Breakout Group Directions

Summit and Breakout Goal. Bring together ~150 invited users and providers of climate adaptation information from diverse climatological regions and economic sectors to provide insight into what is needed for effective climate adaptation and vulnerability assessment and how we should be organized to do that (public and private sectors – federal to local levels). These insights will be incorporated into a broad range of federal climate adaptation planning efforts, including the planning for Climate Adaptation Task Force and the U.S. Global Change Research Program, as well as build on related reports¹.

Breakout Approach and Structure. The Summit is not intended to debate what climate change will and won’t look like. But, using the best available information about projected climate change and impacts from the most recent Intergovernmental Panel on Climate Change and the U.S. Global Change Research Program Impact reports² (see Projected Climate Changes and Challenges box), the breakout participants are being asked to examine what needs, knowledge, and roles must be addressed in the near-term and long-term so you can ensure your community has reliable access to water, food, energy, transportation, and health resources and services, and would any of this change between the lower and higher emissions scenarios? For more clarity, these needs, knowledge, and roles are defined as:

1. NEEDS. What incentives and barriers should be addressed to encourage and facilitate effective climate adaptation and vulnerability assessment (e.g., funding, policy, legal, regulatory, legislative, actuarial, infrastructure, building and other standards and codes, training, cultural, etc)? Of these, which are significant, which are urgent, and which, if altered, could provide the most substantial leverage?


2. KNOWLEDGE. What knowledge (e.g., scientific, technical, information, tools, procedures, best practices, advice, etc) is needed by public and private decision makers (federal, state, local, etc) to adapt to climate change and assess vulnerability? How do we assure this knowledge is responsive to their needs, actionable, and effectively used?


3. ROLES. Who should provide this knowledge and leadership, how should it be delivered, and how should these providers be related to one another? What organizations, structures, and mechanisms might be needed for effectively communicating knowledge to action and vice versa?

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¹2008 NRC Restructuring Federal Climate Research to Meet the Challenges of Climate Change and Informing Decisions in a Changing Climate; 2008 UCAR Actions to Make Our Nation Resilient to Severe Weather and Climate Change; 2008, Coping with Climate Change: National Summit Proceedings, University of Michigan; 2010 America’s Climate Choices
²Intergovernmental Panel on Climate Change 2007 Climate Change Report and 2009 USGCRP Global Climate Change Impacts in the United States report

Projected Climate Changes and Challenges

Projected Climate Changes. According to the 2009 Global Climate Change Impacts in the US report, climate-related changes are already observed in the United States and its coastal waters, including increases in heavy downpours, rising temperature and sea level, rapidly retreating glaciers, thawing permafrost, lengthening growing seasons, lengthening ice-free seasons in the ocean and on lakes and rivers, earlier snowmelt, and alterations in river flows. These changes are projected to grow, with larger changes occurring in higher emission scenarios (Figure 1), including:

1. Temperature. U.S. average temperature has risen more than 2ºF over the past 50 years and is projected to rise more in the future; with more increases projected (Figures 2a and 2b). Many types of extreme weather events, such as heat waves and regional droughts will become more frequent and intense. (Figures 2c and 2d).


2. Precipitation. Precipitation has increased an average of about 5 percent over the past 50 years. Projections of future precipitation generally indicate that northern areas will become wetter, and southern areas, particularly in the West, will become drier (Figures 3a and 3b). The amount of rain falling in the heaviest downpours has increased approximately 20 percent on average in the past century, and this trend is very likely to continue, with the largest increases in the wettest places. (Figures 4a and 4b).


3. Storms. The destructive energy of Atlantic hurricanes has increased in recent decades. The intensity of these storms is likely to increase in this century (Figures 5a and 5b). In the eastern Pacific, the strongest hurricanes have become stronger since the 1980s, even while the total number of storms has decreased. Cold-season storm tracks are shifting northward and the strongest storms are likely to become stronger and more frequent.


4. Sea Level and Ice. Sea level has risen along most of the U.S. coast over the last 50 years, and will rise more in the future (Figure 6). Arctic sea ice is declining rapidly and this is very likely to continue (Figure 7).

Projected Climate Changes Challenges. These kinds of projected climate changes will combine with pollution, population growth, overuse of resources, urbanization, and other social, economic, and environmental stresses to create larger impacts than from any of these factors alone, affecting human well-being in many cases and changing regional and local comparative advantages for social and economic development. There will also likely be a variety of thresholds in the climate system and ecosystems that determine, for example, the presence of sea ice and permafrost, and the survival of species, from fish to insect pests, with implications for society. Based on the recent USGCRP Impacts Report, some of these impacts will include:

1. Water. Water is an issue in every region, but the nature of the potential impacts varies. Drought, related to reduced precipitation, increased evaporation, and increased water loss from plants, is an important issue in many regions, especially in the West. Floods and water quality problems are likely to be amplified by climate change in most regions. Declines in mountain snowpack are important in the West and Alaska where snowpack provides vital natural water storage.


2. Food Production. Many crops show positive responses to elevated carbon dioxide and low levels of warming, but higher levels of warming often negatively affect growth and yields. Increased pests, water stress, diseases, and weather extremes will pose adaptation challenges for crop and livestock production.


3. Coastal. Sea-level rise and storm surge place many U.S. coastal areas at increasing risk of erosion and flooding, especially along the Atlantic and Gulf Coasts, Pacific Islands, and parts of Alaska. Energy and transportation infrastructure and other property in coastal areas are very likely to be adversely affected.


4. Health. Harmful health impacts of climate change are related to increasing heat stress, waterborne diseases, poor air quality, extreme weather events, and diseases transmitted by insects and rodents. Reduced cold stress provides some benefits. Robust public health infrastructure can reduce the potential for negative impacts.

Scenarios of Future Carbon Dioxide Global Emissions and Concentrations FIGURE 1 The graphs show recent and projected global emissions of carbon dioxide in gigatons of carbon, on the left, and atmospheric concentrations on the right under five emissions scenarios. The top three in the key are IPCC scenarios that assume no explicit climate policies (these are used in model projections that appear throughout this report). The bottom line is a “stabilization scenario,” designed to stabilize atmospheric carbon dioxide concentration at 450 parts per million. The inset expanded below these charts shows emissions for 1990-2010 under the three IPCC scenarios along with actual emissions to 2007 (in black). Nakićenović and Swart; Clarke et al.; Marland et al.; Tans92
FIGURE 2a The maps and thermometers on this page and the next page show temperature differences (either measured or projected) from conditions as they existed during the period from 1961-1979. Comparisons to this period are made because the influence on climate from increasing greenhouse gas emissions has been greatest during the past five decades. The present-day map is based on the average observed temperatures from 1993-2008 minus the average from 1961-1979. Projected temperatures are based on results from 16 climate models for the periods 2010-2029, 2040-2059, and 2080-2099. The brackets on the thermometers represent the likely range of model projections, though lower or higher outcomes are possible. The mid-century and end-of-century maps show projections for both the higher and lower emission scenarios. The projection for the near-term is the average of the higher and lower emission scenarios because there is little difference in that timeframe.
FIGURE 2b The maps on this page and the previous page are based on projections of future temperature by 16 of the Coupled Model Intercomparison Project Three (CMIP3) climate models using two emissions scenarios from the Intergovernmental Panel on Climate Change (IPCC), Special Report on Emission Scenarios (SRES).91 The “lower” scenario here is B1, while the “higher” is A2.91 The brackets on the thermometers represent the likely range of model projections, though lower or higher outcomes are possible. Additional information on these scenarios is on pages 22 and 23 in the previous section, Global Climate Change. These maps, and others in this report, show projections at national, regional, and sub-regional scales, using well-established techniques.110
Projected Frequency of Extreme Heat (2080-2099 Average) FIGURE 2c Simulations for 2080-2099 indicate how currently rare extremes (a 1-in-20-year event) are projected to become more commonplace. A day so hot that it is currently experienced once every 20 years would occur every other year or more frequently by the end of the century under the higher emissions scenario.91
Number of Days Over 100 Degrees F FIGURE 2d The number of days in which the temperature exceeds 100°F by late this century, compared to the 1960s and 1970s, is projected to increase strongly across the United States. For example, parts of Texas that recently experienced about 10 to 20 days per year over 100°F are expected to experience more than 100 days per year in which the temperature exceeds 100°F by the end of the century under the higher emissions scenario.91
Observed Change in Annual Average Precipitation 1958 to 2008 FIGURE 3a While U.S. annual average precipitation has increased about 5 percent over the past 50 years, there have been important regional differences as shown above.
Projected Change in North American Precipitation By 2080-2099 FIGURE 3b The maps show projected future changes in precipitation relative to the recent past as simulated by 15 climate models. The simulations are for late this century, under a higher emissions scenario.91 For example, in the spring, climate models agree that northern areas are likely to get wetter, and southern areas drier. There is less confidence in exactly where the transition between wetter and drier areas will occur. Confidence in the projected changes is highest in the hatched areas.
Increases in Amounts of Very Heavy Precipitation (1958 to 2007) FIGURE 4a The map shows percent increases in the amount falling in very heavy precipitation events (defined as the heaviest 1 percent of all daily events) from 1958 to 2007 for each region. There are clear trends toward more very heavy precipitation for the nation as a whole, and particularly in the Northeast and Midwest. Updated from Groisman et al.113
Projected Changes in Light, Moderate, and Heavy Precipitation (by 2090s) FIGURE 4b The figure shows projected changes from the 1990s average to the 2090s average in the amount of precipitation falling in light, moderate, and heavy events in North America. Projected changes are displayed in 5 percent increments from the lightest drizzles to the heaviest downpours. As shown here, the lightest precipitation is projected to decrease, while the heaviest will increase, continuing the observed trend. The higher emission scenario91 yields larger changes. Projections are based on the models used in the IPCC 2007 Fourth Assessment Report.
Figure 5a Frequency histograms of hurricane intensities in terms of central pressure (mb) aggregated across all idealized hurricane experiments in the Knutson and Tuleya (2004) study. The light curve shows the histogram from the experiments with present-day conditions, while the dark curve is for high CO2 conditions (after an 80-year warming trend in a +1% per year CO2 experiment). The results indicate that hurricanes in a CO2-warmed climate will have significantly higher intensities (lower central pressures) than hurricanes in the present climate.
Figure 5b As in Figure 3.8, but for near-hurricane precipitation, estimated as the average precipitation rate for the 102 model grid points (32,700 km2 area) with highest accumulated rainfall over the last 6 hours of the 5-day idealized hurricane experiments in Knutson and Tuleya (2004). The results indicate that hurricanes in a CO2-warmed climate will have substantially higher core rainfall rates than those in the present climate. From Knutson and Tuleya (2008).
Relative Sea-Level Changes on U.S. Coastlines, 1958 to 2008 FIGURE 6 Observed changes in relative sea level from 1958 to 2008 for locations on the U.S. coast. Some areas along the Atlantic and Gulf coasts saw increases greater than 8 inches over the past 50 years.
Arctic Sea Ice Extent (Annual Average) FIGURE 7a Observations of annual average Arctic sea ice extent for the period 1900 to 2008. The gray shading indicates less confidence in the data before 1953.
Arctic Sea Ice Annual Minimum FIGURE 7b Arctic sea ice reaches its annual minimum in September. The satellite images above show September Arctic sea ice in 1979, the first year these data were available, and 2007.

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