Thanks to a fleet of six microsatellites launched almost a decade ago, scientists have access to a new database of temperature records that sprawl out in three dimensions through the lowest layers of the atmosphere. A partnership between the United States and Taiwan, the satellite system has proven to be an extremely accurate, precise, and stable space-borne thermometer, especially for the upper troposphere and lower stratosphere, a region important to our understanding of climate change.
Called COSMIC—the Constellation Observing System for Meteorology, Ionosphere, and Climate—the system makes measurements of several key attributes of the atmosphere that are used to improve weather forecasting. COSMIC is a collaborative effort, conceived, planned, and managed by the University Corporation for Atmospheric Research (UCAR) along with the National Science Foundation, NASA, the National Oceanic and Atmospheric Administration, U.S. Air Force and Taiwan's National Space Organization.
With the recent climate talks in Paris—where representatives from nearly 200 countries negotiated a deal that aims to limit warming this century to 2 degrees Celsius—it's a question many people are asking. It's also deceptively difficult to answer.
Directly measuring the temperature at the surface of Earth, where the 2-degree Celsius goal applies, is hard. In part that's because Earth's surface is not covered in thermometers, and in fact, there are vast regions of the planet—including the oceans and polar regions—with no thermometers at all. But even if it were easy, the information would not give us the full picture of the amount of heat trapped in the atmosphere, which is hundreds of miles thick. Observations of temperature change throughout the atmosphere are needed to better detect and understand climate change.