The United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) is a relic of the cold war. Established in 1955 to study fallout from above-ground nuclear-weapons tests, the committee, which is based in Vienna, acted as one of the few channels for cooperation between the United States and the Soviet Union, and served to exchange information between East and West.

It was invaluable in its time: after the catastrophic meltdown at the Chernobyl nuclear power plant in Ukraine in 1986, the committee's ties to the Soviet Union allowed it to produce some of the first independent assessments of the accident's aftermath and probable implications, at a time when they were sorely needed.

In recent years, however, UNSCEAR has seemed less useful. The cold war has ended, and above-ground nuclear testing is considered so gauche that even North Korea is unwilling to do it. The committee's weighty reports are no longer the first port of call for scientists studying the health effects of radiation, who prefer the convenience of online searches of the open literature. Even within UNSCEAR's small secretariat, some people wondered whether the committee had run its course.

And then, in 2011, came the meltdowns at the Fukushima Daiichi nuclear plant in Japan. Three reactors released radioactive contaminants into the environment and forced the evacuation of thousands of people. Phones at UNSCEAR started to ring again.

Asked to investigate, the committee brought together dozens of scientists from universities and government agencies around the world to review the available data. They are now mid-way through their work, and much remains to be done, but already the value of the exercise, and of the organization behind it, is becoming clear.

UNSCEAR will provide a strong, scientifically sound account of the Fukushima accident.

In the days after the Fukushima accident, Japanese citizens were bombarded with radiation readings. The numbers were delivered in obscure units with little or no context, along with limp reassurances from government authorities. The data were inconsistent, and frequently wrong. Those early readings have been followed by government surveys, academic assessments and independent models of varying quality and message. The cacophony has fed mistrust and fear among local residents and the wider public.

UNSCEAR, however, is carefully reviewing the shaky readings taken during the early days of the accident to establish which of them are useful. It is integrating data from a wide range of sources to see what information has been collected and how it has been calibrated. And it is building its own models to reconstruct exactly what was emitted by the reactors and when. The aim is to come up with a coherent picture of the accident by the end of next year. Much remains to be done, but this week UNSCEAR's working committee on Fukushima has been able to provide a comprehensive — and seemingly reassuring — view of radiation exposure among workers at the plant. That, combined with the available data on public exposure, indicates to many experts that the health effects from the accident will be minimal (see page 423).

Although some of the committee's scientists believe that its work will provide a measure of reassurance to the people of Japan, that is by no means certain. Many of UNSCEAR's members come from regulatory bodies in their home nations — what critics of the nuclear industry view as the establishment. As such, they may struggle to convince outsiders that they act in good faith. One way to build support and bridges with potential critics might be to take more seriously the data collected by independent groups such as concerned citizens and international non-governmental organizations in the immediate aftermath of the disaster. The committee is already considering this, and it should proceed.

There will remain limits to the comfort that science can provide. Cancer is a disease of statistics: some workers will get ill and some will blame it on the dose they received. Indeed, one has already died of leukaemia that is, as far as anyone can tell, unrelated to the accident.

Nevertheless, UNSCEAR has been reborn. The committee is no longer a clearing house — it is a filter. Its work in the coming months and years will provide a strong, scientifically sound account of the Fukushima accident. It will bring consistency to the numbers and mould a single narrative from the disparate data sets. Not everyone will agree with the committee's conclusions, but they will provide a definitive point of reference for discussion and evaluation.

Accidents such as that at Fukushima are thankfully rare, and within a few years UNSCEAR may fade back into obscurity. It can be allowed to slumber, but it must not be forgotten. In the modern information age, its purpose is clearer than ever before.