Governments should treat climate change as seriously as threats to national security or public health, partly by focusing more on the worst scenarios of rising temperatures, an international report said on Monday.

Crop failures, extreme heat waves or high rates of sea level rise could be so harmful that governments should examine even small chances of the most severe impacts, according to the study by about 60 experts from 11 nations.

"The risks of climate change should be assessed in the same way as risks to national security or public health," according to the experts from countries that included Britain, the United States, China, Russia and India.

"When we think about keeping our country safe, we always consider the worst case scenarios," British Foreign Office Minister Joyce Anelay, whose government was among the report's sponsors, said in a statement.

"That is what guides our policies on nuclear non-proliferation, counter-terrorism and conflict prevention. We have to think about climate change the same way," she said.

Read More: Climate Change Dangers Are 'Higher Than Ever': U.N. Report

The study said U.N. reports about climate change focused mainly on moderate warming and rarely mentioned the impacts of 9 degrees Fahrenheit or more, which are far less likely but would be far more damaging.