The Arctic. The more I think about it, the more I am struck by how this stunning, unearthly region with its flat, blinding, moon-like landscapes is the quintessential representation of the environmental dilemma our planet faces.

We all know the Arctic is warming - it is warming more, in fact, than any other region on the planet. Yet, this victim of climate change is also a potential perpetrator of further change: the US Geological Survey estimated in 2000 that it holds at least 14% of global oil reserves and is currently conducting a more thorough survey, with results expected this summer. Those reserves are, paradoxically, becoming ever more accessible as oil and gas burnt elsewhere on the planet warms local temperatures and reduces the ice extent.

Right now, we are at a critical junction in time: if our concerns are primarily environmental, we view the Arctic as a victim of climate change; if, on the other hand, we are more preoccupied with energy security, dwindling oil and gas reserves and booming oil prices, then the Arctic is the pot of gold at the end of the rainbow.

Ironically, the gold in that pot will almost certainly buy more global warming, less ice, more disturbances to the global water cycle, more extreme weather - in essence, more doom and gloom.

In September last year, in response to the sudden attempts made by various governments to land-grab the Arctic, New Scientist called for an Arctic Treaty, which would grant the ocean the same protection as the Antarctic continent.

We are not alone in thinking this is the best option for the region. But yesterday the five nations who have territory within the Arctic Circle, and therefore a claim to portions of the seabed under the Arctic Ocean, appeared to sign away any chance of an international treaty.

Meeting in Ilulissat in Greenland, the foreign ministers of Canada, Denmark, Norway, the Russian Federation and the United States of America signed the Ilulissat Declaration. In it, they say they intend to abide by the UN Law of the Sea, and allow it to determine how the Arctic seabed should be parcelled:

This framework provides a solid foundation for responsible management by the five coastal States and other users of this Ocean through national implementation and application of relevant provisions.

Am I the only one who finds it odd that some of the world's most powerful nations should have to come together to sign a document declaring that they will abide by international law?

If it weren't tragic it would be incredibly comical. I can't help but wonder - what was the alternative? Carving up territory regardless of international law is not exactly unheard of, and inevitably has disastrous consequences. But the next sentence in the agreement hints at the agreement's true purpose:

We therefore see no need to develop a new comprehensive international legal regime to govern the Arctic Ocean.

Clearly, the mighty five have agreed that to duke it out in the International Tribune for the Law of the Sea will offer them their best chance at securing rights to Arctic mineral resources.

"It's depressing," was a colleague's assessment earlier today. At face value, yes.

But maybe this treaty is actually a sign that the Arctic Five felt there was a need to flex their muscles and join forces to resist international pressure that might force them to sign up to an international treaty to protect the Arctic in the same way as the Antarctic.

We have to hope that China and Saudi Arabia - the only two nations that have the clout to force the US and Russia into an agreement - start caring very deeply about the future of the Arctic and state just how upset they would be if the Arctic was turned into an oil field.

Both nations would stand to gain from preventing this happening. Saudi Arabia and other Gulf nations want to maintain as much of a share of the international oil market as possible. And I imagine that China would rather not be held ransom for oil anymore than it already is.

Catherine Brahic, online environment reporter

Behold 2080: temperatures in the south of England are so high, even its once misty shores can no longer produce wines. Instead, according to Richard Selley of Imperial College London, it will be more suitable for making raisins and sultanas - currently the preserve of hot climates like North Africa and the Middle East.

Selley has written a book on the future of British wines. In it, he has combined the predictions of the IPCC's climate models with his own studies of the history of British wines to look at what's ahead.

Echoing a common refrain, Selley points out that the effects of climate change are already being felt in vineyards around the world. So, for instance, in the last 20 years some French grape varieties which normally flourish in warm temperatures have been planted in southeast England, producing internationally prize-winning sparkling white wines.

By 2080, if summer temperatures rise by 5°C, like the more severe climate models predict, these wines could be restricted to the northern UK shores of Scotland.

Further afield, China is set to become a major wine producer in years to come, according to the Future of Wine released earlier this month. Russia, Croatia, Poland, Ukraine and Slovenia are predicted to muck in as well.

According to this article, wine is the canary in the proverbial coalmine - though judging by the number of times that expression is used in relation to climate change, I can only guess that the coalmine is full of dying canaries.

And given reports that climate change is already raising the alcohol content of wines (warmer temperatures mean more sugar which is converted into alcohol) it looks like the taste of climate change is a boozy one.

Catherine Brahic, online environment reporter

Nature parks tend to be isolated islands of greenery - they are rarely interconnected. One exception is an effort by the European Union to create a huge Green Belt stretching from the Arctic Sea to the Mediterranean and the Black Sea, connecting national parks on the way.

If the plan is ambitious, the route is historic: across much of its route the belt traces the path of the Iron Curtain of the cold war.

That's all very well, but conservationists know that biodiversity declines at the edges of habitats, so that a long but narrow park may not conserve as many species as a big plot. According to these maps, the EU belt may only be 25 metres wide in parts.

Still, if wildlife has naturally flourished there in the absence of human development, it must have some value. And connecting such incredibly different ecosystems in one go would be unprecedented - and particularly exciting in Europe where the vast majority of the landscape has been converted to agriculture.

The coolest part of this has got to be the fact that tanks and snipers used to patrol this corridor, and now it has become a strip of greenery and wildlife. It is home to several rare species including the black stork and the lady's slipper orchid.

The project has been underway for some years and it could take decades more to complete it - after all, the Green Belt would pass through 23 countries and so negotiations need to involve all 23 governments. It gets my vote, though.

Catherine Brahic, online environment reporter

Based on shark attack statistics you could be forgiven for thinking the kings of the deep ocean are doing well. Not so, says the International Union for the Conservation of Nature today. Sixteen shark and ray speces of a total 21 are in danger of extinction.

The increase in shark attacks is probably due to more people - not sharks - being in the water. Baiting the sharks doesn't help: a study in French Polynesia published in 2005 showed that of 54 shark attacks, 30 involved divers putting fresh blood and meat in the water to attract the sharks to them. No divers were attacked outside shark feeding activities and the people most attacked were the dive masters, who were doing the feeding.

According to the global shark attack statistics maintained by the Florida Museum of Natural History in the US, just one person died of a shark attack in 2007. On average 90 people die of lightning strikes each year in the US alone. Naturally, the number of sharks that die of human attacks is much, much higher. Shelley Clarke at the University of Hawaii and colleagues estimate that between 26 to 73 million sharks are killed for commercial reasons each year.

Sharks are hunted for their fins, which are made into fin soup and savoured in Asia and elsewhere. They may get some reprieve in years to come, however. Last year, the US decreed that sharks would have to be brought to shore with their fins. The hope is that this should make shark culls easier to monitor.

Catherine Brahic, online environment reporter

As the human death toll from the China earthquake on May 12 tops 50,000, emergency rations are being sent to some of the most endangered survivors - giant pandas.

The China Daily reports that some 4500 kilograms of bamboo leaves and 1050 kg of bamboo shoots, as well as apples, soya beans, eggs and milk powder are being sent to feed giant pandas at the China Giant Panda Protection and Research Center in Wolong, Sichuan province, just 30 kilometres from the epicentre. Five of the centre's workers were killed in the quake, and 2 of 53 pandas were injured.

I've visited the Wolong panda centre - I remember being struck by the number of dead, stuffed pandas displayed around the museum. They seemed to outnumber the living pandas in the grounds, and many of those appeared to be sick. According to some reports, however, the pandas at Wolong roused themselves in the minutes before the quake struck and began acting "in a strange manner".

This begs the question: Can animals predict earthquakes?

Biologist Rupert Sheldrake, for one, thinks some animals have an electromagnetic sense that allows them to predict seismic changes. Most of the "evidence" is anecdotal, but it can be compelling. Buffalo were said to have stampeded to the top of a hill just before the Asian tsunami in 2004.

I might start keeping a catfish to warn me of any upcoming quakes.

Rowan Hooper, online news editor

Let me introduce you to the idea of virtual water: the water supplies that make possible the world trade in commodities, especially food.

The term was the invention of water scientist Tony Allan from King's College London and, I think, it goes a long way to explaining why the world is currently in the grips of a food crisis.

Most crops take extraordinary amounts of water to grow: a thousand tonnes for a tonne of wheat, for instance. In fact, two-thirds of all the water abstracted from the world's rivers and underground reserves goes for crop irrigation. Unsurprisingly, dry countries, like most of the Middle East, don't have enough water to feed their growing populations.

So they import water. They import virtual water. This trade is huge, the equivalent of 20 times the flow of the world's longest river, the Nile. Without it, hundreds of millions would starve. But the trade is in trouble.

The world's biggest supplier of virtual water is, or was until a couple of years ago, Australia. It exported 70 cubic kilometres of virtual water, in the form of fruit and crops, a year. That's 70 billion tonnes, if you can imagine that better.

Then came drought, which has more than halved that figure. Australia's wheat exports are down 60%, its rice exports down 90%. The US, the second biggest virtual water exporter, has been diverting much of its water to growing corn for biofuels and hence has been reducing its own exports.

Meanwhile global demand for virtual water is soaring, especially from China, where water is the main constraint on food production. China has effectively run out of water in its traditional breadbasket region in the north of the country, where the Yellow River now rarely reaches the sea in any volume. China can't feed itself any more.

And other countries will follow. India has been one of the great success stories of the revolution in agricultural production in the past 40 years. Once a byword for famine, it feeds itself today. But at great cost.

Its farmers are estimated to pump, from below ground, 250 cubic kilometres of water a year, of which only 150 cubic kilometres is replaced by the monsoon rains. Water tables are plunging as a result.

This over-pumping cannot go on. Farmland is already falling out of production. Water is very heavy stuff, too expensive to move great distances. So there is no global trade in water itself, in the way there is in oil. But virtual water is traded. And as water shortages emerge round the world – the US, for example, has its own problems – the virtual water trade is turning those local crises into a global crisis.

In Europe, we often consider ourselves immune from water shortages in other parts of the world. But we rely on others' water more than we know. Spain is currently importing water ("real" water, in transport ships) from France.

Britain imports 40 cubic kilometres of virtual water a year, mostly in the form of food. Right now, we are feeling other peoples' water shortages in higher food prices. One day, if countries decide to hang onto their water, the supplies themselves may dry up.

Fred Pearce, senior environment correspondent

Labels: freds-footprint, water

At this year's Royal Chelsea Flower Show, a silver medal in one category went to climate change researchers.

The prize went to a team from the Tyndall Centre for Climate Change Research. They created a garden comparing the traditional British garden of the 1950s with how such gardens could look in 2050. The scientists came up with two future gardens, depending on how much carbon dioxide humanity had emitted in the interim. The 'low emissions' garden was still fairly British in style, while the 'high emissions' garden had more of a Mediterranean feel, featuring plants adapted to summer droughts.

The photos below show the different gardens. Mouse over the images to see notes explaining the specific plants used. You can also see all the images in this Flickr set.

Overview of the garden



Low emissions future garden and 1950s garden



High emissions future garden



High emissions future garden - detail



Michael Marshall, online editorial assistant

Labels: climate change, plants

The popularity of biofuels has taken a hit recently. Blamed for rising food prices, food shortages and deforestation, they are now being flagged up as ecosystem destroyers.

The Global Invasive Species Programme and the International Union for the Conservation of Nature warn today that many plant species slated for biofuel use are potential invasive species. Their report is released today at the Convention for Biological Diversity's annual conference in Bonn, Germany.

The Global Invasive Species Programme (GISP) have catalogued all the species currently being considered as possible sources of biofuels. Turns out most of them are known to be invasive species. See the list of species in the report, here.

Since the introduction of oil palm to Brazil as a biofuel crop, large amounts of jungle have been cleared, to form oil palm monocultures. But it is listed as invasive because it also spreads beyond the plantation and into intact jungle.

Maize does not appear on the list, despite being a major source of ethanol at the moment. According to Geoffrey Howard, IUCN's Global Invasive Species Coordinator, that's because corn is not considered native to any country any more.

It's the switchgrass I'm most interested in though. It has been hailed as the answer to the biofuel problem: it's not a food crop and so will not hike up the price of corn tortillas in Mexico and has the potential to produce more fuel than corn or sugarcane. But according the GISP, it's a weed that could spread far and wide, displacing other species.

Looks like one more nail in biofuel's proverbial coffin.

Catherine Brahic, online environment repoter

Now here's a heart-rending angle on the current global rash of high food prices. Horses, as even the most citified of us knows, like to get their oats. Literally. And grain prices this year are double and sometimes triple last year's, which were already high compared to the 1990s. Lots of people are going hungry, and apparently lots of horses are too, as the cost of feed skyrockets.

On the bright side, if certain young females in your life (or you) have been pestering parents to buy a horse, prices are at an all-time low. On the dark side, in the western US overburdened horse owners (the ones who gave in to a daughter's pleas, I would bet) are now saddled with ageing horses and are turning unwanted animals loose in fields, or dropping them off in wilderness areas at night.

But according to animal scientists who have been lamenting the situation, tame riding horses have no idea how to survive in the wild, even what plants they can eat. The romantic idea of setting them free, as portrayed in certain children's films, doesn't actually work out for the horse.

The traditional alternative, of course, is to sell unwanted horses for meat. The English-speaking world maintains a cultural revulsion against eating horse, although much of the rest of the world has no problem: there is horse steak for sale in my local supermarket in Brussels. But the animal rights movement has pushed hard for bans on horse meat in several US states, and has largely shut down the US horse slaughtering industry.

So unwanted US horses, if not abandoned to die a lingering death or wander onto a motorway, are being shot and dumped illegally. how humanely one doesn't wish to think. Being slaughtered for meat would probably be a lot more humane. And some US horses still are - except this now entails being painfully trucked to distant slaughterhouses in Canada and Mexico. The US Humane Society wants to stop even the export of horses for slaughter; some animal scientists predict an "equine tsunami" if they succeed.

I think most of us hate the idea of cruelty to animals, especially intelligent domesticated creatures like the horse. But efforts to protect animal rights should lead to less cruelty, not more of it. It seems the animal rights people have shot themselves in the foot.

It reminds me of when activists liberated all those mink from European fur farms, helping the bloodthirsty little weasel, an American native, destroy yet more European wildlife.

Debora MacKenzie, New Scientist contributor

Labels: cooking, endangered species

For the past week, every time I have set foot outside I've been accompanied by a gunman. Their instructions are to shoot if threatened by the very species which has just been declared threatened with extinction by the US governmen: Ursus maritimus – the polar bear.

I am on an ice-breaker in the Canadian arctic. The threat of polar bears is not something that keeps me awake at night, but I know the gunmen are not for show. On Sunday, I was woken by a call from one of the officers on the bridge: a bear was directly in front of the boat.

From a safe distance, our visitor was cute and cuddly. It was clearly young and looked playful as it dug around in the blocks of ice and snow. But I would not want to get much closer. I am told the younger and older bears are the most the dangerous: the young ones are fearless because they don't know better and the old ones have nothing to lose. Either way, if they are hungry and you are in the neighbourhood there is a good chance you are for dinner.

But if you are on the ice, should you, would you, be able to shoot it? In Canadian national parks, guns are illegal. This applies to national parks in the Arctic, meaning if you are in these parts and within the borders of a national park (I am not) you cannot legally carry a firearm. In Arctic parks, visitors are informed of the risks of bear attacks and advised to use flares as deterrents.

The law was created with southern national parks in mind, but with increasing interest in the northern territories, it has become something of a problem. I have read of Arctic guides who have decided not to take clients into the northern national parks because it is simply too dangerous.

It is ironic that the US should declare polar bears threatened even as Canada is considering allowing guns in its Arctic parks. It shows just how divided people are when the question comes down to a matter of life and death, us or the bears.

The issue isn't critical at the moment; there are estimated to be about 20,000 bears left. The US decision is based more on a future threat to the bear population as the ice they depend upon disappears, than an immediate threat of extinction. The considerable amount of media coverage the decision has had relates more to the US position on climate change than the actual number of bears remaining in the wild.

Indeed, the US decision is seen as a tacit admission that climate change and melting ice caps are an inevitable feature of the planet's future. The threatened status does not mean the Inuit will no longer be able to hunt bears and run "sport" bear-hunting tourisms.

For how long will this be allowed? How low do we let the number get to until we ban all hunting of the animal?

Catherine Brahic, online environment reporter

A couple of headlines on Tuesday (here and here) reported that world carbon dioxide levels have set a new record, reaching the highest levels in 650,000 years.

This is a good reminder of what people are doing to the planet, but hardly news. For decades, every year has seen a new record high of CO₂, as shown by the annual annoucements from the US National Oceanic and Atmospheric Administration. As Science reported in 2006:

"At no time in at least the past 10 million years has the atmospheric concentration of CO₂ exceeded the present value"

And judging from the data on the website of Yale's Mark Pagani, it looks like it has been about 20 million years since CO₂ levels were as high as today's.

The gas just keeps building up.

What is new about the NOAA's greenhouse gas report this year is that methane levels also showed a clear increase for the first time in a decade.

Methane is a potent greenhouse gas, warming the planet 25 times more, molecule-for-molecule, than CO₂. It doesn't last as long in the atmosphere, which tempers its kick, but it's still enough to give you nightmares.

As Fred Pearce has reported, thawing Arctic permafrost could give off massive amounts of methane, which would warm the planet. Permafrost is basically frozen mud, and when it thaws, microbes start chewing it up, emitting both methane and CO₂, the amounts depending on the temperature, how wet it is, and other factors.

Either way, the released greenhouse gases could cause a positive feedback, with the thawing releasing greenhouse gases, which cause more heating, which cause more thawing... Which is enough to give me nightmares. With the recent increase in methane, we might be seeing the very beginning of this process, but at this point it's hard to say. According to a press release from NOAA that triggered the recent coverage:

Rapidly growing industrialization in Asia and rising wetland emissions in the Arctic and tropics are the most likely causes of the recent methane increase, said scientist Ed Dlugokencky from NOAA’s Earth System Research Laboratory. "We're on the lookout for the first sign of a methane release from thawing Arctic permafrost," said Dlugokencky. "It's too soon to tell whether last year's spike in emissions includes the start of such a trend."

If you want to keep tabs on all these gases yourself, check out NOAA's Interactive Atmospheric Data Visualization. You can select from different stations, gases, and so on to produce your own customised charts. Or, for a longer-term graph of CO₂, click here.

Mason Inman, New Scientist contributor

On board the Canadian icebreaker cum research vessel CCGS Amundsen, the sighting of open water has brought a group of scientists to life. They push themselves into padded bright orange body suits, don hard hats and steel-tipped polar boots, and head for the decks. Within the hour a host of instruments will be lowered into the freezing water.

The Amundsen has been wedged in ice for three days, sampling and measuring the snow, the ice, the algae growing on the underside of the ice, and the water immediately below. This morning it shifted to a "flaw lead".

Flaw leads are what bring the team of 35 scientists presently on board to the Canadian Arctic.

"The leads are windows on the future," says chief scientist Michel Gosselin of Quebec University in Rimouski, Canada.

Flaw leads are swathes of open water in between ice. They form as the ice shifts around the Arctic basin, pushed by winds, currents, and the rotation of the Earth. In places, the movement forces large plates of ice against each other, creating ridges of blue and white ice rubble. Elsewhere, gashes open up.

Inside and around the leads, life abounds. No ice means more light, more plankton, and so a stronger, denser food chain, right up to the top predators. Belugas and bowhead whales navigate down them, and they are not the only ones. "There are polar bears in the area, I'm sure of it," says Captain Stéphane Julien, as he flies over the waters in the ship's helicopter, scouting out the day's route.

The bears stalk the narrow cracks, the edges lined with hundreds of bearded and ring seals. Others have bored holes in the thin ice that forms overnight.

Seals eat fish, the next ring in the food chain and part of the reason Marc Ringuette and Caroline Bouchard of Laval University are here. The seals mostly eat Arctic cod, a fish we know very little about. On Monday, the pair dug a hole in the ice beside the Amundsen and dropped a gill net down, but adult fish remained elusive.

They are definitely around, though. Finer nets have brought back large quantities of larvae, which the researchers shove under microscopes in the labs crammed into every possible nook and cranny of the ship.

The larvae are just one of the signs that the Arctic spring is kicking off. Other teams have drilled cores out of the ice. At the very bottom, the blue-ish ice suddenly becomes brown: ice algae. Everything is sampled and taken back on board.

The expedition is not simply trying to measure the importance of flaw leads and how they function: it is also attempting to understand what the Arctic will look like in future.

The leads' influence extends far beyond Arctic life, and feeds back on the region's weather as well. Ice acts as an insulator, keeping the Arctic ocean warmer than it would be otherwise. In places where the ice opens up, that warmth is released into the atmosphere. "It's a positive feedback," says Chris Fuller of the University of Calgary, Canada.

The Arctic has warmed more than any other region on the planet as a result of climate change. Ice cover is reducing constantly. The US National Snow and Ice Data Center estimates that the extent of ice coverage in March is dropping by 44,000 square kilometers per year on average.

"That means there's more room for the ice to move, and if it moves more, you get more cracks," says John Yackel of the University of Calgary.

Catherine Brahic, New Scientist environment reporter, in the Arctic Ocean

Labels: arctic, climate change

The recent Nature paper suggesting that the world may experience a few years of cooling prompted predictable responses from climate sceptics. Suddenly global warming had been proved "wrong". Commentators who had actually read the paper rightly pointed out that a temporary drop in global temperatures won't mean much, as global warming is a long-term phenomenon.

But more recently there has been some dissent from within mainstream climate research. The scientist bloggers over at RealClimate don't buy the arguments in the Nature paper. What's more, they are prepared to bet on it.

The bloggers don't go into why they think the authors, led by Noel Keenlyside of Kiel University, are wrong, but the terms of their proposed wager are pretty simple. According to Keenlyside, global mean temperatures for the periods 2000-2010 and 2005-2015 will be slightly below the average for 1994-2004. The RealClimate bloggers don't agree. They want to lay two bets of €2500, one for each time period, on temperatures increasing.

So what does Keenlyside say? Nothing as far as I can see, although I've emailed him to ask.

He would have to be pretty confident to put down his cash. Climatologist Roger Pielke has crunched some numbers on the bet and shown that global temperatures would have to cool by 0.3 °C between now and 2010 for RealClimate to be proved wrong. That, says Pielke, "is a bit like giving 50:50 odds that Wigan will come back from a 3-0 halftime deficit to Manchester United."

But the RealClimate folks still have a point. If Keenlyside believes in his result, then shouldn't he put his money down? If he doesn't, why did he submit it a leading scientific journal? (Or any journal, for that matter). Bets are useful like that. If enough money is at stake, a wager forces us to say what we think will really happen, rather than what we want to happen.

Jim Giles, New Scientist contributor

Labels: climate change, climate sceptics

What does predicting where fish will be in a river have in common with preventing disease? The answer is a computer model that can do both.

Ignacio Rodríguez-Iturbe of Princeton University, and colleagues built a computer model of the entire Mississippi-Missouri river basin, which stretches across about half of the US. They divvied it up into more than 800 sub-basins, representing the interconnected rivers as a densely branched network.

Without knowing details of fish ecology, the team were still able to create a realistic map of fish species diversity. For example, in moving through one sub-basin in Louisiana, their estimates of the fish diversity at various distances from the river's outlet "fantastically" matched actual biodiversity measurements, Rodríguez-Iturbe says.

The models show that flow through the various branches of the waterway plays a major role in determining the species richness. So, if rainfall increases because of climate change, the model can tell you how that will affect biodiversity, he says. The same applies if river connectivity changes because humans build a dam.

And with a slight modification, the model works for more than just fish.

Rodríguez-Iturbe and another set of colleagues used a similar river model to predict how cholera would spread through waterways, and tested it against data from a two-year-long outbreak of the disease in South Africa.

The result? The researchers say the scheme is remarkably good at predicting actual cholera outbreaks. The structure of the network determines how the disease spreads, often in a patchy way, similar to how fish species spread or migrate along rivers.

These models are impressive in theory, but I am a bit sceptical about how much they will actually help in practice. In trying to preserve biodiversity, or to prevent water-borne diseases like cholera, it seems we stumble not because we don't understand the causes of these problems, or don't know where they are occurring. It seems the real problems are a lack of funds, regulations, or political will.

But given all these limitations of the real world, maybe models like this are needed to squeeze the most bang out of our limited bucks. If readers know of examples of models that have been especially helpful in preserving biodiversity or preventing disease, please post a comment.

Mason Inman, New Scientist contributor

Nature, DOI: 10.1038/nature06813

Labels: endangered species, environment, life

My last blog brought a big response. A lot of you didn't like my suggestion that the rhetoric behind calls for population control to protect the environment often sounds like green fascism.

I was struck by how similar the tone of many responses was to the 40-year old classic of the genre: Paul Ehrlich's The Population Bomb, which sold about three million copies. But a lot has happened since which seems to undermine the more rabid calls for action.

Ehrlich said that world food production would not be able to keep pace with the soaring population. Wrong. Since then, world population has more than doubled – but food production has kept ahead. As a result his prediction that "billions would die" from famine in the 1980s didn't happen either.

He was wrong too about trends in family size. Little more than a generation ago the average woman had 5-6 children. He predicted people would continue to want large families, and that "family planning does not control populations".

Wrong. That figure has now halved to 2.8 children per woman. Fifty countries round the world have rates of fertility that are at or below replacement levels. So Ehrlich’s demands for coercive population control were based on a false premise. Surely we should learn from this. A little humility, at least.

Most worrying for me, many of the people responding to my blog today are unaware of the rapid decline in fertility across most of the world. Nor the fact that, outside China, this is being achieved largely without coercion.

The fact is that, for all the fears of a demographic doomsday, women are voting with their wombs. They want smaller families and a life outside full-time motherhood.

Of course population is still going up. The developing-world baby boomers born in the 1960s and 1970s are still of childbearing age. But soon that will pass. United Nations demographers are now talking of the world population peaking by mid-century, perhaps at below 9 billion, and then starting to subside. Some say we may not reach 8 billion.

You see, as national fertility rates fall, they do not stop at the nuclear family ideal of mom, dad and two kids. They keep on down. To an average 1.8 children or even lower. In some countries it looks like women are on something close to a childbirth strike as their menfolk work out how to make motherhood easier.

This is the context in which I am amazed to find a resurgence of concern about rising populations. It makes no sense. How much faster exactly do we expect fertility rates to fall?

And there is a more insidious context, which was the prime concern of my original piece. Every time greens stress "over-population" among the poor as an environmental threat, they are denying the much greater threat to global resources from over-consumption among the rich.

I do not really believe in the idea that the planet has some fixed "carrying capacity". How many it can sustain depends on how we live on this planet rather than absolute numbers. Mahatma Gandhi wasn't far wrong when he said there is enough for everyone's need, but not for everyone's greed.

Fred Pearce, New Scientist senior environment correspondent

Labels: freds-footprint

Is trouble brewing among the great and the good of ecological theory? Last week, Richard Zeebe of the University of Hawaii and Ken Calderia of the Carnegie institution in California, two well-respected scientists, published a study in Nature Geoscience about the Earth's system of checks and balances.

The study claimed to be the first to demonstrate empirically that our planet has a self-regulating system to keep atmsopheric carbon dioxide levels in check. Sounds rather like the Gaia theory, if you ask us, and if you ask the originator of the theory too, but more of this in a bit.

Zeebe and Calderia looked at fluctuations in carbon dioxide data during 610,000 years of the Pleistocene. The data showed both the levels of CO2 in the atmosphere (using gas bubbles trapped in ice cores) and in the oceans (using sediment cores).

Overall, in spite of slow rises and drops during successive glacial and interglacial periods, CO2 varied very little. That changed dramatically when the Industrial Revolution kicked in in the 19th century, pumping CO2 into the atmsophere much faster than it had been injected into the atmsophere by volcanoes in the past.

So far, not so new. But Zeebe and Calderia have calculated the total carbon cycle over this period: the carbon stored in the atmsophere, ocean and land masses. They show that overall, the maximum imbalance between the amount of CO2 put into the atmosphere and the amount taken out of it during the 610,000 years was 1-2%.

Volcanoes are the main natural supply of CO2 to the atmosphere. But without some sort of a natural system to suck the CO2 back out of the atmsophere, CO2 would have doubled in 600,000 years. Zeebe's data shows this hasn't happened and the authors conclude that some natural system has been soaking up CO2 whenever volcanoes have spat it into the air.

They say the most likely mechanism is the weathering of rocks by rain, a process which causes the minerals in rocks to react with CO2 in the atmsophere.

This is when bells started ringing with us. So we decided to ask the father of Gaia what he though.

James Lovelock said

The paper by Zeebe and Caldeira in Nature Geosciences is a fascinating and probably important analysis.

He believes Zeebe and Caldeira have missed out on the important role which organisms on or close to the rocks (microbes, mosses) play in accelerating the rate at which CO2 is absorbed.

But mostly, he thinks the latest study is an attempt to "cannonise" the theory of a self-regulating Earth as a US invention. The paper makes no mention of Gaia theory or any of the research carried out over the years by Lovelock and Lynn Margulis.

Gaia has sat very uncomfortably with many, who see it as New Age and paganistic - afterall, the theory was named after a Greek goddess.

"American scientists too often fail to acknowledge that the Earth is a self regulating system made up from all life including humans, the surface rocks, air and oceans and operates with the goal of sustaining a habitable planet. This is Gaia theory and it is sad to see good science, neglected simply because the word Gaia brings up images of Earth mothers and New Age fantasy. If they want to call it Earth System theory instead of Gaia they are welcome, so long as they give credit by literature citation to the sources of the idea. We badly need a proper systems approach to Earth and Life science now that the system itself shows signs of breaking down," says Lovelock.

Catherine Brahic, online environment reporter

What are we to make of headlines like this:

"Next decade 'may see no warming'"?

That, and others like it, have been inspired by a paper in Nature this week that has taken a new look at climate change model data. Sceptics are loving it – but what does it really mean?

Noel Keenlyside of the Leibniz Institute of Marine Sciences in Kiel, Germany, and colleagues used sea surface temperatures recorded over the last 50 years to constrain other variables in an existing climate model. They validated the approach by "hindcasting", that is, by checking that the model predicted the right conditions over recent history.

Then to the forecasting: they reckon that over much of Europe and North America, the coming decade will see cooling, while Pacific regions remain the same temperature.

If it's true, it's a fleeting reprieve, not a commuted sentence; the paper is peppered with the word "temporarily". In about 2020 - and here's the take-home message - the model predicts the temperature curve will begin to rise again, in line with prior predictions like those of the IPCC. Any slowdown in warming would be a decade-long ripple on an upward curve centuries and millennia long.

And it is, after all, a model – built on assumptions and approximations that are not so different from the ones made by your local weather forecaster. While the model looks pretty good for Europe and America, it failed to recreate the conditions in recent decades over central Africa.

In any case we're talking about natural cycles of the Earth's climate, sometimes - and sometimes not - wholly removed from humanity's influences. The global thermostat isn't like a switch that gets turned on and off, a curve that goes only up or only down. It's a whole bank of switches going on and off and try though we might we still don't even know what some of the switches do.

This most recent effort is among the first to even try to do predictions over decade-long timescales, and should be applauded. But the big picture, both in terms of time and of policy, shouldn't be forsaken in light of this educated guess at a close-up.

Jason Palmer, New Scientist reporter

Labels: climate change, climate sceptics