Climate Feedback

The system of surface and deep currents which make up the Atlantic Ocean circulation, a powerful heat conveyor belt and a poster child for abrupt climate change, is a more complex affair than straightforward textbook diagrams suggest.

Atlantic meridional overturning circulation is driven by cold water that sinks in the seas off Greenland and returns towards the equator at depth. How exactly this machinery works, and where its components sit, is interesting for a variety of reasons – not least in that it helps oceanographers look at the right spots for possible system failures.

That’s why a discovery, reported in Nature today [subscription], is worthy of note. Amy Bower of the Woods Hole Oceanographic Institution in Cape Cod, Massachusetts, and colleagues report that on its way back to the tropics cold Atlantic water takes a different pathway than previously assumed.

Bower and colleagues monitored the trajectories of drifting floats released from 2003 to 2006 into the southward-flowing Deep Western Boundary Current off Canada’s east coast. To their surprise, most floats soon drifted towards the high sea instead of strictly following the boundary current which has been thought to be the main pathway linking the Labrador Sea with the subtropical North Atlantic. Virtual floats ‘released’ in a three-dimensional ocean model at similar positions displayed the same preference for internal ocean pathways as did their material counterparts.

A secret interior ocean path? There you go, modelers!

Quirin Schiermeier

Posted by Olive Heffernan on May 13, 2009
Categories: Journal Club, Ocean science, Quirin Schiermeier | Permalink | Comments (0) | TrackBacks (0)

Among the many proposed techno-fixes for climate change, ‘air capture’ seems like one of simplest solutions – what could be more straightforward than sucking greenhouse gases out of air and storing them somewhere else?

But various proposals for the direct removal of carbon dioxide from the atmosphere have largely been sidelined from serious discussions on climate control. Noteworthy scientists and engineers – including those of the Intergovernmental Panel on Climate Change – have regarded the technology as a non-starter owing to the large amounts of energy involved. After all, energy costs money and unless we find ourselves in ‘climate crisis’ mode, solutions to climate change will be considered on economic grounds as well as on efficacy.

But a new study by Roger Pielke, Jr. (of the University of Colorado and Prometheus blog) shows that air capture could be a cost-competitive mitigation option. His analysis, soon to be published in Environmental Science and Policy [uncorrected proofs available from Pielke], compares the average costs of air capture over the 21st century to other mitigation options (namely international greenhouse gas regulation under the UN framework convention) assuming that technologies available today are used to fully offset net human emissions of carbon dioxide. He runs the analysis for 3 different (and citable) estimates of the cost of air capture – $500, $360 and $100 per ton of carbon. The IPCC estimate falls near the middle of this range.

For the two upper values, the cost of air capture would be comparable to the estimated cost of stabilizing atmospheric carbon dioxide at 450 ppm or 550 ppm given by Nick Stern in 2007 and by the IPCC in its last report. But if the costs of air capture decrease to $100 per ton of carbon, then it would prove much more cost-effective than stabilizing at 450 ppm or 550 ppm. We must therefore give air capture the same attention as other approaches to mitigation, argues Pielke, Jr.

Continue reading "Could we count on air capture?" »

Posted by Olive Heffernan on February 04, 2009
Categories: Economics, Journal Club, Mitigation, Olive Heffernan, Technology | Permalink | Comments (3) | TrackBacks (0)

Among the many technologies contending for a role in the future energy mix, thermoelectricity is one area where researchers have hoped that a big breakthrough in technology could reap equally large benefits in improving energy efficiency.

Up until this point thermoelectric technologies, which use materials to draw electricity from heat, haven’t been widely applied to electricity generation owing to their high cost and inefficiency. But changing the materials and their properties could — in theory at least — make a wide range of products more energy-efficient at a lower cost.

Last year the field made some important gains and seemed to be at a high point in terms of both the science and business potential. Early in the year, a MIT spin-off focused on energy efficient thermoelectric products won seed funding from venture capitalists Kleiner Perkins Caufield & Byers. Then in July researchers reported in Science [subscription] that adding trace amounts of thallium to lead telluride, a thermoelectric material used to produce electricity onboard deep space probes, could double its performance.

Continue reading "The truth about thermoelectrics " »

Posted by Olive Heffernan on January 26, 2009
Categories: Features, Journal Club, Olive Heffernan, Technology | Permalink | Comments (0) | TrackBacks (0)

The loss of ice from Greenland ranks as one of the most troubling, and poorly understood, aspects of climate change. Melting of the colossal ice sheet, which is already undoubtedly underway, has the capacity to raise global sea levels by an astounding 7 meters.

Not only is Greenland losing mass from direct surface melting, its outlet glaciers (those that terminate in the sea) are spewing large icebergs directly into the ocean at an increasingly alarming speed as they retreat. Many have worried that these changes are a sign of what’s in store. But a new study published this week in Nature Geoscience [subscription] suggests that the recent rapid retreat of many of Greenland’s outlet glaciers will be short-lived.

A team led by Andreas Vieli at Durham University, UK, used a computer model to reconstruct the recent behaviour of the Helheim Glacier, one of Greenland’s largest outlet glaciers. Helheim retreated some 7 kilometers between 2002 and 2005, during which time it discharged considerable volumes of ice into the ocean.

View image

Vieli’s team looked at whether the recent changes observed in the Helheim Glacier could be explained by one of two hypotheses; the first was that increased surface meltwater reaching the base of the glacier was speeding its slide toward the sea. The second potential explanation was that changing conditions in the area where the glacier meets the sea would trigger a domino effect on the glacier itself, leading to even faster ice flow and thinning upstream.

Their model showed that only the second hypothesis could explain past changes in the Helheim Glacier. Though they only analysed changes in this one outlet glacier, the authors say it is representative of many outlet glaciers south of 70°N that have recently thinned and rapidly released ice to the ocean.

Continue reading "Rapid retreat of Greenland's outlet glaciers may be temporary " »

Posted by Olive Heffernan on January 13, 2009
Categories: Cryosphere, Extreme Events, Journal Club, Olive Heffernan | Permalink | Comments (1) | TrackBacks (0)

The recent food crisis, which saw crop prices sky rocket in 2007/08, demonstrated the fragile nature of the world’s food system. Coping with the short-term challenges of food price volatility is daunting, but the longer-term challenge of avoiding a perpetual food crisis due to global warming could be far more serious.

Temperatures in crop growing seasons across the world will exceed the most extreme seasonal temperatures on record by the end of the century, new research suggests.

View image

Writing in the latest issue of Science, David Battisti at the University of Washington and Rosamond Naylor at Stanford University warn that unprecedented seasonal average temperatures will threaten global food security unless adaptations such as heat and draught tolerant crops, the creation of jobs outside of agriculture for those regions where farming will no longer be viable and appropriate irrigation systems are introduced.

In a new study, they use data from 23 global climate models produced for the Intergovernmental Panel on Climate Change’s 2007 scientific analysis to show that there is a 90% chance that the tropics, sub-tropics and temperate regions will experience unprecedented seasonal average temperatures by the end of the 21st century.

Their research looks at historical case studies of three regions – France, the Ukraine, and the Sahel in Africa – that have experienced extreme heat waves, to illustrate the size of the impact on food production. For example, France felt some of the greatest impacts of the 2003 heat wave in Western Europe, which saw temperatures rise to 32 -33°C in June to August - nearly 4°C higher than the country’s average historical temperature for those months. Over this period, production of maize fell by 30%, fruit harvests declined by 25% and wheat harvests dropped by 21%.

Continue reading "Adaptation needed to avoid world food crisis" »

Posted by Olive Heffernan on January 08, 2009
Categories: Adaptation, Features, Journal Club, Natasha Gilbert, Society | Permalink | Comments (2) | TrackBacks (0)

Scientists have reported the first direct evidence of a link between flooding underneath the Antarctic ice sheet and the rate at which glaciers are discharged into the sea. The study, which was published online on Nature Geoscience yesterday [subscription], has important implications for understanding how ice released into the ocean from the Greenland and Antarctic land masses could raise sea level.

Led by Leigh Stearns of the Climate Change Institute at the University of Maine, the trio of researchers found that ice on the Byrd Glacier in East Antarctica accelerated just as there was a massive release of water from lakes beneath the ice.

Over the past 20 years, researchers have discovered more than 150 lakes beneath the Antarctic ice pack, the largest of which (Lake Vostok) is equal in size to Lake Ontario in Canada.

And more than a year ago, researchers reported that these subglacial lakes could actually lubricate the flow of ice off the continent and into the ocean, as I reported over on Nature News at the time.

Continue reading "Under-ice floods speed glaciers towards the sea " »

Posted by Olive Heffernan on November 17, 2008
Categories: Climate Science, Cryosphere, Features, Journal Club, Olive Heffernan | Permalink | Comments (0) | TrackBacks (0)

More elderly readers of these pages may remember having heard in their school days back (circa 1970s) that scientists then thought an ice age would be coming soon. I certainly do – even though the alleged ‘global cooling consensus’ in the scientific literature of the time has recently been disproved as a myth.

Now an interesting new paper in Nature [subscription] suggests that a rapid natural transition towards a stable glacial climate, with permanent ice sheets covering large parts of North America and Eurasia, could indeed be ahead.

Thomas Crowley and William Hyde ran a coupled energy-balance/ice-sheet model to test their hypothesis. When forced with long-term variations in daily solar radiation which result from small cyclical changes in the Earth’s orbit, the best-fit model run (that is the one which most accurately reproduced ice sheet variations during the last 3 million years) predicted a rapid transition towards a cold climate regime to occur merely some 10,000 to 100,000 years from now.

Models and theory do indeed suggest that at critical points (namely when climate variability is at a maximum) large ice sheets can rapidly develop from very small perturbations in solar forcing.

Continue reading "Glaciation ahead - on a geological time scale " »

Posted by Olive Heffernan on November 12, 2008
Categories: Climate prediction, Climate variability, Features, Journal Club, Quirin Schiermeier | Permalink | Comments (1) | TrackBacks (0)

Cross posted from the Great Beyond

Let us get one thing clear right at the start: lemmings do not commit mass suicide by leaping off cliffs into the sea. However, their populations do undergo massive size fluctuations, leading to mass migrations where the cute critters may go swimming to find new food sources.

At least, they used to undergo massive population explosions. In a paper published this week in Nature a group of researchers analyse the absence of such events since 1994. The culprit, you guessed it, is climate change.

Nils Stenseth and colleagues show that changes in winter weather and snow go hand-in-hand with changes in Lemmus lemmus populations. They further show that when the regular explosion of lemming numbers doesn’t occur predators such as foxes switch their attention to other species, leading to knock-on effects throughout the eco-system.

“A relatively small effect on one particular species is having a broad effect on the system,” Stenseth, a researcher at the University of Oslo, told Reuters.

In a News and Views piece analysing the research, Tim Coulson and Aurelio Malo, of Imperial College London, explain that lemmings like to scurry about in a gap that warm ground melts between it and the snow layer above it. This so-called subnivean space is relatively warm and keeps the rodents safe from things that would like to eat them.

What Stenseth and colleagues found was that climate change seems to have eliminated the subnivean space and, worse, created a sheet of ice over the moss on which lemmings like to nibble.

“The critical reader will complain that the story is based on correlations. Although this is true, it is often the only way to study populations and the consequences of changing climate for ecosystems,” write Coulson and Malo. “The collection of detailed long-term data on the dynamics of free-living populations of animals and plants rarely attracts the same excitement as genomics or particle physics, yet such data are vital in characterizing the consequences of climate change for the natural world on which we depend.”

Continue reading "Climate change hits loveable lemmings" »

Posted by Olive Heffernan on November 06, 2008
Categories: Biodiversity and Ecology, Daniel Cressey, Features, Journal Club | Permalink | Comments (0) | TrackBacks (0)

I wrote here yesterday that ‘I don’t think that anyone knows for sure how close we are to reaching tipping points in the climate system’. As it so happens, a pair of articles published in Proceedings of the National Academy of Sciences this week illustrates this point nicely.

The first is a Perspective by atmospheric scientist V Ramanathan and postdoctoral researcher Yan Feng from the Scripps Institution of Oceanography at the University of California, San Diego, who argue that the Earth is now committed to a 2.4°C rise in temperature above pre-industrial levels.

Anything above a 2°C increase is generally considered to be ‘dangerous’ climate change and would likely trigger several of the Earth’s tipping points, such as the complete loss of Arctic summer sea ice and melting of the Greenland ice sheet. And according to the IPCC, a rise in global temperature by 1-3°C will commit the planet to widespread loss of biodiversity, widespread deglaciation of the Greenland Ice Sheet, and a major reduction of area and volume of Hindu-Kush-Himalaya-Tibetan glaciers, which provide the head-waters for most major river systems of Asia.

The authors argue that for atmospheric greenhouse gas concentrations to remain constant at 2005 levels for the rest of the century, aggressive emissions reductions would be required – yet emissions are rising.

Currently, the warming effect of greenhouse gases in the atmosphere is being masked by the cooling effect of other air pollutants – such as smoke from cooking and agricultural waste burning – that create a dimming effect at the Earth’s surface.

Assuming policies to reduce these air pollutants are successful, the full warming potential of greenhouse gases will soon be realized. So as air pollution measures become effective (and much headway is being made here), the need for reducing carbon dioxide emissions becomes even more urgent, say Ramanathan and Feng.

Continue reading "Could tipping happen any time soon? " »

Posted by Olive Heffernan on September 26, 2008
Categories: Climate Policy, Climate Science, Features, GHG emissions, Journal Club, Mitigation, Olive Heffernan | Permalink | Comments (3) | TrackBacks (0)

As residents of New Orleans prepare to return home and breathe a sigh of relief that Hurricane Gustav was less damaging than feared, new research published today in Nature [subscription] suggests that the strongest tropical cyclones will pick up speed in the coming decades.

Weighing in on the long-running and at times very stormy debate over whether and how warmer seas will affect the intensity and frequency of hurricanes is a team led by climatologist James Elsner of Florida State University.

Using a 25-year archive of satellite data, Elsner and colleagues derive wind speeds for tropical cyclones over the globe. They find that the maximum wind speeds reached by the strongest tropical cyclones increased from 1981-2006 in most ocean basins, with the greatest changes in the North Atlantic and Northern Indian Oceans.

There was no trend in the intensity of cyclones occuring over the South Pacific, however, and the upward trend observed over a couple of ocean regions was not statistically significant. The researchers also found no increase in either the frequency or average intensity of tropical cyclones over the globe.

The approach taken by Elsner and colleagues – looking at whether the most severe cyclones will hit a higher speed limit during their lifetime – is both novel and socially relevant, simply because the most severe storms do the most damage if they make landfall. Once tropical cyclones reach speeds of over 74mph, they are officially classified as hurricanes.

The real bone of contention within the scientific community has been whether hurricanes will become more intense and more frequent as a result of human-induced climate change. Elsner and colleagues steer well clear of linking the trend to global warming though - they can’t attribute cause as their study doesn’t investigate other factors such as cyclone origin and duration, proximity to land, El Niño conditions and solar activity.

Continue reading "As Gustav subsides, new study says strongest cyclones will pick up speed" »

Posted by Olive Heffernan on September 03, 2008
Categories: Atmospheric Science, Extreme Events, Features, In the News, Journal Club, Ocean science, Olive Heffernan, Society | Permalink | Comments (1) | TrackBacks (0)

A new study, published online Sunday by Nature Geoscience, presents solid evidence that temperatures in the Earth's lower atmosphere are increasing in line with temperature changes on the ground.

This issue has been hotly disputed in the past, partly owing to the fact that temperatures measured in the troposhere - the portion of the atmopshere stretching from 12 to 16 kilometeres above the Earth's surface - by satellites and weather balloons in the early 1990s didn't mirror the changes on the ground.

This fact was used as evidence against climate change, despite the fact that it has been long known that there were problems with the original data collection and analysis.

In the search for more accurate measurements, two scientients Robert Allen and Steven Sherwood of Yale University, have now developed a novel approach using wind rather than temperature data. Their research shows that the lower atmosphere has indeed warmed since 1970, as projected by most climate models, and in sync with warming on the ground measured using temperature data.

In a related News and Views article, aslo on Nature Geoscience, Peter Thorn of the UK Met Office Hadley Centre, one of the world's premier climate modelling facilities, writes:

This is not simply an interesting academic aside — not knowing where observational problems begin and modelling limitations end undermines our ability to understand and predict global climate change.

For further reading on the topic, check out the post over on Real Climate last week discussing the same issue, and highlighting some upcoming papers in the Journal of Climate.

Olive Heffernan

Posted by Olive Heffernan on May 27, 2008
Categories: Atmospheric Science, Climate Science, Climate prediction, Features, Journal Club, Olive Heffernan | Permalink | Comments (1) | TrackBacks (0)

Hurricanes may become rarer in the Atlantic throughout the 21st century if the world continues to warm, suggests a new study. The research is the latest to address the question of how – and whether - global warming will affect the intensity and frequency of hurricanes.

Globally, the number of major hurricanes has shot up by 75% since 1970. And although rising ocean temperatures are generally accepted as the key culprit – hurricanes can only form where sea surface temperatures exceed 26ºC - the link to global warming has remained a contentious issue.

In the new study, published online yesterday in Nature Geoscience [subscription], Thomas Knutson of the US National Oceanic and Atmospheric Administration and colleagues showed, using a regional climate model of the Atlantic basin, that the trend in increased hurricane activity in the Atlantic over the past 25 years will not continue into the future, though hurricanes in the area may become more intense and associated with heavier rainfall.

Though they use a different model, the results generally concur with the recent paper by hurricane specialist Kerry Emanuel, which shows that hurricanes are likely to decrease in frequency but increase in intensity in certain locations as temperatures rise.

I’ve written the full story here for Nature News.

Olive Heffernan

Image: NASA / Univ. Wisconsin-Madison

Posted by Olive Heffernan on May 19, 2008
Categories: Climate Science, Extreme Events, Features, Hurricanes, In the News, Journal Club, Olive Heffernan | Permalink | Comments (2) | TrackBacks (0)

Nearly 30,000 phenomena in the natural world - from the timing of plant flowering to the rate of ice melting - are being influenced by human-induced global warming, according to the first study to formally link trends in biological and physical systems to rising greenhouse gas emissions.

Led by Cynthia Rosenzweig of NASA's Goddard Institute for Space Studies in New York, the analysis, published in this week's Nature, brings together data from numerous different studies stretching back to 1970 to gain a big picture view of how climate change is impacting the planet.

Although the latest report from the Intergovernmental Panel on Climate Change (IPCC) concluded that human-induced climate warming is "likely" to have had a discernible effect on physical and biological systems, attributing such changes in natural systems to specific causes in notoriously difficult, as highlighted in the related News and Views article by Francis Zweirs and Gabriele Hegerl, both IPCC panelists.

Rosenzweig and collaborators made this link first by mapping changes in global average suface temperature between 1970 and 2004. They then looked at whether changes in natural phenomena in each region were consistent with warming or inconsistent with warming e.g. earlier blooming of flowers would be expected in a warmer climate.

In more than 90% of cases where there was a trend, it was consistent with the predicted effects of a warming world. As Emma Marris points out in an online news story, the bulk of the data come from Europe and several hundred more come from elsewhere in the world, but Africa, Australia and Latin America are poorly represented.

Olive Heffernan

Image credit: David Inouye

Posted by Olive Heffernan on May 15, 2008
Categories: Attribution, Biodiversity and Ecology, Climate Science, Features, In the News, Journal Club, Olive Heffernan | Permalink | Comments (1) | TrackBacks (0)

The Earth’s greenhouse history of the last 800,000 years is an open book now, thanks to years of detective work by two large international teams of climate scientists.

Nature has two papers this week, here and here, about the levels of atmospheric concentration of the two main greenhouse gases – carbon dioxide and methane – as derived from air entrapped in the EPICA Dome C ice core from Antarctica. Here is an editor's summary.

The first and foremost results: The present day concentration of both gases is higher than has ever been the case in the past 800,000 years. Also, the ups and downs in carbon dioxide and methane curves follows the succession of cold glacial climates and relatively warm periods (such as ours) in between. An 800,000 year temperature record had been reconstructed previously from Antarctic ice cores.

Together, the results provide powerful evidence for a strong link between greenhouse gases and climate. During most of the Earth’s history greenhouse gas concentrations have fluctuated in the absence of humans burning coal and other fossil fuels. But the unprecedented rise of greenhouse gases in the modern atmosphere, to concentrations which threaten to unhinge vital components of the Earth’s climate system, is clearly the result of human activity.

In the past, greenhouse gas concentrations have varied owing to subtle feedbacks between orbital changes and oceanic and terrestrial carbon cylcles. Carbon dioxide concentrations depend on oceanic uptake, whereas methane is linked with the size and distribution of wetlands releasing the gas.

Like all good science, the new data will raise many new questions. One is why the amplitude of the 100,000-year oscillation in methane and carbon dioxide concentrations (which correlates with the 100,000 year temperature cycle) has changes so markedly around 450,000 years ago. Warm periods in the more recent history of the Earth seem to have been warmer than the interglacials prior to 450,000 years ago. Carbon dioxide and methane concentrations mirror this trend, which might hint to the existence of a longer-term cycle not visible in the existing record.

Another question is how greenhouse gas concentrations measured in Antarctic ice cores relate to episodes of rapid warming and cooling in Greenland and the northern hemisphere. It seems that more that 70 such temperature jumps, perhaps as a result of changes in ocean circulation, have occured over the last 800,000 years.

“These new benchmark data for greenhouse-gas variability pose questions as to what a much longer record might show,” writes Ed Brook in a news and views article. The search for the best drilling site which could produce such a record is beginning.

Quirin Schiermeier

Posted by Quirin Schiermeier on May 15, 2008
Categories: Climate Science, Climate variability, Features, Journal Club, Palaeoclimate, Quirin Schiermeier | Permalink | Comments (0) | TrackBacks (0)

While most Londoners spent last week maximising their time spent basking in the glorious sunshine that so rarely comes our way, I spent it largely indoors - at a place that predicts these sorts of unusual occurrences, otherwise known as the European Centre for Medium Range Weather Forecasts (ECMWF) in Reading.

The World Modelling Summit for Climate Prediction held there last week was itself something of a rare event – a union of the weather and climate communities, who met to discuss whether – and how – they can eventually provide climate predictions that are as useful, and as useable, as weather forecasts.

The four-day summit culminated in a call for a massive investment, around a billion dollars, to fund a new global research facility or facilities with computer and research resources that would ‘revolutionize’ climate modelling capabilities, bringing into view the holy grail of ‘seamless’ weather-to-climate prediction.

We’ve covered the summit in some detail in this week’s Nature [subscription], in my news story and an editorial by Oliver Morton.

In short, the idea is that an injection of cash on this scale could bring about a quantum leap in climate simulations by funding climate computers far beyond those in use today. Currently, computers used for modelling the climate are in the 10-teraflop range, which means that they operate at inconceivably high speeds and run models that divide the globe into 100 kilometre cells to roughly project how global climate is likely to change in the long-term.

Though these models have had a key role in warning us of the gradual warming of our planet, they’ve fared pretty poorly when it comes to gauging the likelihood of extreme localised events, such as flooding or more frequent hurricanes. But scientists at the conference said that if they had access to supercomputers – with speeds in the range of hundreds of petaflops (basically 10,000 times more processing power) - they could resolve climate globally on the scale of kilometres, potentially creating models good enough to inform nations of the specific regional challenges they can expect in adapting to climate change.

Continue reading "A revolution - for climate model evolution " »

Posted by Olive Heffernan on May 14, 2008
Categories: Climate Science, Climate prediction, Features, In the News, Journal Club, Olive Heffernan, Technology | Permalink | Comments (0) | TrackBacks (0)

It’s been quite a while since the Gulf Stream was last on the Nature cover. This week the old highlight is back.

Now that’s a topic which has caused an awful lot of confusion before. “How global warming will cause the next ice age”, stuff like that. So just to be clear: the Gulf Stream is the mostly wind-driven upper limb of the Atlantic meridional overturning circulation, which ceaselessly transports warm surface water from the Caribbean to middle and high latitudes on the other side of the Atlantic. Yes, ceaselessly. As long as the Earth keeps rotating there’s really nothing in the world (not even global warming) that could bring it to a halt.

It is common knowledge - and true - that the British Isles and Scandinavia enjoy a much warmer climate than Newfoundland or Labrador thanks to the Gulf Stream. But its climatic influence goes far beyond that, a US-Japanese team report in a paper in Nature this week.

They detected the Gulf Stream’s signature in the entire lower atmosphere - namely in air and cloud temperatures, rain bands, pressure fields and wind convergence - above its meandering cross-Atlantic course, and far inland in Europe.

That the influence of the Gulf Stream might penetrate deeply into the atmosphere has been previously assumed. Firm evidence that this is indeed the case, and vehemently so, comes from the combination of satellite observations, operational weather analysis and atmospheric circulation models which the team utilised for their study.

Very likely the Gulf Stream’s direct local effects on the atmosphere are tele-connected, via planetary atmospheric waves, with weather conditions in far-away regions. How frequent and pronounced these remote responses might be is not at all clear. But it seems at least as if Gulf Stream-driven atmospheric dynamics over the North Atlantic have a marked influence on hemisphere-wide climatology.

This, you’ve guessed it, adds another piece to the climate change puzzle. Come what may, the Gulf Stream will not ‘run dry’. But its strength does vary, and a possible weakening of the Atlantic overturning circulation, to which it belongs, is unlikely to leave the Gulf Stream unaffected.

A new ice age will not come over Europe because of that, but storm tracks and rainfall patterns could be affected in rather unpredictable ways.

Quirin Schiermeier

You can vote or comment on the importance of the new Gulf Stream paper in the Journal Club of Nature Reports Climate Change.

Posted by Olive Heffernan on March 12, 2008
Categories: Extreme Events, Features, Journal Club, Ocean science, Quirin Schiermeier | Permalink | Comments (5) | TrackBacks (0)