by Brianna Crandall — May 9, 2014—The White House released on May 6 the third U.S. National Climate Assessment, which is mandated at least every four years by the Global Change Research Act of 1990. The comprehensive scientific assessment covers current thought on climate change and its existing and expected impacts across every region of the United States and major sectors of the U.S. economy, with the goal of better informing public and private decision-making at all levels.
The report has obvious importance for towns and facilities located along the coast or in extreme weather areas, but also for all buildings in light of an increasing scarcity of water and changes in normal climate/weather expectations around the nation and the world.
Developed over four years by hundreds of the nation’s top climate scientists and technical experts, and informed by thousands of inputs from the public and outside organizations, the Climate Assessment echoes the president’s 2013 Climate Action Plan, which acknowledges that even as the nation acts to reduce the greenhouse-gas pollution that is driving climate change, we must also empower the nation’s communities, businesses, and individual citizens with the information they need to cope with the changes in climate that are already underway.
The White House issued a “FACT SHEET: What Climate Change Means for Regions across America and Major Sectors of the Economy” containing a summary of major points of the report. Some of the most pertinent are listed below.
Climate-Change Impacts in Regions across America
This section addresses each region of the United States, with a more general statement about all of the coastal areas.
- Coasts: “More than 50% of Americans—164 million people—live in coastal counties, with 1.2 million added each year… Humans have heavily altered the coastal environment through development, changes in land use, and overexploitation of resources. Now, the changing climate is imposing additional stresses…” “Coastal lifelines, such as water supply infrastructure and evacuation routes are increasingly vulnerable to higher sea levels and storm surges, inland flooding, and other climate-related changes.” (NCA Highlights: Coasts; NCA Highlights: Overview)
Climate-Change Impacts on Key Sectors of Society and the U.S. Economy
This section addresses the impacts on key sectors of society and the economy such as Health, Transportation, Energy, Water, Agriculture, Ecosystems and Oceans.
- Energy: “Extreme weather events are affecting energy production and delivery facilities, causing supply disruptions of varying lengths and magnitudes and affecting other infrastructure that depends on energy supply. The frequency and intensity of certain types of extreme weather events are expected to change. Higher summer temperatures will increase electricity use, causing higher summer peak loads, while warmer winters will decrease energy demands for heating. Net electricity use is projected to increase. Changes in water availability, both episodic and long-lasting, will constrain different forms of energy production. In the longer term, sea level rise, extreme storm surge events, and high tides will affect coastal facilities and infrastructure on which many energy systems, markets, and consumers depend. As new investments in energy technologies occur, future energy systems will differ from today’s in uncertain ways. Depending on the character of changes in the energy mix, climate change will introduce new risks as well as new opportunities.” (NCA Highlights: Energy Supply and Use)
- Water: “Climate change affects water demand and the ways water is used within and across regions and economic sectors. The Southwest, Great Plains, and Southeast are particularly vulnerable to changes in water supply and demand. Changes in precipitation and runoff, combined with changes in consumption and withdrawal, have reduced surface and groundwater supplies in many areas. These trends are expected to continue, increasing the likelihood of water shortages for many uses. Increasing flooding risk affects human safety and health, property, infrastructure, economies, and ecology in many basins across the United States… Increasing resilience and enhancing adaptive capacity provide opportunities to strengthen water resources management and plan for climate-change impacts.” (NCA Highlights: Water)
Climate Trends in America
- Temperature: “U.S. average temperature has increased by 1.3°F to 1.9°F since record keeping began in 1895; most of this increase has occurred since about 1970. The most recent decade was the Nation’s warmest on record. Temperatures in the United States are expected to continue to rise. Because human-induced warming is superimposed on a naturally varying climate, the temperature rise has not been, and will not be, uniform or smooth across the country or over time.” (NCA Highlights: Climate Trends)
- Extreme Weather: “There have been changes in some types of extreme weather events over the last several decades. Heat waves have become more frequent and intense, especially in the West. Cold waves have become less frequent and intense across the Nation. There have been regional trends in floods and droughts. Droughts in the Southwest and heat waves everywhere are projected to become more intense, and cold waves less intense everywhere.” (NCA Highlights: Climate Trends)
- Hurricanes: “The intensity, frequency, and duration of North Atlantic hurricanes, as well as the frequency of the strongest (Category 4 and 5) hurricanes, have all increased since the early 1980s. The relative contributions of human and natural causes to these increases are still uncertain. Hurricane-associated storm intensity and rainfall rates are projected to increase as the climate continues to warm.” (NCA Highlights: Climate Trends)
- Severe Storms: “Winter storms have increased in frequency and intensity since the 1950s, and their tracks have shifted northward over the United States. Other trends in severe storms, including the intensity and frequency of tornadoes, hail, and damaging thunderstorm winds, are uncertain and are being studied intensively.” (NCA Highlights: Climate Trends)
- Precipitation: “Average U.S. precipitation has increased since 1900, but some areas have had increases greater than the national average, and some areas have had decreases. More winter and spring precipitation is projected for the northern United States, and less for the Southwest, over this century.” (NCA Highlights: Climate Trends)
- Heavy Downpours: “Heavy downpours are increasing nationally, especially over the last three to five decades. Largest increases are in the Midwest and Northeast. Increases in the frequency and intensity of extreme precipitation events are projected for all U.S. regions.” (NCA Highlights: Climate Trends)
- Frost-free Season: “The length of the frost-free season (and the corresponding growing season) has been increasing nationally since the 1980s, with the largest increases occurring in the western United States, affecting ecosystems and agriculture. Across the United States, the growing season is projected to continue to lengthen.” (NCA Highlights: Climate Trends)
- Ice Melt: “Rising temperatures are reducing ice volume and surface extent on land, lakes, and sea. This loss of ice is expected to continue. The Arctic Ocean is expected to become essentially ice free in summer before mid-century.” (NCA Highlights: Climate Trends)
- Sea Level: “Global sea level has risen by about 8 inches since reliable record keeping began in 1880. It is projected to rise another 1 to 4 feet by 2100.” (NCA Highlights: Climate Trends)
- Ocean Acidification: “The oceans are currently absorbing about a quarter of the carbon dioxide emitted to the atmosphere annually and are becoming more acidic as a result, leading to concerns about intensifying impacts on marine ecosystems.” (NCA Highlights: Climate Trends)
The full report is available on the interactive, mobile-device-friendly National Climate Assessment Web site. For a synopsis of the key findings from the Assessment, see the Highlights report or download the 20-page Overview booklet.
