History of global climate change
NASA conducts a program of breakthrough research on climate science, enhancing the ability of the international scientific community to advance global integrated Earth system science using space-based observations.
The agency's research encompasses solar activity, sea level rise, the temperature of the atmosphere and the oceans, the state of the ozone layer, air pollution, and changes in sea ice and land ice. NASA scientists regularly appear in the mainstream press as climate experts. So how did the space agency end up taking such a big role in climate science?
When NASA was first created by the National Aeronautics and Space Act of 1958, it was given the role of developing technology for “space observations, ” but it wasn’t given a role in Earth science. The agency’s leaders embedded the technology effort in an Earth Observations program centered at the new Goddard Space Flight Center in Greenbelt, Maryland, in the U.S.. It was an “Applications” program, in NASA-speak. Other agencies of the federal government were responsible for carrying out Earth science research: the Weather Bureau (now the National Oceanic and Atmospheric Administration or NOAA) and the U.S. Geological Survey (USGS). The Applications program signed cooperative agreements with these other agencies that obligated NASA to develop observational technology while NOAA and the USGS carried out the scientific research. The Nimbus series of experimental weather satellites and the Landsat series of land resources satellites were the result of the Applications program.
This Applications model of cross-agency research failed during the 1970s, though, due to the bad economy and an extended period of high inflation. Congress responded by cutting the budgets of all three agencies, leaving NOAA and the USGS unable to fund their part of the arrangement and putting pressure on NASA, too. At the same time, congressional leaders wanted to see NASA doing more research toward “national needs.” These needs included things like energy efficiency, pollution, ozone depletion and climate change. In 1976, Congress revised the Space Act to give NASA authority to carry out stratospheric ozone research, formalizing the agency’s movement into the Earth sciences.
NASA’s planetary program had a lot to do with scientific and congressional interest in expanding the agency’s role in Earth science. The Jet Propulsion Laboratory, NASA's lead center for planetary science, sent Mariner series probes to Venus and Mars. Astronomers considered these to be the "Earth-like" planets in the solar system, most likely to have surface conditions able to support life.
But that's not what they found. Venus had been roasted by a super-charged greenhouse effect. In contrast to Earth, Venus had about 300 times more carbon dioxide in its atmosphere, no significant water vapor and a surface temperature hotter than molten lead. Mars, on the other hand, had an atmospheric pressure about 1 percent of that of planet Earth and temperatures far below freezing. Pictures showed no surface water - it would have been frozen anyway - but they also seemed to show that it once had liquid water.