The world is becoming a greener place compared to the past 20 years, thanks to India and China. It is the vast tree planting programs in China and agriculture in both countries that have contributed to a greener earth. Data from NASA's Moderate Resolution Imaging Spectroradiometer, or MODIS, system on two satellites orbiting the Earth helped scientists collect decade-long information enabling them to compare the findings. The research was published in the journal Nature Sustainability.

The "greening effect" was first noted by researchers at Boston University who were looking at satellite images from the mid-1990s. While they had been noting it since then, scientists were not sure if human activity is the direct cause. Chi Chen of the Department of Earth and Environment at Boston University, in Massachusetts, and lead author of the study said, "China and India account for one-third of the greening, but contain only 9 percent of the planet’s land area covered in vegetation – a surprising finding, considering the general notion of land degradation in populous countries from overexploitation." UN Says Earth's Ozone Layer is Healing.

The increased green area on Earth (Photo Credits: NASA Earth Observatory)

MODIS helped researchers understand things happening with Earth's vegetation even to 500 meters, or about 1,600 feet, on the ground. The report says that information from the last two decades shows an increase in leaf area equal to that covered by all the Amazon rainforests. Compared to the 2000s, today there are now more than two million square miles of extra green leaf area per year which is a five percent increase.

India and China lead in greenery (Photo Credits: NASA Earth Observatory)

China contributed 42 percent in this green trend with various programs to conserve and expand forests. Around 32 percent through various initiatives to reduce the effects of soil erosion, air pollution and climate change. In India, intensive agriculture contributed to 82 percent of the greening effect with large scale irrigation and fertilisers.

Earth is greener than 20 years ago (Photo Credits: NASA Earth Observatory)

Rama Nemani, a research scientist at NASA’s Ames Research Center, in California’s Silicon Valley, and a co-author of the new work said, "This long-term data let us dig deeper. When the greening of the Earth was first observed, we thought it was due to a warmer, wetter climate and fertilisation from the added carbon dioxide in the atmosphere, leading to more leaf growth in northern forests, for instance. Now, with the MODIS data that lets us understand the phenomenon at really small scales, we see that humans are also contributing." 4 Truths That Make Us Wonder Whether The Earth Will Survive 50 Years From Now.

Land area in both the countries to grow crops which is more than 770,000 square miles has not changed a lot since the 2000s. Multiple cropping practices are among things that helped in largescale production of grains, vegetables and fruits by 35 to 50 percent since 2000. However, researchers say that the greenness in India and China does not balance the damage caused in tropical regions like Brazil and Indonesia. Amazon Forests Failing to Keep Up With Climate Change: Study.

Overall, Nemani sees a positive message in the new findings. He said, "Once people realise there’s a problem, they tend to fix it. In the 70s and 80s in India and China, the situation around vegetation loss wasn’t good; in the 90s, people realised it; and today things have improved. Humans are incredibly resilient. That's what we see in the satellite data."

(The above story first appeared on LatestLY on Feb 18, 2019 04:36 PM IST. For more news and updates on politics, world, sports, entertainment and lifestyle, log on to our website latestly.com).