A gathering of 20 Nobel Prize winners, calling itself the St James's Palace Nobel Laureate Symposium, has released a memorandum stating that 'Global climate change represents a threat of similar proportions' to that of thermonuclear armageddon at the height of the Cold War.
The memorandum, agreed by laureates in fields as diverse as physics, economics, peace and literature, identified three 'key requirements' for the world to avoid global warming of more than 2°C and associated 'unmanageable climate risks'.
The first of these is for the United Nations Climate Change Conference hosted in Copenhagen this December to agree an 'effective and just global agreement on climate change'. The second is for a 'low carbon energy infrastructure', which basically means switching energy production to much less emission-heavy systems. The third is for the protection of tropical forests.
So far, so unremarkable. These are the widely acknowledged political aims of climate-sensitive environmentalists the world over. That is until the bit about thermonuclear armageddon. It's fair to say that the facts relating to the outcome of tossing multi-megaton-yield nuclear warheads around the planet are a little more cut and dried than those relating to climate change.
The qualitative difference between the two threats is perhaps nowhere better expressed, however inadvertently, than by the convener of the symposium himself, Professor Hans Joachim Schellnhuber. Where once we had 'the Cold War notion of mutually-assured destruction,' he told the Times, 'Today we have mutually-assured increases in greenhouse gases.'
OK. But while debates around climate change are still qualified by the words 'might', 'could' and 'predicted', it's probably fair to say that the average person in the street may view the comparison of carbon emissions with things that can vapourise a major city in seconds as unhelpfully alarmist and perhaps just a little bit silly.