THIRD NATIONAL CLIMATE ASSESSMENT: EVERY REGION SEEING CLIMATE CHANGE IMPACTS, MITIGATION NOT COMMENSURATE WITH RISK

Adaptation and mitigation planning underway, but more action needed

Washington, DC – May 6, 2014 — Observed warming and other climatic changes are triggering wide-ranging impacts in every region of the country and throughout the U.S. economy, according to the third National Climate Assessment (NCA) being released today by the White House.

Nearly 300 scientists wrote the report in a process managed by the U.S. Global Change Research Program, a collaboration of 13 federal departments and agencies. This assessment is a requirement of the 1990 Global Change Research Act and is the first  since 2009.

In the years since the second NCA, report authors note the evidence of human-induced climate change has strengthened: “multiple lines of evidence confirm that human activities are the primary cause of the global warming of the past 50 years.” In addition to updating advances in climate science and attribution, the assessment offers region-by-region impacts analyses and examines sectors such as agriculture, energy supply and use, human health and transportation.

Although warming can lead to some positive effects, the report warns that most climate change impacts are negative and will be “increasingly disruptive.” 

The report’s main findings include:

Climate change is impacting Americans now. Impacts have been identified in every region of the country and in economic sectors including construction, transportation, agriculture, forestry, business and more.

Human activities — primarily burning fossil fuels — drove most of the warming in the last 50 years. These changes will continue and will accelerate significantly if global emissions of greenhouse gases are not reduced.

Climate change is costing us. The domestic costs of climate change are already high and will increase further if emissions are not controlled. Climate change will strain our energy, food and water supplies. In the short term, the agricultural sector will need to invest in adaptation. Warming and acidifying oceans are also detrimentally affecting fisheries.

Climate change poses risks to U.S. infrastructure. Sea level rise, storm surge and heavy downpours, in combination with increased development in coastal areas, are increasing damage to U.S. infrastructure. This includes roads, buildings and industrial facilities. Extreme heat is also damaging transportation infrastructure such as roads, rail lines and airport runways.

Climate change is affecting our health. Impacts from extreme weather events, wildfires, decreased air quality, insect-borne diseases, and food- and water-borne diseases will mount as warming continues. Children, the sick, the old and the poor are especially vulnerable. Climate change also jeopardizes water quality and water supply reliability.

Climate disruptions to agriculture have been increasing and are projected to become more severe. Some crops and regions will be more resilient than others, but many will increasingly suffer stresses in the form of extreme heat, drought, disease and heavy downpours. These stresses will negatively affect yields.

Positive steps are underway, but much more needs to be done. Americans are acting both to reduce the effects of climate change and to prepare for the impacts of a warmer world. Action at the local level is especially positive, but further action is needed.