A study based on data gathered by a NASA sensor has revealed China and India, the world's two most populous countries, are primarily responsible for making the Earth greener over the past two decades.
The study, published on Feb 11 in the journal Natural Sustainability, has found that since 2000 the Earth's green leaf area has increased by over 5 million square kilometers. That's an area equivalent to the total of the Amazon rainforests. "China and India account for one-third of the greening, considering the general idea of land degradation (退化) in populous countries from overexploitation," said Chen Chi from Boston University, lead author of the study.
The effect mainly comes from ambitious tree-planting programs in China and intensive agriculture in both countries, NASA said in a statement. China is the source of a quarter of the planet's increase in forest area, despite having only 6.6 percent of the world's vegetated (固定植被的)area, according to the study. Forest conservation and expansion programs account for 42 percent of the increase, and another 32 percent come from intensive agriculture of food crops, NASA said. While raising their green leaf areas, China and India have also greatly increased their food production through" multiple cropping" practices, where a field is replanted and crops are harvested several time each year. "Production of grains, vegetable, fruits and more have increased by about 35 to 40 percent since 2000 to feed their large population," NASA said.
Over the past decades, China has made great efforts to green the land. In 1978, the central government launched a national-level forestation project-the Three North Shelterbelt Forest Program. By the end of 2017, the forest coverage rate among the regions in the project reached 13.57 percent, compared to 5.05 percent 40 years ago. In a greening project, Kubuqi Desert, seventh largest in the country, has seen one-third of its area covered by vegetation during the past three decades thanks to forestation efforts.
