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Ravages of climate change threaten Earth

Global warming affects more than just the weather; it affects individual health and the ability of ecosystems to adapt and survive, writes MARK LYNAS

At first no one could quite believe what was happening. Funeral parlours in Paris were having to turn away dead bodies as elderly people across the French capital dropped like flies in record-breaking 40 degrees celsius heat.

With the morgues overflowing, inflatable refrigerated tents had to be quickly erected to store the surplus bodies. The head of the French health service was even forced to resign after he admitted that the death toll could reach as high as 5 000 people.
He was wrong, of course. The actual death toll from the 2003 summer heat wave was much higher – nearly 15 000 people – some of whom eventually had to be buried in temporary graves when no one could identify the bodies. Britain also saw temperatures climbing above previous records.

A group of German scientists calculated that the statistical probability of such an event was 0.0001. In other words, a heat wave on the magnitude of 2003 should only be expected once every 10 000 years.

However, predictions are that such summers will be regular occurrences by the middle of this century, thanks to global warming.

It’s not just getting hotter in Europe: more than 1 500 deaths were reported when a June heat wave struck India, and in neighbouring Pakistan the city of Jacobabad reached a staggering 52 degrees celsius, a full 8 degrees celsius above normal.

Such temperatures make normal life impossible, and if global warming continues to accelerate, dry subtropical continental areas like Pakistan, the Middle East and North Africa may become literally uninhabitable in future decades.

According to the World Health Organisation, 150 000 deaths were directly attributable to climate change in 2000. Much of this was to do with increases in malaria and diarrhea, each of which kills more than a million people a year at present.

Warmer temperatures can increase disease both directly, by encouraging the faster growth and reproduction of bacteria and other pathogens, and indirectly, through increases in weather extremes.

One study looking at a malaria outbreak in West Papua in 1997, linked it with a severe drought: fast-running streams had dried up into pools of stagnant water, and a population with little natural resistance to malaria and already under stress from food shortages quickly succumbed. As is so often the case, those most at risk are people in poor countries who have done little or nothing to bring about global warming in the first place.

Attempts to quantify the impacts of climate change on human health over the coming decades face considerable obstacles.

In the first place, no one knows just how rapidly global warming is going to accelerate.
In its landmark 2001 report, the Inter-governmental Panel on Climate Change (IPCC) gave an estimated range of 1,4-5,8 degrees celsius for temperature rise during the 21st century.

Most of the uncertainty was due, not to imperfections in computer models or our understanding of the climate system, but to our lack of knowledge about how high greenhouse gas concentrations in the atmosphere are likely to climb.
And that depends, more than anything else, on economics and politics.

What is already becoming clear is that even if all greenhouse gas emissions stopped tomorrow, the climate would continue warming for decades into the future - probably by double the 0,6 degrees celsius so far experienced over the last century.
This would make the planet hotter than at any time since the last Ice Age, and possibly even longer.

The upper range of the IPCC scenario, meanwhile, will take us into uncharted waters, with average temperatures higher than they have been for the last 40 million years, well outside the range ever experienced by humanity or the other species with whom we share this planet.

So what about planetary health? How are species apart from humans being affected?
The rising temperatures make it easier for alien species and pathogens to colonise new areas.

In Alaska, spruce bark beetles have killed 2,3 million acres of trees since 1992. It’s the worst insect outbreak ever to hit North American higher temperatures: in colder winters, the beetle eggs are killed off and the population is unable to explode.

In past episodes of climate change – such as the warming after the last Ice Age – species could shift their range as the temperature warmed up.
But this time, it’s going to be different.

First of all, the rate of temperature rise seems likely to outstrip the migration capacities of many species.

At the end of the last Ice Age, for example, trees could colonise new areas at a speed of up to a kilometer a year, by spreading their seeds and gradually established new saplings.
But projected warming rates will outstrip this rate of adaptation: climatic zones in the 21st century will be shifting north seven times faster than most plant species can follow them.

Secondly, human development now gets in the way. With much of our land space given over to cities, major roads and vast dead zones of intensive farming, ecosystems are trapped in a patchwork of immovable nature reserves.

Finally, the Earth is not shifting from a cold period to warm period, as it did when the ice sheets began to melt 18 000 years ago.

It’s shifting from a warm “inter-glacial” to an even warmer episode, where temperatures are likely to be outside the evolution experience of many species.

The threshold of thermal tolerance is already being crossed for tropical coral reefs, for example, which have been struck by severe mass bleaching episodes in recent years, as a direct result of the warming seas.

Bleaching reached catastrophic levels in the 1998 EI Nino event, when the sixth of the entire tropical coral reef ecosystem on the planet was destroyed.

Yet disasters of this scales are likely to become commonplace within a mere two decades, and with 30 to 50 years severe bleaching could be an annual event – a test the vast majority of corals will not be able to survive.

The likely disappearance of tropical reefs is a very big deal, indeed. Coral reefs are the most bio-diverse marine ecosystems on the planet, containing as many as nine million different types of plants and animals, including a quarter of all known sea fish.
Most of the rest of the planet’s biodiversity is in tropical rainforests – which are endangered not only from direct threats of logging and farming, but from shifts in climate which are already making them vulnerable to fire.

In Indonesia, 80 percent of the original forest cover has now been destroyed, and a drought in 1997-98 led to the worst fires in history.

Computer models developed by the Meteorological Office suggest that a “tipping point” exists where global warming will lead to a rapid collapse of rainforest ecosystems and their eventual conversion to savannah.

This is particularly the case for the Amazonian forest, where the largest undisturbed forest areas remain.

In Australia, the tropical forests of north-eastern Queensland – which are listed as a World Heritage Area due to their high biodiversity – face an “impending environmental catastrophe”, according to Stephen Williams, a scientist who has spent years studying them.

Williams has modeled the effect of temperature rises on some of the species unique to the area, and discovered that even small rises lead to the loss of valuable habitat.
Indeed, for a warming of anything over 3,5 degrees celsius, the wipe-out is almost total.
Studies like these have been repeated at a global level, and the results caused news headlines which went worldwide.

This warning is being heeded to a limited extent by the international community – though not by the US President George Bush Administration - with the UN Framework Convention on Climate Change (which calls on the world to stabilise greenhouse gas emissions at a level that prevents “dangerous” climate change) and its Kyoto Protocol.

If Russia can be persuaded to ratify, Kyoto comes into force, then an important first step will have been taken.

But Kyoto needs tightening up, and all countries ultimately need to enter into an emissions-limiting treaty, ideally through the equity-based solution of “contraction and convergence”.

But as long as governments dawdle – and Bush remains in the White House – it is largely up to individuals to take their own steps.

This might involve joining campaigns calling for change. Or it may involve as simple a step as switching to green electricity in the home or workplace or using bio-diesel to fuel cars and central heating systems.

Reducing personal greenhouse gas emissions remains an option for all of us, but ultimately, only a strong global agreement will protect the planet from the worst ravages of climate change. – Third World Network Features.

• About the writer: Mark Lynas is a writer and campaigner on climate change issues, and author of “High Tide: News from a Warming World” (Flamingo, 2004).

Courtesy of The Herald of 28 September, 2004

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