I'm cool about global warming. I don't doubt that it's going to happen and I confidently expect that the forecasts of the Intergovernmental Panel on Climate Change will be shown up as overly optimistic, in regard both to rising temperatures and controlling emissions. Yes, it's going to happen - and we are not going to stop it. The IPCC estimates a worst-case scenario of a 5 Celsius increase in mean global temperatures, and a best-case one of 1.5 C. It predicates the lower figure on greenhouse-gas emissions controls being implemented right now that go far beyond those envisaged by the Kyoto Protocol; the higher figure is based on a continuing rise in emissions in line with current trends. Devastating wild-card factors, such as the so-called "methane burp" and the possible stalling or even stopping of the Gulf Stream - as envisaged in this year's timely disaster movie The Day After Tomorrow - are left out of the mix.
Let's get this straight: the Kyoto Protocol has not been fully ratified. The world's largest polluter - the United States - has pulled out of it altogether, and the watered-down version of the Protocol which was agreed in Bonn in July 2001 has enough gaps in it to drive ten million exhaust-farting coaches through. The idea of states trading "carbon credits" for the right to continue producing emissions is as fatuous as the notion that planting new-growth woodland (or even crops) can vitiate the depredations of grubbing out aboriginal forests. Even if there were to be a genuine international consensus on controlling greenhouse emissions and a treaty was agreed outlining the best reductions imaginable, it would still be next to impossible to enforce it. Hell, if the United Nations couldn't satisfy the UK and US governments that Saddam Hussein did not have WMDs, how could an environmental inspectorate set up from scratch prevent a tyre factory in Baluchistan from doing whatever it wanted?
Global warming is already happening, with catastrophic results for humanity and myriad other species of flora and fauna. Mark Lynas's book amply demonstrates this, to the satisfaction of even the most apocalyptic among us. Lynas has completed a modern-day version of the Grand Tour, but instead of alighting on the sites of classical antiquity and contemporary progress, this young English gentleman has visited some particularly hot spots around the globe: the rapidly submerging islands of Micronesia; the howling dust storms of Inner Mongolia; the melting permafrost of Alaska; the widening gyre of the hurricanes of the Atlantic seaboard and the retreating glaciers of the Andes.
However, Lynas starts right here in dear old Blighty, where neighbours greet each other on their doorsteps, survey the rainy May weather and quip: "I don't think much of this 'ere global warming." But the point - which High Tide makes crystal clear - is that global warming is not just about long hot summers on the beach. It's about a new instability in the climate overall - more sun and more rain - just not, unfortunately, in the right sequence or the right places. The recent floods in Britain are as much a product of global warming as last year's record-busting heatwave.
Inspired by his father, a geologist who is curious as to how global warming has affected the beautiful glacier that he photographed 20 years ago in Peru's Cordillera Blanca, Lynas brings a youthful idealism and intensity to his travels. He cares, he really cares, and, like every card-carrying environmentalist, he truly believes something can be done. None of the evidence he sees with his own eyes, whether it's Tuvaluan islanders sloshing through the seawater inundating their gardens, or Chinese peasants trying to plough dust, or Alaskan Native Americans shaking their heads over lakes that have drained clean away, manages to shake his faith in the possibility of constructive change. Not even - and this takes some beating - long days spent watching empty-headed wonks at the IPCC trying to negotiate the unnegotiable put him off his stride: Lynas's book is a clarion call to action, complete with website information allowing you to audit your own lifestyle environmentally, as well as apply pressure to the polluters-that-be.
High Tide is an easy read, even if there is rather more about the young Lynas than I for one wanted to know. When he confines himself to the environment, he is clear, lucid and informative, but unfortunately he has the backpacker's tendency to believe that his travel experiences are intrinsically interesting.
Is it all to any purpose? Lynas is tough with himself in doing his own environmental audit, and concedes that the flights that went into researching the book have used up 20 years of his own "carbon allowance". On that basis (and this is leaving the emissions that went into the book's physical production out of the equation), at least 19 readers will have to undertake their own audits to compensate for Lynas's air travel. This is what the environmentalists are up against: they have to inculcate a sense of collective responsibility and foresight in a mass population that is unwilling to do so. Don't get me wrong, I'm not a pessimist, but I do recognise that unrealistic expectations of humanity lead, in the end, to contempt.
Will Self's most recent book is Dr Mukti and Other Tales of Woe (Bloomsbury)