and high-latitude loss of stratospheric ozone, and quantified the impact of In response to the 1990 IPCC Assessment Report which highlighted the potential importance of sulfate aerosols, several USGCRP agencies established research programs to better understand the role of aerosols in the Earth's climate. While key uncertainties still remain, these programs have led to a considerable improvement in our understanding and important convergence between observations and model simulations. The scope and balance of activities in the USGCRP will need to continue to evolve in the future just as they have in the past. This program must, and does, devote significant resources to space and in situ observations and data management in addition to process studies, modelling and analysis. To understand climate change, both natural and anthropogenic, USGCRP will have to place an increasing emphasis on understanding the consequences of climate change at the regional level and on some key socio-economic aspects, including the costs and benefits of reducing greenhouse gas emissions. To perform such an analysis will require, among others, improved techniques to value biological resources and biodiversity, both in terms of market and non-market value, and understanding barriers to the diffusion of technologies into the market place. We need to maintain the high quality science-driven USGCRP that emerged during the Reagan and Bush Administrations and which has been strongly supported by the Clinton Administration. The need to observe, understand and predict the Earth system has been given even greater emphasis by the latest set of findings from the IPCC. In particular, we need to improve our ability to predict climate change at the regional level, and we need an increased emphasis on understanding the consequences of climate change. The latter will require more research into basic ecological processes, development of more sophisticated modeling frameworks, and the establishment of improved capabilities for ground- and space-based monitoring and data management. In addition, we need better databases for vulnerability assessment and planning of adaptation, including data on population trends, resource utilization, and the value of natural and economic resources. The development of a broad range of sectoral and integrated modeling capabilities is also required to determine the potential significance of global change for the United States and the world. Summary The scientists of the world have agreed that climate is changing and that there is a discernible human influence. However, policymakers are faced with responding to the risks posed by anthropogenic emissions of greenhouse gases in the face of scientific uncertainties about the details the magnitude, regional impacts, and rate of climate change. Climate-induced environmental changes cannot be reversed quickly, if at all, due to the long time scales associated with the climate system. Ultimately, it is not for scientists but rather for decisonmakers to decide what "dangerous" means under the Framework Convention on Climate Change. Decisions taken during the next few years may limit the range of possible policy options in the future because high near-term emissions would require deeper reductions in the future to meet any given target concentration. Delaying action might reduce the overall costs of mitigation if potential technological advances are vigorously pursued in the interim, but could increase both the rate and the eventual magnitude of climate change, and hence the adaptation and damage costs. Policymakers will have to decide on the degree to which they want to take precautionary measures by mitigating greenhouse gas emissions and enhancing the resilience of vulnerable systems by means of adaptation. Uncertainty does not mean that a nation or the world. community cannot position itself better to cope with the broad range of possible climate changes or protect against potentially costly future outcomes. Delaying such measures may leave a nation or the world poorly prepared to deal with adverse changes and may increase the possibility of irreversible or very costly consequences. Options for adapting to change or mitigating change that can be justified for other reasons today (e.g., abatement of air and water pollution) and make society more flexible or resilient to anticipated adverse effects of climate change appear particularly desirable. Finally, it is precisely the fact that aspects of global climate change remain uncertain that argues most strongly for a comprehensive research effort. Dealing with the issue of climate change requires a greater understanding of the Earth system. The complexity of the Earth system, a complexity agreed on by all those who have testified today, makes this an immense scientific challenge. I think nearly all the panelists would also agree that strong Federal science programs and Federally funded University research are critical to meet this challenge. The sheer magnitude of this task, combined with the seriousness of the potential consequences of climate change, provide a clear justification for the maintenance of a strong national research program focused on this issue. Chairman WALKER. Thank you. Dr. Michaels? STATEMENT OF DR. PATRICK MICHAELS, DEPARTMENT OF ENVIRONMENTAL SCIENCES, UNIVERSITY OF VIRGINIA, CHARLOTTESVILLE, VIRGINIA Dr. MICHAELS. Thank you. I would hope that I get a few seconds while we figure out how to get the screen down. Chairman WALKER. I'm going to do that. Dr. MICHAELS. Okay. That's magnificent. I'm going to switch microphones, if you don't mind. Well, I hope you have your binoculars with you. Sorry about this. These are things that are beyond our control. I would like to address the issue of climate change, if I could, from perhaps a slightly different perspective than Dr. Watson. But I would like to say that this is a hearing about gathering facts, a hearing about what we understand about climate change and what we need to know in the future. You can put me down as one scientist who believes firmly that in the collection of facts on the issue of global climate change and believes that in the future, we should do whatever we can to attempt to improve our understanding of the atmosphere and our ability to model it. In my five minutes, I'd just like to give you seven examples of how the facts have changed the issue of global climate change in the last five years. I think they have changed the scenario of climate change from what I would call the dangerous scenario to the moderate climate change scenario. And I offer you as an example this chart right here, which compares the performance of the general circulation climate model that was cited very heavily in the report for the 1992 earth summit that was created by the IPCC. These are the temperatures that run out of that model, if you run it with the carbon dioxide concentrations that have evolved over the 20th century, and these are the temperatures in the northern hemisphere underneath. There is a clearly a mismatch here. This mismatch was pointed out by the data. It was pointed out by a data stream that we think may be degrading. In the United States, we have problems now with our large-scale temperature network. And I urge this Committee to do everything they can to make sure that that network remains very high quality. When the disparity was pointed out between the climate models and the observed temperature data, it was thought that sulfate aerosols were a sufficient explanation for the lack of warming. Here is the satellite temperature history that Dr. Christy is going to show you very soon from the southern half of the planet. There are no sulfate aerosols to speak of in the southern half of the planet. Yet, this half of the planet is in fact cooling significantly. Sulfate aerosols cannot be the cause of the cooling in the southern half of the planet. And the satellite records that we have are exceedingly accurate. This is the comparison of the temperature between 5,000 and 30,000 feet, as measured by weather balloons and as measured by satellite. There is no doubt that it is finding a cooling in the southern hemisphere. And finally, we contest whether sulfates in fact are responsible for the failure. In only one item in the scientific literature has anyone ever asked the following question-were the models that predicted the large warmings failing because they didn't have sulfates in them? I know I have very, very few seconds left, and I will merely tell you that we can examine that mathematically and we could look for where the models do very well, which would be the green light, and where the models do make mistakes, numbered categories 2, 3 and 5. This is a place with no sulfates whatsoever. The models should do very well here. All they do is either predict no change where no change was observed, predict change that didn't occur, or predict change that was opposite to what occurred. And here is the model where the sulfate effect should be the greatest. The large green bar is the largest, best performance in the entire model. When you test the model without sulfates in it, it performs best where the sulfates are. Ladies and gentlemen, the thing that has caused the fever in this model, or the illness in this model, is not sulfates. So now we have a new explanation, that somehow ozone depletion in the stratosphere is responsible for the failure of the warming. And that explains the reason that the satellite temperatures do not show warming while the surface temperatures do. Well, this is a graph of the satellite temperatures, which are the open circles, and the ground-based temperatures, which are the closed circles on the right. The areas of ozone depletion are the lower southern hemisphere, and it turns out the records match up perfectly. And there's some depletion in the high northern hemisphere. In the equator, in the tropical regions, there is no stratospheric ozone depletion. And yet the model, the temperature in the satellite and the temperature of the surface do not match. Ozone is not going to explain the disparity between the satellite record and the surface temperature, although that is going to be the next best explanation. I would also like to caution you that we've heard about extreme rainfall events increasing. I'd just like to show you a little bit of data on that, in closing. This is a graph of the percent of rainfall from rainstorms that are more than two inches and it's going up. This is from Tom Karl. This was all over the newspaper as a sign that this was caused by the greenhouse effect. The largest increase occurs from 1930 to 1950, which is long before the greenhouse effect could have done this. This is typical of what we see. We hear stories about bad things being caused by climate change, and when we examine the data closely and do the true scientific test, did the change occur because of the greenhouse effect? In this case, it does not fulfill it. Finally, there's the matter of exaggeration. Rainfall events of more than two inches are not torrential. In fact, 70 percent of all rainfall that is more than two inches turns out to be less than three inches in the summer. Almost all of those rainfall events are beneficial. Well, I leave you with the flavor of this. I'm sure we're going to discuss a lot more of this later. I would merely like to say that the reason that all these facts have come out is because of data, because people were very, very careful to keep data sets intact. We need to do this in the future. We need to take a look at our sensing from the remote sensors up in space. And I'll be happy to talk about this later. Thank you. [The prepared statement of Dr. Michaels follows:] |