to the end of the earth
From The Sunday Times
March 11, 2007
To the end of the earth
This is our future - famous cities are submerged, a third of the world is desert, the rest struggling for food and fresh water. Richard Girling investigates the reality behind the science of climate change
Mark Lynas rummages through his filing cabinet like a badger raking out his bedstraw, much of the stuff so crumpled that he might have been sleeping on it for years. Eventually he finds what he is looking for - four sheets of printed paper, stapled with a page of notes.
It is an article, dated November 2000, which he has clipped from the scientific journal Nature: "Acceleration of global warming due to carbon-cycle feedbacks in a coupled climate model". Even when they are mapping a short cut to Armageddon, scientists do not go in for red-top words like "crisis". If you speak the language, however, you get the message - and the message, delivered by the UK Met Office's Hadley Centre for Climate Change, was cataclysmic.
"There should have been panic on the streets," says Lynas in his new book, Six Degrees, "people shouting from the rooftops, statements to parliament and 24-hour news coverage."
In layman's language, Hadley's message was that newly discovered "positive feedbacks" would make nonsense of accepted global-warming estimates. It would not be a gradual, linear increase with nature slowly succumbing to human attrition. Nature itself was about to turn nasty. Instead of absorbing and retaining greenhouse gases from the atmosphere, the figures suggested, it would suddenly spew them out again - billions of years' worth of carbon and methane, incontinently released in blazing surges that would drown or incinerate whole cities. Ice would melt in torrents, and the Earth's essential green lung, the Amazon rainforest, could be moribund as early as
Next day's newspapers ignored the rescheduling of Armageddon - the headlines were all about faulty counts in the US presidential election, Gordon Brown's fiddling with National Insurance and Lord Falconer's refusal to resign over "the Dome fiasco". Lynas, however, was energised like the hero of a disaster movie. Inconveniently, he had a book to write, but as soon as he'd finished it he pedalled from his
Lynas wanted to see every scrap of paper the library held on global warming. Scanning at speed, he worked his way through two or three hundred every day, tens of thousands in all. Then as now, new pieces of research were emerging almost weekly as computer models were improved, new data collected and analysed. Then as now, there was no single, provable prediction of the future. Without knowing how much more fossil fuel will be burnt, the best science can offer is a range of plausible "scenarios". These vary so widely that the Intergovernmental Panel on Climate Change (IPCC), in its Third Assessment report in 2001, was able to suggest only that global average temperatures by the end of the 21st century will have risen between 1.4 and
On Lynas's laptop were six spreadsheets - one for each degree of warming from one to six. As he worked, he would slot each paper into the appropriate file. Many of them included predictions from climate models, but there was more: "Some of the most interesting came from palaeoclimate studies - investigations of how variations in temperature, calculated by analysis of soil strata and ancient ice-cores, affected the planet in prehistory." It was these that would give some of the most terrifying insights into what the future might be like. Which parts of the globe would be abandoned first? What was the precise mechanism that, eventually, would wipe us out?
The spreadsheets became the six core chapters of Lynas's book - a detailed, carefully annotated, degree-by-degree guide not just to our grandchildren's futures but to our own.
UP TO ONE DEGREE OF WARMING
Even if greenhouse emissions stopped overnight - of which there is about as much chance as Tony Blair holidaying in Skegness - the concentrations already in the atmosphere would still mean a global rise of between 0.5 and
Six thousand years ago, when the world was one degree warmer than it is now, the American agricultural heartland around
"The western
What's bad for
While tropical lands teeter on the brink, the
Out at sea the pace is even faster. "Whilst snow-covered ice reflects more than 80% of the sun's heat, the darker ocean absorbs up to 95% of solar radiation. Once sea ice begins to melt, in other words, the process becomes self-reinforcing. More ocean surface is revealed, absorbing solar heat, raising temperatures and making it unlikelier that ice will re-form next winter. The disappearance of 720,000 square kilometres of supposedly permanent ice in a single year testifies to the rapidity of planetary change. If you have ever wondered what it will feel like when the Earth crosses a tipping point, savour the moment."
Mountains, too, are starting to come apart. In the
At the opposite end of the scale, low-lying atoll countries such as the Maldives will be preparing for extinction as sea levels rise, and mainland coasts - in particular the eastern US and Gulf of Mexico, the Caribbean and Pacific islands and the Bay of Bengal - will be hit by stronger and stronger hurricanes as the water warms. Hurricane Katrina, which in 2005 hit
"Most striking of all," says Lynas, "was seeing how people behaved once the veneer of civilisation had been torn away. Most victims were poor and black, left to fend for themselves as the police either joined in the looting or deserted the area. Four days into the crisis, survivors were packed into the city's Superdome, living next to overflowing toilets and rotting bodies as gangs of young men with guns seized the only food and water available. Perhaps the most memorable scene was a single military helicopter landing for just a few minutes, its crew flinging food parcels and water bottles out onto the ground before hurriedly taking off again as if from a war zone. In scenes more like a
Chance of avoiding one degree of global warming: zero.
BETWEEN ONE AND TWO DEGREES OF WARMING
At this level, expected within 40 years, the hot European summer of 2003 will be the annual norm. Anything that could be called a heatwave thereafter will be of Saharan intensity. Even in average years, people will die of heat stress.
"The first symptoms," says Lynas, "may be minor. A person will feel slightly nauseous, dizzy and irritable. It needn't be an emergency: an hour or so lying down in a cooler area, sipping water, will cure it. But in
"Once body temperature reaches
"These emergency services failed to save more than 10,000 French in the summer of 2003. Mortuaries ran out of space as hundreds of dead bodies were brought in each night." Across
"From the beech forests of northern Europe to the evergreen oaks of the
In the two-degree world, nobody will think of taking Mediterranean holidays. "The movement of people from northern Europe to the
Not only coastal communities will suffer. As mountains lose their glaciers, so people will lose their water supplies. The entire Indian subcontinent will be fighting for survival. "As the glaciers disappear from all but the highest peaks, their runoff will cease to power the massive rivers that deliver vital freshwater to hundreds of millions. Water shortages and famine will be the result, destabilising the entire region. And this time the epicentre of the disaster won't be
Everywhere, ecosystems will unravel as species either migrate or fall out of synch with each other. By the time global temperatures reach two degrees of warming in 2050, more than a third of all living species will face extinction.
Chance of avoiding two degrees of global warming: 93%, but only if emissions of greenhouse gases are reduced by 60% over the next 10 years.
BETWEEN TWO AND THREE DEGREES OF WARMING
Up to this point, assuming that governments have planned carefully and farmers have converted to more appropriate crops, not too many people outside subtropical
To find anything comparable we have to go back to the Pliocene - last epoch of the Tertiary period, 3m years ago. There were no continental glaciers in the northern hemisphere (trees grew in the
"Warmer seas," explains Lynas, "absorb carbon dioxide, leaving more to accumulate in the atmosphere and intensify global warming. On land, matters would be even worse. Huge amounts of carbon are stored in the soil, the half-rotted remains of dead vegetation. The generally accepted estimate is that the soil carbon reservoir contains some 1600 gigatonnes, more than double the entire carbon content of the atmosphere. As soil warms, bacteria accelerate the breakdown of this stored carbon, releasing it into the atmosphere."
The Hadley team factored this new feedback into their climate model, with results that fully explain Lynas's black-comic note to himself: The end of the world is nigh. A three-degree increase in global temperature - possible as early as 2050 - would throw the carbon cycle into reverse. "Instead of absorbing carbon dioxide," says Lynas, "vegetation and soils start to release it. So much carbon pours into the atmosphere that it pumps up atmospheric concentrations by 250 parts per million by 2100, boosting global warming by another 1.5C. In other words, the Hadley team had discovered that carbon-cycle feedbacks could tip the planet into runaway global warming by the middle of this century - much earlier than anyone had expected."
Confirmation came from the land itself. Climate models are routinely tested against historical data. In this case, scientists checked 25 years' worth of soil samples from 6,000 sites across the
In the
It is all too easy to visualise what will happen in
The Indian subcontinent meanwhile will be choking on dust. "All of human history," says Lynas, "shows that, given the choice between starving in situ and moving, people move. In the latter part of the century tens of millions of Pakistani citizens may be facing this choice.
As the land burns, so the sea will go on rising. Even by the most optimistic calculation, 80% of Arctic sea ice by now will be gone, and the rest will soon follow.
Chance of avoiding three degrees of global warming: poor if the rise reaches two degrees and triggers carbon-cycle feedbacks from soils and plants.
BETWEEN THREE AND FOUR DEGREES OF WARMING
The stream of refugees will now include those fleeing from coasts to safer interiors - millions at a time when storms hit. Where they persist, coastal cities will become fortified islands. The world economy, too, will be threadbare. "As direct losses, social instability and insurance payouts cascade through the system, the funds to support displaced people will be increasingly scarce." Sea levels will be rampaging upwards - in this temperature range, both poles are certain to melt, causing an eventual rise of
More immediately,
"The summer will get longer still, as soaring temperatures reduce forests to tinderwood and cities to boiling morgues. Temperatures? in the Home Counties could reach
"Air-conditioning will be mandatory for anyone wanting to stay cool. This in turn will put ever more stress on energy systems, which could pour more greenhouse gases into the air if coal and gas-fired power stations ramp up their output, hydroelectric sources dwindle and renewables fail to take up the slack." The abandonment of the Mediterranean will send even more people north to "overcrowded refuges in the Baltic, Scandinavia and the
One of the most dangerous of all feedbacks will now be kicking in - the runaway thaw of permafrost. Scientists believe at least 500 billion tonnes of carbon are waiting to be released from the Arctic ice, though none yet has put a figure on what it will add to global warming. One degree? Two? Three? The pointers are ominous.
"As with Amazon collapse and the carbon-cycle feedback in the three-degree world," says Lynas, "stabilising global temperatures at four degrees above current levels may not be possible. If we reach three degrees, therefore, that leads inexorably to four degrees, which leads inexorably to five?"
Chance of avoiding four degrees of global warming: poor if the rise reaches three degrees and triggers a runaway thaw of permafrost.
BETWEEN FOUR AND FIVE DEGREES OF WARMING
We are looking now at an entirely different planet. Ice sheets have vanished from both poles; rainforests have burnt up and turned to desert; the dry and lifeless
When temperatures were at a similar level 55m years ago, following a very sudden burst of global warming in the early Eocene, alligators and other subtropical species were living high in the
"Summer heatwaves scorched the vegetation out of continental
Globalism in the five-degree world will break down into something more like parochialism. Customers will have nothing to buy because producers will have nothing to sell. With no possibility of international aid, migrants will have to force their way into the few remaining habitable enclaves and fight for survival.
"Where no refuge is available," says Lynas, "civil war and a collapse into racial or communal conflict seems the likely outcome." Isolated survivalism, however, may be as impracticable as dialling for room service. "How many of us could really trap or kill enough game to feed a family? Even if large numbers of people did successfully manage to fan out into the countryside, wildlife populations would quickly dwindle under the pressure. Supporting a hunter-gatherer lifestyle takes 10 to 100 times the land per person that a settled agricultural community needs. A large-scale resort to survivalism would turn into a further disaster for biodiversity as hungry humans killed and ate anything that moved." Including, perhaps, each other. "Invaders," says Lynas, "do not take kindly to residents denying them food. History suggests that if a stockpile is discovered, the householder and his family may be tortured and killed. Look for comparison to the experience of present-day
Chance of avoiding five degrees of global warming: negligible if the rise reaches four degrees and releases trapped methane from the sea bed.
BETWEEN FIVE AND SIX DEGREES OF WARMING
Although warming on this scale lies within the IPCC's officially endorsed range of 21st-century possibilities, climate models have little to say about what Lynas, echoing Dante, describes as "the
"That episode," says Lynas, "was the worst ever endured by life on Earth, the closest the planet has come to ending up a dead and desolate rock in space." On land, the only winners were fungi that flourished on dying trees and shrubs. At sea there were only losers. "Warm water is a killer. Less oxygen can dissolve, so conditions become stagnant and anoxic. Oxygen-breathing water-dwellers - all the higher forms of life from plankton to sharks - face suffocation. Warm water also expands, and sea levels rose by
There are aspects of the so-called "end-Permian extinction" that are unlikely to recur - most importantly, the vast volcanic eruption in Siberia that spread magma hundreds of metres thick over an area bigger than western Europe and shot billions of tonnes of CO² into the atmosphere. That is small comfort, however, for beneath the oceans, another monster stirred - the same that would bring a devastating end to the Palaeocene nearly 200m years later, and that still lies in wait today. Methane hydrate.
Lynas describes what happens when warming water releases pent-up gas from the sea bed. "First, a small disturbance drives a gas-saturated parcel of water upwards. As it rises, bubbles begin to appear, as dissolved gas fizzles out with reducing pressure - just as a bottle of lemonade overflows if the top is taken off too quickly. These bubbles make the parcel of water still more buoyant, accelerating its rise through the water. As it surges upwards, reaching explosive force, it drags surrounding water ?up with it. At the surface, water is shot hundreds of metres into the air as the released gas blasts into the atmosphere. Shockwaves propagate outwards in all directions, triggering more eruptions nearby."
The eruption is more than just another positive feedback in the quickening process of global warming. Unlike CO², methane is flammable. "Even in air-methane concentrations as low as 5%," says Lynas, "the mixture could ignite from lightning or some other spark and send fireballs tearing across the sky." The effect would be much like that of the fuel-air explosives used by the
Then would come hydrogen sulphide from the stagnant oceans. "It would be a silent killer: imagine the scene at
RED ALERT
If global warming continues at the current rate, we could be facing extinction. So what exactly is going to happen as the Earth heats up? Here is a degree-by-degree guide
1c Increase
Ice-free sea absorbs ?more heat and accelerates global warming; fresh water lost from a third of the world's surface; low-lying coastlines flooded
2c Increase
Europeans dying of heatstroke; forests ravaged by fire; stressed plants beginning to emit carbon rather than absorbing it; a third of all species face extinction
3c Increase
Carbon release from vegetation and soils ?speeds global warming; death of the Amazon rainforest; super-hurricanes hit coastal cities; starvation in
4c Increase
Runaway thaw of permafrost makes global warming unstoppable; much of
5c Increase
Methane from ocean floor accelerates global warming; ice gone from both poles; humans migrate in search of food and try vainly to live like animals off the land
6c Increase
Life on Earth ends with apocalyptic storms, flash floods, hydrogen sulphide gas and methane fireballs racing across the globe with the power of atomic bombs; only fungi survive
Chance of avoiding six degrees of global warming: zero if the rise passes five degrees, by which time all feedbacks will be running out of control