Earth is greener today than it was 20 years ago thanks to 'human activity,' NASA study showsA new findings from NASA revealed that the planet has seen an overall increase in greening over the last 20 years, due mainly in part to “ambitious tree planting programs.” The research published on Feb. 11 found that the greening of earth over the course of the last two decades has shown an overall increase by 5 percent, equal to more than two million square miles of extra green leaf area per year compared to the early 2000s. The data, which compared satellite images from...