Can we push back the sea?
The action of the waves continually erodes beaches and cliffs, so sea walls are often constructed to protect them. It is very expensive to control the action of the sea in this way. Much of the Netherlands originally lay under the North Sea. For centuries, the Dutch have built enormous dykes (banks) to hold the water back. They have also reclaimed land from the sea, increasing the size of their country by almost one-third.
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Hole in one
In the 1970s, scientists discovered a gap in the protective ozone layer around the Earth. Ozone, a form of oxygen, filters out more than 90 percent of the Sun’s damaging ultraviolet rays. So when a gap in the ozone layer was found over Antarctica, scientists were very concerned. Increased ultraviolet radiation can cause skin cancer. The hole in the ozone layer has been blamed on our use of chemicals called chlorofluorocarbons (CFCs). They were widely used in refrigerators, freezers and aerosol cans. Although the use of CFCs is now heavily restricted, it may take years before the ozone layer repairs itself.
Picture credit: google