Global Warming

Source - http://earthobservatory.nasa.gov/Features/GlobalWarming/page2.php

Summary - Earth has warmed and cooled over time. Climate has changed when the planet received more or less sunlight due to subtle shifts in its orbit.. But in the past century, another force has started to influence Earth’s climate: humanity. Global warming is the rapid increase in Earth’s average temperature over the past century primarily due to the greenhouse gases released as people burn fossil fuels. The global average surface temperature rose 0.6 to 0.9 degrees Celsius between 1906 and 2005, and the rate of temperature increase has nearly doubled in the last 50 years. Temperatures are sure to rise even more. Despite increases and decreases from year to year, global average surface temperature is rising. Earth’s temperature begins with the Sun. Roughly 30 percent of incoming sunlight is reflected back into space by bright surfaces like clouds and ice. Of the remaining 70 percent, most is absorbed by the land and ocean, and the rest is absorbed by the atmosphere. The absorbed solar energy heats our planet. As the rocks, the air, and the seas warm, they radiate thermal energy. From the surface, this energy travels into the atmosphere where much of it is absorbed by water vapor and greenhouse gases such as carbon dioxide and methane. When they absorb the energy radiating from Earth’s surface, microscopic water or greenhouse gas molecules turn into tiny heaters. They radiate in all directions. The energy that radiates back toward Earth heats both the lower atmosphere and the surface, enhancing the heating they get from direct sunlight. What has scientists concerned now is that over the past 250 years, humans have been artificially raising the concentration of greenhouse gases in the atmosphere at an ever-increasing rate, mostly by burning fossil fuels, but also from cutting down carbon-absorbing forests. Since the Industrial Revolution began in about 1750, carbon dioxide levels have increased nearly 38 percent, as of 2009 methane levels have increased 148 percent. The atmosphere today contains more greenhouse gas molecules, so more of the infrared energy emitted by the surface ends up being absorbed by the atmosphere. Since some of the extra energy from a warmer atmosphere radiates back down to the surface, Earth’s surface temperature rises.

Opinion - 
This information surprises me because I didn't know how bad global warming was. I didn't know that the amount of methane that we have put into the air has increased by 148% since 1750. I think we need to stop producing harmful chemicals at such a high rate before the Earth gets even worse.

Questions - 
1. How do you feel about global warming?
2. Do you think there are any ways to stop global warming?
3. What do you think can be done about global warming?