Expired · 15th October 2009
Predictions are opinions. But scientific predictions are notably different. Based on extrapolations from existing evidence, they are much more reliable than mere guesses. Consequently, vague glimpses into the future of global climate change are becoming more credible as computer processing gets more powerful, as climate models increase in sophistication, as worldwide data amasses, and as precedent from Earth's early history accumulates. This is why the article, "Surviving a Warmer World", in the New Scientist (Feb. 28/09) is particularly startling.
The New Scientist is a magazine that explores the latest thinking, research, discoveries and technology in a broad base of the sciences. Like many publications, it is giving increasing coverage to global climate change, a subject that is gaining attention as scientific concern intensifies and as nations engage in preliminary negotiations for December's Copenhagen agreement to replace the Kyoto Protocol.
Most climatologists now believe that the action accruing from the Copenhagen commitments will be absolutely critical to the future of life on Earth: to ecosystems, to species, to humanity, and to just about everything that happens on our planet for thousands or even millions of years. Concern is escalating toward alarm – we must dramatically arrest our greenhouse gas emissions and their global warming effects.
The words on the cover of the New Scientist are unequivocal: "EARTH 2099 – Population crashes. Mass migration. Vast new deserts. Cities abandoned. How to survive this century."
The magazine's feature article predicts the condition of the planet in 2099 given an average rise in global temperature of 4°C above pre-industrial levels. Such a rise is plausible, perhaps inevitable. The measurable average global temperature has already risen 0.8°C in the last 250 years. We are likely committed to a 2°C rise because of the continuing increase in carbon emissions – despite the Kyoto Protocol – and the biosphere's delayed response to such emissions. Further, the ability of our biosystems to absorb CO2 is decreasing. Meanwhile, so-called "tipping points" are looming – methane, a greenhouse gas that is about 25 times more warming than carbon dioxide, is now bubbling from thawing locations in Russia, Norway and Canada. And finally, actual measurements confirm that the predictions of almost all previous climate models have been too conservative. Some climatologists expect we will reach this 4°C mark by 2050 and 5.2°C by 2099.
So,what can we expect on a planet that is 4°C warmer? We have precedent from Earth's history. Palaeontologists describe a time during the Palaeocene-Eocene Thermal Maximum 55 million years ago when "huge belches of frozen, chemically caged methane" called clathrates warmed the planet 5°C to 6°C. Oceans acidified and killed most marine life, sea levels rose 100 metres, and almost all the land masses from the tropics to mid-latitudes became deserts.
A computer-generated climate map of a 4°C warmer world looks similar. By 2099, the level of acidifying oceans will have risen by at least one metre, inundating valuable estuaries and drowning such cities as Saigon, New Orleans, Venice and Mumbai. The largest land masses, from about 50° north latitude to 50° south latitude, will be mostly desert. This includes the continental United States, southern Europe and Asia, and most of Africa, South America and Australia. Because of "floods, drought or extreme weather", America's east coast, Central America, central South America, south-east Africa, India, China, the Himalayan region and the East Indies will be largely uninhabitable.
Habitable areas will shift northward to Canada, Alaska, northern Europe, Russia and Siberia. A few other small patches will remain in east Africa, eastern and northern Australia, New Zealand, at the southern tip of South America, and along the north eastern coast of Antarctica. These will be human refuge areas and possible food growing regions – if the soils are appropriate.
James Lovelock, the father of the Gaia Theory and the elder of modern ecology, summarizes the situation with the detachment of someone who thinks in eons rather than individuals. "Humans are in a pretty difficult position and I don't think they are clever enough to handle what's ahead. I think they'll survive as a species all right, but the cull during this century is going to be huge" (Ibid.).
Peter Cox, an expert on "the dynamics of climate systems" at the United Kingdom's University of Exeter, summarizes the responses of his colleagues to the climate threat. "Climatologists tend to fall into two camps: there are the cautious ones who say we need to cut emissions and won't even think about high global temperatures; and there are the ones who tell us to run for the hills because we're all doomed" (Ibid.).
Words such as "cull", "won't even think about" and "doomed" are ominous coming from scientists who usually offer cautious and conservative opinions. They are not alone. The rhetoric is heating in parallel with the rising temperature. The UN's secretary-general, Ban Ki-moon, in urging serious progress during pre-Copenhagen talks, warned that the world is speeding toward a climate catastrophe (The Vancouver Sun, Sept. 4/09).
We have 90 years until 2099. If the end of this century is as dire as the 4°C prediction, getting there will become increasingly unpleasant. The United Nations reports that 9 out of 10 natural disasters are already climate related. But a decade or more of escalating disasters might be necessary to convince all doubters that human carbon emissions are actually the cause of global climate change. By the time we have unanimity of opinion and everyone is willing to support preventative measures, all such efforts will probably be irrelevant.