Global Warming is defined as the increase of the average temperature on Earth. As the Earth is getting hotter, disasters like hurricanes, droughts and floods are getting more frequent.
Over the last 100 years, the average temperature of the air near the Earth´s surface has risen a little less than 1° Celsius (0.74 ± 0.18°C, or 1.3 ± 0.32° Fahrenheit). Does not seem all that much? It is responsible for the conspicuous increase in storms, floods and raging forest fires we have seen in the last ten years, though, say scientists.
Their data show that an increase of one degree Celsius makes the Earth warmer now than it has been for at least a thousand years. Out of the 20 warmest years on record, 19 have occurred since 1980. The three hottest years ever observed have all occurred in the last ten years, even.
Earth should be in cool-down-period
But it is not only about how much the Earth is warming, it is also about how fast it is warming. There have always been natural climate changes – Ice Ages and the warm intermediate times between them – but those evolved over periods of 50,000 to 100,000 years. http://knowledge.allianz.com/en/globalissues/climate_change/global_warming_basics/global_warming_definition.html
What Is The Greenhouse Effect?
Seen from space, our atmosphere is but a tiny layer of gas around a huge bulky planet. But it is this gaseous outer ring and its misleadingly called greenhouse effect that makes life on Earth possible – and that could destroy life as we know it. The sun is the Earth’s primary energy source, a burning star so hot that we can feel its heat from over 150 million kilometers away. Its rays enter our atmosphere and shower upon on our planet. About one third of this solar energy is reflected back into the universe by shimmering glaciers, water and other bright surfaces. Two thirds, however, are absorbed by the Earth, thus warming land, oceans, and atmosphere.
Much of this heat radiates back out into space, but some of it is stored in the atmosphere. This process is called the greenhouse effect. Without it, the Earth’s average temperature would be a chilling -18 degrees Celsius, even despite the sun’s constant energy supply.
In a world like this, life on Earth would probably have never emerged from the sea. Thanks to the greenhouse effect, however, heat emitted from the Earth is trapped in the atmosphere, providing us with a comfortable average temperature of 14 degrees. The switch from carbon dioxide to oxygen
Nitrogen, oxygen, and argon make up 98 percent of the Earth’s atmosphere. But they do not absorb significant amounts of infrared radiation, and thus do not contribute to the greenhouse effect. It is the more exotic components like water vapour, carbon dioxide, ozone, methane, nitrous oxide, and chlorofluorocarbons that absorb heat and thus increase atmospheric temperatures.
Studies indicate that until some 2.7 billion years ago, there was so much carbon dioxide (CO2) and methane in our atmosphere that average temperatures on Earth were as high as 70 degrees. But bacteria and plants slowly turned CO2 into oxygen and the concentration of CO2 in our current atmosphere dropped to just about 0.038 percent or 383 parts per million (ppm), a unit of measurement used for very low concentrations of gases that has become a kind of currency in climate change debates.
Minuscule changes – global impact
But while we are still far from seeing major concentrations of CO2 in our atmosphere, slight changes already alter the way our celestial heating system works. Measurements of carbon dioxide amounts from Mauna Loa Observatory in Hawaii show that CO2 has increased from about 313 ppm in 1960 to about 375 ppm in 2005.
That means for every million particles in our atmosphere, there are now 62 CO2-particles more than in 1960. Even if this does not seem like much, scientists say this increase – most probably caused by human activities – is mainly...