Administration's Scientific Assessment Of Global Change On U.S.

May 29: The National Science and Technology Council (NSTC), together with the U.S. Climate Change Science Program (CCSP), announced the release of a scientific assessment (Scientific Assessment of the Effects of Global Change on the United States) of the effects of global change on the United States, with special emphasis on climate change. Additionally, an updated strategy, the Revised Research Plan for the U.S. Climate Change Science Program," was also released.

Dr. Sharon Hays, Associate Director and Deputy Director for Science for the White House Office of Science and Technology Policy said, "This assessment represents a comprehensive look at the effects of climate change for the United States and will be yet another tool for the Nation’s decision-makers to use when planning for the future." Dr. William Brennan, Acting Director of CCSP said, "Recognizing that this report reflects a snapshot of current research in an area of rapidly increasing knowledge, it’s important to outline an up-to-date strategy for continued research on climate change. The updated research plan that is also being released today does that."

The assessment summarizes and integrates recent findings from several Synthesis and Assessment Products of the CCSP as well as from assessments of the Intergovernmental Panel on Climate Change (IPCC). Analyzing current and future trends in climate for the United States, the report assesses the present understanding of the impacts of climate change on key sectors of the Nation, such as water resources, transportation, agriculture, ecosystems, and human health.

Accompanying the scientific assessment is an updated research plan for the CCSP that provides direction for addressing remaining uncertainties in climate science, including impacts at regional scales and adaptation options. The plan also emphasizes the need for strengthened communication of scientific studies to decision-makers across the United States. An extended opportunity for public review was provided during the development of the revised plan.

The assessment points out that it addresses not only climate change, but also other change in the global environment -- including water resources, oceans, atmospheric chemistry, land productivity, and ecological systems -- that may alter the capacity of Earth to sustain life. This broader set of changes is referred to as ‘global change,’ as defined in the Global Change Research Act. It is indicated that, "The conclusions in this assessment build on the vast body of observations, modeling, decision-support, and other types of activities conducted under the auspices of CCSP. It draws on findings from previous assessments of the science, including reports and products by the Intergovernmental Panel on Climate Change (IPCC), CCSP, and others. Together with CCSP’s 21 Synthesis and Assessment Products, this is arguably the most comprehensive assessment to date of the effects of global change, and especially climate, on the United States." Among the many conclusions:

• U.S. average temperatures increased during the 20th and into the 21st century, and the last decade is the warmest in more than a century of direct observations in the United States.
  
• Continued greenhouse gas emissions at or above current rates are expected to cause further warming and to induce many changes during the 21st century that will very likely be larger than those of the last century.
  
• It is very likely that temperature increases, increasing carbon dioxide levels, and altered patterns of precipitation are already affecting U.S. water resources, agriculture, land resources, biodiversity, and human health, among other things. And it is very likely that climate change will continue to have significant effects on these resources over the next few decades and beyond.
  
• The report presents key findings of climate impacts on the United States in the areas of: The Natural Environment; Agriculture; Water; Population and Society; Health; Energy; and Transportation.

The report indicates that regarding climate extremes, "Human activities have also likely influenced extremes in temperature. Many indicators of climate extremes -- including the annual numbers of frost days, warm and cold days, and warm and cold nights -- show changes that are consistent with warming. Studies for North America suggest that, in the future, abnormally hot days and nights and heat waves are very likely to become more frequent and that cold days and cold nights are very likely to become much less frequent. In addition to temperature extremes, analyses indicate that, on average for North America, precipitation is likely to be less frequent but more intense. It is also likely that future hurricanes will become more intense, with larger peak wind speeds and more heavy precipitation associated with ongoing increases in tropical sea surface temperatures. However, projections of changes in hurricane frequency remain very uncertain. "

Access an Executive Summary of the report (click here). Access a Summary of Findings (click here). Access the complete 271-page report (click here). Access an Executive Summary of the Revised Research Agenda (click here). Access the complete 98-page Revised Research Agenda (click here). Access the NSTC website (click here). Access the CCSP website (click here). [*Climate]