On May 6, the Federal government released the Third National Climate Assessment (NCA), the most comprehensive and transparent examination of peer-reviewed science on climate change impacts in the United States ever produced. The NCA echoes the findings of the latest reports from the United Nations International Panel on Climate Change, which state with high certainty that emissions from human activities are causing global climate change. The report reveals that climate change is already impacting Americans across the country, and its effects are predominantly negative.

“For a long time we have perceived climate change as an issue that’s distant, affecting just polar bears or something that matter to our kids,” commented Katharine Hayhoe, a climate scientist, professor at Texas Tech University, and author of the NCA. “This shows it’s not just in the future; it matters today. Many people are feeling the effects.”

Mandated by the Global Change Act of 1990, the NCA provides centrally located, relevant, and clear climate data for decision-makers domestically and abroad. The report examines climate change over a long-term timescale, observing past trends, current changes, and projecting future scenarios. According to the NCA, “Understanding global change is critical to our Nation’s welfare and economic vitality.” Thirteen federal agencies oversaw the completion of the work under the auspices of the Global Change Research Program (USGCRP). More than 300 scientists from across the public, private, nonprofit and academic sectors volunteered their time as authors.

Since the last NCA report in 2009, climate change impacts in the United States have grown. Temperatures in the United States are now 1.3 to 1.9 degrees Fahrenheit warmer than they were in 1895, with most of the increase happening in the last 44 years. Across the country, sea levels are rising, rainfall patterns are changing, summers are getting longer and hotter, winters are becoming shorter and warmer, and summer sea ice in Alaska is receding. The implications of these changes are large, threatening communities in Alaska with relocation, increasing drastic flood events, extending the wildfire season, and increasing the severity of droughts.

The Third National Climate Assessment examines regional climate impacts in the Northeast, Southeast, Northwest, Southwest, Great Plains, Alaska and the Arctic, as well as Hawaii and the Pacific Islands. The report also examines impacts across sectors, including interactions with human health, water, energy, transportation, agriculture, forests, ecosystems, coastal areas, oceans and marine resources.

In order to make the information as accessible as possible, USGCRP has created a mobile-compatible website which allows users to interactively explore the report. Each individual piece of the report can be shared across social networks. The information is also displayed to enable readers to trace data inputs using the Global Change Information System (GCIS), in order to showcase the links between environmental data streams (including observations from satellites and sensors, and results from modeling) and related scientific findings.

EESI is hosting a series of briefings on the National Climate Assessment. On May 8, EESI will hold an event to give a general overview of the NCA on Capitol Hill, with NCA authors Dr. Gary Yohe, Environmental Science Professor at Wesleyan University, and Dr. Donald Wuebbles, Professor of Atmospheric Science at the University of Illinois.