Saturday, December 31, 2005

New Year Green Resolutions - Use E15 petrol only

My Renault Megan 2.0 litre engine is warranteed to takes up to a 15% blend of ethanol and gasoline. The French have been driving on blended petrol and biodiesel/diesel blends for years. There is an independent petrol station in Randwick selling an E15 blend under the name of ULP. My New Year Resolution is to merge the two happy co-incidences and give them my custom.

The rewards are many. The ethanol is derived from Queensland grown sugarcane so this helps reduce Australia's reliance on foreign oil infrastructure. It gives the Megane more punch when needed and helps reduce greenhouse gas emissions as this report from 2003 shows.

Engine performance and total emissions are both improved by the addition of ethanol to gasoline. The clean burning nature of ethanol allows you to capture more of the work from the fossil portion of the gasoline, which compensates largely for the lower energy content of ethanol itself. In a 10 per cent blend (E10), all other things being held the same, you might get a zero to 2.7 per cent loss in mileage (kilometres per litre).

Another performance benefit from ethanol is its high octane addition to fuel. Of all the commercially viable octane enhancers possible, nothing delivers more punch than ethanol. The populace still feels the ill effects of the tons of poisonous lead that were spewed into urban environments because of the poor decision to accept lead over ethanol as the octane additive of choice.

But will I really achieve any good? Choice Magazine weighs up the pros and cons:
Ethanol-blended petrol has advantages and disadvantages for the environment over normal petrol ? the extent of most of them depends on factors such as the percentage of the blend, the engine type and how the ethanol was produced:
  • A 10% blend generally reduces the car?s emissions of carbon monoxide, hydrocarbons, some carcinogens such as benzene and toluene and ? in some circumstances ? the greenhouse gas carbon dioxide. However, due to the government subsidy, any reduction of carbon dioxide emissions comes at a very high price compared to other initiatives.
  • Ethanol increases the petrol?s volatility, and therefore the amount of evaporative emissions of volatile organic compounds, which can contribute to global warming and the formation of ground-level ozone (summer smog). This can be avoided by changing the volatility of the petrol used for blending.
  • There are higher emissions of carcinogenic aldehydes (such as formaldehyde and acetaldehyde) and ? in most cases ? of oxides of nitrogen.
  • Overall, there seems to be little benefit for urban air quality or greenhouse gas emissions resulting from the use of ethanol-blended petrol. However, as ethanol is produced from agricultural products or waste, it?s a renewable energy source.
In the end analysis, if 15% of the fuel I am using is made from carbons that have been sucked out of the atmosphere rather than the ground that is an overall environmental gain for me. I'll just have to wait till 2007 to order my solar car.

Technorati Tags
,, , , , , , , ,

Friday, December 30, 2005

2005 wins for science

A Concerned Scientist looks back at some wins for science and and conservation in the assult by ID activists, and big oil's search for big deposits. Sustainable Energy 2005 Round-up:
2005 saw it's drastic ups and downs in gas and energy prices, with the threat of Peak Oil to our economy looming, our energy infrastructure remaining a troublesome national security issue, and evidence abounding for the acceleration of global warming and climate change. But renewable energy has seen great progress this last year as well, with numerous local and state initiatives proposed and implemented (even if Bush continues to stand in the way), further R on improving energy and transportation technologies, and a nascent community of private companies taking steps towards a sustainable future (e.g. GE, BP).

At the top of the list are Governor Schwarzenegger's (R-CA) Million Solar Roofs Initiative, the Northeast's Regional Greenhouse Gas Initiative, and a series of other regional projects encouraging Kyoto-like emissions reduction targets. Given the threat posed by a collapse following contraction of our petroleum-based economy, expanding alternative fuels and energies is a must. Significant obstacles remain, however: most solar panels still require expensive highly purified silicon; wind farms are objected to as unsightly and threaten migratory birds/bats; biofuels would take more energy to produce than they would supply and don't represent a permanent solution to carbon emissions; hydrogen fuel cells still require expensive platinum and other components, and hydrogen production/distribution schemes remain unsatisfactory; nuclear power has gotten safer in the last 30 years, but still has questions of waste disposal that need addressing; and coal does nothing to address carbon emissions, although mercury and other pollutants have been cleaned up substantially.

Still, we must laud the initiatives and projects that've seen notable progress this year, as we head towards Peak Oil.
I would add the growing realisation that GM seeds have lower yields than unmodified seeds to be a win. Modifying seeds genetically so they can help sell more chemical fertiliser (at the expense of the environment) does not deserve to be a sustainable business.

It's biodiversity, or bust baby!

Tags: , , , , , , , , ,

EPA sets ethanol content standard in petrol.

The US EPA has finally acknowledged that ethanol blended petrol burns cleaner and mandated a 2.78% blend of ethanol and petroleum gasoline to be sold. The higher octane ethanol burns more cleanly in a combustion engine reducing harmful emissions.

The Environmental Protection Agency said on Wednesday it expects the US oil industry will meet the EPA's new standard that requires 2.78 percent of gasoline sold next year to be renewable fuel, such as ethanol.

Congress passed a broad energy bill which was signed into law in August, requiring ethanol production almost to double to 7.5 billion gallons a year by 2012 to help make gasoline burn cleaner, stretch available US motor fuel supplies and reduce petroleum imports.

This is progress. Although the pace has been set by those Brazilians who use up to 25% ethanol blended petrol without any problems the US is the largest consumer of fuel in the world with the Energy Department forecasting that 141.6 billion gallons of gasoline will be sold next year in the US market. The legislation also encompases biodiesel and other renewable fuels.

Technorati Tags , , , , , , , , , , , , , , ,

Monday, December 26, 2005

Dinosaurs cooked by global warming

Fresh fossil leaves analysis shows there was a sudden and dramatic rise in carbon dioxide in the Earth's atmosphere 65 million years ago. It's what killed the dinosaurs, say researchers. C02 was injected into the atmosphere in vast amounts by the impact of an asteroid striking CO2 rich limestone rock and the ensuing blistering heatwave that followed raised global temperatures by as much as 7.5 Celsius making it impossible for the ancient reptiles and countless other lifeforms to survive. CO2 levels were estimsted to be four to five times higher for 10,000 years after the impact

The researchers from the University of Sheffield, UK, and Southwest Texas State University and Pennsylvania State University, US, studied the fossilised pores of leaf of gingkoes and ferns that grew around the time of the dinosaurs' demise. The number of carbon dioxide-absorbing pores in the fossils reflects the amount of carbon dioxide in the air: the fewer the pores, the more carbon dioxide.

By using computer simulations and doing real experiments on plants, the scientists can show there was a sudden, five-fold increase in CO2 at the end of the Cretaceous.

This can only be explained, they believe, by the sudden vaporisation of between 6,400 and 13,000 billion tonnes of carbon - a substantial component of the limestone rocks that lined the shallow sea that existed at Chicxulub 65 million years ago.

Technorati Tags

Official: 2005 2nd hottest after 1998

Are you feeling it? 2005 is the second warmest globally since the 1860s, when reliable records began. Ocean temperatures recorded in the Northern Hemisphere Atlantic Ocean have also been the hottest on record.

Global termperature trends - graph from 1960 to 2005

Technorati Tags

Sunday, December 25, 2005

2005's Scientific Milestones

With a US court ruling Intelligent Design as religion dressed up as science here's a review of how well science served us in 2005.
With this in mind, the journal of the American Association for the Advancement of Science has declared discoveries about evolution the 2005 winner of its annual list of top 10 breakthroughs.

"Today evolution is the foundation of all biology, so basic and all-pervasive that scientists sometimes take its importance for granted," Science concludes.

Huge numbers of studies in this field are generated annually. But "2005 stands out as a banner year for uncovering the intricacies of how evolution actually proceeds", it says.

The genetic code of a chimpanzee named Clint was deciphered this year, for example, revealing that 96 per cent of our DNA is identical to his.
Other top 10 scientific breakthroughs include discoveries in how miswiring of the brain occurs, climate change events, earth's origins, nuclear fusion, cellular biology, the nature of neutron stars, secrets of flowering, cell communication, voyages to the planets.

It is hugely impressive that mankind has been to the outer rings of Saturn, and landed the European spacecraft Huygens on Titan to find a world where liquid methane rains down to create valleys and lakes. And yet humbling to know that our DNA is 96% match with that of chimpanzee-kind. It is impossible not to admire the minds that discovered that our cells communicate with each other using a chemical network as complex as the Internet, and hard not to feel despair for human beings who ignore the signs and pace of global warming.

My wish for 2006 is a greater respect for all science but particularly the science of climate change, and dramatically greater awarness and responsiveness to global warming. I feel the US Federal Court Judgement to keep religion out of the science class upholds a respect for science, much needed to convice the world to avert dramatic climatic change.

Technorati Tags

Sunday, December 18, 2005

Flat Earth Theory #1: Hotter sun causes global warming naturally.

If global warming is man-made then ignorance must be a root problem, and I will be contesting it in my Flat Earth Theory series.

There are clearly vested interests who fight hard to obscure the fact that the fossil fuel emissions increase the onset of climate change (we just have to see how the US, Saudi Arabia and Australia stonewalled at the Montreal UN Climate Change Conference), and I always find it fascinating how their spin finds itself into the mouths of the general public.

Glitch, a regular (possibly my only one) has forwarded the theory that increased solar activity is the driver behind the global warming we observe:
I'm sorry - but I believe that the earth's temp is PRIMARILY driven by variations in the Sun's output.

If EVERY CAR/TRUCK/PLANE/ELECTRIC POWER PLANT was turned off TODAY, I do not believe it would change the 'global climate' - sea levels will go up and go down...and there is NOTHING humanity can do about it
Glitch has a good point, the sun is indeed the greatest influence on the earth's temperature, but that is not the whole story. I will try to illustrate with an example. If I go sunbathing, the sun will initially be the greatest influence on my body temperature, which would rise. So far Glitch's argument is supported in this example. But then my pores would open in response to my body's increased temperature and I would sweat. This sweating will cause evaporation thus cooling down my body and keeping it at an average temperature of around 37 degrees Celsius. The biological name for a mechanism for maintaining equilibrium is called homeostasis. Without a homestatic mechanism for cooling I would just heat up, cook and die.

If we take the view that the earth is an organism of sorts, as in the Gaia theory of James E Lovelock, then we can attribute Gaia with a homeostatic mechanism that keeps her temperature at an equilibrium that sustains life. Gaia's temperature chart for the last 1800 years (Mann, et al, 2003) indicates that this is indeed what happens.
Graphic showing the earth temperature from AD 200 to AD 2000 from proxy temperature indicators.
One of the main drivers for this mechanism is called albedo, or the reflectivity of the earths surface. The earth, on average, reflects 31% of the sun's heat back into space, keeping it cool, and can be described as having an albedo of .31 while snow and ice has an albedo of .9 and oceans have an albedo of .1, or 10%.

As an aside, it was Leonardo da Vinci who first explained, almost exactly 500 years ago, that the earth reflects the rays of the sun in his Codex Leistercer.

So now you can see why healthy artic and antartic ice and snow belts are vitally important to regulating the earth's temperature. Where do the greenhouse gases that Glitch referred to fit into the picture? Well, they trap the heat that is reflected. If I may return to my previous example of sunbathing. Many underarm deodourants work by closing the pores of the skin, preventing sweating. Now if I was to cover my body with such a deodourant prior to sunbathing, I would be disabling my cooling mechanism and would thus overheat and suffer sunstroke. By not reversing the rate at which we put CO2 in the atmosphere, humanity is collectively doing pretty much the same thing to Gaia; we are disabling her cooling mechanism.

Yes it is a fact that there has been an increase in solar activity:
Since the middle of the last century, the Sun is in a phase of unusually high activity, as indicated by frequent occurrences of sunspots, gas eruptions, and radiation storms. Researchers at the Max Planck Institute for Solar System Research (MPS) in Katlenburg-Lindau (Germany) and at the University of Oulu (Finland) have come to this conclusion after they have succeeded in reconstructing the solar activity based on the sunspot frequency since 850 AD.
But recent studies by German and Finnish research teams conclude that this is just one cause:
The influence of the Sun on the Earth is seen increasingly as one cause of the observed global warming since 1900, along with the emission of the greenhouse gas, carbon dioxide, from the combustion of coal, gas, and oil. "Just how large this role is, must still be investigated, since, according to our latest knowledge on the variations of the solar magnetic field, the significant increase in the Earth?s temperature since 1980 is indeed to be ascribed to the greenhouse effect caused by carbon dioxide," says Prof. Sami K. Solanki, solar physicist and director at the Max Planck Institute for Solar System Research.
In summary, Glitch, it all comes down enhancing our collective albedo. ;)

Technorati Tags

Saturday, December 17, 2005

World's hottest year yet.

2005 is Australia's hottest year recorded and may be the planet's warmest for thousands of years. Add to that the extreme weather events we have been experiencing and you end up wondering how anyone could doubt global warming is occurring at an alarming rate, whether they believe it is anthropogenic or not.

Other points in the SMH article include:

Michael Coughlan of the Australian Bureau of Meteorology said 2005 and 1998 were vying to be the hottest years on record globally, with only two weeks of measurements to be made. "Nineteen ninety-eight has its nose in front, but the race is not over yet."

Dr Coughlan said the record warmth in 1998 was helped along by a strong El Nino event - a warming of the equatorial waters in the Pacific Ocean occurring every three to seven years that tends to increase global temperatures. "The 2005 warmth is remarkable for the fact that it occurred in the absence of an El Nino event," he said.

Will Steffen, director of the Centre for Resource and Environmental Studies at the Australian National University, said temperatures had risen sharply in the past few decades due to increasing greenhouse gas emissions.

"The last time the Earth was this warm was about 5000 or 6000 years ago."


In 1998 the average global surface temperature was 0.54 degrees above the 30-year annual average for the years 1961 to 1990. This year's temperature has so far been 0.48 degrees above the average. Final figures will be released in February.

It's going to be a long hot summer.

Technorati Tags

Friday, December 16, 2005

Software: World map with rising sea levels

animated screendump of images from rising sea levels map generator
Theorising rising sea levels drowned Atlantis drove Dutch Douwe Osinga to write a program to create coastlines maps at various water levels. One expects the Dutch to be more interested than most in this subject of sea levels rising I guess.

Interesting site. Check out his blog as well. See what a Google Europe geek does with his spare time when not writing rising sea levels simulators.

Technorati Tags

Harbingers of the The Great Fry

Climate Hot Spot Map of the harbingers of climate change globally; spreading diseases, early spring, coral bleaching, extreme weather, drougnt and fire, and plant and animal range shifts and population changes. See what is happening for your own eyes. Then do something about it.

I lifted this off my trans-Tasman twin at Cheers.

Technorati Tags

Saturday, December 10, 2005

Nice one Ma'am.

When the British (and Australian ... go figure?) Queen decides that it is her turn to do something about reducing her energy footprint, she shows us how it is done:
London: The Queen is to go green after full planning permission was granted to run Windsor Castle on hydro-electric power.
The $2.3 million, four-turbine plant will be built at Romney Weir on the River Thames.
Charles has obviously been chewing on HRH's ear. His green credentials go way back.
The 56-year-old supported organic farming as far back as 1984, long before it became a mass consumer issue and his vociferous belief in conservation has often been ahead of the times.
The Queen has her own army of devoted fans, and her going green in this way sends them a powerfull message.
Buckingham Palace said the royal household was pleased the project had been approved. "We're constantly looking at ways of saving energy," a spokesman for the Queen said. "We use energy-efficient lightbulbs at Buckingham Palace and recycle 99 per cent of green waste."
The electricity from the new plant will be fed straight into the Queen's Berkshire castle and not into the local grid. The plant will be the biggest of its kind in southern England.
HRH gets my vote, even though she does not run.

Technorati Tags

Study: Those bullied by life bully nature

The rich don't chop down trees because watching the jungle reclaim their upsized backyards appeases guilt over having too much power? The poor take their powerlessness out by dominating nature with the backyard chainsaw?

Wealthy Sydney professionals live in leafy North Shore suburbs because the trees on the streets make them feel comfortable with their power in society, according to a new study.

This week's Institute of Australian Geographers conference will hear that tree cover in city suburbs is closely related to authority and alienation. Jamie Kirkpatrick, a geographer at the University of Tasmania, thinks less affluent urban dwellers often feel powerless in their work and personal lives, so they exert authority by removing the flora around their homes.

Middle-class home owners, on the other hand, want a break from being in charge, and enjoy returning to a wilder, more out-of-control environment.
Bizzare behaviour ... I usually find that getting a jolly good flogging from Mistress Amanda to be a surefire salve when I start fretting about the heady power (courtesy of this blog) that I wield.

Interesting theory, but I don't think this applies where a tree comes between a property owner and their harbour view. The Sun Herald reported on 29/10/2000 that
Professional hit men target harbour trees
WEALTHY residents in Sydney's eastern suburbs are allegedly using "hit men" to poison trees and enhance their harbour views. One of Australia's wealthiest suburbs, Point Piper, has had 41 protected trees poisoned, lopped, or removed without permission over the past 18 months
This must have galvanised some sort of action because there has been only one newspaper report on the subject in the Fairfax press since:
$110,000 fine threat to harbourside gardeners with view to a kill
Harbourside residents have been put on notice that they face hefty fines if caught cutting trees to improve their water views.
Sydney Morning Herald 20/09/2001

Technorati Tags

Thursday, December 08, 2005

In 10 years climate change will be irreversible.

We have 10 years to change our ways, or face irreversible climate change. So says the scientist who first warned of climate change according to New Scientist Magazine Editorial.

Can we change in 10 years? This puts other problems into perspective.

Source: New Scientist
Technorati Tags

Tuesday, December 06, 2005

Site Review: Earth Day's My Footprint

The Ecological Footprint QuizRedefining Progress) seeks to give you its best answer to the question of how much "nature" your lifestyle requires?

The Ecological Footprint Quiz estimates how much productive land and water you need to support what you use and what you discard. After answering 15 easy questions you'll be able to compare your Ecological Footprint to what other people use and to what is available on this planet.

The concept behind an ecological footprint has been around for at least a millennium and a half; back in 5th century Anglo-Saxon England environmental footprints were known as 'hides' and 'hundreds'. A hide describes the amount of arable land it takes to feed a single family for a year, and a hundred describes how much land it would take to feed a hundred families.

I digress. I answered the quiz questions. They break down your Ecological Footprint into Food, Goods, Shelter and Mobility footprints. Press the button and Bob's your uncle:
CATEGORY --------------------- GLOBAL HECTARES
FOOD ........................................................ 3.1
MOBILITY ................................................. 1.9
SHELTER ................................................... 0.9
GOODS/SERVICES ....................................... 2.9
TOTAL FOOTPRINT ..................................... 8.8
8.8 hectares distributed globally in little furlongs, plots and parcels - so I'm not doing too badly, right?



Alright already! I hear you. It's not enough that they admonish me, they graphically drive home the point by whipping up 5.9 planets side by side. So? At least I have room to improve. Multiple global room it seems.

My Food Footprint has the biggest global hectarage (3.1) of all my categories. That's because I eat a lot of meat and dairy. Love it. I am a southern hemisphere born and bred carnivore who emigrated from one barbecue culture to another. I didn't spend evolution clawing my way up the food chain just to eat carrots and pumpkin forever. Nevertheless there are a few sound reasons to cut back on meat and dairy, including the looking after your heart and bowel. I wonder, how many global hectares could I cut back on if:

I cut back on rate of meat and dairy consumption to something more healthy, from Almost always to Often
A. How often do you eat animal based products? (beef, pork, chicken, fish, eggs, dairy products)
  1. Never (vegan)
  2. Infrequently (no meat, and eggs/dairy a few times a week) (strict
  3. Occasionally (no meat or occasional meat, but eggs/dairy almost daily)
  4. Often (meat once or twice a week)
  5. Very often (meat daily)
  6. Almost always (meat and eggs/dairy in almost every meal)
and conscienciously cut back on processed and packaged food, especially that from far away and thus reducing the impact of transportation?
B. How much of the food that you eat is processed, packaged and imported?
  1. Most of the food I eat is processed, packaged, and from far away
  2. Three quarters
  3. Half
  4. One quarter
  5. Very little.
  6. Most of the food I eat is unprocessed, unpackaged and locally grown.
Well my Food Footprint reduced a whole global hectare, from 3.1 to 0 2.1. And this seemed to have a positive effect on my Mobility Footprint, down from 1.9 to 1.8 (please explain?), and my Goods/Services Footprint, down from 2.9 to 2.8. I guess here I generate less landfill. Best of all I bring my Total Footprint in line with the national average of 7.6, a full 1.2 global hectares improvement. I am instantly rewarded from my aspiring good global citizenship by knowing that:
I rate Ecological Footprint Quiz 4.9 planets out of a possible 5 (I'm taking .1 off for being rude) assuming it employs an accurate methodology in its calculations. It does get one thinking, and potentially acting. You could find yourself involved in an email campaign to your local council to get them to consider commissioning an Ecological Footprint index for the community from the good people at Redefining Progress.

Technorati Tags

Sunday, December 04, 2005

Finally some rain where it counts.

It must be Christmas. Finally, finally some rain has fallen in the Warragamba Dam catchment area, despite the fact that NSW has just had the wettest spring since 2000 with average to above average falls. Sydneysiders, long used to water restrictions brought on by the drought and the many false promises of rain falling outside the catchment will not know what to do with themselves.

Yet there is not enough reason to get light headed and wash your car though; this increase in dam levels will only supply us with water for two weeks. If Sydney's catchment area gets no more rain, the dam will run dry in two years.

The reason why so much rainfall misses the catchment area of the Nattai River, the river that gives Sydney 80% of it's water, has been hypothesised by a Macquarie University physical geography professor to be a result of extensive clearing of natural vegetation as great swathes of suburbia are laid down. Using computer modeling Professor Andy Pitman determined that:
the vegetation loss had changed the dynamics of atmospheric convection, which is a key to forming many thunderstorms that strike Sydney on summer days. Without the vegetation, sea breezes could sweep further inland, changing the location where they collided with winds blowing from the south-west.
In related good news: The Australian Bureau of Meteorology climate officer Mike De Salis says the El Nino ocean pattern is subsiding, leading to wetter conditions for eastern Australia. Forecasters predict the drought is finally coming to an end.

Technorati Tags , , , , , , , ,

Saturday, December 03, 2005

Polluters to clean up under Bush

Clinton brought a lawsuit against Duke Power Company for contravening the US Clean Air Act. Bush has quietly dropped it. It is a pattern that reverses previous gains and sets polluters up to pay no heed to breaking the law.
Rep. Henry Waxman, D-Calif claims ?The Bush EPA has been working overtime to change the underlying clean air rules and prevent such enforcement actions from being brought against dirty power plants in the future."
Power corrupts, dirty power corrupts absolutely.

Technorati Tags , , , , , , , , ,

Chinese demand for greenhouse energy will not abate.

Trying to slow global warming without limiting economic growth is one of the central problems facing delegates in Montreal this week at the first climate change conference since the Kyoto Protocol came into effect in February this year. This is not helped when the two largest emitters, both put prosperity ahead of environmental concerns, and both emphasise efficiency measures of greenhouse gas production rather than the absolute amounts.

Mr Sun Guoshun, director of the Department of Treaty and Law at the Chinese Ministry of Foreign Affairs said China had set a goal of increasing energy efficiency by 20 per cent between 2006 and 2010, while President George Bush aims to reduce greenhouse gas production by 18 per cent as measured against gross domestic product.

Technorati Tags , , , , , , , , , ,

Kyoto Protocol cranks into life.

Carbon now has a market value:

Montreal climate conference adopts ?rule book? of the Kyoto Protocol
(Montreal, 30 November 2005)

The United Nations Climate Change Conference in Montreal on Wednesday finalized the ?rule book? of the Kyoto Protocol, the 1997 landmark treaty designed to curb greenhouse gas emissions.

Under the Kyoto Protocol, which entered into force 16 February 2005, more than 30
industrialized countries are bound by specific and legally binding emission reduction targets. As a first step, these cover the period 2008-2012.
The President of the Conference, which includes the first ever meeting of the 157 Parties to the Kyoto Protocol, Stéphane Dion, said: ?The Kyoto Protocol is now fully operational. This is an historic step.?

Technorati Tags , , , , , , , ,

Explaining Global Warming to a child.

If they can't get it, how can the President be expected to.

h/t It's Getting Hot In here.

Technorati Tags

Thursday, December 01, 2005

Europe's water heater is slowing down.

The irony of Global Warming becoming Global Freezing gets more real with the discovery that the ocean currents which circulate heat around the Atlantic have slowed down by about a third.
Europe's relatively mild climate depends on a system of currents known as the North Atlantic heat conveyor.

Warm surface waters from the tropics flow northwards in the Gulf Stream, releasing heat to the atmosphere, before sinking and returning southwards as a deep cold current. Global warming is forecast to disrupt this system by injecting fresh water into the Atlantic near the North Pole as rain increases and the Greenland ice cap melts. A slowdown in the heat conveyor could cause European temperatures to drop by 4 degrees.

In a study published today in the journal Nature, British researchers at the National Oceanographic Centre in Southampton surveyed the strength of currents at various depths in the subtropics.

They found the circulation system had weakened overall by 30 per cent since 1957, with a 50 per cent reduction in the amount of cold deep water flowing southwards and a 50 per cent increase in the amount of water that never leaves the subtropics. "The implications of these observations are considerable," Professor Quadfasel said. In the past, temperatures have dropped by up to 10 degrees in a decade. This happened after a huge amount of fresh water from melting ice sheets, which had been caught behind a natural dam, suddenly flooded the North Atlantic and shut down the heat conveyor about 8500 years ago.

If global warming caused a similar shutdown, this would have "devastating effects on socio-economic conditions in the countries bordering the eastern North Atlantic," Professor Quadfasel said.
A CSIRO scientist, Stephen Rintoul, said it was premature to blame the weakening of the North Atlantic heat conveyor on global warming.

Technorati Tags