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Can we figure out the puzzle of global warming before it’s too late?
Scientists know that global temperatures are rising, but how much of the increase is from man-made global warming, and how much is just natural variation? There’s no way to know for sure, and different scientists have different theories.
1875
2015
▲ The Rhône glacier in Switzerland (above) was an awesome sight to behold in 1875. Today, however, it is much smaller, lying halfway up the mountain. Glaciers have retreated during the past century and a half. However, data compiled every decade show that some glaciers, such as those in Scandinavia, are advancing.
◀ Many scientists believe global warming could have an effect on the weather. It could trigger all kinds of freaky weather – including huge snowstorms.
The Greenhouse Effect
▲ In a natural “greenhouse effect,” gases in the atmosphere trap some of the sun’s heat. Otherwise, Earth would be too cold (the energy would be reflected back into space). But for the past century or so, we’ve put more greenhouse gases, like carbon dioxide, into the air. The extra gases could hold in too much heat, leaving parts of our planet unlivable.
▲ A greenhouse retains heat to help plants continue growing in any season.
▲ This line graph shows the amount of carbon dioxide (CO2) in Earth’s atmosphere. This amount has been rising for a long time, but it has sped up in recent years. The planet’s average temperature has risen with it. CO2 is measured in parts per million (ppm). The CO2 level is now at more than 400 ppm, which means there are more than 400 units of CO2 in every 1 million units of air. That doesn’t sound like a lot, but it can cause big changes in the planet’s temperature!
Causes
▲ Fossil fuels are fuels such as coal, oil, and gas. They produce carbon dioxide when they are burned. The U.S. is one of the biggest per capita (per person) contributors of greenhouse gases. But poorer countries are also starting to burn more fuel as they try to improve the lives of their people.
▲ When forests are destroyed, Earth loses trees and other plants that absorb the greenhouse gas carbon dioxide. Sometimes people burn land to clear it for farming. Burning releases extra carbon dioxide, plus methane and other gases, into the atmosphere.
Possible Results
▲ One possible result of global warming is rough weather. Rainstorms could get heavier, causing floods and mudslides. This photo shows the results of a mudslide in Italy. Meanwhile, the driest parts of the Earth could have more severe droughts. Rising global temperatures would melt icecaps enough to raise sea levels all over the world.
▲ The melting, or collapse, of the polar icecaps could cause the oceans to rise, putting coastal areas such as Florida at risk (as indicated by the green areas on this image). However, that could take centuries to happen.
Think Piece!
Most scientists say we should slow down global warming by cutting down on fossil-fuel use and looking for other energy sources. They can’t say exactly what effects global warming will have or when it might occur. What would you give up to prevent a global warming disaster – even if it might not happen in your lifetime? Would you bike to the mall instead of drive? Would you use a manual lawn mower instead of an electric one?
