Washington Post: JUST HOW much will the Earth heat up over the next 100 or 200 years? Climate scientists are not able to predict with high certainty. They have estimated that average global temperatures will increase by 1.5 to 4.5 degrees Celsius -- 2.7 to 8.1 degrees Fahrenheit -- given a doubling of carbon dioxide in the atmosphere. That range of estimates for "climate sensitivity' would mean the difference between relatively small effects and significant consequences for human welfare.
There are skeptics...