By Spencer Graves;  updated 2020-10-29

On October 24, Honduras officially informed the United Nations Treaty Collection that it had ratified the Treaty on the Prohibition of Nuclear Weapons (TPNW). The TPNW requires 50 parties, and Honduras became number 50. The treaty also says it will enter into force (EIF) 90 days later, which will be 2021-01-22, according to a press release by the office of the UN Secretary-General. 

The International Campaign to Abolish Nuclear Weapons (ICAN) is planning a major celebration for that date. PeaceWorks Kansas City as an affiliate of ICAN is developing plans to do something on that date.

The average time between ratifications is today’s date, 2020-10-29, minus the date of the first ratification, 2017-09-20, divided by the number of ratifications since the first.  This gives me 22.7 days.  If other countries continue to ratify with the same distribution of time between ratifications we’ve seen so far, 4 more countries might ratify by 2021-01-22.  It could 0 or almost any other reasonable number. 

The rate of new ratifications could be slower or faster than it has been. I simulated future ratifications assuming the time between ratifications is essentially the same as it has been since the first countries ratified it in 2017-09-20. The blue, orange and red dashed lines in the upper right of the accompanying plot show the median predictions with the 60 and 80 percent confidence limits on the number of parties to the TPNW by EIF under these assumptions.

We should not rest on our laurels.  The Associated Press reported 2020-10-21 that, “The United States is urging countries that have ratified a U.N. treaty to ban nuclear weapons to withdraw their support“. A letter reportedly sent by the US says that the five original nuclear powers (the US, Russia, Great Britain, France and China) and our NATO allies “stand unified in our opposition to the potential repercussions” of the treaty, claiming the treaty “turns back the clock on verification and disarmament and is dangerous”.

PeaceWorks is adamant that the historical record indicates exactly the opposite:  The world is lucky that we have survived the nuclear age this long.  The continuation of nuclear proliferation increases the risks of nuclear Armageddon.

The progress so far on the TPNW came only because thousands and perhaps millions of activists convinced their governments to ratify, accept, approve or accede to this treaty.

Even after this treaty becomes effective, we still need to work to expand the list of countries that have ratified, accepted, approved, or acceded to it.

I hope that after the TPNW enters into force, many of the parties to it will adopt national security taxes on trade with nuclear weapon states and use some of the money generated by such taxes to promote further steps toward abolition of nuclear weapons. (I have not seen any documents promoting a national security tax, but I’ve heard informally that such has been discussed.)

—Spencer Graves, Ph.D., a statistician (can you tell?) serves on the Board of Directors of PeaceWorks-KC.

(Software with instructions on how to reproduce and update the figure is available with a Wikiversity article on “Forecasting the number of parties to the TPNW“.)

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