- 2.4 billion years ago: first ice age begins
- 100 million years ago: Earth's average temperature was 10 to 20 degrees cooler than today
- 12,500 years ago: last ice age ends
- 1896: Swedish scientist Svante Arrhenius discovers the amount of carbon dioxide in the atmosphere directly influences temperature
- 1957: Scientists Roger Revelle and Hans Suess warn that fossil fuel emissions would cause Earth to warm
- 2003: European heat wave kills 30,000
- 2011: Second hottest summer on record -- and since 1895 -- in the United
What is global warming?
Global warming, fueled by greenhouse gases such as carbon dioxide, is as real as a Texas-sized drought. While the planet’s temperature has increased just 1 degree Fahrenheit (.55 degrees Celsius) during the past century, Earth’s coldest regions have warmed significantly more. As a result, many plant and animal species are on the verge of extinction. Blizzards, floods and hurricanes have become more devastating. Ice is melting, oceans are rising, glaciers are tumbling and the weather has fluctuated wildly from balmy winters to brisk summers.
As Earth’s CO2 levels increase, so will the temperature, some 10 degrees Fahrenheit (5.5 degrees Celsius) by the end of the century. In fact, global temperatures are rising faster than at any other time in the past 1,000 years. Global warming has put many places, including Tuvalu, on the front lines in the war against climate change. While some scientists believe we’re close to the point of no return, others say it's not too late stop global warming. Cutting our current C02 emissions in half within the next 50 years might save the planet.