Smoke from B.C. wildfire supports expert's conclusions for nuclear winter

Unprecedented smoke from British Columbia's wildfires in 2017 is helping scientists model the potential impacts of nuclear war on the Earth's climate, says a study from Rutgers University.

The enormous plume of smoke formed the largest cloud of its kind ever observed, which circled the Northern Hemisphere, says the study published Thursday in the peer-reviewed academic journal Science.

The cloud, called a pyrocumulonimbus, formed over the wildfire and sent black carbon high into the atmosphere, said the study's co-author Alan Robock, a distinguished professor in the department of environmental sciences at Rutgers in New Jersey.

The scientists used a climate model from the National Center for Atmospheric Research in the U.S. to forecast the movement of the dark cloud high into the Earth's stratosphere, where there is no rain, Robock said.

"This smoke that lofted up, that's what our climate models told us would happen if we put smoke in (the model) as a result of fires from burning cities and industrial areas as if there was a nuclear war," said Robock.

The smoke lasted more than eight months in the stratosphere, where there is no rain to wash it away, the study said.

When soot heats up and extends higher into the stratosphere the process is known as self-lofting, it said.

"We had never observed it actually happen," said Robock. "This natural occurrence validated what we had done before in our climate models, so it gave us more confidence that what we were doing was correct."

The team of researchers, including Robock, plugged the data from the B.C. wildfires into their software and successfully compared the real and the projected results, validating their ongoing climate modeling.

Robock has been studying and modeling the potential impacts of a so-called nuclear winter since 1984. Even a relatively small nuclear war between India and Pakistan would, for example, send soot into the stratosphere, causing unprecedented climatic cooling, he said.

"The temperatures wouldn't get below freezing in the summer like they would with a war between the United States and Russia. But it would still have devastating effects on agriculture around the world, far removed from where the bombs were dropped," said Robock, who added that global cooling as a result of nuclear war is by no means a solution to the global heating occurring today.

In the case of nuclear winter resulting from a nuclear war between large superpowers, Robock said temperatures would dip below freezing in the summertime and stay there for years, causing starvation as agriculture grinds to a halt around the world.

The wildfire smoke cloud contained 0.3 million U.S. tons of soot, while a nuclear war between the United States and Russia could generate 150 million tons, Robock said.

It was the consensus on nuclear winter between both Soviet and American scientists that encouraged the de-escalation of the nuclear arms race in the second half of the 20th century, he said.

Robock said he hopes the modeling of the climatic consequences of nuclear war will help convince countries to sign the UN Treaty on the Prohibition of Nuclear Weapons.

There are currently 24 signatories to the treaty, which was adopted by the UN in July 2017 and is meant to be a legally binding mechanism to prohibit nuclear weapons and work towards their elimination worldwide.

Fifty countries must sign on to the treaty before it can come into force.

To date, neither Canada nor any of the nine countries known to be in possession of nuclear weapons have signed the treaty.