BBC News: What is Climate Change?

This article originally appeared on BBC News – Science and Enviornment on October 4th, 2017.

What is Climate Change?

The planet’s climate has constantly been changing over geological time. The global average temperature today is about 15C, though geological evidence suggests it has been much higher and lower in the past. However, the current period of warming is occurring more rapidly than many past events. Scientists are concerned that the natural fluctuation, or variability, is being overtaken by a rapid human-induced warming that has serious implications for the stability of the planet’s climate.

What is the “greenhouse effect”?

The greenhouse effect refers to the way the Earth’s atmosphere traps some of the energy from the Sun. Solar energy radiating back out to space from the Earth’s surface is absorbed by atmospheric greenhouse gases and re-emitted in all directions. The energy that radiates back down to the planet heats both the lower atmosphere and the surface. Without this effect, the Earth would be about 30C colder, making our planet hostile to life.