On 18 April this year US President George Bush was asked whether America was considering using nuclear weapons to resolve the current dispute over Iran’s uranium-enrichment programme. Bush replied that “all options are on the table”. For Jorge Hirsch, this statement was a watershed moment. He believes that at that point the US “walked off a nuclear cliff” and that it has been “suspended over the abyss ever since”.

Hirsch, a physics professor at the University of California, San Diego, thinks it is almost certain that the US will launch a nuclear strike against Iran before the year is out. And he thinks that if this happens, it will lead to an escalation of nuclear proliferation that could finish off civilization. Having spent his career in academia, working on theories to explain the behaviour of superconductors, Hirsch has little experience of political activism. But he thinks that the current stand-off with Iran is potentially so grave that he is now working almost full time to try and prevent it becoming critical. “The situation we face now is more dangerous than the Cuban missile crisis,” he says, “because today there is no deterrent against the US using nuclear weapons.”

Hirsch’s analysis may strike some people as unduly pessimistic or perhaps alarmist. But there are many others who share his concerns. A petition started by Hirsch and a colleague at San Diego, Kim Griest, opposing the use of pre-emptive nuclear strikes against non-nuclear states has now garnered the names of over 1900 physicists. The same sentiment was also expressed by Hirsch and 12 other eminent physicists, a number of them Nobel laureates, in a recent letter to Bush.

For Hirsch, physicists have a special responsibility when it comes to nuclear weapons as it was they who invented the bomb 60 years ago. He believes physicists must do whatever they can to publicize the nuclear threat, be it by lobbying politicians or speaking to local newspapers. In particular, he thinks that it is vital that they clarify what he sees as the misleading term “weapon of mass destruction”. He thinks that lumping nuclear weapons together with the far less potent chemical and biological weapons blurs the sharp divide that has existed between nuclear and all other weapons, and makes the use of nuclear weapons all the more likely.

Looming danger

Hirsch, 54, was born and raised in Argentina but moved to the US to do a PhD in condensed-matter physics in 1976, following a military coup in his homeland. In 1988 he came up with a radical new theory to explain superconductivity based on the idea of charge asymmetry: that electrons and holes are not simply equal and opposite but are fundamentally different. Although initially shunned by many others in the field, Hirsch remains convinced that his theory is correct and hopes that it will be put to the test in the next few years.

Hirsch has also made a name for himself recently by devising a new way to measure the quality of a researcher’s output. This so-called h-index – which states simply that a researcher with an h-index of, say, 20 has published 20 papers that have each been cited at least 20 times – certainly seems to have caught the imagination of other scientists. “My h-index paper has received much more attention than my 80 superconductivity papers put together,” he says. “It just proves that you never know when you are going to make an impact.”

The same could perhaps be said about his stance on nuclear weapons. Until recently, Hirsch admits that he was not particularly concerned about American weapons policy. There was certainly some food for thought – the US “Nuclear Posture Review” of 2001 envisaged a “new mix” of nuclear and non-nuclear weapons against a “diverse set of potential adversaries”, and the “Doctrine for Joint Nuclear Operations” subsequently set out a number of scenarios under which the US may use nuclear weapons, including the use of “bunker busters” to destroy deeply buried military installations (which, if buried deeply enough, may be out of the reach of non-nuclear weapons).

But it was only in September last year that Hirsch came to believe that the US would actually put this policy into practice. That was when the member states of the International Atomic Energy Agency (IAEA) voted to refer the impasse over Iran’s nuclear activities to the United Nations in New York. He thinks the reason the US has been pushing hard for sanctions is not because these are likely to be approved by the security council – they are not, because China and Russia have said explicitly that they would veto such a move – but conversely because the failure of the UN route will then leave the US with a pretext for military intervention. “I woke up one day and everything fell into place in my mind,” he recalls. “I realized we are in an extremely dangerous situation and felt I needed to do whatever I could, out of sheer desperation.”

Hirsch believes that before November – when the Democrats may regain control of Congress in the mid-term elections – the US will launch a limited attack against select military targets in Iran, probably using non-nuclear weapons. A few days later, following the inevitable retaliation by Iran, the US, he says, will then launch a huge attack on the country, using a mixture of non-nuclear and nuclear bombs. As things stand, he estimates the chances of the US launching a nuclear strike before the end of the year to be about 95%.

“Everything that has happened since September has reinforced my belief that we are moving in this direction,” he says. “The point is that there is nothing stopping it, the President wants it and his advisers want it.”

A nuclear world

Some people think that Hirsch has grossly overestimated the threat, however. Michael Levi, a physicist at the Council on Foreign Relations in New York, thinks there is “essentially zero chance” that the US will launch a nuclear strike against Iran. He believes that policy documents such as the Nuclear Posture Review are “quite vague” and “do not have inevitable consequences”. He says that militarily there is no need to strike Iran using nuclear weapons, adding that the Isfahan uranium conversion facility, for example, is above ground and lightly defended.

But Hirsch is in no doubt about the intentions of the Bush Administration. He believes that the US has a deliberate long-term strategy to prevent other nations from acquiring nuclear weapons by threatening them with force. Iran, he thinks, provides American with the perfect opportunity to show that it can follow up its threats with action. This, he says, is a fatally flawed strategy. While he objects to the bellicose rhetoric of Iranian president Mahmoud Ahmadinejad, he believes the best way to ensure that Iran does not have nuclear weapons is to allow it to have a civilian nuclear programme under the watch of the IAEA.

He says that the moment the US drops a nuclear bomb on Iran, the Non-Proliferation Treaty – an international agreement by non-nuclear nations not to develop nuclear weapons as long as nuclear nations take steps to reduce their stockpiles – would become worthless. Many of the 182 non-nuclear weapons signatories of the treaty would start developing nuclear weapons of their own as the only effective means of self-defence. With many more nuclear weapons states and no longer a taboo against using the nuclear option, any regional conflict could then lead to all-out nuclear war.

The US attack on Iran, will not, he says, be a Hiroshima-scale bombing, but instead involve bunker-buster weapons that will probably kill a few hundred people each. The point for Hirsch, however, is not how powerful these bombs are but the fact that they are nuclear. By breaking the 60 year taboo on nuclear weapons use, he says, “you’re crossing a line that you cannot go back across”.

Action required

As a shorthand way of illustrating the scale of the threat, Hirsch uses his own h-index. He points out that the h-index of nuclear proliferation today is eight – in other words, there are eight countries that have at least eight nuclear weapons each. But he believes that if the US does drop a nuclear bomb, then this number will rise to perhaps 50 or maybe even 100 within a few years.

To have any chance of avoiding this situation he believes there has to be a focused effort by scientists on opposing the use of nuclear weapons against non-nuclear countries. Indeed, the American Physical Society recently made a formal statement expressing “deep concern” about such a policy.

Hirsch points out that he is not advocating the complete elimination of all nuclear weapons or the end to all wars. “I believe it is important to focus on what is achievable,” he says. “Every country that has nuclear weapons should renounce the use of those weapons against non-nuclear countries.” Expecting such renunciations may be wishful thinking. But Hirsch is in no doubt that physicists must at least try to bring them about. He believes that if nothing is done, the world could be on a one-way road to disaster.