A nuclear war between world powers would trigger a ‘Little Ice Age’

BATON ROUGE, La. — A nuclear war between NATO and Russia or another pair of world powers would trigger a “Nuclear Little Ice Age” lasting thousands of years, a new study warns.

Firestorms would release ash and smoke into the upper atmosphere that would block out the Sun, resulting in crop failure around the world, according to researchers from Louisiana State University. In the first month following these catastrophic detonations, average global temperatures would plunge by about 13 degrees Fahrenheit, more than during the most recent Ice Age.

That event ended 11,700 years ago, killing off creatures like the woolly mammoth. Overall, the last Ice Age lasted more than 100,000 years, making the world about 10 degrees Fahrenheit colder than it is today.

“It doesn’t matter who is bombing whom. It can be India and Pakistan or NATO and Russia. Once the smoke is released into the upper atmosphere, it spreads globally and affects everyone,” says lead author Dr. Cheryl Harrison in a university release.

Study authors say Russia’s invasion of Ukraine has brought the threat of nuclear escalation to reality once again. The study is based on multiple regional and large-scale computer simulations. It is also the first to provide stark information on the exact impact nuclear explosions would have on the planet.

Nuclear war would trigger a global ocean famine

Nine nations currently control more than 13,000 nuclear weapons, according to the Stockholm International Peace Research Institute. The analysis showed ocean temperatures drop quickly and do not return to their pre-war state even after the smoke clears.

As the planet gets colder, sea ice expands by more than six million square miles and up to six feet deep. This would block major ports including Beijing, Copenhagen, and St. Petersburg. It would also spread into normally temperate coastal regions, preventing shipping across the Northern Hemisphere.

Getting food and supplies into some cities such as Shanghai, where ships are not prepared to face sea ice, would become more difficult. The sudden drop in light and sea temperatures, especially from the Arctic to the North Atlantic and North Pacific, would kill algae — the bedrock of the marine food web. Researchers warn that most fishing and aquaculture would come to an end by the creation of “essentially a famine in the ocean.”

The models mimicked a confrontation between the U.S. and its NATO allies and Russia using 4,400 100-kiloton nuclear weapons to bomb cities and industrial areas. Fires eject 150 teragrams, or more than 330 billion pounds, of smoke and sunlight-absorbing black carbon, into the upper atmosphere.

Other models simulated India and Pakistan detonating 500 100-kiloton nuclear weapons, which led to between five and 47 teragrams (11 billion to 103 billion lbs.) of smoke and ash.

“Nuclear warfare results in dire consequences for everyone. World leaders have used our studies previously as an impetus to end the nuclear arms race in the 1980s, and five years ago to pass a treaty in the United Nations to ban nuclear weapons. We hope that this new study will encourage more nations to ratify the ban treaty,” says co-author Professor Alan Robock of Rutgers University.

Comparing nuclear war to volcanic eruptions

The calculations also demonstrate the interconnectedness of Earth’s systems, especially in the face of disturbances from volcanic eruptions, massive wildfires, or war.

“The current war in Ukraine with Russia and how it has affected gas prices, really shows us how fragile our global economy and our supply chains are to what may seem like regional conflicts and perturbations,” Dr. Harrison adds.

Volcanic eruptions also produce clouds of particles in the upper atmosphere. Throughout history, they have had similar negative impacts on the planet and civilization.

“We can avoid nuclear war, but volcanic eruptions are definitely going to happen again. There’s nothing we can do about it, so it’s important when we’re talking about resilience and how to design our society, that we consider what we need to do to prepare for unavoidable climate shocks,” Harrison concludes.

“We can and must however, do everything we can to avoid nuclear war. The effects are too likely to be globally catastrophic.”

Study authors note that oceans take longer to recover than land. In the worst-case scenarios, it is likely to take decades at the surface and hundreds of years at depth to recover from nuclear war. Changes to arctic sea ice will likely last thousands of years and effectively trigger a “Nuclear Little Ice Age” according to the team.

The findings are published in the journal AGU Advances.

South West News Service writer Mark Waghorn contributed to this report.