414 parts per million CO2 by volume in the atmosphere and adding 2–3 more ppm each year. We know from the geological record that at 325 ppm, which is about where we were when I wrote Climate in Crisis, the equilibrium temperature should be 5 degrees above normal (“normal” being the average across the comfortable Holocene epoch in which mammals evolved into us). And yet, when that book came out, we were only 0.9 degrees above normal. How could that be?

Slowing that 5 degree temperature increase is a huge heat sink that covers 70% of the surface of Earth — the ocean. Deeper in places than Everest is tall, most of it far out of the reach of sunlight, the ocean warms or cools only very slowly, taking thousands of years to catch up to the rest of the biosphere. 

We should all be very thankful for that, because all that water buys us a little time. 

Whether humans will go extinct at 3 degrees, 5 degrees, or warmer is an open scientific question. We will not be able to function well out-of-doors once ambient temperatures go above the capacity of our sweat glands to maintain evaporative cooling for our bodies. This effect is already being observed in places that have never experienced the kinds of heat extremes they are now seeing.

Even if the US rejoins the Paris Agreement and nations accelerate their ambitions to curb the threat, it seems unlikely we will arrest the growth of CO2 before we reach 450 to 500 ppm, and that would imply, from the Vostok record, global atmosphere and oceanic temperature equilibrium will rise well into the double digits above normal, and with that rise will come certain extinction of most terrestrial lifeforms, ourselves included. 

No amount of afforestation or changed grazing patterns would produce a water vapor change rapidly enough to succeed with Walter Jehne’s prescriptive pathway.

However, thanks to the time lag afforded by the oceans, if negative emissions technology can ramp up quickly enough in the next few decades, it is yet possible to turn the gain knob back to 350, 300, 250 and below and perhaps avoid our otherwise certain fate. That is my hope, and I am clinging to it.

Here in Belize we are training people to do exactly what will be needed, and what can be effective, in producing real-world changes in the short time remaining. I love this place, these people, and the great adventure upon which we have embarked.



Robert Gillett said...

Hi Albert,

You say, "No amount of afforestation or changed grazing patterns would produce a water vapor change rapidly enough to succeed with Walter Jehne’s prescriptive pathway."

Yet, these too are negative emissions pathways. So, to pit negative emissions against these solutions ignores that.

Also, it seems the change from evaporated water happens in real-time. When you say it wouldn't produce the change rapidly enough, I suppose you mean that we could not reverse desertification rapidly enough given the difficulty of changing human behavior.

I get it that water vapor is an effect that also adds positive feedback to global warming caused by other greenhouse gasses, but if mitigation efforts are focused on restoring soil health that keeps water in the ground (along with carbon), then would this not possibly alter that currently observed linear relationship toward less water in the upper atmosphere and more under forest and field canopies? Those canopies deflect the incoming light that would otherwise interact upon reflection with this increased moisture. (Albedo makes these solutions effective only between temperate regions). More latent heat in this lower, moist region than sensible heat from bare, dry soil would give cooling to land dwellers.

I might be confused about some of this, but your blog raised more questions for me than what it answered, so maybe you would like to follow it up with more explanation.

Ian Graham said...

Hello Albert, I am glad you are engaging with the work of Walter Jehne, 15 years in the making, of the soil carbon sponge effect on global temperature. It sounds like you 've communicated or even met him; I hope you will send him this analsysis to see his response. A piece that's missing from your commentary is the impact of latent heat of water evaporation can have to cool the planet at a very local scale, hence the importance of putting water back in the soil in all the various ways including biochar, regen ag, etc.
For other readers, here is a link to SoilCarbonCoalition's discussion of soil carbon sponge
Here is Jehne at Harvard, the best video of his talks, imo:
Couple more ag sites referencing this theory: and

Ian Graham said...

Writes Walter to me in response:
Yes what we have focused on is the role of and processes by which water governs 95% of the heat dynamics of the blue planet which is the agreed foundation of our scientific understanding of climatology for the past 70 years or more. As we outline these processes such as transpiration, evaporation, humid hazes, cloud formation ,albedo effects, rainfall nucleation, radiation windows and the re-radiation of heat from bare and cooler green surfaces drive the planets heat dynamics and if modified wisely could rapidly and safely cool the climate naturally. They are additional to greenhouse effect the comments focus on.

However water is also the dominant factor governing our abnormal greenhouse warming. This greenhouse warming is governed by the vastly increased level of heat re-radiation from the over 5 b ha of now bare exposed surfaces and the proportion of this re-radiated heat absorbed by a range of greenhouse gases. The key gas effect is from water vapour in the air (80%) which we also influence via our emission of haze and hygroscopic precipitation nuclei. Certainly CO2 governs 11% of this gas effect and our 30% rise in its level influences this component (Manabe and Wetherald). A further 9% is influenced by minor gases including methane and nitrous oxide which our land management also influences.

Hope these realities helps in defining the context for open democatic discussion of our imperatives. All the best

Ian Graham said...

I posted two comments quite long ones since sunday. Did you see them or did they fall down the rabbit hole?

Robert Gillett said...

I think I have found the key to my understanding of these conflicting views.

Referring to the amount of energy flux equivalent to the current rate of global warming (3 W/sq. m), Jehne says "natural transpiration heat flux from soil used to take away 80-90W/sq m of heat back into atmosphere. So if we can increase green transpiration by 4%, we can get that extra 3W/sq m heat to escape."
When he says "escape", he has to mean into the atmosphere, because what ultimately radiates into outer space is only enough to balance the additional greenhouse effect from the added water vapor.

Jehne is saying that a 4% increase in transpiration would take 3 W/sq. m off the surface into the air which acts as a heat sink with all this additional latent heat, i.e. water vapor.

It would not counteract all of the ills of global warming, but would make the surface a lot cooler, which is important to all of us wingless ones.

The soil carbon sponge is key because it holds the water to supply the additional needs of vegetation. Result: more water in soil=> less sensible heat from dry soil, more water in atmosphere => more latent heat in the atmosphere, more clouds, higher humidity, possibly more rain and larger storms.

The storms (caused by more energy in the atmosphere in the form of latent heat) might be harmful enough to negate the benefit of lower surface temperatures, but maybe weather is more survivable than intense heat.

Robert Gillett said...

I also see the point you are making with the 800,000-year graphs. If we are accurately showing the temperature in this data, there has never been a point in which more or less water vapor from changes in land vegetation caused the temperature to track significantly differently (for any long time period) than what a CO2-driven temperature does. With Jehne offering water as a solution, he is proposing something that has never before occurred according to this data. However, the temperatures in these graphs are not ground-level temperature. They are from gas bubble composition of snow fallen on Antarctic ice. All Jehne is improving by increasing transpiration is ground-level temperature. While sensible heat at the ground level would be lower, the temperature in the atmosphere would be higher due to more cloud formation, consistent with the 800,000-year curves. I guess the comfort level just depends on how much of a boundary layer there is between the florid surface and the warmer, humid atmosphere. That cooler layer is very deep in forests, but also sufficient in fields to make life tolerable. Climate change may not be about water, but terrestrial comfort may be improved by it.

Robert Gillett said...

Reading further from Jehne, it turns out his solution depends on the increased cloud cover to increase albedo. This is why he can claim that water would reduce not only surface, but also atmospheric temperature. He does not explain how, but he says that adding ice crystals, specific salts and certain highly hygroscopic bacteria will cause the formation of clouds. See #6 in appendix of One has to wonder how this is restoration of the natural state of things rather than geoengineering. He says, "Our clearing 75% of the Earth’s primary forests may have also impaired the natural formation of the hygroscopic microbial precipitation nuclei [the kinds of things he suggests dispersing for cloud formation] that were critical in inducing dense clouds and rainfalls in many warmer, inland and forested regions." This is pretty speculative. It is hard to tell how long these solutions could take to implement. Certainly, we can't put all our eggs in this basket, just as we can't from biochar, but why not keep his ideas on the table? It seems he may be on to something.



