The world is literally a greener place than it was twenty years ago, with huge swathes of China and India seeing new tree growth on a scale previously unseen according to new data released by NASA.
Ambitious tree-planting programs in China and intensive agricultural policies are driving the trend.
The greening phenomenon was first detected using satellite imagery in the mid-1990’s, but the original researchers were unable to conclude whether or not human activity was the root casue.
However, twenty years on from the original observations, NASA has developed new technology and observational techniques that show that over the last two decades, plants and trees equivalent to the entirety of the Amazon rainforests have been cultivated as a result of human activity.
“China and India account for one-third of the greening, but contain only 9% of the planet’s land area covered in vegetation – a surprising finding, considering the general notion of land degradation in populous countries from overexploitation,” said Chi Chen of the Department of Earth and Environment at Boston University, in Massachusetts, and lead author of the study.
China’s outsized contribution to the global greening trend comes in large part (42%) from programs to conserve and expand forests. These were developed in an effort to reduce the effects of soil erosion, air pollution and climate change. Another 32% of the greening change in China – and 82% of the greening seen in India – comes from intensivecultivation of food crops.
How the greening trend may change in the future depends on numerous factors. For example, increased food production in India is facilitated by groundwater irrigation. If the groundwater is depleted, this trend may change. The researchers also pointed out that the gain in greenness around the world does not necessarily offset the loss of natural vegetation in tropical regions such as Brazil and Indonesia. There are consequences for sustainability and biodiversity in those ecosystems beyond the simple greenness of the landscape.
The research was published in the journal Nature Sustainability and can be found here