The possibility of nuclear winter was first proposed by scientists like Carl Sagan in the 1980s. It’s a simple concept really. When nuclear weapons destroy cities, massive fires are started that create superheated fumes which carry minute particles of smoke and soot high into the stratosphere where no rain exists to wash them out.

A polluted stratosphere decreases surface sunlight. Temperatures plummet, and rainfall is reduced. The effect on agriculture is devastating. Even a ‘moderate’ nuclear winter can trigger widespread famine, economic devastation, and political chaos far beyond the nuclear impact zones.

Just a Theory?

Once an unproven hypothesis, nuclear winter is now confirmed by major scientific studies. Research performed in Europe, and at Rutgers University beginning in 2007, used advanced computer climate models to see what would happen if India and Pakistan attacked each other with half of their ‘modest’ nuclear arsenals. That would be less than one-fifth of 1% of the world’s nuclear firepower, but millions would still die from starvation as crops failed around the world.

Follow-on studies in 2013 drew even grimmer conclusions. Then, in October 2019, the results of the most comprehensive research on nuclear winter ever conducted were published. Due to their expanding nuclear arsenals, if India and Pakistan had a nuclear war today, as many as 2 billion people would starve to death.

The scientists then performed studies on a nuclear war between America and Russia. A 70% reduction in surface sunlight was predicted. Temperatures would be lower than the peak of the last Ice Age 20,000 years ago, eliminating agricultural growing seasons worldwide for several years. It sounds like overly dramatic fiction, but survivors really would be those who built secret underground bunkers stocked with everything required to live independently for several years.

Tangible Evidence

While those studies are certainly concerning, evidence supporting nuclear winter is not confined to scientific studies. A real-life warning was seen when the largest series of volcanic eruptions in recorded history happened in Indonesia in 1815. The stratosphere was contaminated, but the worldwide temperature drop wasn’t half of what a nuclear war between India and Pakistan would bring today.

Yet 1816 still became known as the “Year Without Summer.” Crop-killing frosts struck every month in New England, while Europe suffered widespread famine. So gloomy was the summer of 1816 that Mary Shelly was inspired to write her classic tale of Horror, Frankenstein.

Although a nuclear war between India and Pakistan today would impact agriculture more than the 1815 volcanoes did, a nuclear war between America and Russia would be unspeakable.

Why This Matters in 2025

The threat of nuclear winter is no longer theoretical speculation. Modern computer climate models consider the impact of aerosol physics, polar ice caps, ocean and atmospheric interactions, and agricultural output data to project both short- and long-term conclusions. The consensus is clear: nuclear winter is not only likely, but a given, if a nuclear war is fought today.

Yet despite overwhelming evidence, nuclear policy discussions still remain focused on nuclear proliferation, deterrence theory, and political posturing. Rarely do they incorporate the far-reaching effects of mass starvation. Recognizing that reality should not be a footnote in nuclear policy making—it should be central to it.

Conclusion

At Our Planet Project Foundation, we believe that addressing nuclear risks means not only confronting the immediate devastation of nuclear war but also its long-term consequences. Armed with that approach, we aim to help build public awareness, foster renewed dialogue, and support policies that ensure our continued survival.