Monday, October 17, 2011

Global warming will cause animals to shrink

Scientists predict global warming will have an effect on the sizes of animals: they are expected to get smaller with higher temperatures. The predictions are based on a period of increased temperatures about 56 million years ago. Researchers have found that, during that time, animals, such as beetles, were between 50 and 75 percent smaller than they are today. A spectacular decrease in size, which would severely disrupt our ecosystem, if it were to happen again in present days. According to the National University of Singapore, the decrease in size of animals will continue during this century.

Evidence for smaller animals millions of years ago was found in the holes they dug underground. Burrows were much smaller during this period of high temperatures. A reason for the decrease in animal size lies in their metabolism. Many animals are cold-blooded, which means they do not have a constant temperature; it varies with the weather. An increase in temperature causes all the enzymes in the body to work at a higher rate, which causes increased energy expenditure. This means animals need more food to survive and keep their body weight at the same level.

Because not all animals respond in the same way to the changing climate, the decrease in animal size could become a problem. Smaller animals that are low on the food chain could disrupt our ecosystem when they are eaten by animals that do not react as heavily to the changing environment. This could cause several species to become extinct.

In addition to metabolic rate, higher temperatures means that seas and oceans increase in acidity. This is due to a complicated balance in certain elements, that is disturbed when the temperature increases. This causes increased difficulties for fish and other sea animals to build a skeleton. In addition, phytoplankton, the lowest organism on the marine food chain, has a lower growth rate in oceans with higher acidity.

Humans will probably not be affected by the climate change, in terms of growth. We are not cold-blooded, and have found ways to shield ourselves against the environment. However, is it possible that our food, be it crops or animals we feed on, decrease in size, making it more difficult for us to produce the same amount of food. With an ever increasing population, this could become a real problem. 

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