A new Environmental Protection Agency report on climate change indicators presents “clear evidence that the composition of the atmosphere is being altered as a result of human activities and that the climate is changing,” the agency said in releasing “Climate Change Indicators in the United States.”

The report, available as a PDF, categorizes indicators across greenhouse gases, weather and climate, oceans, snow and ice, and society and ecosystems.

A few highlights:

  • Greenhouse gas emissions in the U.S. resulting from human activities increased by 14 percent between 1990 and 2008, but emissions per person remained constant during that period.
  • Seven of the 10 warmest years on record for the lower 48 states have occurred since 1990, and the last 10 five-year periods are the warmest five-year periods on record. Across the U.S., temperatures have increased the most in the North, West, and Alaska.
  • Data concerning droughts in the U.S. are not adequate for determining an increase or decrease over time.
  • Glaciers in the U.S. and around the world “have generally shrunk” since the 1960s, with the rate of glacier melting apparently accelerating over the past decade.
  • Lakes in the northern U.S. “appear to be freezing later and thawing earlier” than they did in the 1800s and early 1900s.
  • More than 6,000 deaths across the U.S. are linked to heat-related illnesses such as heat stroke, but year-to-year variability “makes it difficult to determine long-term trends.”
  • Lilacs and honeysuckles across the lower 48 states are blooming “slightly earlier than in the past,” but it is unclear whether these changes are statistically meaningful.
  • Bird species in North America “have shifted their wintering grounds northward by an average of 35 miles since 1966, with a few species shifting by several hundred miles.” Some bird species are moving their wintering grounds inland, “consistent with rising inland temperatures.”
Topics: Climate Science, Policy & Politics