The Obama administration has released its third National Climate Assessment, a document designed as a public presentation of the administration's comprehensive scientific assessment of how climate change is impacting the U.S. people and economy.
A view from the Lincoln Memorial to U.S. Capitol, in Washington, D.C.
The National Climate Assessment summarizes the impacts of climate change on the United States, now and in the future. Produced as a collaboration between over 300 experts guided by the 60-member National Climate Assessment and Development Advisory Committee, the report was extensively reviewed by the public and experts, including federal agencies and a panel of the National Academy of Sciences.
The National Climate Assessment has a broad scope, in terms of both types of impacts and regions covered. Thematically, it analyzes impacts on seven sectors – human health, water, energy, transportation, agriculture, forests, and ecosystems – and on the bigger-picture interactions between these sectors. Geographically, the report also assesses key impacts on all U.S. regions: Northeast, Southeast and Caribbean, Midwest, Great Plains, Southwest, Northwest, Alaska, Hawai'i and Pacific Islands, as well as a more general look at coasts and oceans.
The report states that that increased scientific scrutiny has led to "increased certainty that we are now seeing impacts associated with human-induced climate change":
While scientists continue to refine projections of the future, observations unequivocally show that climate is changing and that the warming of the past 50 years is primarily due to human-induced emissions of heat-trapping gases. These emissions come mainly from burning coal, oil, and gas, with additional contributions from forest clearing and some agricultural practices.
Outcomes predicted under possible future scenarios include continued increases in average air and water temperatures, changes in rainfall and precipitation patterns, air quality decreases, sea level rise, and ocean acidification. These changes can disrupt systems for food production, harm human health, or damage property and risk safety through flooding.
The National Climate Assessment also summarizes options for responding to climate change. These include mitigation: reducing the amount and speed of future climate change by reducing emissions of heat-trapping gases or removing carbon dioxide from the atmosphere. Efforts to limit emissions or promote carbon sequestration are considered mitigation efforts. Other possible responses focus on adaptation: preparing for and adjusting to new conditions -- for example, building levees and seawalls, or promoting farmers' growth of crops more suitable to the changing conditions.
In all, the report provides insight into the Administration’s approach to addressing climate change, and can help people and businesses both minimize risks and identify new opportunities.
The full National Climate Assessment can be explored on the government's climate change website globalchange.gov, or can be downloaded. The entire report, downloaded in print quality resolution, clocks in at over 170 megabytes.