Impacts on Coastal Areas

Q28. On page 15 of your written testimony you also state the following:

"Coastal Areas: Even if concentrations of greenhouse gases are stabilized in the future, sea level would continue to rise long after, perhaps for several centuries, and reach levels much higher than projected for the next 100 years. For example, after an equivalent doubling of CO2, the IPCC expects sea level to rise by 6 - 38 inches over the next century, with a "best estimate" of 20 inches, but the equilibrium sea level rise several centuries in the future is estimated to be at least 6 feet. Rising sea level erodes beaches and coastal wetlands, causes the gradual inundation of low lying areas, leading to human habitat loss and increasing the vulnerability of coastal areas to flooding from storm surges and intense rainfall. The IPCC estimates that 20 inches of sea level rise would double the population at risk from storm surges, from roughly 45 million at present to over 90 million world-wide. A three-foot rise would triple the number of people exposed. Increases in coastal area populations are likely to further increase the number of people at risk.

• Along U.S. coasts, a 20-inch rise could inundate more than 5000 square miles of dry land and an additional 4000 square miles of wetlands if not protective measures are taken. A three-foot rise would have greater impact, inundating much of the Southern tip of Florida among other

areas.

Internationally, low-lying areas, such as parts of the Maldives and Bangladesh, would be completely inundated by a three-foot sea level rise, creating large numbers of environmental refugees, which put stress on governments and social structures. 72 million people in China would be affected, assuming existing levels of coastal development."

Please document these statements.

A28. The IPCC estimates of how much the sea will rise are found in the 1995 report, Climate Change 1995 - The Science of Climate Change (copy attached). All of the statements on the consequences of sea level rise are found in the 1998 report Regional Impacts of Climate Change except for the ones about the number of peoples at risk sue to flooding. The latter comer from Chapter 9 of the 1995 IPCC report Climate Change 1995 - Impacts; Adaptations and Mitigation of Climate Change: Scientific-Technical Analysis. This chapter was provided as an attachment for Q27 above. Also from this chapter are the estimates of the areas of various low lying nations that would be inundated by a rise in sea level.

The estimates of the amount of land flooded with a 20-inch global sea level rise

(Coastal Management, Volume 19, pages 171-204. They are also posted on the internet at http://www.erols.com/jtitus/Holding/NRJ.html. For a map of the impact on South Florida, see http://www.erols.com/dickpark/SLAMM.htm, which was prepared using the model reported by Park, et al. in EPA's 1989 Report to Congress on the Potential Impacts of Global Climate Change on the United States.

Impacts on Agriculture and Food Supply

Q29. On pages 15 and 16 of your written testimony you also state the following:

A29.

"Agriculture and Food Supply: Agriculture is highly dependent on a number of variables that are likely to be affected by climate change, including weather patterns, longer term patterns of climate variability, and, most importantly, water availability. Climate change is likely to lead to increased crop yields in many areas, but decreased yields in others, even for the same crop. The magnitude of these changes can exceed +/- 30 or 40 percent for some crops and locations. Despite these potentially large changes in yields, average global food production is not expected to change substantially. This is because farming practices are considered to be highly adaptable to different climates, because production of important food crops can shift to new locations in response to changes in climate, and because CO2 has beneficial effects for plant photosynthesis and water use efficiency that can offset some deleterious effects of changes in climate. Impacts are likely to vary considerably across regions and some regions may suffer substantial reductions in agricultural production. In general, developing countries are more vulnerable to losses than are developed countries.

Large reductions in soil moisture could significantly reduce flexibility in crop distribution and increase demands on water resources

infrastructure.

Increases in the range of pest habitat could increase vulnerabilities to pests and demand for, and use of, pesticides.

In the United States, large areas of the eastern and central regions of the country face moderate to severe drying. Drought could become more frequent, particularly in the Great Plains."

Please document these statements.

Chapter 13 of the document Climate Change 1995 - Impacts, Adaptations and
Mitigation of Climate Change: Scientific-Technical Analyses summarizes the
IPCC's most recent findings on impacts and adaptations of agriculture in a
changing climate. A copy of this chapter of the document has already been

Unresolved Scientific Issues Relating to the Modeling of the Impact of Future Potential Greenhouse Gas Emissions on Global Temperature

Q30. What are the greatest unresolved scientific issues relating to the modeling of the impact of future potential greenhouse gas emissions on global temperature in order of importance?

Q31. How, by whom and where are the issues identified in the response to question 29 addressed by the U.S. Global Change Research Program?

Unresolved Scientific Issues Involved in Projecting Future Temperature Increases and the Impacts Thereof

Q32. What are the greatest unresolved scientific issues involved in projecting future temperature increases and the impacts thereof?

Q33. How, by whom and where are the issues identified in the response to question 32 addressed by the U.S. Global Change Research Program?

Combined answers to Question 30-33: There is no prioritized listing of the most important unresolved questions relating to predicting the effect of future emissions on global climate. However, there is general agreement on the major issues, as reflected in part by the results of the World Climate Research Program conference last year, a meeting at which the US scientific community was well represented. In addition, based on a study sponsored by the USGCRP, a more directed breakdown of science questions and research priorities, titled Global Change: Pathways for the Next Decade, is to be released by the National Research Council later this spring. Issues relating to modeling of the climatic response to greenhouse gases are intimately tied to these process-related questions, as models can only be as good as our understanding of the processes they represent. Some of the major unresolved issues are as follows:

Role of Natural Fluctuations, such as El Niño, in Climate and Their Predictability: Any temperature signal resulting from forcing by greenhouse gases must manifest itself against the background of natural variability. For example, we know that the present El Niño event is part of a natural phenomenon that is a characteristic of the distribution of the Earth's oceans and land masses. However, the issue of whether the duration and frequency of El Niño events has been affected by greenhouse gases is an open question. Other natural climate patterns acting on longer periods than El Niño will also influence the planet's response to greenhouse gases. For example, the North Atlantic Oscillation, a decade-scale seesaw in atmospheric pressure between the North and South Atlantic, has a dramatic influence on the

Examining the issues of natural climate variability requires analysis of long-term data records and obtaining new data on a global basis. NASA is undertaking extensive reprocessing of existing satellite data to produce the most consistent global records possible as part of its Pathfinder program. Longer-term records are produced through analyses of existing surface records by NOAA and through support for paleoclimatic investigations through NSF and NOAA. This year also marks the beginning of a new era of satellite observations of the Earth with the launch of the EOS AM-1 platform, which will bring a comprehensive suite of sensors to studies of the ocean, land, atmosphere and cryosphere.

Programs examining the mechanisms and predictability of climate variations are ongoing, and their benefits are being realized in the predictions of the 1997-98 El Niño. Research into making even longer-range and more globally extended predictions of El Niño and other seasonal-to-interannual climate phenomena are central parts of the scientific programs of NOAA, NASA and NSF, done in coordination with the international Program on Climate Variability and Predictability (CLIVAR).

Models occupy a central role in both the analysis of natural and anthropogenic climate change. Research into advancing the capabilities of climate models is a prominent component of the science programs of DOE, NSF, NOAA and NASA.

Impact of Aerosols on the Climate System: Aerosols, defined as a suspension of liquids or solids in a gas, can have a marked influence on climate and represent a major uncertainty in our ability to predict climate. They include sulfates, soot, biomass smoke, nitrates, and mineral dust. They exert a direct effect on climate by reflecting, absorbing and emitting radiation, and an indirect effect by influencing the properties of clouds. Overall, they exert a cooling influence over large but localized regions of the globe. These regional changes to the energy balance influence the larger-scale effects by modifying the circulation of the atmosphere.

Several international projects have measured the impact of both natural and anthropogenic aerosols on the radiative balance of the Earth. Direct measurements of aerosol properties have enhanced confidence in estimates of their effects on the global radiative balance. Significant new measurements of aerosols are planned as part of USGCRP. EOS-AM observations will include measurements of aerosol and cloud properties, and the objective of the EOS CHEM mission scheduled for launch in 2002 is to provide comprehensive observations of the chemistry and dynamics of the Earth's atmosphere from the ground to the stratosphere.

Role of the Ocean in Climate Change: Because the upper three meters of the ocean have a heat capacity equal to that of the entire atmosphere, the ocean will exert a strong influence on the timing and extent of any climate change. As such, the role of the ocean in climate change, particularly on longer time scales, remains