Our leaders have been to Heiligendamm and back - but as the G8 summit in the German city ends with a chorus of boos and the tossing of rotten fruit, the two great threats to life on this planet remain as imminent as ever.
The heads of the richest nations could not agree to keep global warming this side of two degrees centigrade, and despite Vladimir Putin pledging to point his nukes at European cities once again, they didn't even talk about reducing the number of nuclear weapons in the world. This means that the odds of mankind making it out of the next few centuries alive just shrank a little bit more.
This sounds, at first glance, hysterical, I know. What's three degrees of warming? A little extra sunscreen and a new pair of Gucci sunglasses, surely. But the overwhelming scientific evidence tells us something very different. The maximum figure of two degrees of warming on the global thermostat was not plucked randomly by Angela Merkel, the German Chancellor who tried to drag the other leaders towards it. No - it is calculated by virtually all the world's scientists to be the threshold beyond which our planet's fragile natural systems will begin to unravel rapidly .
The environmentalist Mark Lynas pores through the scientific studies to explain why in his new book, Six Degrees: Our Future on a Hotter Planet. The Amazon rainforest has no resistance to fire, because it is constantly humid. If the world hits three degrees of warming, that humidity dries out - and the Amazon, the lungs of the earth, burns to the ground. Without the Amazon acting as a vast carbon sink, the world gets warmer still, rising to four degrees. This causes the Siberian peat-bogs to melt and burp out their massive store of methane into the atmosphere. This pushes us up to five degrees - and on.
Once we hit six degrees, we reach humanity's end-game, played out on an unrecognisable planet scarred by crop failure. The last time the world warmed by this much was 251 million years ago. The result was that 95 per cent of everything on earth died. The only survivors were a pig-like creature called Lysotorous, who had the land to himself for the next 50 million years, and a few clams in the oceans.
Staying this side of two degrees is the most urgent cause of our time. But why couldn't we even get agreement on that?
The main obstacle was George Bush, a man whose life has been much in the service of the companies who profit from pumping out warming gasses. His acceptance of a pledge in the summit's final communiquÃƒ© to halve emissions by 2050 was, alas, an empty gesture. His real views on global warming became clear in 2001, when he invited the pulp fiction writer Michael Crichton into the Oval Office to tell him how much he loved his book State of Fear.
State of Fear purports to tell the Real Story about global warming. It shows how a string of environmentalist groups, motivated solely by the desire to raise as many funds as possible, become frustrated that global warming isn't happening. So they decide to manufacture vast weather machines to make it look like it is. They blast a huge chunk of glacier off the Antarctic, and arrange for a tsunami to hit the West Coast of the United States on the day of an academic conference warning about warming.
Close Republican allies of Bush called Crichton to testify on the Hill at scientific hearings, and congratulated him on his " brave exposÃƒ©" . (Soon they will no doubt announce a programme to defend America from all those escaped dinosaurs). But Bush was not alone: for all our talk, here in Europe our greenhouse gas emissions actually rose last year. If you factor in all the manufacturing we have out-shored to China, they rose dramatically.
Another long-term threat - just as serious, if less discussed today - was even more neglected at the G8. The response from Western publics to Putin's nuclear threats was mostly bemused: didn't the mushroom cloud disappear in the rubble of the Berlin Wall? In fact, in the short period since the fall of Soviet tyranny, there has been at least one time when their nukes were very nearly fired.
One morning in January 1995, Boris Yeltsin was awoken from an alcoholic stupor to be told that the United States had fired a nuclear missile at Russia and he must immediately retailate. It turned out the Russian computers were on the blink - a perrennial problem, given the gradual decomposition of the bits of the Soviet nuclear arsenal that have not been stolen. This mistake was only realised at the last moment, just before Yeltsin gave the order to incinerate millions.
The dangers of nuclear exchanges - accidental or deliberate - are multiplying across the globe, as hot-spots turn into Cold Wars. It is only four summers since Britain told its citizens to evacuate India and Pakistan because they were so close to a nuclear war. Even today, there is no nuclear hotline between the rival powers, and Pakistan's Pervez Musharraf is on the brink of being toppled - to be replaced by ... who? If these two countries alone exchanged their nuclear arsenals, there is evidence suggesting there would be a nuclear winter, blocking out the sun's rays and killing us all.
Far from draining the nuclear pressure, the Bush administration is perversely ramping it up. The current moves towards a nuclear missile shield have been misrepresented. No such shield could ever work against incoming nukes, as every test has shown. But what it can do is shoot down non-US satellites. Satellites are now essential for military communications; if you can take them out at will, you have massive and unrivalled power. That's why Putin is asserting his own power in response, and why Bush will decline his offer of a shared base. The Bush administration is choosing to increase its own power, even if the cost is an increase in nuclear danger.
There are rational solutions to this twin-set of nightmares. They lie in a hard, binding international agreement to slash greenhouse gas emissions, and a return to the Nuclear Non-Proliferation Treaty in which all nuclear powers gradually reduce their stashes of WMD.
As Bertrand Russell wrote in 1961 on behalf of the 12 most eminent scientists in the world: "There lies before us, if we choose, continual progress in happiness, knowledge and wisdom. Shall we, instead, choose death, because we cannot forget our quarrels? We appeal as human beings, to human beings: Remember your humanity, and forget the rest. If you can do so, the way lies open to a new Paradise: if you cannot, there lies before you the risk of universal death."
The G8 was a slap-in-the-face reminder that we cannot leave it up to our leaders to choose the sane path. We have to force them through mass democratic movements like Greenpeace and a reclaimed Campaign for Nuclear Disarmament. Perhaps we will fail. Perhaps humanity is such an irrational, poorly evolved species that we cannot overcome our tribalism and mutual suspicions and act in our own self-defence. But when the alternatives are a barren world that is six degrees warmer or a freezing nuclear winter, I think we ought to find out - and fast.
© 2007 The Independent