Climate Feedback

The predicted effects of climate change can be counted on to shake up international relations, even far from the impoverished, politically wobbly regions where the most obvious conflicts loom. A case in point is the tranquil Arctic seabed, believed to hold a substantial fraction* of the world's undeveloped oil reserves - which, as the summer sea ice extent decreases year by year, is suddenly set to become accessible for extraction.

As such, the Arctic Ocean is a new source of friction among the five countries that claim portions of it as their sovereign territory: the US, Canada, Norway, Denmark, and Russia, the latter of which elicited clucking from some of the others in August when it sent a submersible to the sea bottom and planted a titanium national flag at the underwater North Pole. And more than the pole is up for grabs. In a great piece on the politics of Arctic climate change in Vanity Fair, Alex Shoumatoff writes:

Last summer, Canada’s Northwest Passage was nearly free of ice and completely navigable for a few weeks—for the first time since records have been kept. This fabled route to the Orient, which eluded Henry Hudson, Sir Francis Drake, and Martin Frobisher, and was finally navigated by the Norwegian Roald Amundsen in 1905, would reshape global trade, being thousands of miles shorter than most currently used shipping routes, though it won’t be clear long enough to be commercially viable for at least another 15 to 20 years. Canada has claimed the passage as its internal waterway since the early 1970s, but the U.S. maintains that it is an international strait, through which any vessel, including submerged submarines gathering intelligence, has the right of “transit passage.”

On Wednesday, the five Arctic-bordering nations met in the tiny town of Ilulissat, Greenland, with the intention of staving off inconvenient squabbles over the newly unfrozen oil and gas sources. The high-level delegates sent to handle the promise of a new oil rush agreed to proceed in an orderly fashion and allow the UN to decide who owns what (Reuters, New York Times, FT).

When the UN rules on territorial rights, it will be ruling on geoscience. At issue is how far the continental shelf under each nation extends into the ocean - the criterion for sovereignty under the 1982 UN Law of the Sea Convention (still not ratified by the US Senate, which will apparently have to overcome past reluctance in order to achieve the country's Arctic aims). Wednesday's declaration gives the claimants time to gather scientific evidence to present to a commission on continental shelves.

The agreement also avoids aiming for a treaty like the one concocted to settle wrangling over Antarctica in the 1950s. A 1991 addition to the Antarctic treaty forbids exploitation of mineral resources until 2048, which may be why the delegates in Ilulissat hastened to hand their disagreements over to the UN and emphasize that no special laws would be necessary up north. Environmental groups, excluded from the meeting, would naturally prefer a treaty that could offer strong protection for Arctic ecosystems already stressed by warming.

Anna Barnett

Photo: North Pole sign set up by the crew and scientists of the German research vessel Polarstern; Hannes Grobe

*Often said to be 25% - erroneously, according to Shoumatoff.

Posted by Anna Barnett on May 30, 2008
Categories: Anna Barnett, Cryosphere, Energy, In the News, Politics | Permalink | Comments (3) | TrackBacks (0)

Cutting global greenhouse emissions by half of 1990 levels by 2050 will not be sufficient to prevent major damage from climate change, say scientists in a Commentary published today on Nature Reports Climate Change.

Earlier this week, environment ministers from the world’s leading industrialised countries, the Group of Eight, called for a deal to slash global greenhouse gas emissions by 50% by mid-century.

This would still commit the world to substantial harm, even if it is “widely considered to be the most stringent politically achievable target”, says Martin Parry, who co-chaired the impacts assessment group for the Intergovernmental Panel of Climate Change, and others.

By analysing the regional and global impacts that would occur by 2050 and 2100 for various greenhouse gas emissions targets, Parry and co-authors argue that compared with 50 per cent cuts, slashing emissions by 80% below 1990 levels by mid-century would substantially reduce the damage caused; for example, halving the number at risk of water stress and flooding.

They call on world leaders at the forthcoming UN climate change talks in Bonn in June and July's G8 summit in Hokkadio, Japan to boldly declare their commitment to dramatically reducing greenhouse gases.

The current global food crisis should serve as a ‘wake-up call’ to G8 and UN leaders, they say, who suffer from “false optimism’ that “we can find a way to fully avoid all the serious threats of climate change”.

They caution, however, than even with 80% cuts, damages will still be large, which is why world leaders must also step up their commitment on funding adaptation. Current efforts are vastly below par, with a mere US$67 million donated to date of the estimated tens of billions needed for developing-world adaptation alone.

At the same time as world leaders are being urged to consider stricter targets for 2050, others are urging them to seriously consider shorter term targets – for 2020 – a goal believed to be important if emissions are to peak within the next 10 to 20 years.

Olive Heffernan

Posted by Olive Heffernan on May 29, 2008
Categories: Climate Policy, Features, In the News, Mitigation, Olive Heffernan | Permalink | Comments (0) | TrackBacks (0)

The 20th century warming trend is not a linear affair. The iconic climate curve, a combination of observed land and ocean temperatures, has quite a few ups and downs, most of which climate scientists can easily associate with natural phenomena such as large volcanic eruptions or El Nino events.

But one such peak has confused them a hell of a lot. The sharp drop in 1945 by around 0.3 °C - no less than 40% of the century-long upward trend in global mean temperature - seemed inexplicable There was no major eruption at the time, nor is anything known of a massive El Nino that could have caused the abrupt drop in sea surface temperatures. The nuclear explosions over Hiroshima and Nagasaki are estimated to have had little effect on global mean temperature. Besides, the drop is only apparent in ocean data, but not in land measurements.

Now scientists have found – not without relief - that they have been fooled by a mirage.

The mysterious post-war ocean cooling is a glitch, a US-British team reports in a paper in this week’s Nature. What most climate researchers were convinced was real is in fact “the result of uncorrected instrumental biases in the sea surface temperature record,” they write. Here is an editor’s summary.

Continue reading "Post-World War II cooling a mirage" »

Posted by Quirin Schiermeier on May 29, 2008
Categories: Climate Science, Climate variability, Quirin Schiermeier | Permalink | Comments (7) | TrackBacks (2)

The British Antarctic Survey and the UK's Met Office have released a pair of new layers for Google Earth that depict the effects of climate change across a 3D map of the globe. In one fell swoop, this about doubles the amount of climate content that's easily accessible from the Google Earth Gallery and Showcase pages.

To check out the maps, download and install Google Earth, then click here to download and open the map file (in KML format) from BAS and here for the Met Office map. (If Google Earth doesn't run when you click those links, you'll have to run it yourself and open the KML files from the File menu.) They will load into the 'Places' bar on the left - checking boxes there displays the content.

Both maps make good use of the program's time-series tool: as you watch an animation or drag a slider, BAS shows Antarctic ice shelves receding over recent decades, and then the Met Office steps in with a color-coded overlay of expected future warming under a medium-emissions scenario. There are also 'push-pins' in both layers that, when clicked, pop up photos, videos and text on climate impacts around the world.

Hours of fascinated clicking may or may not ensue, but the animated 3D globe definitely works well for representing the big scope of global warming in space and time - at least to those interested laypeople who can jockey the occasionally perverse controls. (Word to newcomers: skip the play button in the left-hand panel, which just flies you around helplessly. To start the time series, you want the one that appears at the top of the screen after you click the left-hand checkbox 'Vanishing Ice Sheets' or 'Temperature Animation'. Note also that you must reach the 21st century before the Met Office push-pins will appear.)

What's missing from this particular Google Worldview is much sense of the rich complexity of climate data and the science that produces it. Outside the climate world, ecologists studying bristlecone pines at the University of California have posted a terrific KML file demonstrating how they use the program to collectively record their fieldwork. They include a tree-by-tree data set of coordinates and photos alongside notes such as "not a good site - dead cow here".

Are there any climate science or geoscience labs making maps that cool - and would they consider going public?

Anna Barnett

Posted by Anna Barnett on May 28, 2008
Categories: Anna Barnett, Communicating Climate Change | Permalink | Comments (0) | 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)

With much of the corporate world competing to be ahead of the decarbonization curve, it's not uncommon to see investors actually begging governments for more regulations, as a prominent group in the US did this week. More remarkable is witnessing oil goliath Exxon Mobil torn by a climate-driven shareholder revolt and its backlash.

On fossil fuels and climate change, Exxon in the past has not so much failed to read the writing on the wall as actively attempted to efface it. That's changed, but not enough, say the heirs of John D. 'Standard Oil' Rockefeller, whose ancestral ex-monopoly forms Exxon's core. The Rockefellers are sponsoring four shareholder resolutions that will come to a vote at the company's annual shareholder meeting May 28. According to The Independent, they say Exxon needs to research how climate change will affect the developing world, fund alternative fuels, reduce its carbon footprint, and spur more managerial debate by splitting up the roles of chariman and CEO - both posts are currently held by Rex Tillerson. At last year's meeting, says The Guardian, a call to split up Tillerson's jobs got 40% yays, and addressing climate change got 30%. With a vast green tide and 19 institutional investors backing up the Rockefellers (who own only 0.006% of Exxon's stock, the company says), this year could see even greater support.

But the Wall Street Journal - ever the champion of the little guy - noted in an editorial yesterday (subscription required) that blue-collar investors have struck back. According to the Journal, US police union leader Chuck Canterbury wrote to Tillerson that the resolutions

would impose "rigid, ideologically-based conditions on the company's future," would nullify "the judgment of a highly successful management team," and would "undercut every project and business operation." This would "hamstring ExxonMobil's profitability and growth, thus directly harming the police officers, firefighters, teachers and public employees whose retirement savings are invested in the company."

Continue reading "Oil heirs mutiny at Exxon" »

Posted by Anna Barnett on May 23, 2008
Categories: Anna Barnett, Business, Energy, In the News | Permalink | Comments (0) | TrackBacks (0)

Isotope chemistry is a bit of an arcane world for the non-initiated. But variants of elements that differ only in the number of neutrons in their nuclei are common tools of the trade of archaeologists, geologists and climate researchers.

In the past 50 years, a much-improved chronology of past climatic events has evolved through analyses of the oxygen isotope record of marine shells and minerals in deep-sea and lake sediments. But information about the Earth’s deep geological past, in particular concerning the chemical composition of the atmosphere, is still hard to get by.

The debut of a new stable mineral-isotope proxy for ancient atmospheric condition is therefore a remarkable event, the editors of a paper in this week’s Nature note in their summary.

When analysing the triple oxygen isotope composition of ancient sulphate deposits, a team of geophysicists led by Huiming Bao of Louisiana State University found that they exhibit variable negative oxygen-17 anomalies over the past 750 million years. They propose that these small anomalies, first noticed a few years ago in a study unrelated to atmospheric chemistry, reflect those of atmospheric oxygen and carbon dioxide in the past.

The new proxy is hardly sensitive enough to record the relatively subtle variations in atmospheric oxygen and carbon dioxide content during the Pleistocene, the Earth’s recent period of repeated glaciations.

It could be useful, though, when evaluating extreme climates much earlier in our planet’s history. For example, oxygen-17 anomalies in barite sulphates display a negative spike – hinting at an extremely high level of atmospheric carbon dioxide - around 635 million years ago, when the Earth was likely recovering from a period of global glaciation in the Early Cambrian. This finding supports the not undisputed ‘snowball’ Earth hypothesis and/or massive methane release in the aftermath of Neoproterozoic glaciation

Quirin Schiermeier

Posted by Quirin Schiermeier on May 22, 2008
Categories: Atmospheric Science, Climate Science, Palaeoclimate, Quirin Schiermeier | Permalink | Comments (0) | 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)

In debates over how to mitigate the effects of climate change, is the burgeoning human population an elephant in the room? A projected 9 billion people will have to share a warming planet by 2050, yet as Kerri Smith writes in Nature Reports Climate Change this week, the climatic effects of their rising numbers and shifting demographics has received surprisingly little study.

Population is a touchy subject, bringing to mind oppressive campaigns against growth - like China's one-child system, or forced sterilization programs - as well as false past predictions of an imminent catastrophe. But it’s becoming clear that the problem is more complex than a ticking ‘population bomb’. Numbers are exploding in the world’s poorest societies - a trend that CIA chief Michael V. Hayden recently chose above climate or energy issues as one of the key changes facing the 21st century. Because of the low emissions per head in these societies, Smith explains,

Reducing population growth in Niger, for example, where the population size is predicted to triple by mid-century, would not have a dramatic effect on emissions right now. And in many countries in Europe — where reducing emissions levels is more pressing — populations are declining, so a demography-based climate strategy would be ineffective. In a generation's time, however, when developing countries begin industrializing apace, a large population could be bad news.

An aging industrialized world could wrinkle the picture further, as could increasing urbanization. Meanwhile, Hayden fears that the population patterns themselves will precipitate political instability - which climate change is expected to exacerbate.

The solutions to this complex problem could be subtle, or at least subtler than enforcing a small average family size. Fred Meyerson, an ecologist, demographer and environmental policy researcher, told Smith that simply improving access to family planning in the last 50 years has very effectively reduced population growth, and the UN Population Division's Thomas Buettner pointed out the knock-on effect that this has had on greenhouse gas emissions. (A new book by the WorldWatch Institute’s Robert Engelman puts a finer point on it, arguing that in countries where empowerment of women gives them say over the matter, they invariably choose to have two children or fewer on average.)

And this month's headlines show how far-reaching the links are between slowing population growth and preventing climate-induced crises, Meyerson added in an email:

Each million/billion [people] we add puts more people in the path of natural disasters such as the recent Asian cyclone and drought/starvation, some of which are climate change-induced. Adaptation to those changing conditions (including migration, if needed) is obviously much more manageable with 8 rather 11 billion people. And emissions mitigation - for instance, a move from fossil fuels to biofuels - is also much more problematic if the lion's share of the solar energy budget of the terrestrial surface is needed to meet the food needs of a large population and not available for energy production. (That debate is already ongoing with the spike of food prices and the use of corn for ethanol production, but it will surely increase as we add ~75 million people each year to the population over the next few decades.)

Anna Barnett

Photo: Lusi, SXC

Posted by Anna Barnett on May 16, 2008
Categories: Adaptation, Anna Barnett, Climate Policy, In the News, Society | Permalink | Comments (1) | 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)

Money talks, and so do bloggers. Unable to resist the correlation, a number of climate scientists and analysts have adapted their online podiums into betting tables. The RealClimate team are the latest to roll up to the climate casino, staking €5,000 against the predictions of a recent Nature paper (subscription required) that in the next decade, falling temperatures in some regions will cause a slight slowdown in global warming.

The paper's authors, Keenlyside et al., have yet to accept or reject the bet, and it's not available to any other cooling proponent who may be feeling lucky. But if your opinion on global warming is burning a hole in your pocket, you have some options. Brian Schmidt's Backseat Driving, for example, lists several standing offers to all takers.

Those like Schmidt who back the scientific consensus that the Earth is warming, however, have had a hard time convincing anyone to gamble large sums on cooling. A few bookmaker's highlights:

Continue reading "RealClimate roll up to the climate casino" »

Posted by Anna Barnett on May 09, 2008
Categories: Anna Barnett, Climate prediction | Permalink | Comments (9) | TrackBacks (0)

One of the more irritating aspects, if you will, of global change is that air pollution has so far prevented the planet from warming more rapidly than it actually did. Clean air is of course a good thing. But reducing pollution might expose an as of yet ‘masked’ portion of global warming.

This could have a dramatic affect on the Amazon rainforest. A team led by Peter Cox of the University of Exeter, UK, reports in a paper in this week’s Nature that reductions in aerosol pollution will tremendously increase the risk of severe drought in the Amazon region. Here is an editor’s summary of the paper.

Although it accounts for nearly a quarter of the world's fresh water, drought is not unknown in Amazonia.

In the dry season, from July to October, rainfall in the region is linked to sea surface temperatures (SST) in the tropical Atlantic. In years with a pronounced temperature gradient - warming of the tropical Atlantic north of the equator relative to the south – the normal’ position of high and low atmospheric pressure systems can shift, delaying or suppressing the onset of the South American monsoon.

The effect has been observed in 2005, when large parts of the Amazon region were hit by the worst drought in decades. See a Nature news story by Mike Hopkin here (subscription required) and a New York Times story here about the devastating event.

Cox thinks that the 2005 drought was a harbinger of things to come. Their “simulations for the 21st century show a strong tendency for the SST conditions associated with the 2005 drought to become much more common, owing to continuing reductions in reflective aerosol pollution in the Northern Hemisphere.”

Droughts like in 2005 will happen every two years by 2025, and in nine out of ten years by 2060, the model suggests.

How robust is this dire prediction? The Amazonian climate, for reasons not quite understood, is notoriously difficult to simulate. But the Hadley Centre’s climate model which was used for this study has previously reproduced features of the regional climate with greater accuracy than other models.

In Mike Hopkin's words, “the ultimate fear is that the Amazon forest - often touted as an invaluable piece of armour against climate change - could become part of the problem rather than a key element of the solution. Droughts make it more likely that it will become a net source of greenhouse gases to the atmosphere, rather than mopping them up.”

Quirin Schiermeier

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

Posted by Quirin Schiermeier on May 08, 2008
Categories: Biosphere feedbacks, Climate Science, Climate prediction, Extreme Events, Quirin Schiermeier, Topics | Permalink | Comments (5) | TrackBacks (0)

A paper in this week’s Nature predicts that, rather than warming, North Atlantic sea surface temperatures may actually decrease slightly in the next decade. What’s more, the paper suggests global surface temperatures may not actually increase either.

Has global warming stopped? Is this a nail in Al Gore’s coffin?

Well, no.

Despite headlines such as ‘Doubt is cast over global warming’ and ‘Global warming could stop NATURALLY for ten years, say scientists’ that is not what this paper is about.

What this new paper by Noel Keenlyside, of the Leibniz Institute of Marine Sciences in Germany, sets out to do is incorporate data on short term variations in climate into our models of climate change. By doing this they push us into the arena of creating shorter term predictions, in this case of the next decade.

In a “News and Views” commentary on the piece in the same issue of Nature Richard Wood explains:

Keenlyside and colleagues’ model uses a very simple ocean initialization method in which they add heat to or remove it from the ocean surface until sea surface temperatures across the globe are close to observed values. They use their model to produce a set of retrospective ‘forecasts’ starting from earlier states, which they test against what actually happened. Their system produces refined temperature predictions a decade ahead for large parts of Europe and North America.

Whether their prediction of a plateau for warming for a decade in North America and Europe is correct or not, their research may signal a shift that many climate researchers have been calling for for awhile now — toward service-oriented climate science ...

I am sure that this is an excellent paper by world class scientists. But when I look at the broader significance of the paper what I see is that there is in fact nothing that can be observed in the climate system that would be inconsistent with climate model predictions. If global cooling over the next few decades is consistent with model predictions, then so too is pretty much anything and everything under the sun.

Cross posted by Daniel Cressey on The Great Beyond

Posted by Olive Heffernan on May 01, 2008
Categories: Climate Science, Climate prediction, Climate variability, Daniel Cressey, In the News | Permalink | Comments (8) | TrackBacks (0)