Climate Change: Background and Implications American Public Works Association Conference on Climate Change Tempe, AZ April 9, 2008 Peter Schultz U.S. Climate Change Science Program Office, Director
Outline Whirlwind tour of the current state of science Some examples of implications for public works Many figures courtesy of CCSP and IPCC
Synthesis and Assessment Products
Courtesy NASA/GISS
See CCSP S&A Product 1.1
Confirmation from Multiple Sources of Information Bore Hole Temperature Reconstructions
Causes of Global Warming
Causes of Global Warming Most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations. (IPCC, 2007) IPCC SPM
Temperature Projections for 2090-2099 3 Different Emission Scenarios B1 N. America, Scenario A1B, in Summer & Winter Winter A1B A2 Summer IPCC WG1 Ch11
Hot Days to Become Much More Common Return frequency of 1-in-20-yr days by 2090-2099 See CCSP S&A Product 3.3 (forthcoming)
Urban Heat Island Effect Exacerbates Global Warming Day Downtown Atlanta Night Red ~ 100 120 F Green ~ 75 100 F Blue ~ 60 70 F See CCSP S&A Product 4.6 (forthcoming)
Observed Precipitation Trends
See CCSP S&A Product 3.3 (forthcoming)
Gully Washer Rains Tend to Become More Common Return frequency of 1-in-20-yr events by 2090-2099 See CCSP S&A Product 3.3 (forthcoming)
DJF Average Precipitation Projections 2090-2099 relative to 1990-1999 JJA IPCC, scenario A1B, multi-model
Lake Mead See CCSP S&A Product 3.3 (forthcoming)
Vulnerability to extended drought increasing as population growth and economic development create more demands from agricultural, municipal, and industrial uses, resulting in frequent over-allocation of water resources See CCSP S&A Product 3.3 and 4.3 (forthcoming)
See CCSP S&A Product 3.3 (forthcoming)
Milly et al, 2005
Changing Water Supply Snow Water Change (% change; 1950-1997 for April 1) Changing Runoff Peak (1948-2000) Mote et al, 2005 Stewart et al, 2004 See CCSP S&A Product 4.3 (forthcoming)
U.S. Water Withdrawal and Population
Water Management Runoff and evaporation changes likely to affect reservoir performance, water management effectiveness, etc. Declines in surface water might not be able to be offset by increasing groundwater withdrawal due to decreasing groundwater recharge Increases in water-use efficiency likely to continue, which will help reduce impacts of climate change on water resources. Water quality likely to be affected in future by climate change; however, to-date other factors have been more important Increases in intense rains will increase sediment and pollutant loading Saltwater intrusion into groundwater likely in some coastal regions Changes could impose huge costs on water treatment infrastructure. Less reliable water supplies likely to create challenges for managing urban water systems. Examples of vulnerable U.S. regions include: western systems relying on capturing snowmelt runoff New York area, as a consequence of greater water supply variability Island and coastal regions susceptible to saline intrusion Past not a good guide to the future!
NAST, 2001 Multiple interacting factors a key concern, e.g., combined effects of demographic, infrastructural, and wealth shifts together with changes in hurricanes, sea level rise, river flooding, wave heights, etc.
Hurricanes & climate change
2005 Hurricane Season
See CCSP S&A Product 3.3 (forthcoming)
20 cm (7 inches) in a century Huge uncertainty associated with melting ice sheets
See CCSP S&A Product 4.1 (forthcoming)
Increasing Fire Threat A scene outside Steamboat Springs Pine Bark Beetle See CCSP S&A Product 4.2 (forthcoming)
Health Effects and Adaptation to be addressed by later speakers Temperature Mortality Relationships 11 U.S. Cities See CCSP S&A Product 4.6 (forthcoming)
Energy Demand Decline in winter heating; increase in summer cooling Increase in peak demand for elec. in most regions, except Pac NW Northern regions (blue-yellow) to reduce consumption of heating fuel more than increases in consumption of elec.; Reverse true in the south Increase in energy consumed for refrigeration and industrial cooling Increase in energy consumed for climate-sensitive processes, such as irrigation pumping Climate Zones
Energy Supply Direct impacts from increased intensity of extreme weather events Reduced water supplies in regions dependent on water resources for hydropower and/or thermal power plant cooling Facility siting decisions affected by changing conditions Positive or negative impacts on production of biomass, wind power, or solar energy where climate conditions change.
Transportation Warmer / less snowy winters: improve ground and air transportation reliability decrease the need for winter road maintenance More intense winter storms could increase risks for traveler safety and require increased localized snow removal. Summer heat waves: railroad track buckling/kinking road softening and traffic-related rutting Increased frequency of extreme precipitation, river, and coastal flooding events may contribute to: increased accident rates more road closures due to flooding and landslides (single point failures) more frequent short-term flooding and bridge scour more culvert washouts exceedence of storm drain capacity
Transportation Great Lakes: fewer ice threats to navigation reduced water depth would lead to the need for light loading Far northern transportation infrastructure particularly vulnerable permafrost degradation season for transport by barge extended season for ice roads compressed Gulf Coast and southeastern transportation vulnerability increasing Some of these risks can be offset by proactive adaptive measures and improvements in technology and information systems. Costs of proactive adaptation in vulnerable regions generally much less than the costs of reactive responses.
CCSP Strategic Planning Interim Revised Research Plan release in late May 08 Developing underpinnings of a new strategic plan during 08 and early 09 - Building block approach - Listening to science & stakeholder communities We want to hear from you! so that we can better focus and frame the research we do and the information we provide to better meet your needs.
Thanks!