Altering Climatic Conditions Responsible for Species' Reducing Size: Study

Starting from the huge polar bear to the tiny house sparrow, a new study has suggested that a wide range of species on Earth seems to be shrinking in size, and researchers have blamed increasing global temperatures and changing climatic conditions for that.

In the study, published online on Sunday in the journal Nature Climate Change, researchers suggested that climate change is stunting the growth of animals and plants as warmer temperatures and lack of water is causing them to shrink. In addition, researchers also indicated to possible impacts on food production in the future.

According to the research, conducted by Jennifer Sheridan, a conservation biologist at the University of Alabama, and David Bickford, an evolutionary ecologist at the University of Singapore, the decrease in size is not uniform among species and because of that it could cause a major imbalance in the food chain.

The worst-case scenarios ... are that food crops and animals will shrink enough to have real implications for food security, said Bickford.

Over the past two years, researchers have documented the trend. They have also compiled and reviewed other studies and found that as many as 38 animal and plant species out of a total of 85 have showed a documented decrease in size over decades.

Included in the study are examples of species which have already shown marked decrease in their size such as the Soay sheep found in the Scottish highlands. The sheep is now five percent smaller than it was in 1985.

The study also showed that the polar bears aren't as big as they once were. The reason behind polar bears getting smaller in size is the lower levels of sea ice, according to the research.

From fossil records, the researchers also came to know that during a warming event some 55 million years ago, many species like spiders, beetles, bees, ants and cicadas shriveled in size by 50 to 75 percent over time.

Other specimens include cotton, corn, strawberries, bay scallops, shrimp, crayfish, carp, Atlantic salmon, frogs, toads, iguanas, hooded robins, red-billed gulls, California squirrels and wood rats.

An experiment, as noted by the researchers, showed that shoots and fruit are 3 to 17 percent smaller for every degree Celsius of warming in a number of plants. It is suggested that each degree of warming also trims down the body size of marine invertebrates by 0.5 to 4 percent and for fish the decrease is 6 to 22 percent.

However, the research doesn't imply that there will be any drastic changes in animal's size or sudden shrinkage in the size of humans.

I don't think that organisms will shrink to the degree that you'll walk outside and see that trees are suddenly half the size that they sued to be, Sheridan said. The theory is as things get warmer they don't need to grow as large.

According to LiveScience, some modern shrinkage is expected to come about indirectly. For instance, increasing acidity in the ocean - caused by increased carbon dioxide in the atmosphere - interferes with some organisms' ability to build their calcium carbonate shells or skeletons like corals.

However, since the present conditions are changing faster than the earlier times, it's not easy to predict the effects.