Despite Deforestation, the World Is Getting Greener

Carbon flows between the world's oceans, air and land.  It is present in the atmosphere primarily as carbon dioxide (CO2) - the main climate-changing gas - and stored as carbon in trees.

Through photosynthesis, trees convert carbon dioxide into the food they need to grow, locking the carbon in their wood.

The 4-billion-tonne increase is minuscule compared to the 60 billion

tonnes of carbon released into the atmosphere by fossil fuel burning and cement production over the same period, said Yi Liu, the study's lead author and a scientist at the University of New South Wales.

"From this research, we can see these plants can help absorb some carbon dioxide, but there's still a lot of carbon dioxide staying in the atmosphere," Liu said by telephone from Sydney.

"If we want to stabilize the current level of carbon dioxide in the atmosphere - and avoid the consequent impacts - it still requires us to reduce fossil fuel emissions."

Liu, who specializes in observing the water cycle including rainfall and soil moisture, used a new technique of collecting satellite data on radio frequency radiation naturally emitted by the Earth to calculate the amount of vegetation in a given area.

Before, scientists measured vegetation through satellite images and other techniques, looking at canopy greenness and plant height, he said.

Read more at Despite Deforestation, the World Is Getting Greener: Scientists