Wild New Carbon Capture Idea Suggests Tackling Climate Change With Massive Undersea Nuclear Explosions

Climate change is a big deal and is probably one of the most pressing existential threats we face as a species. If we are unable to change the current trajectory for global warming, we may see not only irreparable damage done to the natural environment, but also the displacement of hundreds of millions of people and economic losses of between $100-200 trillion by the end of the century.

It’s a dire situation to be in, so researchers are seeking various ways to limit the multitude of factors contributing to this escalating problem.

One such approach is finding ways to remove carbon from the atmosphere. At present, so called “negative emissions technologies” are being developed to achieve this, therefore reducing greenhouse gas concentrations. These technologies include direct air carbon capture materials, such as new concrete, that sequester carbon in new structures, as well as finding ways to enhance natural carbon sinks, such as producing biochar to be applied to soils, planting more trees to absorb more carbon dioxide, or finding ways to accelerate natural weathering of rocks that are known to absorb greenhouse gases.

It is this latter option, known as enhanced rock weathering, has caught the attention of 25-year-old Andy Haverly at the Rochester Institute of Technology, a private research university in Henrietta, New York. The natural breakdown of silicate rocks, such as basalt, could significantly aid in carbon capture, especially if larger quantities of it could be pulverized quickly. But here’s the rub:

“The principal barrier to [enhanced rock weathering] is the immense energy and logistics required to mine, crush, and transport billions of tonnes of rock,” Haverly writes in a preprint paper he posted in January this year (it should be stressed here that preprints are preliminary papers that have not yet been peer-reviewed by other experts).

Even at its best, existing enhanced rock weathering techniques would only soak up a small fraction of our greenhouse gas emissions. So how can we get past this barrier, we hear you ask? Well, Haverly suggests detonating enormous nuclear explosions at the bottom of the seafloor to quickly pulverize large amounts of basalt. 

To do this, Haverly argues, a nuclear weapon would need to be buried at least 3 kilometers (1.9 miles) below the Southern Ocean seabed so that its explosion could be sufficiently constrained and its nuclear fallout initially (we’ll come back to this) limited. This, he believes, would maximize the amount of rock the bomb would powderize while also minimizing the risk to life.

This idea takes inspiration from the historical projects proposed under Project Plowshare, a US program that sought to find ways to use nuclear explosions for peaceful construction purposes. Past projects proposed under Plowshare included using nuclear explosions to create sites for ports, highways, or canals. Experiments were also conducted in the 1960s to produce new heavy isotopes that are otherwise unobtainable without nuclear reactions.

In his proposal, Haverly envisions using an 81-gigaton range nuclear explosion to break up around 3.86 trillion tons of basalt. To put this into perspective, the largest ever nuclear explosion, known as the Tsar Bomba, had a yield of 50 megatons (which is the equivalent of 50,000,000 tons of TNT). A 1-gigaton explosion would be 20 times more powerful than this historical example, so you can imagine how ridiculously enormous an 81-gigaton device would be.

At present nothing like this has ever been built or tested, and Haverly’s paper is pretty light on how such an explosive could be created and transported safely to its intended destination and then installed at the desired depth.  

“Nuclear explosions are inherently unsafe. They release vast amounts of uncontrolled energy. However, by detonating this nuclear device in a controlled environment we can minimize the impacts,” Haverly explains in his paper.

Given the remote location of this intended project, the author believes loss of life from nuclear fallout and radiation would be minimal… at first.

“The long-term effects of global radiation will impact humans and will cause loss of life, but this increased global radiation is ‘just a drop in the bucket’.”

This is because, so he argues, the impacts of the coal power plants we already use are contributing to loss of life and environmental degradation. Although this is certainly true, there is a “you have to break some eggs to make an omelette” logic here, which is usually proposed by people who rule themselves out as potential eggs for breaking. 

The same logic is applied to the environmental damage caused by this explosion. Haverly admits that it would cause extreme damage and long-term radiation, but quickly downplays it by suggesting it will be “contained almost entirely to the dozen square kilometres around the detonation site”.

It is important to note that the author is neither a climate scientist, nor a geologist or a nuclear physicist/engineer, but rather a PhD student working on quantum computing. As Vice reports, a lot of the reaction to the proposal so far from experts in the field has been less than enthusiastic. 

But regardless of its feasibility, the fact that such an idea is being entertained has experts and advocacy groups worried. Such interventions do nothing to challenge our use of things that cause emissions to be released in the first place – despite research suggesting that carbon capture in general may not be the anti-emissions hero many had hoped for. 

In such a scenario, where we focus on carbon capture rather than fossil fuel usage, nothing would really need to change – no one would need to adjust their own behaviors and wealthy elites wouldn’t need to minimize their operations in ways that challenge their income. Instead, the world could carry on as it does and we would just find ways to have our carbon cake and eat it, as long as we could justify setting off nuclear explosions in distant places. 

After all, once it has done its job any fallout can be someone else’s problem.

The paper, which has not been peer-reviewed, is posted to the arXiv.