Friday, February 5, 2010

More carbon dioxide in atmosphere, more forest cover will be there to absorb it.

Increasing carbon dioxide benefits trees.
Dr. Nitish Priyadarshi

Almost 100% of the observed temperature increase over the last 50 years has been due to the increase in the atmosphere of carbon dioxide and other greenhouse gas concentrations like water vapour, methane and ozone.. The largest contributing source of carbon dioxide gas is the burning of fossil fuels. Research says more carbon dioxide more heating of the earth. This is one aspect of the carbon dioxide. Other aspect is its relation with the trees. If we believe on the researches by the scientists, increasing carbon dioxide benefits trees.

Scientists from the University of Wisconsin-Madison and the University of Minnesota at Morris have found that increased levels of atmospheric carbon dioxide have led to the rapid growth of certain tree species. The quaking aspen, a popular North America deciduous tree, has seen a 50 percent acceleration in growth over the past 50 years due to increased CO2 levels.

Trees are necessary climate regulators since they process carbon dioxide and give off oxygen. Humans process oxygen and give off carbon dioxide, working harmoniously with natural plant life to maintain proper atmospheric composition. Since natural forests represent about 30 percent of the earth’s surface, they are highly effective at segregating greenhouse gases.

For many a tree, the first response to the increase of carbon dioxide levels in the air is an increase in photosynthesis. More carbon dioxide, CO2, in the air means more sugar can be made by photosynthesis. Making more sugar pushes the tree into a growth spurt. Trunks and branches grow taller, longer, and thicker; new branches and leaves form; and roots send out more long, thin root strands covered with root hairs.

As more fossil fuels are burned than ever before, more CO2 is dumped into the air than ever before. The trees will respond with more photosynthesis and fresh growth more quickly than ever before.

Africa's tropical forests have stored huge amounts of carbon over the last four decades and become a critical sponge for greenhouse gases.

Long-term measurements taken across the continent's tropical belt showed that African forests absorb as much carbon dioxide as those in the Amazon.Tropical forests only account for seven-to-ten percent of the Earth's land area. But they hold up to half of the carbon locked inside the planet's terrestrial vegetation, giving them an outsized role in regulating greenhouse gases in the atmosphere. Forests are carbon stores, and they are carbon dioxide sinks when they are increasing in density or area.Previous studies in South America have shown that Amazonian old-growth forests have absorbed, on average, an extra 620 kilogramme (1,364 pounds) of carbon per hectare (2.47 acres) per year. About 70-80 billion tonnes of carbon dioxide are fixed annually by terrestrial and aquatic photoautotrophs.
African tropical forests are providing important ecosystem services by storing carbon and being a carbon sink, thereby reducing the rate of increase in atmospheric CO2, the main driver of global warming.

If increasing carbon dioxide benefits trees. And trees absorb carbon, then why we are so worried about increasing carbon dioxide?

Worry is that with increasing carbon dioxide, forest cover is depleting many folds either due to forest fire or due to civilized human beings. The accelerating destruction of the rainforests that form a precious cooling band around the Earth's equator, is now being recognized as one of the main causes of climate change.

So if we have to fight global warming and increasing carbon dioxide level we have to give space for more forest cover. We will have to protect growing trees which are the major consumers of carbon dioxide. Slogan like “MORE TREES, MORE OXYGEN AND LESS CARBON DIOXIDE” is more relevant in present scenario.

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