The risk of nuclear war

Hey there, time traveller!
This article was published 30/04/2025 (333 days ago), so information in it may no longer be current.

India and Pakistan have had several shooting matches since they carried out a total of nine underground nuclear weapons tests in 1998. However, they don’t make Putin-style thinly veiled threats to use their nukes (around 170 nuclear warheads each at the moment), and they do understand that escalation from smaller, “conventional” wars is the real danger.

However, the relationship between the two countries is fundamentally unstable, because Pakistan has only one-sixth of India’s population and one-tenth of its wealth.

Conventional wars are basically wars of attrition, which means Pakistan would almost certainly lose a non-nuclear conflict. By contrast, both countries would be destroyed in a nuclear war, so threatening to escalate a war to the nuclear level would give Pakistan a weird kind of leverage.

The two countries have not strayed that far into the swamp of nuclear deterrence theory yet, but they will probably get there in the end. Yet the rest of the world pays almost no attention to these ‘local’ calculations, because other countries doesn’t feel threatened by a nuclear war between India and Pakistan. They believe it would largely stay within South Asia.

They are wrong about that, which is why the present confrontation between the two is far more dangerous for the world than the Ukraine war or any other current conflict.

The trigger for the India-Pakistan crisis this time was a terrorist attack in the Indian-controlled part of Kashmir on April 22 by four gunmen who stepped out of the woods at a well-known tourist site and machine-gunned a group of Indian tourists, killing 26 of them.

All the dead but one were Indian Hindus. The terrorists have been identified as Kashmiri Muslims or Pakistani citizens of Kashmiri origin, and the Indian government has declared that they were supported by the Pakistani government. That is possible, but India has offered no evidence and a homegrown Kashmiri group is an equally plausible alternative.

Kashmir was India’s only Muslim-majority state, and since Prime Minister Narendra Modi’s sectarian Hindu and ultra-nationalist regime ended its special status in 2019 it has been boiling with resentment and is effectively occupied by the Indian army.

Matters have now got worse, with Modi suspending the Indus Waters Treaty of 1960 that regulates the sharing of the six rivers’ water between India and Pakistan. The water is important for India but utterly existential for Pakistan, where it irrigates 80 per cent of the land on which the country grows the food for its quarter-billion people.

Many other countries have leaders just as reckless, but few of them have nuclear weapons. And Modi is playing with far more lives than the others: not just the 20 million “prompt” dead expected from blast, fires and fall-out in a full-scale Indo-Pak nuclear war, but the 200 million to two billion dead predicted elsewhere in a ten-year “nuclear winter.”

A nuclear winter is a long period with conditions cold enough to cut global food production. It would start with hundreds of firestorms in cities hit by nuclear explosions that boost enormous amounts of soot in the stratosphere. The soot blocks much of the incoming sunlight — and it stays there for years because there is no rain in the stratosphere to remove it.

The original calculations were done in the 1980s for an all-out nuclear war between the U.S. and the Soviet Union, but a decade ago a team led by professors Alan Robock and Brian Toon of Rutgers and Colorado Universities redid the calculations for an Indo-Pak nuclear war on fast modern computers with a huge data-processing capacity. The results were horrifying.

Several hundred burning cities in India and Pakistan provide the initial boost of soot into the stratosphere over South Asia as before, but we now know that prevailing upper-altitude winds would carry most of it east and north until it blankets most of the northern temperate zone as well.

Countries south of the equator would fare somewhat better, but countries in North America, Europe, the Middle East and East Asia would not be spared. Famine conditions would prevail worldwide for about 10 years.

Go on worrying about Ukraine, Gaza, Iran, Taiwan and so on, but the big threat is a nuclear war between India and Pakistan.

Gwynne Dyer’s new book is Intervention Earth: Life-Saving Ideas from the World’s Climate Engineers.