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The Rising Nuclear Threat and How Physicists Can Help Reduce the Danger

Comments by Stewart Prager (Princeton University)

Webinar on Scientists, the Bomb and Implication for Today
July 21, 2023
Sponsored by the Physicists Coalition for Nuclear Threat Reduction

I will focus my comments on the physics community, and what we can do with regard to nuclear weapons. I would like to address two issues. The first one is inward looking. I will ask the question: should we, physicists, work on nuclear weapons? What are the consequences of such work, both negative and positive? Then I will discuss an outward looking issue – how can the physics community effect positive change on this issue? This outward-looking issue is one of great opportunity.

But first I would like to sketch the current nuclear landscape globally. This can be described by simply listing a few facts.

At the current time, nine nations possess nuclear weapons (Russia, China, US, UK, France, india, Pakistan, Israel, North Korea). Within this set of nations are embedded various rivalries, rotating leaders, with many scenarios that can lead to nuclear conflict by accident, miscalculation or intention. It is a complex, multipolar situation. It is not a stable state.

These nine nations possess about 10,000 nuclear weapons collectively in their active military stockpiles. On average, each weapon has the explosive power in the range of 20 times that which was used to destroy Hiroshima in 1945, with over 100,000 civilian deaths. Somewhat more than 90% of the weapons are held by Russia and the US, but the size of the arsenals in the other nations, each which measures in the 100s, are also exceedingly lethal. The arithmetic from these numbers is simple. If these weapons were used, they could kill billions of people. In addition about 2,000 weapons are on alert status, ready to be launched within minutes of receiving a launch order. This condition is held 24/7, so that at all times, every day, we are only moments away from nuclear catastrophe if one of the world leaders with nuclear weapons chose to do so.

There are indirect effects that are becoming progressively better understood. One grave indirect effect is that nuclear weapons can alter the global climate. In recent years climate scientists have applied modern climate models to this problem. The macroscopic physics is easy to understand. If nuclear bombs land where there is flammable material, such as in cities, it generates fire, the fires produce carbon soot which rise into the stratosphere, spreads around the globe, partially blocks out sunlight and reduces the global temperature, destroying or reducing crop production. Climate scientists have considered the hypothetical of a regional war between India and Pakistan in which they bombard each other’s cities with less than 1% of the world’s arsenal. Directly this could kill some 20 million people in India and Pakistan, but the starvation that would accrue to those already food insecure could kill on the order of one billion people. So even a regional war could be much more damaging to innocent bystander nations than the war-fighting nations themselves. An all-out war between the US and Russia could produce global starvation and essentially end civilization.

Despite all these numbers, we are now again in a nuclear arms race. Most, if not all, nuclear-armed nations are either upgrading, modernizing, expanding or innovating their nuclear arsenals. One example, the one we know best, is the US program. The program to modernize its nuclear arsenal will cost over $1T over the next few decades, laying the basis for a commitment to nuclear weapons to the end of the century. Given all this, there is a widespread view that the danger from nuclear weapons now is as large as that of any prior time. So, we are in a situation that, through whatever strategic reasoning government leaders use to determine policy, we are now continuously advancing a system that will enable our destruction. It is not hyperbole to say that this can only be described as a collective insanity.

Nuclear weapons are not war-fighting weapons. They are often described as weapons of mass destruction. But that is an understatement. In 1945 the physicists Fermi and Rabi in a report to the government described nuclear weapons as “having a practical effect almost of one of genocide” and “it is necessarily an evil thing considered in any light.” So nuclear weapons are perhaps appropriately described as weapons of mass genocide.

So the landscape is bad. What can physicists do?

Let me focus now on the inward-looking issue: Should physicists work on nuclear weapons? We are a critical part of the nuclear weapons complex. What are the consequences of us participating in this work? This was a prominent, debated and hot issue at the beginning of the nuclear era. Physicists discussed their decisions. Now the discussion is quite muted, to my knowledge. There is not an active discussion of such questions, but it is severely needed, for the physics community in general, for young physicists selecting their research paths in particular, and for those who have already decided to work on nuclear weapons.

I will frame the issue briefly. There are those that conclude from observed changes in China and Russia that the US should actively expand our nuclear arsenal as a necessity to keep US residents secure, and physicists should rally around this effort. There are also those that conclude that nuclear weapons always make us less safe, will lead us to a horrible ending, are intrinsically evil, and physicists should not work in this area. I should state that the way I frame this issue reflects my own perspective which falls, with some caveats, in the second camp.

Many physicists work within the stockpile stewardship program in the US. It is an R & D program. Its primary purpose, as stated in documents, is to support “stockpile sustainment, stockpile modernization, warhead production and the future nuclear security enterprise.” Therefore, if one works within the stewardship program, it should be clear that such work is actively advancing the development and use of nuclear weapons as tools of geopolitics and potential tools of war.

A prominent example of work in the stewardship program is the well-known National Ignition Facility (NIF). The engineering of NIF is remarkable and the unclassified physics that has derived from NIF is fascinating - fascinating in the basic physics of how matter behaves at extremely high energy density. And the information learned about fusion energy is exceedingly important.

But THE purpose of NIF, and the reason it is funded, is to advance our understanding of warhead physics to support the continued evolution of nuclear weapons. It is often stated that one policy benefit of NIF and the stewardship program is that we can learn what we would otherwise learn from nuclear testing, allowing us to support the global moratorium on nuclear weapon testing. But there are many questions about this claim. First, why do we need to test? We have done more tests than any other nation, more than 1,000. And if we get the same information from NIF as we would from testing, then NIF can be viewed as a work-around the ban. It could be viewed as conveying to other nations – if you wish to understand nuclear weapons like we do, then you either need your own NIF or you need to test. Thus, NIF can be viewed, in this sense, to encourage proliferation.

There is no time here for a detailed discussion of the many issues that correlate to these questions. I will just draw two conclusions. First, the decision of a physicist to work on nuclear weapons is consequential for that individual, and for society. Someone weighing that decision should carefully consider the consequences., and in my view consider the spinoff benefits as a secondary issue. Second, this topic requires active discussion in our community which is not underway now. That discussion can be had through conferences, webinars, print media, job fairs etc. But we should do it soon.

Now I turn to the last issue – looking outwards what are the opportunities for physicists to have a positive effect on public policy? There is an opportunity here because physicists are linked to this issue; our input carries weight with stakeholders and with the public. We can advocate, not as experts on nuclear weapons, but as informed citizen-scientists. As physicists we are sometimes reluctant to speak on areas in which we do not do research. But nuclear weapons are different. In a sense, no one is an expert. No one has ever fought a nuclear war. No one has any experience in the paths for escalation from conventional to nuclear conflict. No one sufficiently understands or has sufficient predictive capability of the physical and societal consequences of using the weapons that we own. So our views as citizen-scientists are valuable and we should feel comfortable expressing them. There have been many successes when physicists have organized among themselves in the past.

However, since the end of the Cold War as a community we have somewhat tuned out to this problem, much as has the general public. It is now time to re-engage. There is much we can do, unilaterally, to lessen the risk. There are actions which will make the US more secure and set an example for other countries to follow. I will not discuss them, but just list a few. We can eliminate the launch-on-warning option, de-alert our nuclear weapons, adopt a no-first-use policy, eliminate the sole authority of one person to launch nuclear weapons, restart nuclear negotiations with Russia, fulfill our legal obligation under the Non-Proliferation Treaty to negotiate toward disarmament, renegotiate an anti-ballistic missile treaty, reduce our ICBM force which endangers the homeland, and many, many more. The field is rich with opportunity to do good in this area.

I would like to close with one particular opportunity for physicists to engage and have a positive influence. About three years ago a new organization was founded in the United States - The Physicists Coalition for Nuclear Threat Reduction. It is a national network of physical scientists who are interested in being informed and having a route to make their viewpoint known. It was started by the American Physical Society. It is now funded by philanthropic organizations, partnered with a non-partisan NGO – the Arms Control Association – and managed through the Princeton Program on Science and Global Security. It has two goals. One is to provide information to physicists. The other is to facilitate advocacy by physicists.

For the educational part, a key element is that we have a team of 14 physicists with experience in this area who visit physics institutions to give colloquia and have in-depth discussion. To date we have visited 140 physics departments, labs, and nuclear engineering departments. For advocacy, we have established a national network, currently with 1,000 members spread around the nation. As we know, if even several hundred people contact Congress in concert, on one issue, there is a multiplicative effect and it can have an impact. We have such a network now. We have launched five advocacy campaigns over our short history. The Coalition does legwork to minimize the time required for members to take action. We are now beginning to have exploratory discussions with physicists from other nations to see how we can work together on this global problem. We welcome physicists from outside the US to be part of our Coalition.

If you are interested in taking advantage of this opportunity for access to information and to a network for advocacy, we invite you to join the Coalition. The Coalition is open to all physical scientists – those in astronomy, earth science, and so on, as well as those involved in engineering sciences. If you wish to join, you can do so on our website (physicistscoalition.org). And if you would like to have a colloquium at your institution that can be done through the same link.

Clearly this problem is made by humans. And clearly it can be solved by humans, with some substantial effort.