For artists, clouds are endless sources of fascination, inspiration, contemplation, and comfort. They’re similarly captivating for scientists, albeit for different reasons. Clouds and climate change are the focus of important research being conducted at NASA and elsewhere — and the topic of two presentations coming up at Caltech.
“The Future is Cloudy: NASA’s Look at Clouds and Climate,” happening in Caltech’s Ramo Auditorium this Friday, will feature Dr. Kate Marvel of the NASA Goddard Institute for Space Studies and Columbia University; Dr. Graeme Stephens of JPL’s Center for Climate Sciences; and Dr. Brian Kahn of JPL’s Atmospheric Infrared Sounder Cloud Algorithm Lead. “Clouds and Climate Tipping Points” is a lecture being given by Caltech Professor Tapio Schneider in the school’s Beckman Auditorium on Wednesday, April 24.
Schneider and Marvel are gratifyingly clear and down to earth as they explain how clouds are enlightening scientists about climate change. Schneider’s study is focused on making more accurate modeling for climate prediction.
“That’s the key,” he says in calm, measured tones. It’s hard to say whether cloud behavior’s changing, he explains, but what is clear is that “uncertainties about how clouds will change dominate all uncertainties of climate predictions. These uncertainties are quite large. For example, marine stratocumulus clouds off the coast of California here cool the global climate by perhaps as much as 12, 13 degrees just by reflecting sunlight; it would be 12, 13 degrees Fahrenheit warmer without them, or even 14 degrees. They have an enormously important effect on climate, yet current models cannot simulate them well. … We need to understand better what clouds will do.”
“As the temperatures rise the climate changes, and those climate changes themselves can affect the temperature changes,” Marvel says. “We call those feedback processes. Some are fairly straightforward: you melt the ice in the Arctic, it’s less reflective, and that loss of that reflective shield makes the planet warmer. But clouds are evidence of feedback that’s not necessarily straightforward. And it turns out that the primary physical reason that we don’t understand how hot it’s going to get is because we don’t understand what clouds are going to do.”
Attaining more accurate information about cloud behavior has practical benefits for things like infrastructure planning. Schneider recalls an unexpected storm several years ago just east of the Caltech campus.
“I heard a rumbling outside and thought someone was taking the trash out, but it was pouring. In fact, there were trash cans and cars floating down the street. One of the storm drains that bring the water down from the foothills toward the ocean was overflowing; there was a giant sinkhole in the street, and water coming out of it. It was a case of stormwater management infrastructure being too small for intense rainfall. Rainfall will get more intense as climate warms, and you want to make sure whatever infrastructure is put underground is correctly sized for whatever will come.”
With so many cloud-analyzing instruments on satellites orbiting Earth, are efforts being made to affect cloud behavior? The question itself feels like something ripped from science fiction.
“Definitely,” acknowledges Marvel, who is also an eloquent writer and popular speaker. “But we are creating that science fiction.”
Part of what is surreal about our current situation is the force with which some political entities have pushed back against scientific findings regarding climate change. But as Marvel points out with no-nonsense clarity, “ice doesn’t care about politics. It just melts.
“Physics continues to exist whether or not anybody believes in it,” she says. “There has been a recent political attempt to understand that a lot of these things are interrelated, so you don’t care about climate change OR the economy; you have to care about both. Because climate change is going to have so many effects.
“People tend to think about climate change like it’s going to be a disaster movie. And in a lot of places, it will — like Paradise, California; that was a disaster. But I’m actually more scared about what it’s going to make us do to each other. History is full of examples of societies reacting in really counterproductive ways to adversity, and climate change is going to bring a lot of adversity. That’s where I think there’s such a place for the arts, for the social sciences, for all these different disciplines to really grapple with what’s coming. How do we prevent that scariest feedback, which is humans turning on each other and blaming each other?”
Schneider is skeptical that cloud research will solve current global warming problems, but expresses confidence that “we’ll figure out a way to reduce emissions” and improving climate model accuracy with data from that research will help greatly. Climate change is a serious problem “that can be dealt with,” but he acknowledges having concerns that he did not have a few years ago.
“Increasingly, the evidence coming in now points to the climate system being more sensitive to increased greenhouse concentrations,” he says. New models and data all point to “greater sensitivity,” which translates into greater climate impacts due to increased future CO2 concentrations. He simultaneously finds cause for optimism in “how much cheaper it has become to produce electricity energy from renewable sources. In many countries it is now cheaper to build a new solar plant than a new coal or oil-fired power plant.”
“We know what’s causing climate change; we know it’s greenhouse gases, primarily carbon dioxide, and we know what we’re doing to put those into the atmosphere,” Marvel states. “The fact that that causal relationship is so clear means that we know exactly what we have to do. I’m not minimizing the scale of that endeavor, but it’s not as if this is some natural phenomenon that we don’t understand and we have no power to stop.
“We very much have the power to stop this. Whether we will or not, I don’t know, but I think we have to try.” n
“The Future is Cloudy: NASA’s Look at Clouds and Climate” takes place 7-8:30 p.m. Friday, April 19, at Caltech’s Ramo Auditorium, 1200 E. California Blvd., Pasadena. “Clouds and Climate Tipping Points” takes place 8-9:30 p.m. Wednesday, April 24, in Beckman Auditorium. Both events are free, with no reservations required; seating is first come, first served. Info (626) 395-4652. marvelclimate.com, climate-dynamics.org, Caltech.edu