Nuclear Freeriders: How the CTBTO Provides a Global Public Good Despite (some) States’ Failure to Pay

DATAINT
DATAINT
Jun 4, 2019 · 6 min read
Locations of International Monitoring System (IMS) facilities (Credit: CTBTO)

Note: There is an absurd amount of acronyms at the beginning of this article. It’s about nonproliferation, so this couldn’t be avoided.

As far as organizational founding ideals go it doesn’t get more, uh, idealistic, than those of the Comprehensive Test Ban Treaty Organization (CTBTO). The CTBTO exists to monitor signatories’ compliance with Comprehensive Test Ban Treaty (CTBT), which was opened for signature by the United Nations General Assembly (UNGA) in 1996, and bans all nuclear explosions of any size for any reason. The CTBTO enforces the CTBT via a network of acoustic, atmospheric, and seismological sensors known as the International Monitoring System (IMS). The IMS is a truly global system, currently consisting of 297 facilities in over 80 countries. Together, the IMS and CTBTO represent an important and frankly underrated accomplishment of the international community. For each of North Korea’s nuclear tests, it was the CTBTO/IMS that provided the world with information that everyone could implicitly trust. They represent the best of the international community, making manifest the idea that we can set aside our grievances and work together to build something technically incredible, and which underwrites our continued existence as a species.

Pictured: Heroic nerds underwriting our existence as a species at an atmospheric monitoring station in Australia (credit: CTBTO)

But underwriting humanity’s continued existence isn’t free, and it definitely isn’t profitable, so the CTBTO must be funded through contributions from its member states. The CTBTO determines how much each member state owes via the “Scale of Assessments” (SOA) system, virtually identical to the system used by the United Nations and International Atomic Energy Agency (IAEA). In essence, each member state is assessed to owe some fraction of the CTBTO’s total budget request for that year. The size of that fraction is proportional a member state’s Gross National Income (GNI), which is as good a measure as any for the size of a state’s economy. Every two weeks, in the interest in appearing transparent, the CTBTO releases a PDF showing who owes what, and who has actually paid.

There is an important difference between “appearing transparent” and actually “being transparent.” The data is surely accurate, but it is in a format that is difficult to comprehensively analyse, effectively ensuring that such a thing won't happen, unless some obsessive weirdo with too much time on their hands decided to scrape the PDFs and make a project out of it for their data visualization portfolio.

Note: I’ve posted all of the code I used to scrape the PDFs, munge the data, and create the dataframes, in a GitHub repo. The link is at the bottom of the article.

The above chart tells us a few things, the most important of which is that a handful of high GNI member states are responsible for about 2/3rds of the CTBTO’s operating budget every year. This isn’t surprising, global wealth distribution being what it is, but it highlights a vulnurability in the CTBTO’s funding system, namely, that it is dependent on a handful of high GNI states’ ability (or willingness) to pay. This means that the CTBTO’s budget is considerably affected if even one high GNI member state decides to lapse in its payments (as we will see later in the case of Brazil). The CTBTO lacks a standing army (save for a few security guards at its headquarters in Vienna), so a member state’s decision to pay what they owe is essentially voluntary. Given this, how much of the CTBTO’s budget request does it actually get per year?

What the CTBTO assessed its member states to owe versus what it actually received

As we can see, the CTBTO does okay in this regard, though the gap between what it requests and what it receives every year is around USD ten million, which is not nothing. I suppose we should be happy that the CTBTO collects anything at all, considering a member state benefits from the CTBTO’s work regardless of its decision to pay. The CTBTO provides assurance to the international community that no state is clandestinely testing nuclear weapons, something which it can’t withhold from freeriders. Speaking of which, who are those freeriders anyway?

Mirroring what we saw earlier, a handful of high (ish) GNI member states are responsible for the vast majority of the amount owed to the CTBTO. The four big stand outs are Brazil, Columbia, Iran, and Venezuela.¹ None of those countries (save for Brazil in 2018) paid anything significant to the CTBTO between 2012 and 2018, letting their total debt to organization tick up and and up. According to the bylaws of the CTBTO, a member state loses its voting right if its total debt exceeds what it has been assessed to owe over a two year period. Also interesting to note is that the US appears in both the top contributors and top debtor charts; the US sometimes comes up short on the 31st of December but always seems to pay off what it owes in short order in the new year.

While Brazil seems to have had a change of heart, Venezuela, Colombia, and Iran seem happy to let their debt accrue and their voting right continue to lapse. This makes practical, if not ethical, sense; a state benefits from the work of the CTBTO regardless of its standing with the Organization.² Indeed, a state benefits from the work of the CTBTO even if it has not joined the Organization or signed the treaty. For example, every day the CTBTO verifies that neither India nor Pakistan (neither have signed the CTBT) are testing nuclear weapons, and because it is neutral the international community at large trusts what it says. I would argue that North Korea is one of the biggest beneficiaries of the CTBTO. Without the CTBTO providing independent verification of their nuclear tests, the international community would have to rely on the claims of North Korea and other states, all of whom have their own agendas. The claims could conflict with one another, and many would throw up their hands and resign the issue to ambiguity, throwing the existence of North Korean nukes into doubt, and thus weakening their value as a deterrent.

The goal of this article is not to make any dire claim about the financial health of the CTBTO, but rather to point out how well the Organization executes its mission despite the vulnerabilities and pressures I have outlined. However, one can reasonably conclude that the shock of several high-GNI member states failing to pay, perhaps in the wake of a post-Brexit economic slowdown (or perhaps as the result of empty-headed legislators grandstanding on issues they know nothing about), could hold at risk the CTBTO’s capacity to perform the necessary and stabilizing work from which we all benefit.


As always, here is a link to the GitHub Repo where I’ve stuck all the code I used to scrape the pdfs, munge the data, and create the visualizations. I’ve also posted the data I scraped from the PDFs in csvs.

Once again, this should be standard practice among data journalists. Much like bad facts lead to bad conclusions, so do bad code and bad data practices.


  1. Interestingly enough, there seems to be coordination among certain states in their non-payment. For the years 2013–2015 Brazil, Venezuela, Iran, and Colombia all paid the same (tiny) fraction of what they owed to the CTBTO. Not only was it the same, it was the same to the sixth decimal place. Argentina joined in this behavior for 2014 and 2015, probably other states did as well. There is simply no way this is a coincidence. If you wish to look at the data it is in a csv file labeled vcbia_debt in the “data” directory in the GitHub repo for this article.
  2. It is true that the CTBTO, in addition to naming/shaming and voting right suspension, can also suspend a member state’s access to the reams of data collected by the sensors of the IMS, which are of tremendous scientific and academic interest. Alas, unless you’re a seismologist, this suspension of access doesn’t really sting much.

DATAINT

Written by

DATAINT

Selling my soul at the crossroads of data and national security analysis.

DATAINT

DATAINT

Selling my soul at the crossroads of data and national security policy analysis

More From Medium

Also tagged Python

Also tagged Python

Also tagged Nuclear Nonproliferation

Welcome to a place where words matter. On Medium, smart voices and original ideas take center stage - with no ads in sight. Watch
Follow all the topics you care about, and we’ll deliver the best stories for you to your homepage and inbox. Explore
Get unlimited access to the best stories on Medium — and support writers while you’re at it. Just $5/month. Upgrade