Politics undoubtedly cloud the issue of climate change. But if 97 percent of actively publishing climate scientists, 18 American scientific associations, 200 worldwide scientific organizations, and numerous science academies, U.S. government agencies and intergovernmental bodies are right about human-caused climate change, you should be afraid. Very afraid [source: Shaftel].
Here are the facts. Sea levels have risen 6.7 inches (17 centimeters) over the past century. As of 2016, the 10 warmest years since 1880 have all happened within the past 12 years. Oceans are warming and acidifying. Ice sheets, Arctic sea ice, glaciers and snow cover are all retreating [source: NASA, "Climate Change"]. And the cause of all these changes, atmospheric carbon dioxide, has risen to concentrations that are unprecedented in human history. In 2016 an important measurement station in Tasmania recorded levels exceeding 400 parts per million, which is higher than any time in the past 15 million years [source: Readfearn].
So what's the big deal? Some of the consequences of a warming planet are already happening, including accelerated sea rise, more intense rainfall, more severe heat waves, increased wildfires and decreased water availability. A trend toward stronger and more frequent hurricanes, though not yet definitively tied to climate change, is also expected to accelerate.
Those in vulnerable areas, like the low-lying Pacific island nation of Kiribati, are particularly concerned but determined to fight back. That nation's leader directed a Japanese firm draw up plans for a floating island to sustain part of the country's population and purchased land on nearby Fiji to evacuate the rest [source: Worland]. While such actions may seem crazy now, they could one day prove necessary. Scientists believe climate change will continue to affect the planet through this century and beyond [source: NASA, "The Consequences"].