Some of the world's top environmental scientists are calling for safer nuclear power as a way to minimize fossil fuel use, news sources reported.

Climate and energy experts James Hansen, Ken Caldeira, Kerry Emanuel and Tom Wigley released an open letter Sunday urging environmental groups and politicians around the world to support the development of safer nuclear power generators, CNN reported. 

The scientists said wind and solar energy will not be enough to fend off global warming and deliver the amount of affordable and dependable energy the world needs, the Associated Press reported. 

"Those energy sources cannot scale up fast enough," the letter said, the Associated Press reported. 

Without safer nuclear energy systems, the scientists think the planet's overall energy consumption will become too great to reverse the effects of fossil fuel pollution, which puts polar ice sheets and rising sea levels at risk, CNN reported.

In sending this letter, the scientists are "putting their reputations on the line to do something that the ultra-greens regard as treason," said Burton Richter, Nobel-winning physicist from Stanford University, CNN reported.