The Nuclear Ban Treaty and the CTBT

By Alicia Sanders-Zakre

The new Treaty on the Prohibition of Nuclear Weapons’ (TPNW) includes a provision prohibiting nuclear testing but some questions have emerged about the relationship of the new treaty to the CTBT.

While some claim that prohibiting nuclear testing in the TPNW would strengthen the Comprehensive Test Ban Treaty (CTBT) by further reinforcing the global moratorium on nuclear testing, others argue that it could undermine the CTBT by creating inconsistencies in between the two treaties.

Many TPNW advocates assert that since the nuclear ban plays a normative role, the inclusion of a prohibition of testing in the treaty would serve to bolster the non-testing norm and could be an important complement to the CTBT.

The TPNW includes several references to nuclear testing and the CTBT. Its preamble recognizes the “vital importance” of the CTBT “as a core element of the nuclear disarmament and non-proliferation regime.” Its first operative article prohibits the testing of “nuclear weapons or other nuclear explosive devices.”

The TPNW goes beyond the CTBT in recognizing the suffering of those impacted by nuclear testing. The TPNW’s preamble acknowledges the “unacceptable harm” caused to victims of nuclear testing. Article 6 requires that states-parties provide humanitarian assistance to those affected by nuclear weapons testing and take steps toward environmental remediation of areas contaminated by nuclear testing.

Some states participating in the TPNW negotiations claimed that the new treaty’s testing prohibition also bans subcritical tests and computer simulations that are related to nuclear weapons research and development, which are not covered by the CTBT because subcritical tests are not nuclear explosions. Cuba, Iran and Nigeria stated after the adoption of the text that they would interpret the prohibition to include these elements, although they are not explicitly named in the text. Although this did not represent the consensus view of the conference and is unlikely to be the official interpretation of the article, it could be seen as an inconsistency between the nuclear ban and the CTBT.

Others have brought up the concern that by including a prohibition of testing in the TPNW without requiring signature and ratification of the CTBT by states-parties, states could choose to support the testing prohibition in the TPNW without ratifying the CTBT, thereby impeding the entry into force of the CTBT.