Climate change, "nuclear winter" version

The Iran nuclear deal (JCPOA) is important because it's about nuclear arms control. And nuclear arms control and disarmament is extremely important. And urgent.

It's common to hear these days that our greatest danger is climate change. And that's true. But we also have to remember that the form of climate change that could literally make the planet uninhabitable for homo sapiens is that which would follow an all-out nuclear war, i.e., a nuclear war between the US and Russia. Because the immediate deaths from the explosion and the early effects of radiation pollution and the massive destruction of critical infrastructure aren't even the deadliest part of the effects.

It's a sign of how well the weapons industry at moving nuclear arms reduction off the top priorities of the American political agenda that the main research on "nuclear winter" effects was done in the 1980s. The Britannica Online article on it (07/20/1998) provides this summary:

The basic cause of nuclear winter, as hypothesized by researchers, would be the numerous and immense fireballs caused by exploding nuclear warheads. These fireballs would ignite huge uncontrolled fires (firestorms) over any and all cities and forests that were within range of them. Great plumes of smoke, soot, and dust would be sent aloft from these fires, lifted by their own heating to high altitudes where they could drift for weeks before dropping back or being washed out of the atmosphere onto the ground. Several hundred million tons of this smoke and soot would be shepherded by strong west-to-east winds until they would form a uniform belt of particles encircling the Northern Hemisphere from 30° to 60° latitude. These thick black clouds could block out all but a fraction of the Sun’s light for a period as long as several weeks. Surface temperatures would plunge for a few weeks as a consequence, perhaps by as much as 11° to 22° C (20° to 40° F). The conditions of semidarkness, killing frosts, and subfreezing temperatures, combined with high doses of radiation from nuclear fallout, would interrupt plant photosynthesis and could thus destroy much of the Earth’s vegetation and animal life. The extreme cold, high radiation levels, and the widespread destruction of industrial, medical, and transportation infrastructures along with food supplies and crops would trigger a massive death toll from starvation, exposure, and disease. A nuclear war could thus reduce the Earth’s human population to a fraction of its previous numbers. [my emphasis]

I'm sure there's some smirking Republican meme out there somewhere saying, "See, that would fix global warming by cooling everything off, yuck, yuck."

I guess rapidly wiping out the vast majority of the human race would really "own the libs", huh?

Just to be clear, one of the key aspects of our current climate crisis is that atmospheric temperatures are rising at rate not seen in millennia. Even smaller changes can have a great deal of impact.

The nuclear winter cooling described there would be a drastic sinking of temperatures in a few weeks time which would trigger disastrous weather events in a radically shorter time frame than what we are already seeing with intensifying hurricane strength, rising sea levels, and monster forest fires.

That's the context in which we need to see reports like this one on the still huge risks of nuclear war: Elizabeth Eaves, Why is America getting a new $100 billion nuclear weapon? Bulletin of the Atomic Scientists 02/08/2021.

America is building a new weapon of mass destruction, a nuclear missile the length of a bowling lane. It will be able to travel some 6,000 miles, carrying a warhead more than 20 times more powerful than the atomic bomb dropped on Hiroshima. It will be able to kill hundreds of thousands of people in a single shot.

The US Air Force plans to order more than 600 of them.

On September 8, the Air Force gave the defense company Northrop Grumman an initial contract of $13.3 billion to begin engineering and manufacturing the missile, but that will be just a fraction of the total bill. Based on a Pentagon report cited by the Arms Control Association [...] and Bloomberg News, the government will spend roughly $100 billion to build the weapon, which will be ready to use around 2029.

Eaves also gives us this grim reminder of the calculations involved in planning and arming for nuclear war:

Deterrence is the main argument for having a nuclear arsenal at all. But America’s land-based missiles have another strategic purpose all their own. Housed in permanent silos spread across America’s high plains, they are intended to draw fire to the region in the event of a nuclear war, forcing Russia to use up a lot of atomic ammunition on a sparsely populated area. If that happened, and all three wings were destroyed, the attack would still kill more than 10 million people and turn the area into a charred wasteland, unfarmable and uninhabitable for centuries to come.

She also discusses the risks involved that the configuration of this new generation of global suicide missiles currently called the GBSD (Ground-Based Strategic Deterrent). would have to be fired off on a "launch on warning" basis, the implications of which she explains briefly. Including, "Whereas a bomber can be turned around even on approach to its target, a nuclear missile launched by mistake can’t be recalled."

Eaves' article runs to 47 printed pages, so it includes a lot of additional material on US nuclear strategy and the dangers of nuclear arms proliferation.

Left assumptions in need of reformulation: Existential threats, nuclear and climatic

Back in the 2003 when I first started blogging, the notion of "counterintuitivity" was more often discussed as a position that establishment pundits used to shhow their supposed independence of mind. Actually, even by that time it mostly meant supposedly liberal pundits taking conservative positions.

But there are a couple of current tropes on the left/center-left that I find problematic. Both of them came up repeatedly at the Netroots Nation 2019 cofererence I attended in Philadelphia last week.

One is the now-common assertion that climate change is the biggest threat to humanity's future. I would call nuclear proliferation and climate change the biggest threats. Both are literal existential threats to humanity. But I do see nuclear war as still the more urgent threat.

As Max Tegmark noted a couple of years ago (Why 3,000 Scientists Think Nuclear Arsenals Make Us Less Safe Scientific America Online 05/26/2017):

Why is superpower nuclear war so risky? First of all, massive firepower: there are more than 14,000 nuclear weapons today, some of which are hundreds of times more powerful than North Korea’s and those dropped on Japan. Over 90 percent of these belong to Russia and the US, who keep thousands on hair-trigger alert, ready launch on minutes notice. A 1979 report by the US Government estimated that all-out war would kill 28-88 percent of Americans and 22-50 percent of Soviets (150-450 million people with today’s populations).

And he continues with the close link between nuclear war and climate catastrophe:

But this was before the risk of nuclear winter was discovered in the 1980’s.Researchers realized that regardless of whose cities burned, massive amounts of smoke could spread around the globe, blocking sunlight and transforming summers into winters, much like when asteroids or supervolcanoes caused mass extinctions in the past. A peer-reviewed analysis published by Robock et al (2007) showed cooling by about 20°C (36°F) in much of the core farming regions of the US, Europe, Russia and China (by 35°C in parts of Russia) for the first two summers, and about half that even a full decade later. Years of near-freezing summer temperatures would eliminate most of our food production. It is hard to predict exactly what would happen if thousands of Earth’s largest cities were reduced to rubble and global infrastructure collapsed, but whatever small fraction of all humans didn’t succumb to starvation, hypothermia or epidemics would probably need to cope with roving, armed gangs desperate for food. [my emphasis]

I haven't yet encountered it, but I'm sure there are climate-deniers out there somewhere cynically declaring that forecasts of "nuclear winter" show that them thar fancy scientists cain't make up their minds about whether the climate is heating or cooling.

Of course, outside the FOX News bubble, we know that a change of one or two degrees centigrade over decades can have huge effects on climate. The kind of radical, very rapid changes nuclear winter would bring would be dramatically faster and more severe. Even though it would result from cooling of the atmostphere rather than heating.

In this way, nuclear war is a part of the climate problem. Because the greater loss of life in an all-out nuclear exchange would result from the climate repercussions.

But that doesn't mean that nuclear risk and climate change can be completely identified with each other, either. Eliminating fossil fuel emissions won't get rid of the nuclear weapons stockpiles or solve the proliferation problem. And eliminating all nuclear weapons won't make fossil fuel emissions any less destructive. Both are urgent dangers and both deserve far more serious and responsible attention than they currently get.

The study on nuclear winter which Tegmark cites is Nuclear winter revisited with a modern climate model and current nuclear arsenals: Still catastrophic consequences Journal of Geophysical Research Atmospheres 112: D13107 (July 2007).