The coincidence and severity of such natural disasters as the Russian heat wave, Pakistan floods and the breaking up of the Greenland ice-sheet in recent months has prompted renewed debate about the role of global warming and whether such crises are merely a foretaste of things to come.

Scientists emphasise that there is no hard data directly linking these recent disasters to specific changes in the earth’s climate due to human interference but warn that such crises fit unnervingly well into scientific projections that higher global average temperatures will increase the frequency and intensity of these sorts of extreme weather events.

Already, global average temperatures have risen by 0.7C in the last 130 years. In 2007, the UN Intergovernment Panel on Climate Change told the world that at current rates of increase of fossil fuel emissions, we were heading toward a rise in global average temperatures of around 6C by the end of this century. If trends continue, by 2025, 1.8 billion people would be living in regions of water-scarcity, and two-thirds of the world population could be subject to water stress.

Things are, however, getting worse faster than previously imagined. Currently, governments talk about stabilizing global average temperatures below 2C, at an atmospheric concentration of greenhouse gases at 450 parts per million (ppm). But according to Dr James Hansen, head of the NASA Goddard Institute for Space Studies, the upper limit for a safe climate is far lower, at around 350 ppm.

The problem is that even 350 ppm could be far too conservative. Professor John Schellnhuber, Director of the Potsdam Institute for Climate Impact Research, warns that a safe level of emissions is more likely between 280 and 300 ppm. With the earth already beyond 300 ppm, we are heading for a minimum rise of 2C this century. Scientists at Lawrence Berkeley National Laboratory and the University of California at Berkeley project that at current rates of fossil fuel emissions, we are set to reach temperature rises of up to 8C within 90 years.

The latter accounted for the effects of ‘positive-feedbacks’ not factored into previous studies -- that is, the fact that the collapse of any one of these ecosystem hotspots could have a domino effect on the entire climate system. Global warming impacts in one ecosystem could feedback into other ecosystems, with the danger of tipping the climate over into a process of exponential, runaway warming. These “positive-feedbacks” mean that as temperatures rise, the capacity of the earth to naturally absorb human fossil emissions increases, multiplying the warming effect.

Irreversible collapses of key interdependent ecosystems could occur if carbon emissions do not drastically drop to zero by 2020. For instance, global warming has already accelerated the melt of Arctic permafrost, releasing methane into the atmosphere. Methane is twenty times more powerful as a greenhouse gas than CO2. Above 1C, this process of melting and methane release would be further accelerated, raising temperatures higher, thus releasing more methane, and so on.

According to former US Energy Department geologist John Atcheson, “Once triggered, this cycle could result in runaway global warming the likes of which even the most pessimistic doomsayers aren’t talking about.”

Additionally, one of the most disturbing developments is the Arctic where summer sea-ice is rapidly disappearing year-on-year with a possible ice-free summer by 2012. Among other effects, freshwater from the ice-melt as well as increased regional rain and snow could dump enough freshwater into the North Atlantic to interfere with -- and perhaps even stop -- the Gulf Stream, a strong ocean current which brings warmth to Western Europe. The slow-down or collapse of the Gulf Stream would kick-start abrupt, dangerous and irreversible climate changes, leading to drastic cooling in North America and Western Europe, and frequent droughts in food-basket regions.

The environmental disaster stoked by the BP oil spill in the Gulf of Mexico may have amplified this probability. Dr. Gianluigi Zangari, a theoretical physicist at the Frascati National Laboratory in Italy, has analysed satellite data-maps from May-June, which confirm “for the first time direct evidence of the rapid breaking of the Loop Current, a warm ocean current, crucial part of the Gulf Stream,” in an area adjacent to BP’s Deepwater Horizon platform. Zangari concludes that it is “plausible to correlate the breaking of the Loop Current with the biochemical and physical action of the BP Oil Spill on the Gulf Stream.”

The instability in the Gulf Stream -- whose pathway directly affects global weather and climate patterns -- may well be linked to the erratic behaviour of the polar jet stream, whose blocking appears to be partially responsible for the extreme weather in Russia, Pakistan and elsewhere.

The window of opportunity to prevent disaster is closing fast. Conventional discourse on climate change tends to underestimate the gravity of what current trends actually imply -- not merely an inconvenient and growing disruption to our lives, but at worst, a permanent rupture between humankind and the natural world, which threatens not only the continuity of industrial civilization as we know it, but also the survival of our species.

The scale of the potential catastrophe around the corner -- not to mention the scale of our seeming systemic inability or unwillingness to respond -- indicates that the climate crisis cannot be dealt with merely by tweaking the global system. There is something deeply wrong with our global political economy, given its obsessive compulsion to ‘grow’ and accumulate without recognition of natural or social limits; with our values, which privilege money-maximization and consumerism to the degree that we are exhausting the earth’s resources beyond repair; and with our understanding of human nature, when the wealthiest societies are simultaneously the most unequal and unhappy

If we are to overcome this crisis, we will need not only to act preventively and adapt strategically, but to transform the regressive political, economic and social structures that continue to accelerate ecological collapse. This process can only truly begin when a critical mass of people recognize that imminent climate catastrophe is symptomatic of deep-seated problems in the way industrial civilization is currently organized.

Dr Nafeez Mosaddeq Ahmed is executive director of the Institute for Policy Research & Development in London. His latest book is A User’s Guide to the Crisis of Civilization (Pluto Press, 2010).

Copyright © 2010 Le Monde diplomatique – distributed by Agence Global