Evidence points to mass extinction
The worst mass extinction in the history of the planet could be replicated in as little as a century if global warming continues, according to new evidence.
Researchers at Bristol University have discovered that a six-degree increase in the global temperature was enough to annihilate up to 95 per cent of species which were alive on Earth at the end of the Permian period, 251 million years ago.
Up to six degrees of warming is now predicted for the next century by United Nations scientists from the Intergovernmental Panel on Climate Change (IPCC) if nothing is done about emissions of the greenhouse gases, principally carbon dioxide, which cause global warming.
The end-Permian mass extinction is now thought to have been caused by gigantic volcanic eruptions, which triggered a "runaway greenhouse effect" and nearly put an end to life on Earth. Conditions in what geologists have termed this "post-apocalyptic greenhouse" were so severe that only one large land animal was left alive, and it took 100 million years for species diversity to return to former levels.
The new finding is revealed in a book by Professor Michael Benton, the head of Earth sciences at Bristol University.
Prof Benton said: "The end-Permian crisis nearly marked the end of life. It's estimated that fewer than one in ten species survived.
"Geologists are only now coming to appreciate the severity of this global catastrophe and to understand how and why so many species died out so quickly."
Tropical latitudes were the first areas of the Earth to feel the effect of the warming, and loss of species diversity spread out from there.
Reduction of vegetation, soil erosion and the effects of massively increased rainfall wiped out the lush diverse habitats of the tropics, which would today lead to the loss of animals such as hippos, elephants and all of the primates, according to Prof Benton.
He added: "The end-Permian extinction event is a good model for what might happen in the future because it was fairly non-specific.
"The sequence of what happened then is different from today because then the carbon dioxide came from massive volcanic eruptions, whereas today it is coming from industrial activity. However, it doesn't matter where this gas comes from; the fact is that if it is pumped into the atmosphere in high volumes, then that gives us the greenhouse effect and leads to the warming with all the other consequences."
Modern predictions of the apocalyptic consequences of global warming and climate change due to increases in carbon dioxide first began to circulate in the early 1980s.
Carbon dioxide is, like oxygen, translucent to sunlight but opaque to infra-red radiation. After the sun's rays have warmed the Earth and sea, the heat produced can therefore not be re-radiated back into space.
When the industrial revolution began about 200 years ago, there were roughly 280 parts per million (ppm) of carbon dioxide in the atmosphere. Today, there are 350ppm.
More carbon dioxide is being pumped into the atmosphere as the human population grows and turns to heavy industry, and less is being removed by the rest of nature because, possibly due to human activity, global vegetation which removes the damaging gas is in retreat.
In the mid-1980s, scientists first started to predict that temperatures would increase somewhere in the order of between four and six degrees by 2080. Sea levels were also predicted to rise 20cm by 2030, and 45cm by 2070.
In the light of modern records, these estimates were a little overstated. Dr Ian Brown, a senior researcher with the Tyndall Climate Research Centre at the University of East Anglia, said: "More or less every year now we have a temperature which is higher than the previous year and the Met Office has predicted this year that there is a 50 per cent chance it will be the warmest on record.
"Each year is now pretty much an exceptional one by previous standards.
"Sea-level rise is more complicated because we have a shorter record. At the moment, in global terms, it is probably in the order of about one and a half millimetres per year.
"By the end of the century, the rise in sea level could then be a lot more than five or even ten centimetres.
Certainly in the past two decades we have now recorded rises in sea levels in the region of one or two millimetres a year which are measured by tide gauges at various sites.
"These instruments are quite precise and show that predictions of the consequences of global warming are certainly observable."
He added: "Much land has in the past been reclaimed from the sea, such as in the Forth estuary, and those areas are now looking increasingly vulnerable."
Climate experts and environmentalists said yesterday they were appalled that a disaster of such magnitude could be repeated within this century because of human activities.
Mark Lynas, an author who has written extensively on global warming and recently travelled around the world cataloguing impacts of climate change, said the findings must be a wake-up call for politicians and citizens alike.
"This is a global emergency," he said. "We are heading for disaster and yet the world is still on fossil fuel autopilot. There needs to be an immediate phase-out of coal, oil and gas, and a phase-in of clean energy sources.
"People can no longer ignore this looming catastrophe."