Changing Planet

Climate Certainties, Climate Confusion: Kim Cobb at PopTech

Scholars need to do a better job of distinguishing between what’s known (that fossil fuel use warms the planet) and what we’re still learning (what that means in terms of droughts, monsoons, big storms, and other consequences), says climate scientist Kim Cobb.
By Ford Cochran

Georgia Tech geochemist and climate scientist Kim Cobb is one of 18 new PopTech Science and Public Leadership Fellows, part of a program launched this year with sponsorship from National Geographic. She spoke last week at the annual PopTech Conference in Camden, Maine, about her research on the long-term El Niño record preserved in Pacific corals, about what’s known with confidence about global warming, and about the ways scientists themselves have contributed to public confusion around human-induced climate change. I caught up with her between conference sessions.
You’re doing work on Earth’s climate and coral records in the Pacific ocean. Tell me a little bit about your research.

What I do is study coral paleoclimate records, which means I use corals to reconstruct climate of the past. What that involves is going out to the islands in the middle of nowhere to try to hunt the climate signals that we’re most interested in in the tropics. The El Niño events, as you may know, occur sporadically every two to seven years along the Equator. So that’s where we have to go in order to reconstruct these climate events.

We’ve been down there many, many times on different planes, trains, and automobiles. (Maybe not the trains part.) And definitely, each expedition lends something new to my repertoire of great field stories.

What we do with these records is look for patterns of past climate variability, current trends and how they compare to the magnitude of past climate changes, try and understand how global-warming-related effects are impacting that area of the world for which we have so little information from the instrumental climate record.
So extending the data sets that we have to inform the models from which we then predict the future of Earth’s climate?

Right. Our ultimate goal is to try to compare the climate simulations of these time periods in the past with the records that we actually have, telling us what actually happened, and see if those models can accurately reproduce that climate variability from the past. We find that in general they do well in some areas–for example, the 20th-century trends seem to be pretty well reproduced. But going back further in the past, they seem to have more trouble. This is particularly problematic in terms of understanding some of the limitations of their accuracies for projecting 21st-century climate trends, for example.

One of the takeaways from the terrific talk that you gave Thursday at the opening PopTech session was that the public is grappling with the complexities of this issue because they put all of their concerns about the validity and certainty of the science of climate change in one big box. Tell me a little bit more about that.

That’s been really frustrating, to go from what might have been seen as a relative high after something like the Al Gore movie, with the message that that carried of importance and the recognition and awareness that occurred after that movie. There’s been a slow erosion of that information, in terms of climate science awareness and people’s understanding of what’s going on.

I think that that’s kind of our own fault as climate scientists in messaging the point, in taking over from where Al Gore left off and refining his message in terms of letting the public know what is settled science, and what aspects of the work that we are doing represent highly uncertain areas of climate science. We have kind of failed to distinguish between those two in some important ways, and left ourselves open to some very bruising attacks.

I’d like to think about speaking to the 50 percent of Americans who don’t believe that we are warming the planet by CO2 emissions and tell them that I understand where they’re coming from, that I understand why the confusion exists. We have ourselves to blame in part as climate scientists, and we have an opportunity here to address exactly those folks with more refined messages of packages of science that are settled science on the one hand, and here’s a suite of climate impacts, of climate change, that we don’t understand yet. And here’s what we’re working on to try to reduce those uncertainties. And then from there have a non-scientific discussion of what we should do about it, if anything.

That’s really a distinction I think the public needs to understand, and that climate scientists need to be much better about communicating.
In brief, are there one or two things that you would say the public ought to regard as the base of the pyramid that you drew for us [in your PopTech presentation], the things that scientific consensus would say are at least relatively certain, and then a couple of examples of the things that need to be researched more before we can make concrete predictions about where we’re going?

The settled part of the science is clearly that the CO2 emissions that are resulting from fossil fuel burning are warming the planet, globally speaking. That is a certainty. And the fact that that is still not recognized by all but one of the Republican Senatorial candidates reflects the fact that this is an area of significant confusion for the public. That’s settled.

We have not really chosen to communicate that message as strongly as we could. We have a trove of data: Real observational data, paleoclimate data of the sort that I generate, the model data that we have. Again, all of these things combine into the foundation of that scientific point, which I think the public needs to fundamentally understand. Is this happening? This is absolutely happening.

Moving on from there, what are the impacts of this? It’s all well and good to say the planet is warming, but what does it mean for rainfall in Georgia, for example, where I’m from? What does it mean for hurricane landfalls in Florida? What does it mean for the monsoons in India? These are the questions that are much more difficult to address with models and with data.

We don’t have a lot of rainfall data. We don’t have a lot of hurricane data. So these and the extreme events: What about the evolution of severe droughts and severe floods, the kinds of things that truly disrupt our society. These things need a lot more study.

When we use that fear factor to scare people into action, that’s where we begin to lose our path as scientists. So differentiating: This is a hypothesis we are testing, we have some data to support this, but we are actively and intensively researching these areas so we can provide better constraints about the things that people care most about.
Learn more about global warming and energy choices from National Geographic.
Photograph of Kim Cobb by kk+

Ford-Cochran.jpgFord Cochran directs Mission Programs online for National Geographic. He has written for National Geographic magazine and NG Books, and edits BlogWild–a digest of Society exploration, research, and events–and the Ocean Now blog. Ford studied English literature at the College of William and Mary and biogeochemistry at Harvard and Yale, with a focus on volcanoes, forests, and long-term controls on atmospheric CO2. He was an assistant professor of geology and environmental science at the University of Kentucky before joining the National Geographic staff.

More posts by Ford Cochran

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