Bengaluru: Two of the world’s three biggest carbon dioxide emitters, India and China, are also the biggest contributors to global greening, a study has claimed.
Greening is the increase in the world’s green cover, including forests and crop area.
The study, published in the Nature Sustainability journal, says India and China accounted for over 32 per cent of the greening between 2000 and 2017 thanks to “efficient” planting of trees and crops.
Conducted by researchers at Boston University, US, the study is based on satellite data.
China crusade pays off
The global leaf area, according to the study, is increasing at the rate of 2.3 per cent per decade.
According to the study, the global green leaf area increased by 5 per cent, or 5.5 million square kilometres, between 2000 and 2017. This is roughly equivalent to half the area of Europe.
While China accounted for 25 per cent of the increase, India was a distant second with a share of 6.8 per cent. Europe comes in third.
Explaining China’s huge contribution, the study notes how the country is “engineering ambitious programmes to conserve and expand forests with the goal of mitigating land degradation, air pollution and climate change”.
The research also credits India and China’s high share to a 35 per cent increase in food production in both countries, boosted by improved agricultural practices, fertiliser use, and irrigation.
Other studies that have measured the impact of these processes and policies have found that India and China are lowering land pollution and degradation of top soil as well as lowering surface temperatures. This, however, has stressed water resources.
Also read: India and China are greener than you think, says NASA
‘Global greening’ and global-warming denial
Global greening is something climate-change denialists swear by. They have used reports about greening to claim that fossil fuels and carbon dioxide are actually good for Earth.
On the face of it, the logic makes sense, but it is accompanied by dire caveats that are often left out of such narratives. Intuitively, an increase in carbon dioxide would mean more fuel for plants. This leads to a sudden spurt in the growth of forests and grasslands around the world — hence the term ‘global greening’ or ‘carbon dioxide greening’.
It is very much a real phenomenon and responsible for the slight increase in greening across the world seen in satellite images, including in places like Australia and Alaska.
However, not all greening is good.
Plants that grow in higher than normal levels of carbon dioxide tend to be less rich in nutrients and minerals. The more they work to convert all that carbon dioxide by photosynthesis, the more they will use up more nutrients, causing them to deplete the soil much quicker.
Then, there’s respiration. As the sun sets, plants reverse their photosynthetic process and begin respiration, where they release carbon dioxide into the air. Given the increase in the number of plants, the amount of carbon dioxide going into the air climbs up as well.
Finally, more carbon dioxide won’t always mean more greenery. Our rates of emissions are expanding exponentially and plants will eventually stop keeping up.
Human effort
Dire as this sounds, though, the study notes that human efforts had a big role to play in the increasing greening.
It notes that, according to satellite data, the greening has been intentional, not a by-product of global warming. The report shows that human habits lead to direct changes in the amount of woody vegetation. Furthermore, human-generated crops are responsible for large amounts of greening.
“Our results indicate that the direct factor is a key driver of the ‘Greening Earth’, accounting for over a third, and probably more, of the observed net increase in green leaf area,” the researchers note in the study.
Also read: Greening may not be the answer to a warming planet