Climate Change - An Overview

Climate change is a significant and lasting change in the statistical distribution of weather patterns over periods ranging from decades to millions of years. It may be a change in average weather conditions, or in the distribution of weather around the average conditions (i.e., more or fewer extreme weather events). Climate change is caused by factors that include oceanic processes (such as oceanic circulation), biotic processes, variations in solar radiation received by Earth, plate tectonics and volcanic eruptions, and human-induced alterations of the natural world; these latter effects are currently causing global warming, and "climate change" is often used to describe human-specific impacts.

Global warming is the rise in the average temperature of Earth's atmosphere and oceans since the late 19th century and its projected continuation. Since the early 20th century, Earth's

The World is Green

On December 7, 1972, the Apollo 17 crew members—commander Eugene Cernan, lunar module pilot Harrison “Jack” Schmitt and command module pilot Ron Evans—captured the full sphere of Earth, a first of its kind image, from about 28,000 miles into space. Al Reinert, a screenwriter for Apollo 13, reflected in a 2011 essay in the Atlantic on the photograph, called the Blue Marble, and just how privileged the astronauts’ view was that day:

“You can’t see the Earth as a globe unless you get at least twenty thousand miles away from it, and only 24 humans ever went that far out into space…. In order to see our planet as a fully illuminated globe you need to pass through a point between it and the sun, which is a narrower window than you might think if you’re traveling at 20,000 miles an hour.”