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ScienceMay 20, 2018

What happens to NZ after global nuclear war breaks out?

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We’re at the bottom of the world, but what would happen to bolt-hole of choice New Zealand after even a ‘limited’ nuclear war? Branko Marcetic talked to scientists about what will happen to the ecology, economy and overall quality of life after a hypothetical nuclear war.

A woman’s flesh burns away as she clings to a chain-link fence in a city turned to hot dust. Mushroom clouds balloon and change shape across the globe to the tune of Vera Lynn’s “We’ll Meet Again.” A shirtless man pounds his fist into the sand at the sight of a half-buried Statue of Liberty.

Anxiety over nuclear annihilation is lodged in our collective psyche, as these massive film spoilers attest to. And fair enough: we’ve blundered our way to the precipice of nuclear warfare so many times by this point that it’s a wonder how we never made it over the edge.

Next month, Donald Trump and North Korean dictator Kim Jong Un will, all going well, attempt to alleviate these fears somewhat, in what is arguably the best opportunity in decades to end conflict in the Korean peninsula and drive nuclear tensions down. But even if North Korea successfully de-nuclearises and the US stops its sabre-rattling, the world won’t be safe from the threat of future catastrophe: there remain around 15,000 nuclear weapons in the world today, nearly 14,000 of which are held by Russia and the United States, two countries currently experiencing a renaissance of mutual loathing.

Of course, the question on everybody’s lips is: should global nuclear war break out, what will happen to New Zealand? We after all currently enjoy the status of being the “bolt hole” for the world’s terrified billionaires, and our geographic distance and general disentanglement from the rest of the world’s geopolitical jostling suggests that should the worst happen, we at the very least won’t be in the firing line.

This is a small consolation. According to various experts, New Zealand would indeed likely be the best place to be in the event of a nuclear holocaust. But “best” is a relative term, and this belies just how hellish life could become on one of the world’s last inhabitable countries.

Nailing down the exact consequences of a nuclear war isn’t easy, and not just because it’s never happened. With so many variables at play – the countries involved, where they’re located, the number of weapons deployed, what time of the year it is – there’s no definitive post-war scenario.

Still, some have tried to map out a potential aftermath. In a 2014 paper for Earth’s Future, a team of scientists attempted to model the effects of a limited, regional nuclear war between India and Pakistan that would see each country use 50 warheads, each with a yield of 15 kilotons, about the same as the bomb dropped on Hiroshima.

The results weren’t pretty. Even a “limited” war like this would send five megatonnes of smoke into the stratosphere, heating it by up to 100°C and wiping out most of the earth’s ozone layer for as long as a decade. This means the average burn time in the sun would halve for humans, while the resulting surge of UV radiation would wreak havoc on the world’s vegetation and sealife, including, in the latter case, disrupting the entire food chain of the ocean and damaging marine life in its early, developmental stages.

More alarming is the fact that the colossal amount of black carbon sitting up in the stratosphere would cause a global nuclear winter, the coldest average surface temperatures in 1,000 years. That means shorter growing seasons and the destruction of crops by killing frosts, which Brian Toon, one of the authors of the report, has said would reduce yields of corn, wheat and rice by 10-40% for years afterwards.

And this is just for a “limited” war.

“After a full scale nuclear war, temperatures would plunge below Ice Age conditions,” Toon explained to a TED audience earlier this year. “No crops would grow. It’s estimated 90% of the population of the planet would starve to death.”

Where does New Zealand fit into all this? Based on what several experts have told me, there’s good news and bad news.

The good news is, we would likely be spared the worst consequences of all this. Experts like Toon and Brian Martin, a social scientist at the University of Wollongong who has a PhD in theoretical physics, say that we’d have little to fear from radiation drifting our way. The most harmful isotopes would decay before reaching our shores, and even fallout drifting over from a potential attack on Australia would likely be blown eastward, where it would be rained out.

It’s a similar story when it comes to surface temperature. According to the 2014 study, the scenario it’s based on would produce a drop of around somewhere between 1 and 1.5 degrees – nothing to sneeze at, but substantially less than the 5-7 degrees below normal predicted in the centres of North America and Eurasia.

“In New Zealand, you can still be growing crops,” says Michael Mills, an atmospheric scientist at the National Centre for Atmospheric Research, and another of the study’s authors.

Brian Toon, however, sees a less cheerful forecast in the case of a full-scale nuclear war. “It would cause low light levels and winter conditions in New Zealand for several years, perhaps up to a decade,” he says. “No one has evaluated the impact directly on New Zealand, but I would imagine nothing would grow for several years.”

Opinion is similarly split when it comes to the impact of enhanced UV radiation. Martin believes New Zealand’s geographical position means it has little to fear, though he concedes there “might be agricultural effects.”

“It might increase skin cancer rates, but that’s not the worst outcome,” he says.

Toon and Michael Mills are less sure. “I would think the oceans around New Zealand would be affected by UV radiation,” says Mills.

“I think all of these effects are global, and would impact New Zealand in the same way as other locations,” says Toon, referring to the study’s prediction that enhanced UV radiation, a drop in rainfall and other effects would create mayhem among global fisheries.

Then there’s the question of the knock-on effects on our marine ecosystems from the damage to the rest of the world’s oceans. Chris Hepburn, director of the University of Otago’s Aquaculture and Fisheries Programme says that this isn’t out of the realm of possibility.

“Indirect knock-on effects from damage to distant ecosystems comes down to connectivity,” he says. “If there is strong connectivity over long distances, such as migrating birds that perform important roles in our ecosystems, they could be impacted and thus affect ecosystem functioning in New Zealand.”

A protest against action against military vessel HMS Ark Royal in 1988. Photo: Greenpeace

Now for the bad news: even if we’re spared the worst of these effects, the impact of nuclear war would reverberate in the South Pacific thanks to trade and the economy. This wouldn’t be the case in every scenario, says Ilan Noy, Victoria University’s Professorial Chair in the Economics of Disasters, who examines economics and public policy as they relate to the management of natural disasters. In the case of a local war between India and Pakistan, which aren’t large traders, the effects would be somewhat muted.

“I don’t see world trade collapsing,” he says. “It would dent the New Zealand economy – fewer tourists, uncertainty in the world, the need to find trade replacements.”

It’s a different story when the combatants are Russia and the United States.

“I don’t really know how to think about that kind of world,” he says. “If there is an event between Russia and the US, it becomes a mess. There’s no shipping, no trade for a while, we are all down to every country surviving by itself.”

Noy says the sudden halting of global trade would create a “dramatic change in our lives.”

“Practically everything we consume is imported, directly or indirectly,” he says. “The meat we consume is not imported, but a lot of the machinery we use to extract it is imported.”

According to Noy, daily life would be set back a century, when most people relied on subsistence farming to survive – except in this case, most of us no longer have the rudimentary skills and knowledge needed to eke out this kind of existence.

“It was once estimated that New Zealand could not keep its electrical grid operating for very long due to lack of parts and expertise to repair it,” says Brian Toon. “I suspect that times would be very difficult in New Zealand.”

Toon believes fish would be the major food available in New Zealand for the first six months or so after a full-scale nuclear war, when crops would struggle to grow and trade would cease. But with fishing stocks already under pressure from overfishing, and potential damage to local and global marine ecosystems, who knows how viable this would be as a long term solution. “Mass starvation is likely,” he says.

Noy says that Australia and New Zealand together could produce enough food to survive, but the reorientation of domestic production would be a hard period of life. “In New Zealand right now, we produce way too much milk and too little of anything else,” he says. “To stop trade tomorrow and have enough food, there would be an adjustment period that would be incredibly painful.”

Brian Martin also points to the political implications of nuclear war, limited or not. If the September 11 attacks led to governments around the world stretching the reach of state power in the name of stopping terrorism, a single nuclear war could well lead to martial law. Then there’s the issue of refugees potentially knocking on our door in the hope of sanctuary – though their demographic may not be what you’d expect.

“The most significant refugee problem would be nuclear armed ships from the US or Russia, who might decide to get away by heading down and threatening New Zealand,” he says. “The rich and powerful would be the biggest threat.”

Then there are other nightmare scenarios: that this initial nuclear war is just the first of a series of world wars, or that survivors of the first war become more eager to obtain nuclear weapons. But there could be an upside too.

“One of the results of studies of disasters is that people behave rationally, are generous and communities pull together,” he says. Rather than crisis spurring on panic, violence and hatred, in other words, it could create the opposite outcome.It’s tough to say exactly what would happen to New Zealand in the aftermath of nuclear war, since there has been little to no scientific study of the subject.

“It might be the case that it’s the best of very bad choices,” says Michael Mills.

It’s fair to say, however, that this “best” choice is still not great. In the best case scenario, our economy will be dented, the ecosystems we depend on to live will be heavily damaged, and we’ll have far less food to pass around. At worst, we’ll experience mass starvation, be plunged backward in time and forced into lives we’re in no way prepared to live, and possibly be invaded by heavily armed ships led by an irradiated Jeff Bezos. It’s a sobering thought.

These conclusions largely echo a 1987 study commissioned under the Muldoon government, which likewise envisioned a society collapsed to its knees thanks to the halting of global trade and the shrinking of food supplies. Among other things, that study also pointed to the danger in losing access to pharmaceuticals, most of which were imported from the Northern Hemisphere at the time. Medical and pharmaceutical products still represent a large share of our imports today.

It’s a reminder that whatever happens on June 12 and at future global nuclear negotiations, New Zealand is not a disinterested bystander – and neither are those around the globe who want to treat this country like their own personal bomb shelter. No one gets to opt out of nuclear war.

This article was amended on May 25 to add reference to the 1987 study.


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