Environmental Protection Agency

Published date August 2, 2016

Climate Change Indicators in the United States 2016 - Fourth Edition

Summary of Key Points

Greenhouse Gases

  • 7 percent—the increase in US greenhouse gas emissions caused by human activities from 1990 to 2014 
  • 7 percent—the decrease in total US greenhouse gas emissions since 2005
  • 35 percent—the increase in worldwide, net emissions of greenhouse gases from human activities from 1990 to 2010
  • 42 percent—the increase in carbon dioxide emissions, which account for about three-fourths of total emissions, from 1990 to 2010
  • 800,000—the number of years compared to which current current global atmospheric concentrations of carbon dioxide are unprecedented, as shown by historical measurements
  • 37 percent—the increase in total warming effect from greenhouse gases added by humans to the Earth’s atmosphere from 1990 to 2015
  • 30 percent—the increase in total warming effect associated with carbon dioxide alone from 1990 to 2015

Weather and Climate

  • 10 hottest years occurred between 1998 and 2015
  • 0.08 inches—the average rate of increase in precipitation per decade over land areas worldwide since 1901
  • 9 out of 10—the number of top years for extreme one-day precipitation events in the US that have occurred since 1990 
  • 20 to 70 percent—US land area experiencing abnormally dry conditions at any given time from 2000 through 2015


  • 0.6 inces—the rate at which global sea level has risen per decades since 1880
  • 8 inches—the increase in sea level registered along the Mid-Atlantic coast and parts of the Gulf coast between 1960 and 2015

Snow and Ice

  • September 2012—when scientists measured the lowest annual minimum Arctic sea ice extent as the melt season for Arctic ice grows
  • 24 days—the maximum number of days earlier that thaw dates have shifted among northern lakes in the US over the past 110 years
  • 80 percent—the number of locations studied that saw more winter precipitation fall in the form of rain instead of snow in the US since records began in 1930
  • 3,300 square miles—the average decrease per year in the portion of North America covered by snow between 1972 and 2015
  • Two weeks—the amount of time shorter that snow covers the ground since 1972 in the US
  • 90 percent—the proportion of measurement sites showing a decrease in early spring snowpack in the western US between 1955 and 2016
  • 23 percent—the average decline in early spring snowpack across all measurement sites in the US between 1955 and 2016

Health and Society

  • 9,000—the number of heat-related deaths reported since 1979 in the US
  • 28,000—the number of heat-related hospitalizations across 20 states from 2001 to 2010
  • 100 percent—the nationwide increase in reported cases of Lyme disease since 1991
  • 10 out of 11—the number of studied locations in the central US and Canada that experienced an increase in the length of ragweed pollen season since 1995


  • 9 out of 10—the number of years with the largest acreage burned due to wildfires that have occurred since 2000 in the US, with records going back to 1983
  • 5 days—the least number of days earlier that US rivers and streams show peak winter-spring runoff compared to the mid-20th century
  • 79 percent—the proportion of measurement sites showing an increase in water temperature in the Chesapeake Bay region from 1960 through 2014
  • 1.2°F—the average temperature increase across all Chesapeake Bay stream measurement sites from 1960 through 2014
  • 2.2°F—the average temperature increase at stream sites in the Chesapeake Bay where the trend was statistically significant from 1960 through 2014
  • 40 miles—the average northward shift of wintering grounds for North American bird species since 1966
  • 10 miles—the shift northward along US coasts of the average center of biomass for 105 marine fish and invertebrate species between 1982 and 2015
  • 20 feet—the average shift deeper of 105 marine fish and invertebrate species between 1982 and 2015
  • 119 miles—the average shift northward of American lobster, black sea bass, and red hake between 1982 and 2015