Dr. Jerry Mahlman spent 30 years at NOAA’s Geophysical Fluid Dynamics Laboratory at Princeton (the last 16 as its director) before moving in 2001 to NSF’s National Center for Atmospheric Research at
Earthzine: You’ve been intimately involved in not only the science of climate change but also the challenge of communicating science to the public. What are your thoughts about the reception of the most recent IPCC reports? Are you satisfied with the degree to which the information impacted the public and the response of political leaders?
Mahlman: To say I’m 100% satisfied would be unfair. But if you look at the increment of improved buy-in by the global public to what we science people are telling the world, I feel pretty good. There’s been a substantial uptick of recognition that human-caused global warming is a very real thing that affects very real people and creatures and ecosystems and ocean life.
Earthzine: We’ve come a long way since the beginnings of the IPCC process in the late 1980s? How did people respond to the early IPCC reports?
Mahlman: The first report came out in 1990 and nobody paid any attention to that whatsoever. Then the next IPCC report came out it in 1995 with what I call the ‘triple-wimpy’ statement. The IPCC said that while the ability to quantify the human influence on global climate was still limited and uncertain, “Nevertheless, the balance of evidence suggests that there is a discernible human influence on global climate.” It’s wimpy because it’s a single sentence with three caveats. You don’t find that in the English language very often. The hardcore climate scientists said ‘we know the physics of this, we know it’s real, but we don’t have buy-in’ and that’s why the triple wimpy statement came out.
Earthzine: You invented the betting-odds scheme that the IPCC uses to quantify and express uncertainty (99% certainty = virtually certain, greater than 95% certainty = extremely likely, greater than 90% = very likely, etc). Did you do that because you saw a need for better communication in the wake of the early IPCC reports?
Mahlman: Actually I cooked up the betting odds scheme back in 1988 for the National Academy of Sciences. I wrote out a first draft of how you could estimate uncertainty using essentially elementary probability theory. It’s basically College Statistics 101. The idea is to make it as simple as possible so that ordinary human beings can get the essence of it.
Earthzine: Do you think that the earlier reports would have benefitted from a more consistent approach?
Mahlman: I absolutely think that’s true. There was enough uncertainty at that time that you really couldn’t take it very far. It was easy to pick it apart.
Earthzine: The media seems to have accepted the legitimacy of climate scientists. Do you think the media has changed fundamentally?
Mahlman: There are still parts of the media that have editors that say ‘you’ve got to have balanced stories’. It’s sort of like saying ‘let’s go out today and see whether the acceleration of gravity is still the same at 32 ft/second squared’. They really don’t know what they’re doing.
Earthzine: How about the journalists themselves? Do you feel like they are learning how to talk to climate scientists?
Mahlman: They’ve learned much better how to get the stories right and still tell the story in a way that is interesting. Are you aware of the series of workshops for climate scientists and journalists that Bud Ward and Tony Socci have organized since 2003? That has been a revelation for the writers and the press people. They’ve learned that we climate scientists are an ethnic subculture. We have our own set of mores of what constitutes truth, what constitutes courtesy to your colleagues, the ethic of reviewing each others’ work, clobbering each other and nobody gets mad. A lot of people in the press don’t understand why we don’t put out papers on what we did in the lab last week? The answer is [it takes] maybe 6 months or a year [for] an exhaustive review process. There is no analogue to that in the press other than what your editor might do to you in the process.
Journalists are realizing that climate scientists don’t have political agendas. We’re militantly careful not to let our ideologies get in the way. The reporters see this and their respect for us has really jumped up. I get more and more calls from writers and reporters that are digging for the facts and trying to get the science straight so they can communicate it on to other people, which I assume is your job at the moment, right?
Earthzine: Have climate scientists become better communicators as well?
Mahlman: There’s a new generation of climate scientists who are really excellent communicators. They realize that if they’re going to be real climate scientists and particularly if they’re going to be involved in the global warming problem they’re going to have to be accurate and eloquent.
Earthzine: Let’s turn to Earth observation. You have long been critical of both the reach and quality of the U.S. Earth observation programs.
Mahlman: To check the level of accuracy and verisimilitude in the models, you need darn good measurements. To me it’s a public disgrace that we don’t have a calibrated, continual climate monitoring system. Global warming is a problem that soars into the trillions of dollars. It’s not just
That said, there are some spectacular exceptions. The altimeters that are measuring sea level heights and glacial heights from space are incredibly accurate. Another are the Argo floats now measuring what’s happening in the upper 300 meters of the world’s oceans. They’re now beginning to measure acidity in the oceans. The good news is that carbon dioxide is absorbed by the ocean and taken up. The bad news is that it turns into carbonic acid and becomes more acidic and therefore can poison life in the upper 300 meters of the ocean. That’s a great observation system. It tells a grim story, but at least we’re beginning to understand it well.
Earthzine: What, in your view, are some of the bigger holes in the system?
Mahlman: There’s never been a NASA satellite that purports to measure the total output from the sun that actually has a rational time series. Every time they change the satellite that looks at the rays coming from the sun the next observational platform gives a different answer. Same thing with the higher levels of the atmosphere. We monitor carbon dioxide in the atmosphere excruciatingly well. We monitor methane very well. We monitor nitrous oxide extremely well. But all of these are gases that distribute over the entire earth so it’s easy to get it. And we’re not monitoring at all whether the deserts are getting hotter and dryer faster than the areas outside the deserts.
Earthzine: What is your solution?
Mahlman: It doesn’t have to be expensive. There’s no reason, for example, why you can’t double or quadruple the number of radiosonde balloons [carrying wireless atmospheric sensors] that are sent around to check out how the weather’s doing. You could probably do it for $10 million for the entire planet. That’s almost dirt cheap. Is anybody doing it? No, because it’s not sexy enough. But that’s exactly what we need to do.
Earthzine: Is the situation any better outside the
Mahlman: I think the World Meteorological Organization has to step up. The World Climate Research Program has to step up. IPCC needs to step up. It’s really important that certain aspects of the climate are being monitored by highly accurate calibrated measurements whether from space or from weather balloons or measuring at the surface of the Earth.
Earthzine: I’m assuming you’re familiar with GEO and the GEOSS that it’s pulling together?
Mahlman: If GEO can do that right it would be a wonderful achievement. There’s no reason not to have a global observing system for the world. It’s an international disgrace that we have been perfectly happy for the last 25 years to not invest globally in a system that will monitor how the climate is changing and to see whether those climate changes are consistent with what we’re projecting from our mathematical models. I’m saying this to really get your attention.
Earthzine: You officially retired from NCAR in October but you’re still taking calls in your office there. Does this mean you plan to keep pushing on climate change communication?
Mahlman: Yes. The obvious point is that there’s passion here. We want to get this right. And my job is to help you get it right. I could have blown you off after five minutes but I respect the questions you’ve been asking. You’re doing a good job.