According to a study recently published by NASA in the journal Nature Sustainability, the planet has become greener in the past 20 years. And the main contributors are unexpected: China and India. Together, they account for a third of the increase in leaf area.

The discovery is based on data gathered by MODIS, an instrument that has been orbiting the Earth for almost 20 years. At first, NASA thought that the greening of the planet was a result of a warmer, wetter climate and of fertilization from the added carbon dioxide in the atmosphere. But now, investigators have revealed that those aren’t the only reasons.

“The effect stems mainly from ambitious tree planting programs in China and intensive agriculture in both countries,” NASA explained. Specifically, 42% of China’s contribution to the “global greening trend” is from programs to conserve and expand forests; another 32% comes from “intensive cultivation of food crops.” As for India, 82% of the greening is the result of intensive agriculture.

Besides contributing to a greener Earth, the efforts these nations have taken on led to an increase in food production. Since 2000, the cultivation of grains, vegetables, and fruits rose between 35% and 40%.

The increase in leaf area in plants and trees reported by NASA is equivalent to the area covered by all the Amazon rainforests. However, the investigators note, this gain “does not offset the damage from loss of natural vegetation in tropical regions, such as Brazil and Indonesia. The consequences for sustainability and biodiversity in those ecosystems remain.”

Want to get news like this in your inbox? Subscribe our newsletter.