Climate-Nuclear Nexus

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Nuclear weapons and climate are two existential threats to the whole planet. One is not more urgent than the other. They both require immediate attention, on a scale commensurate with the scale of the threat they pose. Both require an absolutely herculean effort to overcome the obstacles put in place by the fossil fuel and nuclear weapons industries.

If nuclear weapons were ever used again, they would create a climate catastrophe at least as severe as the impending catastrophe caused by global carbon emissions. And the impending climate catastrophe is itself increasing the risk of nuclear war between the major world powers.

To save the planet, we have to eliminate both of these threats now. As of this moment, we still can.

Nuclear weapons are a climate issue

Nuclear weapons are designed to destroy entire cities and kill millions of people. We know from nuclear power plant disasters like Chernobyl and Fukushima how fast and how far radioactivity can spread, affecting people many thousands of miles away from a nuclear accident or explosion.

Radioactive particles get into the air we breathe, the water we drink, and the soil we depend on for food. They work their way up the food chain, and people eventually die – years or even decades later – from cancers and other effects of radiation poisoning.

As noted in Chapter 7, as many as 2.4 million people worldwide have died or will die from cancers caused by the nuclear weapons testing in the atmosphere during the 1950s and 60s – nearly 10 times as many as died initially from the atomic bombs dropped on Hiroshima and Nagasaki in 1945.[1]

The numbers of people killed by radiological after-effects of a nuclear war would also likely outnumber those killed outright by the bombs themselves. And yet even these numbers pale into insignificance compared to the climate effects of a nuclear war.

As we saw in Chapter 7, a full-scale exchange of nuclear weapons between the US and Russia could blast as much as 150 million tons of soot into the upper atmosphere, lowering global temperatures by as much as 7 degrees C (or 12 degrees F) for an extended period of time, plunging major food-producing regions of the world to below-freezing temperatures for several summers in a row and causing widespread famine.[2]

Results of more recent modelling of the climatic effects of a nuclear war were published in 2022.[3] These suggest that as many as 5 billion people worldwide could die from a nuclear war between the US and Russia. This new research takes into account the drop in ocean temperatures as well as the impact on crop production. It also takes into account the collapse of global trade in the aftermath of a nuclear war and many other factors.

Of course there are too many unknown variables to predict with any certainty what would happen in the event of an all-out nuclear war. But there can be little doubt that such a war would have serious climatic impacts on top of the immediate devastation of entire cities and the longer term radiation effects.

The possible use of nuclear weapons is therefore also a climate issue. The risk to human civilization and to the planet is roughly equivalent, whether the earth is suddenly overheated as a result of fossil fuel burning or suddenly overcooled as a result of nuclear war. In either case, billions of people would die of famine and the underlying ecosystems we all depend on would be at serious risk of collapsing.

Unfortunately, the two potential climate catastrophes do not cancel each other out. A little bit of nuclear winter is not the antidote for a little too much carbon dioxide in the atmosphere.

It’s not just radiation that contaminates the entire planet in a nuclear war. Nuclear weapons also cause severe adverse affects on the climate.[4]

Figure: Climatic effects of a regional nuclear war[5]

Worsening climate increases the risk
of nuclear war

Meanwhile, a worsening global climate is likely to significantly increase the likelihood of global conflict, including nuclear war. We’re already seeing climate-related competition for scarce resources causing armed conflicts in countries like South Sudan and Syria.[6] Countries like the United States have historically used military force to enforce their “right” to retain access to vital economic resources like oil, and we can expect to see increasing conflicts over water as well.

We’re already seeing climate refugees migrating in large numbers to escape food insecurity and extreme weather events like hurricanes, floods, wildfires, mudslides, extreme heat, and extreme cold. Rising sea levels in countries like Bangladesh, Nigeria, and Indonesia would displace many more millions of people, putting enormous pressure on neighboring countries to house and feed them at the same time as their own economies begin to suffer from the effects of climate change.

Alarmingly, rising sea levels threaten three neighboring nuclear-armed countries that have large coastal populations: China, India and Pakistan. Meanwhile, climate change will put increasing pressure on the economies of Europe and North America, exacerbating existing tensions with Russia. 

Figure: Climate Migration and Rising Risks[7]

Risk of major power confrontation

Tensions between Russia and the US/NATO have risen to their highest levels since the Cold War over Russia’s invasion of Ukraine. No one has so far suggested that the climate crisis is in any way responsible for the war in Ukraine. However, the war in Ukraine has itself exacerbated the climate crisis in a number of ways.

The bombing of the Nord Stream pipeline is a prime example. The jury is still out on who caused the explosion – the US? Russia? Ukraine?[8] In any case, this war-related sabotage resulted in a major ecological and climate disaster. Somewhere between 75,000 and 230,000 tons of methane were released into the atmosphere.[9]

The pipeline explosion damaged Russia’s ability to export fossil fuel to Europe, but the sanctions following its 2022 invasion of Ukraine have made that even harder. To compensate for reducing Western dependence on Russian supplies, there has been a seven-fold increase in foreign direct investment in oil and gas extraction worldwide,[10] especially in the US, South America and West Africa.[11] Needless to say, the largest fossil fuel companies have seen their profits skyrocket.

The risk of nuclear confrontation between the US and Russia has never been higher,[12] nor has the reversal of climate commitments been as severe.[13] And yet the prospect of a worsening climate only increases the risk that world power competition will lead to open conflict and potentially to nuclear war.

[1] Lockard, J. (2000). Desert(ed) geographies: cartographies of nuclear testing. Landscape Review6(1), 3–20.

[2] Robock, A., Oman, L., & Stenchikov, G. L. (2007). Nuclear winter revisited with a modern climate model and current nuclear arsenals: Still catastrophic consequences. J. Geophys. Res112(D13), 1–14.

[3] Xia, L., Robock, A., Scherrer, K. et al. Global food insecurity and famine from reduced crop, marine fishery and livestock production due to climate disruption from nuclear war soot injection. Nat Food 3, 586–596 (2022).

[4] IPPNW. (1991). Radioactive Heaven and Earth (p. 164). Zed Books.

[5] Change in surface temperature (K) for (a) June to August and (b) December to February. Values are 5 year seasonal ensemble averages for years 2–6, experiment minus control. Reprinted by permission from Michael J. MillsOwen B. ToonJulia Lee-TaylorAlan Robock, “Multidecadal global cooling and unprecedented ozone loss following a regional nuclear conflict,” Earth’s Future, AGU, Vol.2 no.4, April 2014, 161-176:  

[6] See Vidal, John (2011), “Sudan – battling the twin forces of civil war and climate change,” the Guardian, 21/11/2011. and Medglobal (2022), Climate Change, War, Displacement and Health: the Impact on Syrian Refugee Camps, 30pp.

[7] Graphic, Vicki Elson

[8] Nordstream 1 cost around $16 billion and Nordstream 2 cost around $11 billion to construct. Each pipeline was able to transport 60 billion cubic meters of gas from Russia to Germany. Russia was getting an estimated $55.5 billion in revenue in 2021 from just one pipeline, and that would have presumably doubled with the second pipeline entering into operation. See Natural Gas Intelligence. (n.d.). How much does Russia make from natural gas?

Although all Western fingers initially pointed at Russia as the likely saboteur, Seymour Hersh produced a convincing case for the US being the culprit, see Hersh, S. (2023, February 8). How America Took Out The Nord Stream Pipeline. Substack.

Since then fingers have mostly pointed at Ukraine, but could Ukraine have carried out such a feat without support from the US? See Entous, A., Barnes, J. E., & Goldman, A. (2023, March 7). Intelligence Suggests Pro-Ukrainian Group Sabotaged Pipelines, U.S. Officials Say. The New York Times.

[9] UNEP. (2023, February 20). UNEP finds Nord Stream gas leak may be the highest methane emission event, but still a drop in the ocean. United Nations. Initial estimates of the amount of methane released were as high as 500,000 tons. These have been reduced by further research, but even at the low end of 75,000 tons, this was the largest single release of methane ever recorded.

[10] Irwin-Hunt, A. (2022, October 11). Energy crisis triggers new wave of oil and gas investment.

[11] Bousso, R., Adomaitis, N., & Bousso, R. (2023, July 3). Focus: Oil giants drill deep as profits trump climate concerns. Reuters.

[12] According to the Bulletin of Atomic Scientists (see chapter 7).

[13] Bennhold, K., & Tankersley, J. (2022, June 26). Ukraine War’s Latest Victim? The Fight Against Climate Change. The New York Times.