How Do We Know Global Warming is Human-Caused?

We all know that warming—and cooling—has happened in the past, and long before humans were around. Many factors (called climate drivers) can influence Earths climate—such as changes in the suns intensity and volcanic eruptions, as well as heat-trapping gases in the atmosphere.

So how do scientists know that todays warming is primarily caused by humans putting too much carbon in the atmosphere when we burn coal, oil, and gas or cut down forests?

Creative Commons Licensed photo credits:

The United Nations Building
Steve Cadman
http://www.flickr.com/photos/98115025@N00/74266867

Smog of Shinjuku
wili_hybrid
http://www.flickr.com/photos/wili/267257905/

Category:

Science & Technology

Tags:

• human causes
• global warming
• faq
• carbon dioxide
• climate change
• questions