Throughout its long history, Earth has warmed and cooled time and again. Climate has changed when the planet received more or less sunlight due to subtle shifts in its orbit, as the atmosphere or ...

Earth has experienced climate change in the past without help from humanity. We know about past climates because of evidence left in tree rings, layers of ice in glaciers, ocean sediments, coral reefs ...

In 1967 Hansen went to work for NASA’s Goddard Institute for Space Studies, in New York City, where he continued his research on planetary problems. Around 1970, some scientists suspected Earth was ...