The ozone layer is a thin band in Earths upper atmosphere. It blocks out the Sun's harmful ultraviolet (UV) rays. If it gets too thin, the harmful UV rays can damage crops, wild animals, and our skin.
The El Niño effect is the interaction of the wind and the sea and the warming of sea water. During a year when there is no El Niño, trade winds move surface water west across the Pacific Ocean and bring cold water from deep below to the top. The cold water from the ocean floor has food in it that the fish eat, such as plankton and algae. When El Niño happens, the strong, steady, easterly winds die off and cold water does not rise any more from the deep. Then the water at the surface warms up and fish food is not replaced. So, the fish food stays at the bottom of the ocean where they cant get to it. Since the fish dont have food to eat, they swim to other oceans where they can find food. But the most important impact of El Niño is the effect on the weather.
It isn't really a "hole", but a large decrease in the total amount of ozone overhead. It is truly a large decrease over Antarctica at certain times of the year, but there are significant general reductions in ozone elsewhere, including the Northern Hemisphere. The "hole" and the general reductions elsewhere are not getting better yet. We expect that things will improve, starting early in the next century.
We earthlings have damaged the ozone layer with chemicals (called chlorofluorocarbons or CFCs) that are used in refrigerators and air conditioners. This has been proved by a long series of measurements from space and on the ground. In fact, the Nobel Prize in Chemistry has been awarded to three atmospheric scientists for having discovered and explained this link.
Every three to five years during the months of December and January, fish in the waters off the coasts Peru and Ecuador vanish like magic. This causes much damage to the area's fishing industry. A long time ago fishermen who fished in these waters called this big fish disappearance "El Niño," because it happened near the celebration of the birth of Jesus, the Christ Child. El Niño is Spanish for referring to the Christ Child.
It sure does. The weakening of trade winds that causes the waters temperature in the Pacific Ocean to rise knocks many of Earths climates out of whack! Warm water in the Pacific ocean moves the jet stream (fast winds, 8-10 miles high) so that storms that used to hit Alaska now reach California. Scientists believe El Niño caused flooding in Texas during the winter of 1991-1992 and very warm temperatures in the southeast part of the U.S. that same winter. It may have caused droughts which made some bird species become extinct.
Polar ice is ice that covers the Earths polar regions. It makes up 10% of the Earths surface. It is made of different kinds of ice: sea ice, glaciers and ice sheets. Sea ice forms when sea water freezes. Ice sheets and glaciers form when snow builds up faster than it can melt. Polar ice affects the Earth in many ways. It can change the water level of the oceans, the temperature and climate of an entire region, and alter the exchange of heat between the ocean and the air above.
Yes, oceans are rising on the average. Rising by as much as 15 to 20 cm (about 6 to 8 inches) in the last 100 years. The seas actually appear to be rising fast because the land is actually sinking in some places and rising in others. On the average, though, the global sea level is rising, sometimes at a much faster rate. We do not know yet how much of the rising sea level is caused by melting of glaciers, that add water to the oceans, or by expansion of the existing ocean water due to slow warming. Rising ocean levels would make hurricanes and other storms more dangerous. More than half the U.S. population lives within 50 miles of a coastline. Some entire nations - like Bangladesh and the Netherlands - are at or near sea level.
Sea ice reflects the suns rays. When the sun shines down onto the ice, it reflects the sunlight back into space away from Earth. The more sea ice there is, the more solar energy gets reflected back into space and the less heat stays on Earth. This causes the climate to become colder.
The two largest ice sheets are in Greenland and Antarctica. Together, they contain 75% of the world's fresh water. If all this ice melted back into the ocean it would raise sea level by over 75 meters. This would change Earths surface in a big way: large areas of the continents would be flooded! This is why Earth scientists use satellites to measure the ice levels on Greenland and Antarctica to see if they are growing or shrinking.
The climate would get warmer. Since there would be less ice to reflect the sunlight back into space, more of it would be absorbed by Earth making it warm up.
The heat radiated from the Earth is absorbed by carbon dioxide, water vapor, and other gases in our air. Thus, the Earth keeps more of the heat that would otherwise have been lost to space. The amount of carbon dioxide in the air has increased a lot in the past hundred years. And recently we have seen increases in the other greenhouse gases. Many scientists believe this will lead to a gradual warming of the Earth. Others believe that different factors cancel this warming effect. Studying these processes is difficult, because they are very complicated.
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