Global Warming

Carbon dioxide making earth greener, reveals new research

The earth is getting greener because of higher carbon dioxide (CO2) levels in the atmosphere, new research shows.

Observations by Nasa satellites over the past 33 years show that there has been a steady increase in leaves on plants and trees, which scientists think is because of the higher CO2 levels. Leaves absorb CO2 and combine it with water to produce food for the plants. The study was done by an international team of 32 scientists from 24 institutions in eight countries and has been published in the journal Nature Climate Change.

Burning oil, gas, coal and wood for energy releases CO2 in to the air. The amount of CO2 in the air has been increasing since the industrial age and currently stands at a level not seen in at least half-a-million years. It is the chief culprit of climate change.

About 85% of the Earth's ice-free lands is covered by vegetation. The area of all green leaves on Earth is equal to, on average, 32% of the Earth's total surface area - oceans, lands and permanent ice sheets combined. "The greening over the past 33 years reported in this study is equivalent to adding a green continent about two-times the size of mainland USA (18 million km2), and has the ability to fundamentally change the cycling of water and carbon in the climate system.

Every year, about one-half of the 10 billion tons of carbon emitted in to the atmosphere from human activities remains temporarily stored, in about equal parts, in the oceans and plants.

Does this mean that high emissions are beneficial for the earth and humanity? Although many contrarians have argued this, the study authors warn that this is not so.

The fallacy of the contrarian argument is two-fold. First, the many negative aspects of climate change, namely global warming, rising sea levels, melting glaciers and sea ice, more severe tropical storms, etc. are not acknowledged. Second, studies have shown that plants acclimatize, or adjust, to rising CO2 concentration and the fertilization effect diminishes over time.

CO2 fertilization is only one, albeit a predominant, reason why the Earth is greening. The study also identified climate change, nitrogen fertilization and land management as other important reasons.