Climate scientists discuss what they know about global climate change today, and how they know it.

The Southern Oscillation Index tracks differences in air pressure between the eastern and western sides of the tropical Pacific.

Temperatures measured on land and at sea for more than a century show that Earth's globally averaged surface temperature is experiencing a long-term warming trend.

This week, Beyond the Data looks at one of the more well-grounded “rules of thumb” for understanding climate change: cooler "things" are warming more quickly than warmer things.

For those who are still waiting for winter's first snow, Deke Arndt blogs about using historical climate data to ballpark when it might arrive. 

This week's bloggers use the historical record to generate 10,000 possible scenarios for the remainder of 2015. In 97% of them, 2015 sets a new record temperature.

In this activity students work with data to analyze local and global temperature anomaly data to look for warming trends. The activity focuses on the Great Lakes area.

This animation shows the warming of Earth's surface temperature from 1870-2100 based on results from the NCAR Community Climate System Model.

Two short, narrated animations about carbon dioxide and Earth's temperature are presented on this webpage. The first animation shows the rise in atmospheric CO2 levels, human carbon emissions, and global temperature rise of the past 1,000 years; the second shows changes in the level of CO2 from 800,000 years ago to the present.