Climate Change Science Program: Difference between revisions

Revision as of 12:37, 17 March 2016

Revision as of 09:10, 19 March 2016

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* The Arctic has recently been warming about as rapidly as it has ever warned throughout the entire record of past Arctic climate.

* The loss of sea ice during summers over the last few decades is highly unusual compared to the last few thousand years. Changes in Earth's orbit alone would have increased summer sea ice.

* Sustained warming of at least 2 to 7 °C would be likely to eventually melt the entire [[Greenland ice sheet]], which would raise sea level by several meters.

* The past tells us that when thresholds in the climate system are crossed, climate change can be very large and very fast. No one know whether human activities will trigger such events in the coming decades and centuries.

====Attribution of the causes of observed climate change (SAP 1.3)====

NOAA released ''Re-Analyses of Historical Climate Data for Key Atmospheric Features: Implications for attribution of causes of observed change''<ref>[http://www.climatescience.gov/Library/sap/sap1-3/default.php CCSP, 2008] Reanalysis of Historical Climate Data for Key Atmospheric Features: Implications for Attribution of Causes of Observed Change. Randall Dole, Martin Hoerling, and Siegfried Schubert (editors). National Climatic Data Center, Asheville, NC, 156 pp.</ref> in December 2008. According to the report, from 1951 to 2006 the yearly average temperature for North America increased by 1.6° Fahrenheit, with virtually all of the warmingsince 1970. During this period, the average temperature has warmed approximately 3.6&nbsp;°F over Alaska, the Yukon Territories, Alberta, and Saskatchewan, but no significant warming occurred in the southern United States or eastern Canada. More than half of the warming of North America is likely (more than 66 percent chance) to have resulted from human activity.

There is less evidence that precipitation is changing. The report found no significant trend in North American precipitation since 1951, although there have been substantial changes from year to year and even decade to decade. Moreover, it is unlikely that a fundamental change has occurred in either how often or where severe droughts have occurred over the continental United States during the past half-century. Nevertheless, drought impacts have likely become more severe in recent decades. It is likely that the impacts have been more severe because the recent droughts have lasted a few years, and because warmer temperatures have created stresses in plants, which make them more vulnerable.

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DOE ''released Effects of Climate Change on Energy Production and Use in the United States''<ref>[http://www.climatescience.gov/Library/sap/sap4-5/default.php CCSP, 2007]. Effects of Climate Change on Energy Production and Use in the United States. Thomas J. Wilbanks et al. (editors). Department of Energy, Office of Biological & Environmental Research, Washington, DC., USA, 160 pp.</ref> (SAP 4.5) in October 2007. The report concludes that the possible impacts of climate change on energy production are important enough to start considering how to adapt. The report's executive summary summarized the report with three questions and answers:

* ''How might climate change affect energy consumption in the United States?'' The research evidence is relatively clear that climate warming will mean reductions in total U.S. heating requirements and increases in total cooling requirements for buildings. These changes will vary by region and by season, but they will affect household and business energy costs and their demands on energy supply institutions. In general, the changes imply increased demands for electricity, which supplies virtually all cooling energy services but only some heating services. Other effects on energy consumption are less clear.

* ''How might climate change affect energy production and supply in the United States?'' The research evidence about effects is not as strong as for energy consumption, but climate change could affect energy production and supply (a) if extreme weather events become more intense, (b) where regions dependent on water supplies for hydropower and/or thermal power plant cooling face reductions in water supplies, (c) where temperature increases decrease overall thermoelectric power generation efficiencies, and (d) where changed conditions affect facility siting decisions. Most effects are likely to be modest except for possible regional effects of extreme weather events and water shortages.

* ''How might climate change have other effects that indirectly shape energy production and consumption in the United States?'' The research evidence about indirect effects ranges from abundant information about possible effects of climate change policies on energy technology choices to extremely limited information about such issues as effects on energy security. Based on this mixed evidence, it appears that climate change is likely to affect risk management in the investment behavior of some energy institutions, and it is very likely to have some effects on energy technology R&D investments and energy resource and technology choices. In addition, climate change can be expected to affect other countries in ways that in turn affect U.S. energy conditions through their participation in global and hemispheric energy markets, and climate change concerns could interact with some driving forces behind policies focused on U.S. energy security.

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The [[United States Department of Transportation]] released ''Impacts of Climate Variability and Change on Transportation Systems and Infrastructure—Gulf Coast Study''<ref>[http://www.climatescience.gov/Library/sap/sap4-7/default.php CCSP, 2008] Impacts of Climate Change and Variability on Transportation Systems and Infrastructure: Gulf Coast Study, Phase I. M. J. Savonis, V.R. Burkett, and J.R. Potter (editors). Department of Transportation, Washington, DC, USA, 445 pp.</ref> (SAP 4.7) in March 2008. The report was prepared by Michael Savonis of the Federal Highway Administration, Joanne Potter (a consultant to DOT), and Virginia Burkett of USGS.

The premise of SAP 4.7 was that climate is changing. Sea levels in the Gulf of Mexico are likely to rise by two to four feet over the next 50 to 100 years from the combination of climate-induced warming and land subsidence. Tropical storms are anticipated to increase in intensity and the number of heavy precipitation events is expected to increase, raising prospects of flooding and structural damage. And the number of very hot days (i.e., >90&nbsp;°F) could rise by 50%.

The report concluded that the expected impacts of these climate effects on transportation are striking. A significant portion of the region's road, rail, and port network is at risk of permanent flooding if sea levels rise by four feet. This includes more than 2,400 miles (27%) of the major roads, 9% of the rail lines, and 72% of the ports. More than half (64% of interstates; 57% of arterials) of the area's major highways, almost half of the rail miles, 29 airports, and virtually all of the ports are subject to temporary flooding and damage due to increased storm intensity. The increase in daily high temperatures could increase wear on asphalt and the potential for rail buckling. Construction costs are likely to increase because of restrictions on workers on days above 90 degrees Fahrenheit.

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* [[Effects of global warming]]

* [[National Assessment on Climate Change]]

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==Notes==