Category Science

            Have you ever worn a pair of glare glasses? In the hot sun, the tinted glasses give comfort to our eyes and protect them from the sun’s harmful rays. The ozone layer does a similar job, protecting the life forms on Earth from the harmful rays of the sun.

            The ozone layer or ozone shield is a region of Earth’s stratosphere that absorbs most of the sun’s ultraviolet radiation. It contains high concentrations of ozone, an inorganic oxygen molecule. The ozone layer is mainly found in the lower portion of the stratosphere and also in the troposphere. The layer was discovered in 1913 by Charles Fabry and Henri Buisson, two distinguished French physicists.

            Ozone in the troposphere pollutes the air there; and this in turn helps the forming of smog. Ozone in the stratosphere protects life on Earth by absorbing some of the sun’s harmful ultra-violet rays. The ozone layer absorbs 97 to 99 percent of the sun’s medium-frequency ultra-violet light, which otherwise would potentially damage exposed life forms near the surface.

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            You must have seen pictures of the beautiful white polar bears that live near the North Pole. These majestic animals live in extreme cold and cannot live elsewhere, where there is no ice.

            However, today, the very existence of these animals is threatened because of climate change. Fondly called the white giants of the Arctic, these glorious animals spend much of their life in, around, or on the water predominantly on sea ice. However, it is a sad fact that sea ice in the Arctic is melting earlier and forming later each year, because of global warming. This means that polar bears are left with less time on the ice to hunt for food, mainly seals, and build up their fat stores for survival in the cold.

            As their ice habitat shrinks, skinnier and hungrier polar bears could become extinct by the end of this century. This would be a tragedy because polar bears help us gain an understanding of what is happening of what is happening throughout the Arctic region. If polar bears are at risk, it may also be an indication that something is terribly wrong with the entire Arctic marine eco-system too.

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               While it is easy to comprehend the dangers of global warming that animals and humans would face because they live on land, it would be interesting to know what would happen to the animals in the oceans. We tend to think that the waters are far safer than the land. However, the truth is quite the contrary. Many sea animals are at high risk.

               Whales and dolphins are at risk because of global warming. Those animals that rely on polar waters, such as belugas, narwhals, and bowhead whales, are likely to be affected by the reduction of sea ice. Less sea ice will allow more commercial shipping, oil, gas, and mining exploration and development, and military activities in previously untouched areas. This will hit nature adversely.

               The oceans will absorb more carbon dioxide, and become more acidic. This means there will be more cetacean disease epidemics, and lower reproductive success and survival rates. Climate change could also mean the end of the 300 or so endangered North Atlantic right whales, as it is affecting their food sources. River dolphins will also suffer from loss of habitat.

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                Man had begun agriculture and farming thousands of years ago. Humans are probably the only species that cultivate and grow their own food in such an elaborate manner. We depend so much on the environmental and climatic conditions that our food habits will be in jeopardy if there is even a slight variation in these circumstances.

                Global warming can have a disastrous impact on agricultural yields. The majority of the world’s one billion poor people depend on agriculture for their livelihood. As mentioned earlier, agriculture, unfortunately, is the human enterprise most vulnerable to changes in climate. Studies have shown that South Asia and Southern Africa are especially at risk because higher temperatures and drops in rainfall could cut yields of the main crops people grow there.

            Droughts or floods have already affected harvests in Russia, Germany, Canada, Argentina, Australia and Pakistan. It is estimated that half the world’s population will face serious food shortages in this century, because of global warming.

            Have you heard that forests are the lungs of the earth? Forests play a crucial role in keeping our planet liveable. When Man, out of his greed, destroys trees with chainsaws, fire and building materials, he is destroying the planet’s biodiversity and habitability.

            About 30 per cent of the world’s land area is covered by forests. However, they are being cut down at an alarming rate, and this is called deforestation. Felling of trees deprives the forest of portions of the canopy that blocks the sun’s rays during the day and holds in heat at night.

            These disruptions lead to more extreme temperature swings that can be harmful to plants and animals.

            Trees also help maintain the water cycle by returning water vapour back into the atmosphere. If there are not enough trees to play this role, many forestlands can quickly turn into barren deserts. Trees also play a critical role in absorbing carbon dioxide. Since more carbon dioxide in the atmosphere will mean increase in the speed and severity of global warming, forests are playing a vital role in preserving life on Earth.

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               We often think that the oceans are stagnant without strong undercurrents. It is a wrong notion! The water in the oceans does move about and has a regular pattern of movement. The movement of the ocean water in certain directions due to various causes is known as ocean currents.

               What moves ocean water? The rotation of the moon around the earth is the major force behind ocean currents. There are circular currents in the north and south of the Pacific and Atlantic oceans. Another key current travels around Antarctica.

               Ocean currents affect climate. The oceans have warm and cold surface currents that act like a global heating and air conditioning system. For example, the Gulf Stream in the North Atlantic Ocean carries warm salty water from the equator up to the coast of Greenland in the Arctic. This water travels near the surface of the ocean. As it travels to the Arctic, the warm water heats the countries of the North Atlantic, like Britain. It then cools down, thus increasing the density of water. The dense water sinks to the bottom, where it is carried back to the equator.

               Global warming is making the ice caps melt, and they will flow into the ocean, and dilute the salty equatorial water. This will make it less dense, and stop it from sinking. In this way, global warming could stop ocean currents, causing drastic climate changes.