This website is the digital version of the 2014 National Climate Assessment, produced in collaboration with the U.S. Global Change Research Program.

For the official version, please refer to the PDF in the downloads section. The downloadable PDF is the official version of the 2014 National Climate Assessment.

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Welcome to the National Climate Assessment

The National Climate Assessment summarizes the impacts of climate change on the United States, now and in the future.

A team of more than 300 experts guided by a 60-member Federal Advisory Committee produced the report, which was extensively reviewed by the public and experts, including federal agencies and a panel of the National Academy of Sciences.

Explore the effects of climate change
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Figure 21.1: Observed Shifts in Streamflow Timing

Observed Shifts in Streamflow Timing

Figure 21.1: Reduced June flows in many Northwest snow-fed rivers is a signature of warming in basins that have a significant snowmelt contribution. The fraction of annual flow occurring in June increased slightly in rain-dominated coastal basins and decreased in mixed rain-snow basins and snowmelt-dominated basins over the period 1948 to 2008.1 The high flow period is in June for most Northwest river basins; decreases in summer flows can make it more difficult to meet a variety of competing human and natural demands for water. (Figure source: adapted from Fritze et al. 20111).

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References

  1. Fritze, H., I. T. Stewart, and E. J. Pebesma, 2011: Shifts in Western North American snowmelt runoff regimes for the recent warm decades. Journal of Hydrometeorology, 12, 989-1006, doi:10.1175/2011JHM1360.1. URL | Detail

The National Climate Assessment summarizes the impacts of climate change on the United States, now and in the future.

A team of more than 300 experts guided by a 60-member Federal Advisory Committee produced the report, which was extensively reviewed by the public and experts, including federal agencies and a panel of the National Academy of Sciences.

United States Global Change Research Program logo United States Global Change Research Program participating agency logos