Long-range forecast.

PositionWorld climate change - Interview

Among the thousands of scientists who have studied the onset of global warming, there is one--the chief of the 191 -nation Intergovernmental Panel on Climate Change (IPCC)--who ought to be in a better position to speak definitively on this subject than any other.

Unfortunately, the IPCC chief is not only an authority but a lightning rod for one of the planet's most politically volatile debates. When the IPCC issued its landmark year-2000 report projecting higher temperature increases than previously expected--and confirming the roles of the oil, coal, and automotive industries in exacerbating these increases--the U.S. government was not pleased. In 2001, under heavy political pressure from the Bush administration, IPCC chairman Robert Watson was forced out of his job. He was replaced by Rajendra Pachauri.

For this issue, Worldwatch senior researcher Janet Sawin interviewed both Watson and Pachauri on humanity's prospects for both mitigating and adapting to oncoming climate change.

Rajendra Pachauri

Interview with Dr. Rajendra Pachauri, Delhi, 31 October2002

World Watch: Which questions about climate change do you think are the most important to address in the coming years?

Rajendra Pachauri: There's a whole range of questions that are important, and you can't see them in isolation. You really need to understand the extent and nature of climate change to begin with. And that [requires] a very strong research underpinning. Then you need to look at what the impacts of those changes are going to be, and clearly those impacts vary from place to place, from ecosystem to ecosystem.

Therefore, what we need is much more focused and reliable research on a localized basis, and much more research on the specific impacts that each part of the world is likely to suffer. So, in general, I think what we really need to do is to come down from the aggregate to the particular. We are hoping that, by the time the Fourth Assessment Report takes shape, probably sometime in 2004 or 2005, we will have research output giving us this kind of detail at a regional level.

WW: How do you expect the next report, under your chairmanship, to differ from the previous one?

RP: First of all, one hopes that the science itself is advancing, so to that extent we hope we can go beyond the Third Assessment Report. The Third Report, in my view, is an excellent document, and I'd like to pay tribute to Bob Watson for having led this effort with so much academic rigor and vitality.

But, in the next report, I would like to see some greater emphasis on a few things. First, we should try to bring about much greater integration between the various elements. There should also be some greater level of consistency between the work of the different IPCC working groups. There are several cross-cutting themes--"uncertainties" is one of them--which we need to incorporate into the work of all three working groups. So I hope we can do a lot more to incorporate these cross-cutting themes in the next report. And finally, we need to go, to the extent possible, into much greater detail in looking at the socioeconomic impacts. We've done that in the Third Report, but we need to do much more in the next one.

WW: What are some of the "uncertainties"?

RP: If you look at, let's say, the extent of temperature change, or changes in precipitation that are likely to take place, we really have not been able [as we have progressed] to come up with estimates wherein the extent of uncertainty is reduced. Now we have created much better models and have much more sophisticated computers, so one hopes that these models will help us to reduce the uncertainties of the predictions that we come up with.

Even in assessing the impacts of climate change, it's not easy for us to reduce the level of uncertainty in the projections that we make. And the same is true of mitigation. After all, how technologies will evolve, and how rapidly these technologies will get disseminated, [will be affected by] a whole range of variables that we really don't have a perfect handle on.

So the theme of uncertainties runs through everything we are doing. And I think if we bring some degree of consistency to how we address uncertainties in each element of the next assessment, and look into how they are linked together, we'll be a little wiser.

WW: When you mention scientific uncertainties about impacts, are you talking about climate feedback effects such as increased water vapor and clouds?

RP: Absolutely. We are dealing with such complex systems, where we really don't know all the feedback effects. We don't know, in some cases, even the causal linkages. So all of that has to be addressed by the research that's being done.

WW: Do you believe that people around the world are already experiencing extreme weather events--such as flooding, droughts, and storms--as a result of human-induced global warming?

RP: I really can't say that on any scientific basis, but if you go purely by the recent record, the fact that 1998 was the warmest year in recorded history is something to worry about. Also the fact that droughts have become more prevalent. And the World Meteorological Organization has assessed that in the last 10 years the number of extreme events, the way they define them, has actually doubled. Now, if that's the case, then you clearly arrive at least at a tentative conclusion that there is a relationship between climate change and some of these extreme events. I'm not too sure we can say this with perfect or reasonable scientific certainty. But I hope that in the Fourth Assessment Report we can address this question also.

WW: There is growing pressure to undertake cost-benefit analyses of proposed actions to reduce the threats of climate change. Can this be seen as an effort to stall the process of...

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