New Scientist (pg. 28), February 25, 2009
HOW TO SURVIVE THE COMING CENTURY
[Rachel's introduction: Alligators basking off the English coast; a vast Brazilian desert; the mythical lost cities of Saigon, New Orleans, Venice and Mumbai; and 90 per cent of humanity vanished. Welcome to the world warmed by 4 degrees Celsius [7.2 degrees Fahrenheit].]
by Gaia Vince*
Explore an interactive map of the world warmed by 4 deg. C [7.2 deg. F.]
Alligators basking off the English coast; a vast Brazilian desert; the mythical lost cities of Saigon, New Orleans, Venice and Mumbai; and 90 per cent of humanity vanished. Welcome to the world warmed by 4 deg. C [7.2 deg. Fahrenheit].
Clearly this is a vision of the future that no one wants, but it might happen. Fearing that the best efforts to curb greenhouse gas emissions may fail, or that planetary climate feedback mechanisms will accelerate warming, some scientists and economists are considering not only what this world of the future might be like, but how it could sustain a growing human population. They argue that surviving in the kinds of numbers that exist today, or even more, will be possible, but only if we use our uniquely human ingenuity to cooperate as a species to radically reorganise our world.
The good news is that the survival of humankind itself is not at stake: the species could continue if only a couple of hundred individuals remained. But maintaining the current global population of nearly 7 billion, or more, is going to require serious planning.
Four degrees [Celsius] may not sound like much -- after all, it is less than a typical temperature change between night and day. It might sound quite pleasant, like moving to Florida from Boston, say, or retiring from the UK to southern Spain. An average warming of the entire globe by 4 deg. C [7.2 deg. F.] is a very different matter, however, and would render the planet unrecognisable from anything humans have ever experienced. Indeed, human activity has and will have such a great impact that some have proposed describing the time from the 18th century onward as a new geological era, marked by human activity. "It can be considered the Anthropocene," says Nobel prizewinning atmospheric chemist Paul Crutzen of the Max Planck Institute for Chemistry in Mainz, Germany.
A 4 deg. C [7.2 deg. F.] rise could easily occur. The 2007 report of the Intergovernmental Panel on Climate Change, whose conclusions are generally accepted as conservative, predicted a rise of anywhere between 2 deg. C and 6.4 deg. C [3.6 deg. F. and 11.5 deg. F.] this century. And in August 2008, Bob Watson, former chair of the IPCC, warned that the world should work on mitigation and adaptation strategies to "prepare for 4 deg. C [7.2 deg. F.] of warming".
A key factor in how well we deal with a warmer world is how much time we have to adapt. When, and if, we get this hot depends not only on how much greenhouse gas we pump into the atmosphere and how quickly, but how sensitive the world's climate is to these gases. It also depends whether "tipping points" are reached, in which climate feedback mechanisms rapidly speed warming. According to models, we could cook the planet by 4 deg. C [7.2 deg. F.] by 2100. Some scientists fear that we may get there as soon as 2050.
If this happens, the ramifications for life on Earth are so terrifying that many scientists contacted for this article preferred not to contemplate them, saying only that we should concentrate on reducing emissions to a level where such a rise is known only in nightmares.
[To save space, we have had to truncate this important article. Please continue reading the full article in printer-friendly format here. --Rachel's editors]
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* Gaia Vince is a freelance science writer who is travelling the world. www.wanderinggaia.com