I don't know much about nuclear weapons, but having listened to a recent talk by former Secretary of Defense William Perry about the ongoing risk of nuclear conflict, I am primed, at the moment, for related subject matter to catch my eye. Of course, the United States is the only nation so far to have detonated a nuclear weapon in combat—over Hiroshima and Nagasaki in Japan during the closing stages of World War II. You can actually view color photos of the aftermath, which indicate both the reach and severity of the destruction.

Alex Wellerstein, a nuclear historian at the Stevens Institute of Technology, reminds us that the novelty of the atomic bomb was as much one of scale as it was of kind:

The atomic bombs used during World War II killed most of its victims by burning and crushing them — the classic medieval tortures, made wholesale by technology but not much more modern. (Only about 15-20% of the people at the cities died truly “modern” deaths, from the radiation effects.)

According to Perry, though, we lost sight of the threat posed by nuclear weapons after the Cold War ended, despite the fact that more countries than ever have access to the Bomb. He believes, contrary to the relative invisibility of the issue, that the risk has in fact never been higher, citing the potential for terrorist groups or other non-state actors to gain access via improvised devices or poorly monitored nuclear stockpiles.

The picture he paints in his talk is unnerving. Considering the existential threat that nuclear war poses, the mere hint of its possibility conjures goosebumps, not to mention the fact that, in 1983, the world really and truly found itself on the brink of nuclear war. For one, relations between the US and USSR were extremely contentious. Furthermore, many of us likely owe our lives to a Russian officer named Stanislov Petrov, who, in that same year, correctly identified not one but two false alarms thrown by the USSR's early warning system, which seemingly indicated incoming nuclear missiles.

Had he responded as if to a live attack…

So with this rattling around in my head, I was drawn to two datasets Jeremy Singer-Vine shared via his (I have just found out) excellent newsletter Data Is Plural. The graphic below uses data from the Stockholm International Peace Research Institute (SIPRI) on nuclear detonations between 1945 and 1998. This dataset was much cleaner than the Okalahoma Geological Survey's, the other set that Singer-Vine shared, which is why I chose to work with it.

According to SIPRI, atmospheric testing was banned via treaty in 1963, marking the end of such testing by the US, USSR, and the UK. (This ban extended to underwater and outer-space testing as well.) China and France ceased atmospheric tests a decade or so later. Therefore, much of what this map shows are underground tests. I highly recommend reading the SIPRI report, which has a plot of its own on page 9 summarizing the depths/heights of these explosions.

A few notes on the information contained in the graphic below:

  1. The SIPRI report indicates that 2052 detonations have occurred, while the dataset contained 2051 observations.
  2. Not all of these detonations were tied to military testing. Some were so-called "peaceful nuclear explosions" conducted for civil purposes (e.g., excavation, other research, etc.).
  3. The gap in the bar plot corresponds to a voluntary moratorium on nuclear testing observed by the US, USSR, and the UK between November 1958 and September 1961.
  4. I've corrected some errors in the dataset as well, in order to get the correct regional weights you see on the map. These refer to the number of detonations in a given region. Where latitude and longitude were missing (6 observations), I looked the region up on Google Maps and took coordinates from near the center of the marked area. The center of each circle is aligned with the average detonation latitude and longitude within the given region. (Had I left the latitude/longitudes at 0/0 for these 6 observations, they would have distorted the average coordinates in their respective regions, pulling the circles off-target. For the purposes of the map, the exact detonation locations are not crucial.)
  5. The colors shown apply to both the bar plot and the map.


The image above is in SVG format, and I can't get the bottom legend to render quite right in this format, for whatever reason, but here is a PNG in case you want to share it. I just ask that you link back to this post.

For a truly breathtaking visualization of our nuclear history, check out this animation by Isao Hashimoto, which charts very similar information to that shown above but accounts for the time between detonations.

Since 1992, the US has voluntarily imposed a moratorium on its own nuclear weapons testing, and in 1996 the UN General Assembly adopted the Comprehensive Test Ban Treaty (CTBT). The SIPRI report had this to say in 1998 regarding the treaty (emphasis mine):

The treaty bans only actual physical explosions, not subcritical tests or computer-simulated tests. This means that even after entry into force of the complete ban, the nuclear powers will be permitted to verify the safety and reliability of their nuclear weapon arsenals. Moreover, in the opinion of experts, the CTBT cannot prevent any state aspiring for nuclear status from constructing, without explosive testing, a small arsenal of fission weapons, and doing so with some degree of certainty that the weapons will perform as envisaged. It is, however, considerably more difficult to develop thermonuclear weapons without test explosions.

As of 2015, according to the Wikipedia entry, eight more states must sign and ratify the CTBT before it can take effect, including the United States, who has signed but not yet ratified.