The National Wildlife Federation

Donate Donate

The Heat Is On

The Northern Hemisphere has been hotter since 1980 than at any time during the past two millennia, say scientists.

  • Laura Tangley
  • Dec 01, 2003
Skeptics who still doubt that human activities are heating up the planet may have trouble explaining away the most recent evidence: An analysis by an international team of scientists found that the Northern Hemisphere has been hotter since 1980 than at any time during the past two millennia. To reach the conclusion, published in Geophysical Research Letters, the researchers examined historical records from several countries and, for the period before such records exist, analyzed rings from the trunks of ancient trees and air bubbles trapped in 2,000-year-old ice cores from Antarctica and Greenland.

Get Involved

   Please leave this field empty

Where We Work

More than one-third of U.S. fish and wildlife species are at risk of extinction in the coming decades. We're on the ground in seven regions across the country, collaborating with 52 state and territory affiliates to reverse the crisis and ensure wildlife thrive.

Learn More
Regional Centers and Affiliates