Transcript

Host: This is "On The Line," and I'm Eric Felten. The Earth is growing warmer, and human activity is to blame, according to a new report by the United Nations intergovernmental panel on climate change. "Warming of the climate system is unequivocal," the panel concluded, pointing to observed increases in air and sea temperatures, melting ice and snow, and rising sea levels. The scientific panel says that the increase in global average temperature is "very likely due to human activity.”

Burning fossil fuels adds carbon dioxide to the atmosphere. Increased agriculture adds methane to the air. These greenhouse gases, as they're called, trap heat that would otherwise escape into space. An increase of these naturally occurring gases are said to increase the heat trapped in the atmosphere. The U.N. climate-panel report said that even if the growth of use of fossil fuels were stopped and emissions of gases were reduced to the levels in the year 2000, global warming will continue.

President George W. Bush, in his State of the Union address, urged the development of new technologies to address concerns that the planet is warming. Bush: America's on the verge of technological breakthroughs that will enable us to live our lives less dependent on oil. And these technologies will help us be better stewards of the environment. And they will help us to confront the serious challenge of global climate change.

How robust is the science of climate change, and how reliable are the estimates of the U.N. panel? What options are there for addressing global warming? I'll ask my guests: Robert Corell, program director at the H. John Heinz III Center for Science, Economics and the Environment; Bret Schulte, an associate editor for U.S. News and World Report who writes on environmental issues; and joining us by phone from Boulder, Colorado, Roger Pielke, Sr., a senior research scientist at the University of Colorado at Boulder; and joining us by phone from West Lafayette, Indiana, is Dev Niyogi, an assistant professor of earth and atmospheric sciences at Purdue University and Indiana state climatologist. Welcome. Thanks for joining us.

Robert Corell, how solid, at this point, is the science of global climate change?

Corell: Well, the intergovernmental panel that you mentioned is a panel of about 2,500, 2,600 scientists who work together over a 3- or 4-year period to assess the state of knowledge and do the best we can, through the peer-reviewed literature, to let the world know what it is we know about climate change. And I think, from your introduction, the science is pretty clear. It's pretty unequivocal. And I think we need to make it clear that some of the warming is due to greenhouse gases, some of its due to land-use changes, and some of it's natural variability. And one way to think about it is that the planet is warming slowly over long time scales -- decades, centuries. And sitting on top of that is a variability of climate just due to the way that the Earth works. All of those concepts are built into the intergovernmental panel's assessment. I think the IPCC is one of the great social inventions of the 20th century, latter part, because scientists now work together to take their knowledge not only into the literature but to transform it in ways that the public can understand and let that be a part of supporting the process of policy.

Host: Roger Pielke, Sr., are you there by phone?

Pielke: Yes, I am.

Host: What's your sense of the state of climate science?

Pielke: Well, I have to disagree a little bit with Bob. I think that the assessment that was done in 2005 by a National Academy panel that talked about expanding the concept of radiative forcing shows that there are a diversity of climate forcings that are inadequately explored by the IPCC, at least as reported in their statement for policymakers that was just released, and one of the things is the importance of regional climate forcings due to aerosols and land-use change that can affect weather there, as well as through weather systems propagate downstream thousands of miles. And so we have to recognize the climate system is perhaps oversimplified in the IPCC report that the human intervention in the climate system is more complex than implied by the report. And there is supporting peer-reviewed literature to support that view, and I don't think the IPCC is covering that adequately.

Host: And, Dev Niyogi, are you there by phone, as well?

Niyogi: Yes, I am.

Host: What's your sense of the scientific credibility and how robust the scientific knowledge is represented in the IPCC report?

Niyogi: Well, I think both Robert and Roger do a very good job in presenting the broader perspective. IPCC, as it is right now -- it is trying to assimilate the state of literature into a state of knowledge, and, as it stands, even though it is trying to look at the issues associated with the greenhouse-gas warming or whether issues because of the land-use or natural variability, to quote Bob, it is more or less almost heavily biased to the greenhouse-gas based aspects of climate change and many of the other features, which are what we will call the nonradiative forcing, are those associated with land use or aerosols, particulates, clouds are somewhat poorly represented, and that causes, we know from the literature, significant changes both in the magnitude and direction of the effect at regional scales within that concept and projection of that hypothesis. Some of the questions that IPCC is trying to answer, in its science, may be too simplified and others may be, perhaps, there. But overall, I think the stepping-stone is in place. We are definitely not onto the point where we have reached a conclusion on this topic.

Host: How do you think that, Bret Schulte, the report has been received in policy circles in Washington?

Schulte: Well, I think people have been anticipating this report. I mean, people have known what this report was going to say for a long time. There's been a lot of buildup. The reaction to it, even from the White House, which has been reluctant to discuss much, how to handle climate change other than the technology down the road is somehow going to be the answer, issued a report of its own -- or issued a statement of its own the day the IPCC came out basically agreeing with its conclusions and defending its own actions in climate change. The White House says it has spent $29 billion since 2001 on climate-change technology. It says it's the leader in the world on this. But it still is rejecting this idea of carbon-dioxide caps. Now, the Congress is moving in the opposite direction on that since the Democrats took over. Senator Barbara Boxer, who's chair of the environment committee, is promising legislation this year, and it is most likely going to be Cap-and-Trade legislation, which is going to be very similar to the Kyoto Protocol that Congress rejected under the Clinton administration, that the Bush White House has also rejected. And in the House, Nancy Pelosi says that we are going to see legislation from that body, as well, by July 4th.

Host: Let me ask Robert Corell on this question of capping emissions. This has been the goal of the Kyoto plan, and yet the IPCC report says that even if you had a cessation of any increase in emissions from as of 2000 that global warming is going to go on. Is the response in sync with the dire predictions that are in the IPCC?

Corell: Well, it's hard for people to understand that this thing we call climate is really a supertanker. It's going to take a lot of energy and a lot of technology change to slow it down. The CO2 that is in the atmosphere takes about 120 years to cycle through and become oxygen through photosynthesis, and it's that inertia that causes these large time scales. The second part of it is we already know we've warmed the planet maybe a little more than a degree Fahrenheit. There's already in the ocean enough to warm the planet another 1/2 or more degrees. And those things do two things. One, it causes the ocean to expand. Whenever you heat something, it gets -- you know, expands. So that causes some sea-level rise, and that's the primary source of sea-level rise. And the reason that's important is that it takes a long time for that sea-level process to take place because the heat is slowly moving into the ocean and expanding so that we can see hundreds of years of effects even though we might stop CO2 right now. So it's that supertanker effect that I see that really controls the long time scales of the response to climate change.

Host: Let me ask Roger Pielke if he thinks that the solutions being proposed and debated in Washington are consistent with the predictions that are being presented for global climate change.

Pielke: Well, actually, I think what's being discussed in Congress and throughout the world is really energy policy and not climate policy because if we're really interested in things that have a long-term impact -- and I agree with Bob -- CO2 lasts in the atmosphere a long time, but so does land-use change. And aerosols -- they may be washed out of the atmosphere, but they get deposited on the soils and can have lots of effect over long time periods. And there's also some interesting observations that show that the system is much more complicated than implied by the IPC. For example, from 2003 through at least 2005, the upper ocean actually has cooled. So there was global cooling, and the ocean is where most of the heat changes occur. And that doesn't mean we shouldn't be concerned about CO2, but it means that if we're tying everything to this global average surface temperature and we're expected to continue to rise, if it doesn't continue to rise, does that mean we shouldn't do some of these things with respect to energy? So what my plea is that we really need to separate the two, that climate policy is not adequately represented by the IPCC, in my view, and what we're really talking about, in terms of these actions in Congress, are really energy policy.

Host: Let me ask Dev Niyogi on this question of sea-temperature changes. In the 2001 report from the IPCC, the panel on climate change, there was a prediction that sea level might rise by as much as 3 feet over this century, and yet now, in the 2007 report, that number was revised not to represent a more dire scenario but rather to rein in that estimate, and now the prediction in the report is 7 to 23 inches. What's happened there?

Niyogi: Well, I think science is evolving. We have been understanding the processes, and as Roger also said, that the more of the feedback that we try and introduce into the system, we recognize that we cannot lump everything into one feedback. In this case, as you posed the question, it is the sea-surface rise. In some other discussion, it could be global warming or temperature changes that might come up. The whole problem is that this is an extremely interactive and feedback-based system. And the way I try explaining it is akin to what happens when you go to a physician and you ask that if you're having some symptom, the doctor will ask you if you're taking any medicine. And if there is some other medicine that comes with it, there might be some unavoidable or unintended consequences by what we call the drug interactions. In the same sense, if we do not understand and look at the feedback, in terms of how it is going to change in terms of the space and time, we may be addressing a wrong problem and, worse, creating perhaps even additional, unintended problems. So the -- in response to the direct question that you have, I would say that it is a change of our understanding in the science, and that has been shown both with regards to the sea-level changes and, much more dramatically, what I found was with regards to the diurnal temperature changes, because one of the highlights of the 2001 IPCC was that nighttime temperatures may be warming much higher, and this report now has identified that that may not be the case. And it may just be that our science is evolving in a way that we look at more factors and we start figuring out that a system may be more resilient at times and other times it may not be.

Host: Bret Schulte, let me ask you, one of the things in this issue of global warming that has gotten a lot of publicity has been the film by former Vice President Al Gore. And one of the predictions that is central to that documentary is the claim of a 20-foot sea rise in this century, and yet we see in this report a prediction of 7 to 23 inches. In the public debate that's shaping policy, which of those kinds of predictions is more in the front of people's minds?

Schulte: Well, there's no doubt that Al Gore's movie has had a tremendous impact on the debate. I believe it's the highest-grossing documentary of all time now. He could win an Academy Award for it. But people immediately started quibbling with some of the science. In general, I think, people feel he got it right, but he also may have picked some of the worst-case scenarios because it's also a Hollywood movie, and that's the kind of stuff that sells. I mean, if people want to have, you know, the most conservative and consensus-driven and most scientific evidence out there, they should be looking at the IPCC report, not Al Gore's movie.

Corell: I would add to that that 23-foot sea-level rise is what would happen if all of Greenland went, and even Al knows that that's a 1,000-year problem, not a 100-year problem. And we have some evidence in the paleo record that we've had meters of sea-level rise, but to have all of Greenland go would be a new enterprise, and it's way beyond our capacity to predict with any assurance, other than it's of the order of 1,000 years. Let me say another thing about the sea-level piece in the report. There was a difference between the 2001 and the current assessment on sea-level rise, methodologically. In 2001, the models were used to come up with some numbers, and then there were judgmental -- judgments made about how much might come from melting of Greenland or Antarctica or the glaciers -- in other words, all the land-based ice that would flow into the sea and cause it to rise. And so they made a judgment on that. They made a different judgment this time that says, "Let's rely on the models to give us the range," and then with some modifying sentences further on in the report, recognize that there may be some additional sea-level rise that come from these other sources. And I think that's a reasonable thing to say. You know, "Here's what we know, and here's what we don't have as solid of evidence on.”

Host: Let me ask Roger Pielke on that question. Is it possible to get away from those kinds of judgments in how these models, that are predicting decades a century out, are designed?

Pielke: Well, I think the models are very valuable to understand climate processes, but I think they're inadequate for projections because they haven't been able to project regional-scale information for the last 20 or 30 years, and I think you could argue they haven't even been able to do global ones correctly. So what we actually have proposed is a new perspective -- that is, to look at vulnerability -- vulnerability of important resources to environmental variability and change on all time scales and all space scales. So, for example, if you're interested in water resources in the western United States, you ask the question, "What are the biggest threats? What can we do to reduce the threats to that resource?” And we can then use the models and that as one set of scenarios, one set of possibilities. But the reality of it is, if you look at the historical or the paleo record, there are some scary things that have happened, such as the -- in the western United States, the 16th-century megadrought that lasted for 50 years and more or the 1930s dust bowl. These occurred because of the natural variability of the climate system. We're now perturbing it by human influences in these diverse ways. And so, I think if we take a vulnerability perspective, we're going to be able to move the policy discussions forward, whereas we focus just on CO2 as a way to control these climate events. I think we're going down a dead end.

Corell: I'd like to --

Host: Robert.

Corell: You know, if you look at this report, you'll find -- and let me just use a few words. "It's very likely," which means in the high percentage, "hot extremes, heat waves, heavy precip," blah, blah, blah. "Snow cover will be projected to contract. Sea ice will come down" -- a whole series of projections about the nature of the planet. The trouble -- and here's where Roger is absolutely right -- these things that affect humans are on regional scales. You know, to tell the world that the temperature is going to vary by a degree or two, on average, gets rid of all of the texture of the process. And we know that greenhouse gases are part of the equation, as I said in the beginning. We also know that land use and the changes of the whole topography and the use of land around the planet, plus all this natural variability... So I think once we're going to see the IPCC go from this kind of global perspective, global average, global means to the kinds of things that Roger's talking about, and that is understanding the process at scales that are meaningful to humans. And that is this drought that we're going to see in, let's say, the southwest -- that's going to be decadal in character, and that's different from looking at the whole planet because we get a very different perspective on precipitation.

Host: Well, one area where there's been some specific finding in this report is in Antarctica, and I want to ask Dev Niyogi about this. The IPCC report on page 17 says, "Current global-model studies project that the Antarctic ice sheet will remain too cold for widespread surface melting and is expected to gain in mass due to increased snowfall.” So much of the problem has been posed in terms of melting ice caps, and yet we see the report saying that there's actually an increase of ice mass in Antarctica. How is that affecting the models?

Niyogi: Well, I think it's really important to highlight that models are going to respond to the changes that are prescribed to it. Let me give you an example. If we add more of the aerosols or more of the industrial emissions to the model, they will have a different response than what it has been doing right now. Similarly, if we changed some of the cloud characteristics, the amount of radiation coming in, whether it is going to be reaching the surface or whether it is going to stay in the middle atmosphere and then heat up the middle atmosphere, and as a result of which change over a period of time, these whole factors -- they seem like nuances, but they are actually extremely important factors which can change the magnitude and direction of many of the processes that come out.

Host: I'm afraid that's going to have to be the last word because, unfortunately, we're out of time today. But I'd like to thank my guests -- Robert Corell of the H. John Heinz III Center for Science, Economics and the Environment; Bret Schulte of U.S. News and World Report; and joining us by phone from Boulder, Colorado, is Roger Pielke, Sr., of the University of Colorado at Boulder; and by phone from West Lafayette, Indiana, Dev Niyogi of Purdue University. Before we go, I'd like to invite you to send us your questions or comments. You can reach us through our website at www.voanews.com/ontheline. For "On The Line," I'm Eric Felten.