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The Avalanche of Evidence

28 October 2009

The Avalanche of Evidence

 By Gwynne Dyer

The news is bad, and it’s coming in fast. Turn tens of thousands of scientists loose on a problem for two decades, and the results will seem pathetic for the first few years, because it takes time to gather the data – even to build the equipment with which you gather the data. But slowly the flow of data will grow, and at the end of twenty years you can expect major new insights every month or so.

That’s where we are now with climate change. September’s unwelcome news, from the Hadley Centre for Climate Prediction and Research in Britain, was that if fossil fuel use continues on the present trend line, the planet will be an average of 4 degrees C warmer by the 2060s. This contrasts with the prediction of the Intergovernmental Panel on Climate Change, published in 2007, that we might see 4 degrees C, at the most, by 2100.

This month’s bad news came from the drilling ship JOIDES Resolution (Joint Oceanographic Institutions for Deep Earth Sampling), which brought up cores from the ocean bottom containing sediments dating back 20 million years. The news was that when the carbon dioxide in the atmosphere was last at 450 parts per million, the average global temperature was 3-6 degrees C hotter than now, and the sea level was 25-40 metres (80-130 ft) higher.

That is bad news because 450 parts per million is where we are hoping to halt the rise in CO2 in the atmosphere this time around. (We are currently at 390 ppm.) All the world’s major governments have agreed in principle that the warming must never be allowed to exceed 2 degrees C, because beyond that we risk runaway warming – and it was thought that 450 ppm would let us stop at that point.

Not so, it would appear, or at least not for long. The leader of the JOIDES research team, Aradhna Tripati of the University of California at Los Angeles, put it bluntly: “What we have shown is that in the last period when CO2 levels were sustained at levels close to where they are today, there was no icecap on Antarctica and sea levels were 25-40m higher.”

Suspicions that the 450 ppm target is much too high have been growing for some time. Late in 2007 James Hansen, the director of NASA’s Goddard Institute for Space Studies in New York, made a public appeal at a meeting of the American Geophysical Union to move to a 350 ppm target.

Hansen’s study of ancient climates had led him to the conclusion that the first time permanent ice appeared on the planet, after a complete absence for tens of millions of years, was when the amount of carbon dioxide fell to 425 ppm some 35 million years ago. His calculations had a possible error of plus or minus 75 ppm, so for safety’s sake he settled on 350 ppm as the long-term target for human stewardship of the atmosphere.

Did that word “stewardship” throw you? Many people instinctively recoil from any direct human intervention in the atmosphere, on the grounds that we don’t know enough to get it right. But when we have already been changing the atmosphere unintentionally for two centuries, since the start of the industrial revolution, it’s a bit late for such qualms. We have already destabilised it, and only we can reverse the changes we have caused.

Hansen even thought that 350 ppm might still be too high, because the “normal” level of CO2 during the 10,000 years of human civilisation, before we began burning fossil fuels, was only 280 ppm. Now JOIDES has given us a more accurate measure of ancient climate, from closer to the present.

By 20 million years ago, almost all the ice on the planet had been lost again, due to a prolonged period of volcanic activity in the Columbia River basin of North America. The carbon dioxide emitted by that activity had raised the average global temperature to 3-6 degrees C above the current level, and all the melted ice had raised the seal level by 25-40 metres. But the actual level of CO2 that caused all that was only 400 ppm.

We will be there in five years, but we must not stay there for very long or history will repeat itself. In reality, we are going to go to at least 450 ppm, and more likely 500 ppm, before we get our emissions under control, and then we will have to commence the long and arduous task of getting the CO2 in the atmosphere down to a level that will preserve our present climate over the long term. That may have to be as low as 300 ppm.

And all through that time, we must prevent the warming from exceeding 2 degrees C, which means that a resort to various methods of geo-engineering to keep the heat down is almost unavoidable. That is what these numbers are telling us, and we would be wise to listen.


To shorten to 750 words, omits paragraph 8. (“Did…caused”)

Last Exit for the Holocene

29 June 2008

Last Exit for the Holocene

By Gwynne Dyer

“Damn! I think we just passed the last exit for the Holocene!”

“I’m sorry, honey, I wasn’t looking.”

“We have to get off this highway. What’s the next exit?”

“It’s a long way ahead. Goes to somewhere called Perdition.”

(Ragged chorus from the back seat) “Are we there yet, Daddy?”

The Holocene era is that blessed time of stable, warm climate (but not too hot) and unchanging sea levels in which human civilisation was born and grew to its present size. In ten thousand years our numbers have increased about a thousandfold — but we may be about to leave the Holocene, and that would be too bad. No other climatic state would let us maintain our current numbers, and massive die-backs are no fun at all.

James Hansen, the director of NASA’s Goddard Space Flight Center in New York, is one of the most respected scientists working in the field of climate studies. It was his famous speech to the US Congress twenty years ago that put climate change on the US political agenda, and led indirectly to the Earth Summit and the Framework Convention on Climate Change of 1992 and the Kyoto Protocol of 1997. Now he has something else to say.

For most of the past decade, Hansen adhered to the emerging consensus among climate scientists that the maximum permissible concentration of carbon dioxide in the atmosphere is 450 parts per million (ppm). That was believed to give us a fifty percent chance of getting away with an average global temperature only 2 degrees C (3.6 degrees F) hotter than it was at the beginning of the 1990s. Now Hansen doesn’t believe in 450 ppm any more.

450 ppm was chosen partly because it seemed impossible to stop the rise in carbon dioxide before that — we’re already at 387 ppm, and going up almost 3 ppm per year — and partly because it seemed relatively safe. Two degrees C hotter would turn a lot of sub-tropical land into desert, cause bigger hurricanes, and turn most of Asia’s big rivers into seasonal watercourses that are empty in summer, but it would not melt the icecaps. At least that’s what they thought, although everybody knew that the numbers were soft.

You can do a lot with climate models, but the Earth hasn’t actually seen a carbon dioxide (CO2) concentration as high as 450 ppm since about 35 million years ago. So Hansen and some colleagues went to work on exactly that period, and came back with some bad news. If you leave the world at even 425 ppm for very long, all the ice will probably melt: Greenland, Antarctica, the lot. And the sea level will go up 70-80 metres (240-270 ft.)

How do they know? Because the world was very hot and completely ice-free for a long time before 35 million years ago, but the amount of carbon dioxide in the atmosphere was falling gradually. When it reached 425 ppm, Antarctica began to freeze over. So if that’s where the first permanent ice appeared while CO2 was on the way down, it’s probably where the last permanent ice will disappear when CO2 is on its way back up.

Now, there’s a big margin of error when you are dealing with 35 million years ago: plus or minus 75 ppm, in this case. That means that the fatal number when all the ice disappears could be as high as 500 ppm — or it could be as low as 350 ppm. If that is the range within which ALL the world’s ice will eventually melt, and you like living in the Holocene, then you probably should not put all your money on a 450 ppm ceiling for CO2.

So James Hansen is now spearheading a campaign to get 350 ppm recognised as the real long-term target we should be aiming at. Tricky, since we are already at 387 ppm and rising fast, but last week, when I spoke to him at the Tallberg Forum’s annual conference in Sweden, he explained: “To figure out the optimum is going to take a while, but the fundamental thing about the 350 [ppm target], and the reason that it completely changes the ball-game, is precisely the fact that it’s less than we have now.”

“Even if the optimum turns out to be 325 or 300 or something else, we’ve go to go through 350 to get there. So we know the direction now that we’ve go to go, and it’s fundamentally different. It means that we really have to start to act almost immediately. Even if we cut off coal emissions entirely, CO2 would still get up to at least 400, maybe 425, and then we’re going to have to draw it down, and we’re almost certainly going to have to do it within decades.”

But there is time. The oceans and the ice-sheets react so slowly to changes in the air temperature that you can overshoot the limit for a while, so long as you get the temperature back down before irreversible changes set in. Stop at 450 ppm in twenty-five years’ time, then get back below 400 in another twenty-five, and down to 350 by, say, 2075. It could work: there is still one last exit for the Holocene.


To shorten to 725 words, omit paragraphs 1 and 5. (“Damn…Daddy?”; and “450…soft”) Treat the dialogue at the start as one paragraph.

Oil and the Arctic

25 May 2008

Oil and the Arctic

By Gwynne Dyer

What connects oil at $135 a barrel with last month’s discovery of huge cracks in the Ward Hunt ice shelf off Ellesmere Island at the top of Canada’s Arctic archipelago? And what might connect those two things with a new, even Colder War?

The cracks in the ice, further evidence that the ice cover on the Arctic Ocean is melting fast, were discovered by scientists tagging along with a Canadian army snowmobile expedition that was officially called a “sovereignty patrol.” The army was showing the flag because Canada, like the other Arctic countries, suspects that valuable resources will become accessible there once the ice melts. And the most valuable of those resources are oil and gas.

The strongest evidence for accelerated melting is the fact that more and more of the Arctic sea ice is thin “first-year” ice. Only about a metre (three feet) thick, it spreads across the ocean each winter, but tends to melt the following summer.

Melting has taken big bites out of the edge of the much thicker “permanent” ice in most recent summers, and unless some of the “first-year” ice that replaces it lasts through the following winter, then the melting really is speeding up. So everybody is watching to see what happens this summer, explained Dr Jim Maslanik of the University of Colorado — Boulder.

“If we see all the first-year ice melt out again, then probably we will have another record reduction in ice cover,” said Maslanik. “If we see this a couple of years running, that tells us…that we are about twenty or thirty years ahead of where we are supposed to be based on the climate models.”

If we are heading for an Arctic Ocean that is mostly ice-free in the summer, then drilling for gas and oil beneath that ocean can soon begin. Hardly a week goes by without somebody pointing to the US Geological Survey’s report that the Arctic basin contains a quarter of the world’s undiscovered oil and gas. But the event that did most to trigger this new concern about sovereignty was Artur Chilingarov’s publicity stunt last summer.

Chilingarov is a polar explorer of the old school (he was made a Hero of the Soviet Union in the old days for saving an ice-bound ship in Antarctica), but he is now deputy speaker of the Russian Duma (parliament) and Vladimir Putin’s personal “envoy” to the Arctic. Last summer, he took a three-man submarine down to the bottom of the Arctic Ocean precisely at the North Pole, and planted a Russian flag in the seabed.

“The Arctic is Russian. We must prove the North Pole is an extension of the Russian landmass,” he said afterwards, and affected surprise at the fact that other countries with an Arctic coastline saw this as a challenge to their sovereignty. Canada’s Prime Minister Stephen Harper, for example, flew to the Arctic the following week, and subsequently announced that Canada would built six to eight new “ice-strengthened” warships for Arctic patrols.

The other three countries with Arctic coastlines, the United States (Alaska), Denmark (Greenland) and Norway, are equally suspicious of Russian intentions. The real issue is about who owns the rights to the seabed, and the Russian claim is pretty ambitious.

Moscow claims that the Lomonosov Ridge, the subsea mountain range that goes straight across the middle of the Arctic Ocean, is an extension of the Russian territorial shelf, and therefore belongs to Russia all the way to the North Pole. Alternatively, if the Law of the Sea tribunal does not ultimately accept that claim, Moscow may have an even broader claim in reserve.

In the early 20th century seven countries laid claim to parts of Antarctica on the basis of “sectors”: pie-shaped slices running along lines of longitude (which converge at the poles). The width of those slices depended on where the various claimants owned territories near Antarctica, mostly islands in the Southern Ocean. Those claims are dormant because of a subsequent treaty banning economic development in Antarctica, but the precedent has not been forgotten.

By that precedent, Russia could lay claim to about half the Arctic Ocean on the basis of lines of longitude running from the far eastern and western ends of the country up to the North Pole — and in 1924 the old Soviet Union did precisely that. Nobody else accepted that claim then, and they wouldn’t now if Russia raised it again. But Russia has the big Arctic ports and the nuclear-powered ice-breakers to make its claim stick, and nobody else does.

That is where the current panic comes from. It probably won’t end up in a new Cold War, but it has certainly got the hens in the chicken coop all stirred up.

As is often the case with hens, they are over-reacting. Russia is in a more assertive mood than it was a decade ago, but there are no signs that it intends to pursue its claims by force. Moreover, there is no serious basis for the claim that a quarter of the world’s undiscovered oil and gas reserves lie under the Arctic Ocean.

It always seemed implausible, given that the Arctic Ocean only accounts for slightly less than 3 percent of the Earth’s surface, but in fact the US Geological Survey never said anything of the sort. Neither has any other authoritative source, yet this factoid has gained such currency that it even influences government policy. Isn’t it interesting how readily people will believe something when they really want to?


This article is 925 words. To shorten to 725 words, omit paragraphs 3, 4, 5 and 9. (“The strongest…models”; and “The other..ambitious”)

More Death and Devastation

30 August 2004

More Death and Devastation

By Gwynne Dyer

The past month has brought us a choice of potential global disasters. Maybe the Black Death will return, and kill more than half the people on the planet as it once killed over half the population of Europe. Or we could have another meteor strike like the one that hit Antarctica 780,000 years ago, which could do much worse than that. Luckily, the Big One hit Antarctica during an ice age, which is probably why our proto-human ancestors survived it.

It has become orthodox to link the great extinctions of the archaeological record to huge asteroid strikes. The age of the dinosaurs was probably ended by a massive rock between four and seven miles (six and twelve km) in diameter that slammed into the sea off Mexico’s Yucatan peninsula 62 million years ago. There were massive tsunamis, continent-wide fires, and a lengthy “impact winter” when dust blasted into the stratosphere shrouded the sun and dropped temperatures by tens of degrees.

The dinosaurs didn’t make it — but many other species including our distant mammalian ancestors did. Recent research suggests that it was a mere fluke. Normally, you would expect the impact winter to be followed by an “ultraviolet spring” when the sun returned, shining through an atmosphere stripped of the ozone that normally screens out the harmful kinds of ultraviolet light.

Mutations, cancers and cataracts would have soared, plant photosynthesis would have been suppressed, and many species that survived the initial devastation would have died out. But the Yucatan strike hit a bit of the earth’s crust that is rich in anhydride rocks, producing a 12-year sulfide haze that blocked much of the ultraviolet.

It was worse the first time. The greatest extinction of all, 251 million years ago, when 90 percent of all ocean species and 70 percent of land species disappeared, was caused by an asteroid about the same size as the Yucatan one. It did more execution because it hit a different part of the planet, under different conditions — which brings us to the one we didn’t know about, the one that almost got us.

At the International Geophysical Congress in Glasgow on 18 August, Dr Frans van der Hoeven of Delft University of Technology in the Netherlands revealed that a similar asteroid hit Antarctica only 780,000 years ago, a mere blink of an eye in geological time. We are still here for three reasons, all of them flukes.

The asteroid broke up just before hitting the earth, creating five smaller impact craters over an area measuring 1,300 by 2,400 miles (2,100 by 3,800 km) rather than a single huge impact crater. Most of the pieces melted through the deep East Antarctic icecap before cratering the underlying bedrock, which limited the amount of dust boosted into the atmosphere. And there was already permanent winter over most of the planet, so it was much less of a shock to the biosphere.

“The extraordinary thing about this meteor strike is that it appeared to do so little damage,” said Professor van der Hoeven. “Unlike the dinosaur strike there is no telltale layer of dust (in the geological record) that demonstrates the history of the event. It may have damaged things and wiped out species but there is no sign of it.” Apart from the craters, the only indication that something big happened 780,000 years ago is that the earth’s magnetic field reversed at just that time.

Asteroids got the dinosaurs, but they didn’t get us. Whereas the Black Death did get Europe repeatedly between the fourteenth and the seventeenth centuries. Then it went away — but maybe not for good.

For the past century, the Black Death has been explained as an outbreak of bubonic plague, spread by fleas living on rats, but there have always been huge problems with that diagnosis. The fatality rate is far lower with bubonic plague, the incubation period doesn’t match, and the standard measure to contain the spread of the Black Death — quarantine — would not have worked if the vector was rats.

Now along comes “Return of the Black Death,” a book by Christopher Duncan, Emeritus Professor of Zoology at Liverpool University, and social historian Susan Scott, which convincingly argues that the Black Death was a haemorrhagic fever related to Ebola and other current quick-killer African diseases that spread directly from person to person. What made it so lethal was its extremely long incubation period, almost a month. That allowed plenty of time for an affected person to infect many others before the symptoms appeared.

It eventually died out in Europe because by the seventeenth century a large portion of the surviving European population had developed a genetic immunity to the virus. Scott and Duncan suggest that the immunity of between 5 and 20 percent of Europeans to the HIV virus is a relic, now diluted by time, to this tragically acquired immunity to the Black Death. But they also suggest that the original virus or some mutated successor is still out there somewhere — and that by now Europeans’ immunity is severely eroded, while nobody else has any at all.

Meanwhile, in Vietnam, three people have died in the past month from the A(H5N1) avian influenza virus, which has a two-thirds mortality rate in human beings. “We’re talking hundreds of millions of people afflicted if it is a pandemic out there lurking,” said Anton Rychener, Vietnam director for the UN Food and Agriculture Organisation. “What I have learned makes me shudder.”

If one thing doesn’t get you, another thing will. Gather ye rosebuds while ye may.


To shorten to 725 words, omit paragraphs 3, 4 and 8. (“The dinosaurs…ultraviolet”; and “The extraordinary…time”)