THE GREENHOUSE EFFECT
Some of the heat from the Sun that warms the Earth’s atmosphere goes
back into space. But more and more of that heat is being trapped by the
atmosphere because the atmosphere contains much more carbon dioxide
than it did a hundred years ago. Carbon dioxide acts like the glass in a
greenhouse: heat comes in but the glass doesn’t let the heat get out. This
trapped heat is leading to global warming and a world climate change.
If the Earth’s temperatures go up significantly, the polar ice caps will melt,
and sea levels will gardually rise. Cities on the sea coasts then will be
under water and coastal areas will be cloudier and wetter, while large
inland areas will become drier and deserts will get bigger. More deserts
mean less area for growing food, though the world’s population is
increasing. All this will lead to a global catastrophy.
What is causing the increase in carbon dioxide that is responsible for the
greenhouse effect? Burning fossil fuels (coal, oil, gasoline/petrol) and
wood for energy causes it. Trees produce the oxygen we need by using
carbon dioxide, but there are fewer trees and forests because of
deforestation, so there is more carbon dioxide and less oxygen. Large
areas of rain forests are being cut down and burned for agricultur and to
make areas for cattle to graze.
To make matters worse, we have created a hole in the ozone layer which
protects us from harmful ultraviolet (UV) radiation. The hole has been
caused by too many CFCs (chlorofluorocarbons), which are used in
aerosols, plastic production and refrigerators. Too much UV radiation can
cause skin cancer and other problems.
1. Hogy működik az üvegházhatás?
2. Mi történik, ha a föld felületének hőmérséklete jelentősen
megemelkedik?
3. Mi az oka annak, hogy a légkörben egyre nagyobb mennyiségben
van jelen a széndioxid?
4. Mi okozta az ózonlyuk kialakulását és milyen káros hatásai
lehetnek?