Oranges are seen in a tree as the citrus industry tries to find a cure for the disease 'citrus greening' that is caused by the Asian citrus psyllid, an insect, that carries the bacterium, 'citrus greening' or huanglongbing, from tree to tree on May 13, 2013 in Fort Pierce, Florida. There is no known cure for the disease that forms when the insect deposits the bacterium on citrus trees causing the leaves on the tree to turn yellow the roots...

World leaders are gathered in Paris for , or COP21, to try create international legislation to help solve the world's greatest climate change issues. Here are five things you should know about COP21 as it kicks off in Paris today: Protests and Presidents Hundreds of thousands of people across several countries marched in a collective call to action Sunday with the goal of putting political pressure on world leaders to collectively lower emissions and reduce long-term global warming. According to...

This image from space shows widespread smog in eastern China on Nov. 30, 2015. (NASA's Earth Observatory) For millions of Chinese residents, a cold front brought exactly what they'd been waiting for: a chance to see the sky again. Thick, choking, dangerous smog blanketed the city for days, forcing people to stay inside. Pollution levels were off-the-charts awful in China's second-largest city, and officials raised the alert level to a code orange– the second-highest level– for several days. What caused...