Climate Feedback

Ozone never ceases to surprise. Scientists report in this issue of Nature that halogen compounds such as bromide and iodine oxide play an unexpectedly large role in chemically breaking down the gas in the troposphere.

Ozone is best known for its presence – or in fact for its seasonal absence - in the upper atmosphere. The stratospheric ozone layer, which protects the earth from harmful ultraviolet radiation, is still being chemically attacked by reactions involving long-lived chlorofluorocarbons (CFCs) banned 20 years ago. But Nature reported last year about a puzzling inconsistency discovered in the established chemical model of stratospheric ozone destruction.

The troposphere is a very different story, though. Near the ground, ozone can affect human health; in high concentrations it is even toxic. Above the ground layer it acts as a greenhouse gas which, when it chemically breaks up, initiates the removal of methane (an even stronger greenhouse gas) and other hydrocarbons from the atmosphere. So ozone loss in the troposphere is a good thing, really.

The gas is typically destroyed in marine regions by chemical reactions involving water vapour. Tropical oceans regions, where levels of solar radiation are high, are thought to be the most important ozone sink.

So what about halogens? Anthropogenically produced CFCs are stable in the troposphere, and are therefore not a reactive halogen source there. But models studies have suggested that bromine and iodine chemistry does contribute to breaking down ozone in the troposphere, potentially changing the global ozone budget by up to 20 %.

The measurements which Katie Read of the University of York and her team have made in the tropical Atlantic Ocean now provide strong confirmation of substantial ‘halogen-mediated’ ozone destruction. An editor's summary and the paper are here.

The team analysed the first eight months of measurements from the new Cape Verde Atmospheric Observatory on the remote island of São Vicente in the tropical Atlantic. They found that average daily ozone loss was around 50 % more than predicted by a state-of-the-art chemistry model that excludes halogen chemistry. Aircraft-borne observations in the area confirmed these findings.

But the team also measured ubiquitous daytime concentrations of iodine and bromine oxides in the layer of the troposphere where most ozone loss occurs. These reactive molecules are emitted by marine algae and liberated from salty sea spray.

In a simple model calculation, the observed halogen concentrations induced just about the extra 50 % ozone loss in the region. The omission of halogen sources in atmospheric models “may lead to significant errors in calculations of global ozone budgets,” the authors write.

What’s special about this study, says Roland von Glasow in an accompanying news and views article here (subscription required), is that the measurements were made in the open ocean where they cannot be influenced by local features that produce halogens.

But even so, the results are significant. Ozone is a powerful oxidizing agent and a key constituent of the troposphere; changes in its concentration will feedback on the lifetime of methane and other hydrocarbons in the air.

It is good to know that tropical ocean regions are a larger-than-thought ozone sink. But the composition of the atmosphere is in such fine balance that its cleansing ability cannot be taken for granted as being permanent. In the face of the new measurements it seems essential to include halogen sources and chemistry in global climate models.

The measurements are likely more representative of the troposphere above the global ocean than previous studies near coastlines. But as Cape Verde is surrounded by biologically highly productive waters one must still be cautious when extrapolating the results, says von Glasow.

Note: RealClimate has an interesting discussion on how the media have spun the story.

Quirin Schiermeier

Picture caption: Model of an ozone molecule. Image created by Ben Mills.

Posted by Quirin Schiermeier on June 26, 2008
Categories: Atmospheric Science, Quirin Schiermeier | Permalink | Comments (0) | TrackBacks (0)

Twenty years ago yesterday, Dr. James Hansen gave a landmark testimony to US Congress in which he told senators that global warming was real, it was happening, and humanity was to blame.

Yesterday, he appeared before Congress, where he told most of official Washington we are now at the point of a “planetary emergency”.

For the low-down of yesterday's speech, and links to the best media coverage, check out Alex Witze's post over on The Great Beyond.

Olive Heffernan

Posted by Olive Heffernan on June 24, 2008
Categories: Communicating Climate Change, Features, In the News, Olive Heffernan | Permalink | Comments (2) | TrackBacks (0)

“People are broadly concerned, but not entirely convinced”, concludes the latest poll on public opinion of global warming by social marketing group Ipsos Mori.

Despite the deluge of media reports in the last year documenting the scientific consensus on climate change and the startling rapidity at which impacts are being seen around the world - most notably perhaps the ever-decreasing Arctic sea ice - 60% of the British Public is uncertain that climate change is caused by humans, and many others believe that scientists are overstating the problem.

Writing in Sunday’s Observer, Juliette Jowit provides the following explanation:

There is growing concern that an economic depression and rising fuel and food prices are denting public interest in environmental issues. Some environmentalists blame the public's doubts on last year's Channel 4 documentary The Great Global Warming Swindle, and on recent books, including one by Lord Lawson, the former Chancellor, that question the consensus on climate change.

While it’s reassuring to know that the public questions the status quo, if Jowitt is correct, what’s frustrating is the ability of blatantly misrepresentative arguments to sway public opinion.

The Great Global Warming Swindle resulted in a record 250 complaints to regulatory watchdog Ofcom (including the first ever peer reviewed complaint), but that’s still a fraction of the 2.5 million viewers. Like many of those who saw the Channel 4 documentary, readers of Lawson’s offering on climate change ‘An Appeal to Reason’ are probably unaware it has been scientifically discredited in almost every review, including one on Nature Reports Climate Change by Sir John Houghton, Honorary Scientist at the UK’s Hadley Centre.

As Sir Houghton writes:

Promised as a "rare breath of intellectual rigour" and a "hard headed examination of the realities" of climate change, this offering is neither cool nor rational….and is largely one of misleading messages.

Lawson’s fundamental misunderstanding of basic scientific concepts is first displayed in his interpretation of the temperature records for the first part of this century, with which he attempts to discredit the science of climate change, and the work of many thousands of researchers who’ve dedicated entire careers to the problem. More recently, he repeats this in an amusing attack on the recent Nature paper by NASA’s Cynthia Rosenzweig.

Writing as a guest over on Susan Hills’ blog, Lawson’s piece starts off with a failure to grasp the term 'meta-analysis' – he clearly thinks that this is merely a lumping together of existing data. On the contrary, Rosenzweig and colleagues have used a powerful scientific tool to analyze changes in early 30,000 phenomena in the natural world - no mean feat - and in doing so, have shown that warming is aready having a worldwide impacts.

As Houghton rightly points out, Lawson is in need of climate science 101. But then, it seems, he's not alone - at least on that count.

Olive Heffernan

Posted by Olive Heffernan on June 24, 2008
Categories: Adaptation, Climate Policy, Climate Science, Communicating Climate Change, Features, In the News, Mitigation, Olive Heffernan, Opinion, Reviews | Permalink | Comments (17) | TrackBacks (0)

Don't grieve the Boxer-Lieberman-Warner climate bill, urges Joseph Romm in a Nature Reports Climate Change Commentary this week. Romm, voice of the Climate Progress blog, writes:

Although hailed as landmark legislation, the proposal, which died after it failed to muster close to the required 60 votes [in the US Senate], would not have put the nation on the path required to help avert catastrophic climate change.

The bill, like most climate plans now up for serious debate around the world, relied heavily on imposing a financial penalty for carbon emissions. But Europe's up-and-running emissions market has done little to curb the continent's appetite for carbon, and that should make legislators and negotiators queasy, argues Romm.

"The United States simply cannot wait another decade to find out whether domestic cap-and-trade legislation will drive carbon dioxide to a high enough price to curb emissions growth sharply," he says. Nor is new technology the answer:

Such is the urgent need to reverse emissions trends by deploying a multitude of low-carbon technologies that we must rely on technologies that either are already commercial or will very shortly be so. Fortunately, venture capitalists and public companies have begun to inject many billions of dollars into the development and short-term commercialization of most plausible low-carbon technologies. Governments should now focus their R&D spending on a longer-term effort aimed at a new generation of technologies for the emissions reduction effort after 2040, but the notion that we need a Manhattan Project or Apollo programme for technology development is mistaken. Instead, what is urgently needed is an effort of that scale focused on the deployment of technology.

Romm said more about this Thursday in a cross-posted entry at Climate Progress and Grist, in the process resurrecting a set-to with Roger Pielke, Jr, on their respective blogs in April and May.

Romm at that time argued for the importance of carbon costs - though only as one prong on the pitchfork he was wielding against a Nature Commentary by Pielke and co-authors.

Meanwhile, the most recent opinion Pielke's offered on our site is that the need for R&D isn't up for debate anymore - it's all about how to price carbon.

Anna Barnett

Posted by Anna Barnett on June 23, 2008
Categories: Anna Barnett, Climate Policy, Mitigation, Opinion, Technology | Permalink | Comments (0) | TrackBacks (0)

Development economist Jeffrey Sachs, famous for the economic turnarounds he's helped engineer as an advisor to Latin American and Eastern European governments, is also known for his optimism that the living standards of the world's poorest can be raised much higher without sacrificing either the wealth of the industrialized world or crucial natural resources. But among analysts of global change, optimism is relative. "I believe that there is most likely a path of sustainable development, but we can't quite be sure," Sachs told a sold-out lecture hall at the London Zoo last night. "It's a question mark."

Sachs spoke on big themes from his new book Common Wealth: Economics for a Crowded Planet, notably the need for expansion beyond market-based thinking to face problems not dreamt of in Adam Smith's philosophy. Before and after this rousing overview (if you'd bet ahead of time that Sachs would quote John F. Kennedy at length, you'd have won), I had the chance to get some nittier, grittier details on how Sachs wants to deal with climate change.

More and better government investment in foreign aid and green tech is the number-one key for Sachs - only the US presidential turnover seemed to run a close second, and cap-and-trading was off in the distance. So he didn't hesitate to offer a laundry list of projects that he thinks need much more political commitment - among them carbon capture and storage, passively heated and cooled green buildings, and super duper climate computers.

Technological solutions often raise ownership problems, though. If, for example, the agrobiotech industry produces new 'climate-proof' crop varieties that survive floods and droughts - an innovation Sachs welcomed at a recent climate modelling summit - can the developing world afford to buy the seeds?

"One of the things we’ve learned from the battle over access to anti-retroviral medicines," Sachs said - and this was a battle he himself fought - "is that it’s possible to create hybrid systems where you have intellectual property rights applied mainly in the high-income markets and you have access at the cost of production, or on a no-profit basis, in the poor countries."

In the case of African food shortages, he added, simple, readily available remedies like chemical fertilizers and high-yield non-GMO crops had been "sitting on the shelf" until the global food price crisis grabbed headlines. We shouldn't have to wait for disasters before we take the equivalent action on climate change, he said.

What about politics? Since Sachs's talk didn't go much beyond sighing relief at Bush's departure, I asked him afterward about his hopes for the upcoming G8 conference in July. More dubious optimism here: "There are a lot of things I'd hope for. That doesn't mean I'm expecting much to happen."

Honoring commitments to monetary aid and technology transfer is the first step, he told me. To get a global climate agreement out of the UN process, he also thinks we need to start by welcoming the economic growth of rapidly developing nations like China and India. "That's the icebreaker on this first date," he said. From that viewpoint, country-specific emissions targets can be set that correspond to growth along the greenest possible paths.

By 2050, he explained, that might mean that the North cuts its greenhouse emissions by 80% while India's emissions are allowed to double - a contraction-and-convergence plan. Because China and India have even more to fear from climate change than does the wealthier world, he said, it's an ultimatum they'll have to accept: "You're going to develop. But you're going to do it with the best technology."

Anna Barnett

Photo: Sachs working in the Millennium Village of Mwandama, Malawi.

Posted by Anna Barnett on June 18, 2008
Categories: Adaptation, Anna Barnett, Climate Policy, Mitigation, Society | Permalink | Comments (1) | TrackBacks (0)

What happens to the planet if air traffic keeps multiplying too fast for new climate-friendly plane upgrades to keep pace with the rising greenhouse emissions? The IPCC mulled it over almost a decade ago, even before sounding its 2001 global warming alarm call. Lately the problem has been pressing ever harder on European consciences, so that EU parliament members recently vowed to fast-track plans for trading aviation emissions on a carbon market - while airlines yelped defensively that they'd gotten an unfair tarring in mediagenic protests.

London's Science Museum examines this race of energy efficiency against passenger numbers in a new exhibit, Does Flying Cost the Earth?, which I took a look at in Nature Reports Climate Change this week. Much of the show is reproduced online, including the museum's smart matrix of pros and cons for various technologies proposed to clean up jet fumes. (There are more details in a recent roundup of aviation innovation from Nature News; subscription required.) For a quick gut-level hit of the central dilemma, the museum has included a very simple video game where you're in charge of containing the damage from a booming aviation industry.

The exhibition doesn't manage to answer whether flying costs the earth, as I explained in my review, but it astutely reflects the general anxiety about how to take iconically modern airplanes into a greener future. "We all love to travel," Rough Guide travel writer Mark Ellingham told journalists and industry sponsors at the exhibit's opening, "and we don't want to feel a sense of shame about it."

Anna Barnett

Images: The 1935 Lockheed Electra (top), an early commercial airliner featuring a then-cutting-edge aluminium-alloy skin, overlooks the entrance to the Science Museum's exhibition of green aviation technology for the twenty-first century. Highly aerodynamic 'blended-wing' plane designs (bottom) may be seen on runways in 25 years.

Posted by Olive Heffernan on June 13, 2008
Categories: Anna Barnett, Communicating Climate Change, Reviews | Permalink | Comments (0) | TrackBacks (0)

For all tree huggers out there, this week’s Science is dedicated to ‘forests in flux’, paying tribute to the trees and their contribution to the greater good. A special collection of articles in print, with complementary and online material, examines the fate of the world’s forests, in the face of climate change and an escalating human population.

If it’s been a while since you’ve had the chance to appreciate the languid leafiness of forest foliage, check out the online video. Or for those of you hoping for a more ‘hands on’ experience, there’s a whole section of Science Careers dedicated to opportunities in forest ecology.

There’s lots of serious science, with six Perspectives and one Review by researchers from all over the globe who give their tuppence worth on what’s needed to better understand forests and manage them properly.

Of particular relevance to discussions on how forests can mitigate global warming, Lera Miles and Valerie Kapos have a Perspective highlighting the risks involved in proposed schemes such as REDD (reduced emissions from deforestation and forest degradation) and how to minimize them. Also on this topic, Josep Canadell and Michael Raupach write on what science currently tells us is the best way to manage forests for sequestering carbon.

Drew Purves and Stephen Pacala discuss how forest dynamics remain one of the largest uncertainties in predicting future climate change and detail some of the efforts underway to improve their representation in models. Or for a really solid review of how forests affect climate change, check out Gordan Bonan’s piece here.

Or if that seems like a lot of tree pulp to get through, here are some interesting stats from the issue:

Forests cover ~42 million km2 in tropical, temperate, and boreal lands, and cover ~30% of the land surface

They store ~45% of terrestrial carbon and account for ~50% of terrestrial net primary production.

Forests hold more than double the amount of carbon in the atmosphere.

Carbon uptake by forests in the 1990s contributed to ~33% of anthropogenic carbon emission from fossil fuel and landuse change.

Olive Heffernan

Image: Plantations of Pinus radiata and Eucalyptus nitens in Gippsland (Victoria, Australia); courtesy of Michael Ryan.

Posted by Olive Heffernan on June 13, 2008
Categories: Biodiversity and Ecology, Biosphere feedbacks, Carbon markets, Climate Policy, Climate Science, Climate prediction, Deforestation, GHG emissions, Mitigation, Olive Heffernan, Uncertainty | Permalink | Comments (1) | TrackBacks (0)

Cross-posted from The Great Beyond

Over at Canada's Financial Post, Lawrence Solomon is excited about the increase in biomass over the past two decades.

Planet Earth is on a roll! GPP is way up. NPP is way up. To the surprise of those who have been bearish on the planet, the data shows global production has been steadily climbing to record levels, ones not seen since these measurements began.

GPP is Gross Primary Production, a measure of the daily output of the global biosphere --the amount of new plant matter on land. NPP is Net Primary Production, an annual tally of the globe's production. Biomass is booming. The planet is the greenest it's been in decades, perhaps in centuries.

Judging by his record Mr Solomon likes to find new, surprising stories that over turn the evil IPCC-led consensus on climate science. Not clear, though, that he's very successful: this is neither new nor surprising. The work cited seems to be a 2004 paper by Steve Running and colleagues on monitoring NPP using the MODIS satellite data set (BioScience 54, 547-560 (2004) -- pdf), so it's hardly news. What's more, everyone studying carbon dioxide levels agrees that there are "biological sinks" -- places where more carbon-dioxide means more biomass, either because of the direct carbon-dioxide-fertilisation effect (it is, after all, plant food) or because the climatic effects are to the benefit of plants. Growth in sinks = growth in biomass. And a billion tonnes of carbon or so flowing into sinks every year will add up, over time. No denying that.

Continue reading "Biomass boosting" »

Posted by Oliver Morton on June 09, 2008
Categories: Biosphere feedbacks, Oliver Morton | Permalink | Comments (1) | TrackBacks (0)

Whether and how to put a price on carbon has been something of a hot topic this week, primarily due to the proposal of a landmark climate change bill to the US Senate that would "cap and trade" emissions of the greenhouse gas.

Perhaps somewhat unsurprisingly, the climate change bill offered by Senators Boxer, Lieberman, and Warner died today in the Senate after Democrat leaders fell a dozen votes short of the 60 needed to defeat Republican obstruction.

Republicans opposed the global warming bill over fears of the economic costs of pricing the greenhouse gas, though Democrats argued there would be no cost to consumers, who would be aided with tax relief. The debate over "cap and trade" legislation is now expected to be postponed until next year, when there is a new president in the White House.

Both presidential nominees back mandatory greenhouse gas reductions and indicated they supported moving forward on discussing the bill offered to the Senate this week, but whether "cap and trade" is the the best way to price carbon remains contentious.

The issue is taken up this week on Nature Reports Climate Change by Roger Pielke Jr who reviews Earth: The Sequel by Fred Krupp and Miriam Horn of the Environmental Defense Fund. The basic tenet of the book is that a US carbon market with tradable credits would provide the profit incentive needed to energize potential innovators of low or no-carbon technology – thus meeting the world's escalating demand for green energy. But Pielke Jr argues:

By placing their attention on the need for innovative energy technologies, Krupp and Horn have focused on the one area where advocates for action on greenhouse gas reduction are in strong agreement. They have avoided engaging in the real debate over the policies necessary to decarbonize the growing global economy and, crucially, over whether and how to put a price on carbon dioxide.

You can read the full review here.

Meanwhile, over on Dot Earth, Andy Revkin has written about an alternative, though less popular, pricing approach known as “cap and dividend”. The scheme, being strongly endorsed by NASA climatologist James Hansen, is based on the principle of making the polluter pay without placing the burdening of rising costs on the consumer, the most commonly cited down-side of "cap and trade" (discussed by Pielke Jr in the above review).

Revkin explores two proposals for “cap and dividend”: one by Hansen that involves taxing fuels by their carbon content, and another by investment pioneer Peter Barnes that entails selling a steadily declining number of permits for emitting carbon dioxide. The latter would force polluters to eventually pay the full whack of their carbon consumption, and the revenue would be returned to citizens. You can read the full story here.

Olive Heffernan

Posted by Olive Heffernan on June 06, 2008
Categories: Carbon markets, Climate Policy, Features, In the News, Olive Heffernan, Politics, Technology | Permalink | Comments (1) | TrackBacks (0)

From tomorrow, Nature reporter and Climate Feedback blogger Quirin Schiermeier will be spending a week aboard the Canadian research icebreaker CCGS Amundsen, as part of a project to study climate change in the high Canadian Arctic.

He will join an expedition of one of the largest projects in the International Polar Year research programme - the Circumpolar Flaw Lead System Study, led by David Barber of the University of Manitoba.

During the field season, from October 2007 to August 2008, more than 200 scientists from 15 countries will be studying the impact of climate change on sea ice, Arctic peoples, and marine ecosystems in some of the biologically most productive areas of the Arctic.

Quirin will board the Amundsen in Inuvik, in Canada's Northwest Territories, as the crew changes over for Leg 9 of the expedition and he'll be blogging a trip diary over on the Nature newsblog during the coming week.

Image: Arctic Ocean Sciences Board

Posted by Olive Heffernan on June 04, 2008
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From claims that obese Westerners are devouring the world's produce to pleas that panicked developing nations stop hoarding it, recriminations were flying at a two-day UN conference focused on soaring international food prices this week - and The Guardian reports that anger ran highest over US policies aggressively promoting biofuels farming. Small wonder: the International Monetary Fund has estimated that the trend toward farms producing fuel instead of food is responsible for 20-30% of recent price spikes, the International Food Policy Research Institute, a US think tank, came up with 30%, and the clean-energy research firm New Energy Research offered a more conservative 8%. But US agriculture secretary Ed Schafer would own up to only 3%.

And while the food riots resulting from price rises are easy to see, the environmental benefits of biofuels are not. Report after report this year has warned that flight from fossil fuels to biofuels could see forests cleared and cropland diverted while both food costs and greenhouse emissions rise.

Ethanol fuel made from corn - big business in the US - has taken particularly heavy blame for food prices, as it uses up grain that could feed people and livestock, and fields that could be planted with other edible crops. Last year's US energy bill included a full-steam-ahead target to quintuple ethanol production in 15 years - a commitment that John McCain and 23 other Senate Republicans last month urged the EPA to ignore because of the food crisis. Across the pond, the EU is still trying to figure out how to insert sustainability caveats into its controversial plan to make 10% of all transport fuel renewable (i.e. plant-based) by 2020.

Aside from the ethanol acrimony, the UN meeting heard another strident message: Ban Ki-moon's call for 50% more agricultural production by 2030 to support a rising global population. To make this much food, the world may not be able to spare many fields for ethanol.

For more on what's driving food prices - including the possibility that we've lost some arable land to global warming and are set to lose more - Grist's breakdown and this International Food Policy Research Institute report are good places to start. And this recent Nature News story (subscription required) has a look over the biofuel industry's horizon.

Anna Barnett

Photo: Harvey Leifert

Posted by Anna Barnett on June 04, 2008
Categories: Anna Barnett, Energy, In the News, Politics, Society | Permalink | Comments (0) | TrackBacks (0)