Former NASA Chief Scientist: ‘We’re Effectively Taking a Sledgehammer to the Climate System’

“You really have to work to not believe it,” Dr. Waleed Abdalati says of anthropomorphic climate disruption (ACD, also known as climate change). He should know: More than 20 years ago, Abdalati began observing ACD firsthand in Greenland, as a scientist working on his doctoral thesis, for which he created an algorithm used to remotely detect changes in the spatial extent of the Greenland ice sheet experiencing melt each year.

Abdalati, previously NASA’s chief scientist,is now an associate professor of geography, director of the Earth Science and Observation Center, and a fellow of the Cooperative Institute for Research in Environmental Sciences (CIRES) at the University of Colorado in Boulder. His research interests are in the use of satellite and airborne remote sensing techniques, integrated with in situ observations and modeling, to understand how and why the earth’s ice cover is changing.

Dr. Waleed Abdalati (Photo CU Boulder)
Dr. Waleed Abdalati (Photo CU Boulder)
In particular, his research focuses on the contributions of ice sheets and high-latitude glaciers to sea level rise, and their relationship to the changing climate. Toward that end, he has been heavily involved in the development of NASA’s Ice Cloud and land Elevation Satellite (ICESat) and its successor, ICESat-II, (the benchmark Earth Observing System mission for measuring ice sheet mass balance, cloud and aerosol heights, as well as land topography and vegetation characteristics) and has worked on cryospheric applications of various other satellites and aircraft instruments. Most of his research is supported by NASA, where he worked as a scientist for 12 years before joining the department of geography at the University of Colorado.

During his tenure at NASA, Abdalati was appointed to the post of chief scientist, where he advised Administrator Charles Bolden on NASA science programs and strategic planning. He also served NASA as head of cryospheric sciences at Goddard Space Flight Center between January 2004 and June 2008, was awarded the NASA Office of Earth Science Award three times, the NASA Exceptional Service Medal and the NASA Space Systems Award, among other recognitions.

Truthout interviewed Abdalati about what he saw while working on the Greenland ice sheet during the 1990s, his observations about the indisputable evidence of the reality of ACD, and the urgent need for an honest, society-wide conversation about the future that we are facing.

Truthout: You’ve spent a lot of time in the Arctic studying what is happening to the ice and the climate there. Given that the Arctic is known as the canary in the coalmine regarding climate change, talk about what you saw there, and why we should be concerned.

Dr. Waleed Abdalati: More relevant than what I saw when I was physically there is what we’ve been seeing on the satellite data. But I’ll start with when I was physically there. It’s hard to ascertain from one or two spots on an ice sheet what is going on Arctic wide, but one of the things I did when I was in the field was some ground truth to support the development for a method for detecting melts on the Greenland ice sheet. And then once those satellite observations’ data were validated by the ground truth measurements I made, we then applied it to the whole ice sheet. Over time we’ve seen this very steady marked increase in the melting. You probably saw or even wrote some stories about the excessive melt in 2012 . . . this melting was all observed by satellites, not by sitting on the ice itself. That was only part of the method of understanding what is happening.

Things are different now. The place I used to go where I did these measurements was called the equilibrium line, where the balance between accumulation and melts is realized on the ice sheet. There’s a certain altitude where above it the ice gains mass, below it the ice loses mass, where melting exceeds accumulation below it, and above it melting is less than accumulation. This equilibrium line was set up in 1991, and camp was placed there.

That line has now moved quite a bit further up slope. So now that camp I used to go to that was situated so that it wouldn’t be buried or that it wouldn’t stick way out of the ice after next years melt had to be reinforced. It had to be secured with these long steel poles put into the ice because it’s now above the ice. Rather than sitting on it, you have to take a ladder up to it. So that’s just one change in one area. But in terms of the equilibrium line, its crept up slope progressively year after year so that it’s far higher than it was at the time I was there. I don’t know exactly how far or how high it is, but it’s tens of kilometers inland.

What I saw, and I started going in 1993, the Arctic was beautiful and we were trying to figure out what was happening. There were some hints that ice sheet was melting, the sea ice might be shrinking, but the time series of the satellite record was so short that we couldn’t draw substantive conclusions at the time. And now, all of those things that were hinted at back then have been realized.

When I got to the village that we used to fly into, before we would fly onto the ice in a helicopter we used to take a hike in the evening, because it’s light until midnight, out to the ice edge. We could walk to one part of the town and look across the ice edge right in front of us. Now that ice edge is 10 miles back from where it was. So this is one place over one short period of time, but it’s an indication or symptomatic of a retreating ice cover.

The Arctic Ocean is leading the way in acidification. Just as there is a long lag time between increasing greenhouse gas emissions and increased temperature, changes in ocean acidity lag very far behind alterations in atmospheric carbon dioxide, according to the February 2014 issue of Environmental Research Letters. What does an increasingly acidic Arctic Ocean mean for that part of the globe?

I’m not an expert on this. But the ecosystems have evolved under a certain pH structure. And once you change that pH, once you make it more acidic, these systems are vulnerable. And once you make it more acidic, it starts with coral. Not so much in the Arctic, but it starts with elements low on the food chain that have ripple effects all the way up the food chain. So if the smallest creatures are most vulnerable creatures and find themselves in an environment that they can’t survive in, it’s got ripple effects throughout the food chain and ultimately reaches humans as well.

What concerns you most about what you studied in the Arctic?

The significant loss of ice in Greenland has me concerned about sea level rise. The loss of Arctic sea ice has me very concerned about its implications for ocean circulation. The climate patterns that we’ve come to rely on for our own regional climate characteristics which affect the crops we grow, how we prepare for storms or flooding or drought and what not, and then third, the energy balance. As we lose ice the rate of warming on the earth continues to accelerate.

Of those three, I think the sea level rise is the most concerning. Not because it’s the biggest threat, although it is an enormous threat, but because it is the most irrefutable outcome of the ice loss. We can debate about what the loss of sea ice would mean for ocean circulation. We can debate what a warming Arctic means for global and regional climate. But there’s no question what an added meter or two of sea level rise coming from the Greenland ice sheet would mean for coastal regions. It’s very straightforward.

Some scientists are predicting the Arctic will begin to see periods where it is ice-free in the summer as early as next summer. The US Navy has released a study predicting this will begin by 2016. Whenever it begins to happen, and as it becomes ice-free for longer periods during the summer, what will this do to planetary weather systems?

We don’t know for certain. What I will say is this is a major perturbation to the climate system. Humankind has never known an ice-free Arctic as far as we can tell. You remove this cap of ice that helps keep us cool and maintain the Thermohaline circulation, things like the Gulf Stream and other northern latitude ocean circulation features, and we don’t really know what the outcome would be.

We just know that we’re effectively taking a sledgehammer to the climate system and in my view it’s scary and insufficient to simply hope for the best.

This April was the second-warmest April on record globally, and marked the 350th month in a row (29 years and counting) that saw above-average temperatures. With so much evidence about the dramatic impact of ACD, what do you say to people who refuse to believe ACD is real?

Those are two separate questions. More important than April being the warmest is the statistic about the consecutive months of warming. It’s very risky to pick an event or a moment in time and point to it and say, “There’s your proof.” Rather, you want a preponderance of the evidence, which involves and requires looking at the longer-term information you have and putting it in a physical context. What I would say to people is not the April date, but that it’s the 350 months that tells us we are in a warm period. It is warm. We understand the basic physics, the basic principles that have led us to this point. We are at a time in history where everything we know and all that nature is showing us is that we should be getting cooler, yet we’re not. What’s different? And that’s where the greenhouse gases come into play.

In the simplest sense, if you put heat-trapping gas into the atmosphere it will trap heat. We are putting heat-trapping gas into the atmosphere, and our measure of heat, temperature, has responded pretty dramatically. It’s basic physics that you learn in high school. There’s nothing magic about it.

The earth is a complex system that goes through cycles and regional variability over time, but when you put together what we have over the time periods, we have it over the spatial areas we’re monitoring over the globe, and you look at the most fundamental physical principles, it’s pretty obvious. You have to work very hard, and be pretty creative to come up with a different explanation. And frankly, different explanations don’t support what we see now.

Are you familiar with Occam’s razor, which says the most simple and obvious of explanations is usually what it is? [Occam’s razor states that among competing hypotheses, the one with the fewest assumptions should be selected.] People go out of their way to find other reasons for what we’re seeing, when there is a very obvious reason confronting us.

You really have to work to not believe it [anthropogenic climate disruption].

Talk about the Arctic, melting glaciers and rising sea levels is common when it comes to discussing ACD. But what aren’t we talking about? Is there something else that isn’t on the table yet that we should be discussing?

I think it is all on the table. In terms of the changes we’re seeing on earth, it’s all out there and I don’t think we’re missing anything. There does need to be a more robust discussion on the complexities of the climate system. There’s a lot we don’t know and a lot we don’t understand. We would all do well to delve into these things we don’t understand and try to understand these phenomena.

Things like why Antarctic sea ice is growing and parts of the Antarctic are getting cooler while the rest of the world is warming. We think we have answers to that, but too often these are just grabbed at as a very simplified explanation or small pieces of evidence. If models don’t support what you’re seeing, and I’m speaking facetiously now, but your models don’t support what you’re seeing so you run them again, and you introduce this voodoo sensitivity factor of aerosols and voila, you can claim something that previously you couldn’t.

I think honest conversation about what we do and what we don’t know, what we can’t say and what we can say, is critical. But the indicators of a warming climate, the basic underlying physics of what is causing it, are all very clear. We are talking about the right things when we are talking about what is going on. But we are talking about the wrong things when we point to very local, very short-term occurrences that run counter to what the globe seems to be doing.

Any last thoughts?

It is incumbent upon us as members of society to have honest and open conversation about what we do know and what we don’t know, what the risks are or may be, and what our strategy for confronting those risks or mitigating those risks will be.

Unfortunately, the conversation is a little too shrill, and a little too cast in the context of extremes, and I think this continues to inhibit meaningful progress and meaningful discussion about what we need to do about what lies ahead.

I may be repeating myself here, but the basic physics of greenhouse warming are very straightforward. The data we have make it very clear that the earth is warming. The data and the physics make it very clear that the bulk of the warming is being caused by human activity.