redOrbit: The Intergovernmental Panel on Climate Change believes the Earth will not have to warm up as much as recently thought to experience the consequences of global warming, including more extreme weather and increasing threats to plants and animals. Researchers estimated that the risk of problematic severe weather would rise with a global average temperature increase of between 1.8 degrees and 3.6 degrees Fahrenheit above 1990 levels. Researchers point out that “increases in …