The world is a greener place than it was 20 years ago. A study published in the journal “Nature Sustainability” said that recent satellite data reveals a greening pattern that is strikingly prominent in China and India. The study shows that human activity in China and India dominates this greening of the planet, thanks to tree planting and agriculture. The effect comes mostly from ambitious tree-planting programs in China and intensive agriculture in both countries.
“China and India account for one-third of the greening,” said lead author Chi Chen of Boston University. “ That is a surprising finding, considering the vague idea of land degradation (毁坏) in populous countries from overexploitation,” added Chen.
China alone accounts for 25 percent of the global net increase in leaf area with only 6.6 percent of global vegetated area. The greening in China is from forests (42 percent) and croplands (32 percent), but in India, it is mostly from croplands (82 percent) with minor contribution from forests (4.4 percent).
China's outsized contribution to the global greening trend comes in large part from its programs to conserve and expand forests with the goal of preventing land degradation, air pollution, and climate change.
“Once people realize there is a problem, they tend to fix it,” said Rama Nemani, research scientist and co-author of the study. “In the 1970s and 80s in India and China, the situation around vegetation loss was not good. In the 1990s, people realized it, and today things have improved. Now we see that humans are contributing.”
Land area used to grow crops is comparable in China and India—more than 770, 000 square miles—and has not changed much since the early 2000s. Yet these regions have greatly increased both their annual total green leaf area and their food production.
This was achieved through multiple cropping practices, where a field is replanted to produce another harvest several times a year. Production of grains, vegetables, fruits and more have increased by about 35%～40% since 2000 to feed their large populations.
