A group of scientists and students at the University of Colorado Boulder are working to calculate the environmental and human impact of a potential nuclear war.

Professor Brian Toon of CU Boulder's Laboratory for Atmospheric and Space Physics, and Rutgers professor Alan Robock have been studying the threat in-depth for decades, but are launching a new study to calculate in detail for the first time the impacts of nuclear war on agriculture, the oceanic food chain and on humans.

They use weather maps and study patterns of fires started by nuclear detonations.

"One of our goals for this study is to inform people how dangerous these weapons are by providing a solid scientific analysis of the issues," Toon said.

He and Robock say the big problem with nuclear war is a term you've probably heard, "nuclear winter," which would affect the world's supply of food.

"These weapons start massive fires in cities and huge amounts of smoke are carried into the upper atmosphere, which spreads around the Earth - blocking the sun and throwing the world into sub-ice age temperatures, which means basically, you can't grow anything for several years," Toon said.

Toon's team uses climate models developed by the National Center for Atmospheric Research in Boulder to calculate fire fuels around the world and agricultural and world trade food models.

They are also calculating how much smoke might be produced by nuclear blasts.

The new project is funded by a three-year, $3 million grant from the Open Philanthropy Project headquartered in San Francisco.