Atmospheric nuclear test explosions – more than 500 of which were conducted, from 1945 to 1980 – had a particularly harmful effect, dispersing radioactive particles far and wide. Their combined destructive force was equal to 29,000 Hiroshima bombs.

Today, every person alive carries in their body radioactive substances from atmospheric tests, increasing their risk of disease. Physicians project that, over time, these past tests will cause at least four million premature deaths from cancers and other illnesses.

Nuclear test explosions conducted underwater and underground have also had long-term health and environmental impacts.

In the latter half of the 20th century, worldwide concern about the effects of nuclear testing gave rise to large-scale protest movements in many parts of the world, prompting leaders to negotiate a partial ban in 1963 and a comprehensive ban in 1996. Both have helped halt nuclear testing globally.

But the implications of past testing for people’s lives and the Earth’s fragile ecosystems will continue to be felt for generations to come. The international community has a duty not only to ensure that such destruction is never wrought again, but also to work to address the harm already done.

Few survivors of nuclear testing anywhere in the world have ever been compensated for their suffering, and efforts to clean up former nuclear test sites have been woefully inadequate. At some sites, dilapidated infrastructure poses an ongoing risk of further contamination.