Climate Feedback

Posted by Olive Heffernan on behalf of Alex Witze

June 1 is almost here, and for residents of the eastern US, Caribbean and Central America that means just one thing: stock up on the plywood and batten down the hatches, for the Atlantic hurricane season is upon us.

This week’s Nature features a minor rush of hurricane-related items. First off, in a technical manuscript, Ryan Sriver and Matthew Huber of Purdue University spell out how tropical cyclones could play a significant role in mixing the ocean’s topmost layers. They find that about 15 percent of the peak ocean heat transport can be linked to the ocean mixing caused by cyclones. Kerry Emanuel of MIT has had much the same idea before, but the Purdue work extends and better quantifies the role of hurricanes. It’s an interesting study that turns some conventional wisdom on its head: instead of worrying about how climate change affects hurricanes, maybe we should be worrying instead about how hurricanes affect climate change. Quirin Schiermeier, our correspondent in Munich, has a longer news feature on this, plus more on ocean mixing in general. (See also Martin Visbeck’s essay on ocean mixing from last week).

I've got a short news story previewing the 2006 Atlantic hurricane season. The National Hurricane Center in Miami has put out almost exactly the same forecast as last year, calling for an above-average number of storms. The 2006 predictions didn’t pan out so well – blame a late summer El Nino that surged unexpectedly, quashing the number of expected hurricanes. This year, forecasters don’t expect that to happen – and in fact anticipate a weak La Nina, the opposite weather pattern that should permit more hurricanes to form. In other words, buckle up.

One of the interesting things about this year’s season is that there is a new director for the hurricane center. This is a very big and high-profile job in the US; the center director serves as a public face for warning of dangerous storms, including trying to get people to evacuate when necessary. The previous director, Max Mayfield, was well liked by nearly everyone (even if New Orleans officials didn’t listen to his warnings as much as perhaps they should have as Hurricane Katrina approached the city in August 2005). Now the hot seat belongs to Bill Proenza, a former director of the southern region of the National Weather Service. He’s a frequent and outspoken critic of his bosses, and this month has been complaining that his center doesn’t get enough money for forecasting. He may be right, but the Atlantic is by far the best-funded and best-studied of all the world’s hurricane regions. Let us not forget the Pacific or the Indian oceans, which get hammered regularly without the benefit of a highly regarded, highly publicized hurricane center to spread warnings.

The other thing to pay attention to is the relative merits of the different ways of studying wind directons above the sea surface. The US currently has two satellites that measure this factor, but in two very different ways. The QuikSCAT satellite is a scatterometer, bouncing microwaves off the surface and measuring them when they return. The Coriolis satellite uses a radiometer, which measures microwave emissions from the ocean surface itself. Which is the better approach? Each has its merits for detecting wind vectors and each has its disadvantages. Members of Congress, though, are upset that no plans are in the works to replace the QuikSCAT scatterometer, which is far past its intended lifetime. One thing that didn’t make it into the story is the fact that Europe operates its own scatterometer, ASCAT.

If you want to stay up to date as the hurricane season progresses, I recommend checking out the Florida newspapers. The Miami Herald and the St. Petersburg Times are particularly good sources of local information. For more of an overview, check out this week’s New York Times science section , which has a pair of lead stories devoted to hurricanes; John Schwartz, a technology reporter who covered much of the Katrina failure, has a piece on how engineers try to outwit the storms through construction. And Cornelia Dean, who has long covered coastal development issues, has a good overview on the ongoing debates over the potential links between climate change and hurricanes.

Here at Nature, we too will do our part to keep you involved and informed. Complementing our existing coverage online and in print, Nature Reports Climate Change, NPG's dedicated climate change website will be launching next week - check in with us for updated coverage as the season gets underway.

Alex Witze
Senior News and Features Editor
Nature

Posted by Olive Heffernan on May 30, 2007
Categories: Recent contributors, Alex Witze, Climate Science, Hurricanes, In the News | Permalink | Comments (0) | TrackBacks (0)

As devotees of Nature's print edition know, one of its treasures is the Research HIghlights spread at the beginning of every issue, put together with great care and flair by my colleague Jenny Hogan. Most of the spread consists of little comptes rendus of papers elsewhere about which we find ourselves enthused, but there's also a little micro-column at the end called Journal Club. In this column Jenny invites a scientist of note to recommend a paper from the recent literature and explain why she or he is enthused about it.

A while back it struck us that these journal club pieces would be enhanced if they were easily discussable -- discussion being the point of a journal club, really. So we decided to load them up on a blog, one entry per post, and let them find their interactive audience. Voila. So far we have all 2007's offerings posted, and we'll be filling up the archives with 2006's entries over the next few weeks, as well of course as adding a brand new entry every Wednesday evening.

For climate relevant stuff, of which there's a nice amount, try the Earth and Environment category. It boasts Peter Liss on the links between phytopankton and clouds, Andrew Watson on the circulation of the southern ocean and its importance in ice ages, and Eric Wolff on phase-locking and Milankovitch cycles. And there's plenty more for the broad of interest -- try Axel Kleidon on the emergent properties of life and climate, David Wilkinson on what it means to be putrid or Daniel Pauly on pirates, bio-oceanography and short collective memories.

Go -- enrich their comment threads with your insight and speculation.

[Update 31/v/07: The journal club blog was asking visitors for passwords over the weekend. We've made it stop doing that now. Oliver.]

Posted by Oliver Morton on May 25, 2007
Categories: Oliver Morton | Permalink | Comments (1) | TrackBacks (0)

Posted by Olive Heffernan

Solutions to climate change could come in extremely small sizes, according to a report released last week by the UK Department for Environment Food and Rural Affairs (DEFRA). “Environmentally Beneficial Nanotechnologies: Barriers and Opportunities” explores the application of nanoscience in five key areas that could reduce greenhouse gas emissions, namely: insulation, photovoltaics, electricity storage, engine efficiency and the hydrogen economy.

Nanotechnology is a hugely exciting, if relatively young, branch of science with seemingly limitless possibilities. What scientists are discovering is that everyday materials, at very small sizes of one or several nanometers (a nanometer is equivalent to one billionth of a metre), can behave in completely out of ordinary and rather strange ways. This knowledge is resulting in an explosion of nanotechnology-enabled products entering the market, with the number expected to grow dramatically from $30 billion in 2005 to $2.6 trillion by 2014.

The report suggests that applying nanotechnology in these five key areas could contribute to reducing greenhouse gas emissions by up to 2 % in the short term and up to 20 % by 2050 with similar reductions in air pollution.

In the short term, nanotechnology has the potential to improve fuel efficiency and eliminate CO2 emissions from transport, concludes the report. Adding nanoparticles as a fuel additive to diesel engines could reduce emissions by 2.1 million tones with little infrastructural change. Nanomaterials could improve the efficiency of fuels cells, and their incorporation into batteries and supercapacitators could reduce the charge time for electric cars. In the longer term, the report says that nanotechnology could play a key role in developing renewable hydrogen production. A hydrogen economy is estimated to be 40 years away from potential universal deployment, but nanotech developments could be crucial to achieving efficient hydrogen storage, which is thought to be the largest barrier to wide scale use.

Nanotech innovations could also provide a solution to reducing cost and increasing efficiency of solar cells. The report says this is unlikely to result in significant GHG emission reduction in the UK, where there is relatively little sun, but could be of significance to reducing global emissions. Jonathan Kohler at the Department of Land Economy, University of Cambridge, however, believes that photovoltaics can have a significant output even in British climatic conditions. If the cost was reduced through advances in nanotechnology, we could see the large scale application of photovoltaics in the UK in the next twenty years, he says. A nanotech application with clear benefits for a country like the UK where 50% of energy demand is domestic would be the development of effective insulation for solid walled buildings.

As a branch of science in its infancy, significant peer-reviewed research in this area is yet to come – as a result the latest IPCC WGIII report on mitigating climate change doesn’t consider nanotech solutions to climate change. Aside from the funding and research required to develop these concepts, there are specific concerns that need to be addressed such as the potential toxicity of newly developed materials and the need to allay public fears that the materials could behave both strangely…and unpredictably.

This area of science looks set to offer some interesting green applications in the future. To keep on track of the latest research developments in nanotechnology, check out Nature Nanotechnology.

Posted by Olive Heffernan on May 25, 2007
Categories: Mitigation, Olive Heffernan | Permalink | Comments (2) | TrackBacks (0)

Posted by Olive Heffernan on behalf of Kevin Vranes

Far off the American radar screen, and perhaps not a bright blip on the European one either, is the perverse incentive problem for carbon emissions offsets. As voluntary offset purchases by both individuals and corporations ramp up, a strong backlash against "offsetting your guilt" is building astride. But offsetting guilt as a personal choice or for corporate strategy on an individual basis is one thing. Using an international financial trading mechanism embedded in an international treaty is quite another. And when the mechanisms of one international environmental treaty leads to the subversion of another international environmental treaty, well, you can just hear the collective "whoops!" echo across the Atlantic and Pacific.

Here is the situation: Annex I countries that cannot meet their GHG emissions targets under the Kyoto Protocol pay into the Clean Development Mechanism (CDM) fund, which then pays for emissions reductions in developing countries. These emissions reductions can take many forms as long as "additionality" can be proven – that is, the reduction in GHGs would not have occurred without the CDM funding. CDM projects have included capturing landfill-produced methane, creating facilities to burn biomass for energy, and installing wind power capacity. However, CDM projects have also included burning HFC-23 and this is where the perverse incentive creeps up.

HFC-23 is the byproduct of HCFC-22 production. HCFC-22 is a refrigerant and strong ozone depletor, ostensibly banned by the Montreal Protocol on Substances That Deplete the Ozone Layer. Developing countries, however, were given a loophole arrangement under the Montreal Protocol (MP) specifically for HCFC-22, so while most countries in the world with any degree of industrial activity have agreed to abide by the MP, developing countries do not have to meet HCFC-22 phase-out targets. Because of this loophole, as a cheap and effective refrigerant HCFC-22 continues to be an important industrial chemical, produced in especially high volume by "rich developing" countries such as China, India and Korea.

Both HCFC-22 and HFC-23 are also strong greenhouse gasses, but HFC-23 has a 270-year lifetime in the atmosphere, HCFC-22 only 12 years, and thus HFC-23 has over ten times the Global Warming Potential of HCFC-22 at 14,800 times CO2-equivalent (see Table TS.2 in the WGI Technical Summary of IPCC AR4). Those seeking to fund CDM projects jumped early at the chance to abate the release of HFC-23 to the atmosphere. It turned out to be quite easy (read: cheap) to install capture-and-burn equipment on HCFC-22 factories, and with a ton of HFC-23 burned being the equivalent of over 14,000 tons of CO2 prevented from reaching the atmosphere, the race to fund HFC-23 burn projects was on.

The problem from an international policy perspective is that producers of HCFC-22 now make more money burning HFC-23 than they do selling HCFC-22. Imagine what being paid handsomely to burn your waste does to your incentive to reduce your waste. If your waste stream costs you to dispose of it, you might try to improve your production to reduce waste and thus save money. And even if you did get paid to burn your waste, it might make financial sense to reduce waste anyway if your efficiency improvements paid more in reduced operating expenses than burning waste generated in income. But neither is the case for HCFC-22 factories. For them a double financial incentive now exists: keep making HCFC-22 in copious amounts at a profit, which will produce HFC-23 as a now-valuable waste product. And since HCFC-22 producers need not even lift a finger to burn their HFC-23 (those funding the CDM project fund the capture and burn device), any incentive for switching away from the ozone-depleting HCFC-22 as a refrigerant is also destroyed.

Aside from very good in-depth reporting from Fiona Harvey of the Financial Times, based in part on the work of Michael Wara of Stanford (see the 8-Feb-07 issue of Nature), the HCFC-22/HFC-23 issue has gone largely unreported thus far. While the New York Times has run a small handful of articles in the past year on HCFC-22 and its ozone-depleting properties, none have raised the HFC-23 specter. According to my Lexis-Nexis search, no other American newspaper has covered the issue.

As individual states in the U.S. begin forming interstate agreements on GHG trading in advance of a federally-instituted nationwide emissions reduction program, unintended consequences like depleting stratospheric ozone in favor of reducing GHGs will need to be carefully watched for.

Posted by Olive Heffernan on May 22, 2007
Categories: Carbon markets, Climate Policy, Kevin Vranes | Permalink | Comments (2) | TrackBacks (0)

Posted by Olive Heffernan on behalf of Michael Hopkin

It looks as if the Southern Ocean - the great white hope for sucking up mankind's carbon emissions - is slowly losing its efficiency as a carbon sink due to largely unforseen climate feedbacks. It's early days, but this first real-world measurement of a slowdown in the ocean's ability to dissolve carbon could have worrying implications for those currently thinking about how to stabilize atmospheric greenhouse levels.

Read more on the Southern Ocean's reduced CO2 uptake here

Michael Hopkin
News reporter, Nature

Posted by Olive Heffernan on May 22, 2007
Categories: Recent contributors, Climate Science, In the News, Michael Hopkin | Permalink | Comments (1) | TrackBacks (0)

Posted by Olive Heffernan on behalf of Kevin Trenberth

The 2007 hurricane season is about to get officially underway. Never mind that nature has already provided the first named storm in the North Atlantic: Andrea. Several forecasts suggest that the 2007 season in the North Atlantic will be well above average. Sea surface temperatures (SSTs) are above normal and atmospheric conditions look likely to be favorable for tropical storm activity.

In 2005, the record breaking year in the North Atlantic, record high SSTs in the critical region from 10 to 20 degrees N in the North Atlantic provided ample fuel for the 28 named storms (normal about 15, previous record 21 in 1933) and 15 hurricanes (normal about 6, previous record 12). Atmospheric conditions were favorable with weak wind shear (that otherwise tends to tear a vortex apart) and the absence of stable layers that prevent convection from developing. In contrast in 2006, SSTs were much lower and closer to the long term normal, and the atmospheric conditions were not favorable, as a developing El Niño in the Pacific created an atmospheric circulation that increased the wind shear in the Atlantic. This year, in 2007, there is no El Niño in the Pacific, and SSTs and the upper ocean heat content are more favorable for Atlantic storms.

There seems to be general agreement on these points, yet the whole issue of Atlantic hurricanes is mired in controversy over the role of global warming. It is not a disagreement that SSTs are higher but rather whether the warming is due to natural processes such as the Atlantic Multi-decadal Oscillation or global warming. To the public, the result is the same for now. To me this is obvious: global warming is “unequivocal” to quote the recent IPCC Working Group I report and global SSTs have increased about 0.6 degrees C. In the last half century this warming is associated with increased greenhouse gases in the atmosphere. It is not possible that the Atlantic has escaped from this warming.

The latest shot fired on this issue was by Chris Landsea in Eos on the long term Atlantic hurricane record. The Atlantic has the best record of tropical storms owing in part to aircraft surveillance since 1944. It is widely recognized that the older records are less reliable as the reports depend on shipping or landfall of the storms. Landsea makes this case quite well, but he goes further. He assumes that the percentage of landfalling storms should be constant over time and this provides a basis for adjusting the older records and increasing the numbers of storms by 2.2 per year from 1900 to 1965, when the satellite era began. The critical assumption is that this fraction should remain the same, yet it is abundantly clear that SSTs have increased and so other things have not remained the same. Given the dependence of hurricanes on high SSTs above about 26 degrees C, shouldn’t increased SSTs increase the scope for storms to develop farther to the east over what were colder waters and for the tracks to become longer? An example may be Vince in October 2005, which was the first tropical storm to make landfall in Spain and Portugal. Indeed shouldn’t one expect a decreasing fraction of landfalling storms in a warming climate?

Continue reading "Global climate change and hurricanes" »

Posted by Olive Heffernan on May 16, 2007
Categories: Climate Science, Kevin Trenberth, Ocean science | Permalink | Comments (3) | TrackBacks (0)

Coming up for two weeks in, a few words about this blog and its somewhat chequered early career.

Our intention was, and remains, to provide readers with pointers to interesting climate news and informal summaries of the state of play on various topics. We wanted, and still want, to offer a wide range of views, and to move beyond the natural sciences into the social sciences and the political world as and when necessary. To this end we supplemented the various staff members at Nature, Nature Reports Climate Change and the nascent Nature Geoscience who can blog on this site with invited contributors, thinking of those who had responded to our invitations as our early “core contributors”.

Along with our own initial posts, we then kicked off with a pair of posts from two of our invited contributors. In their separate ways, both posts were seen to be more controversial than other content here and, taken together, gave an impression that the blog would have a particular slant. This was not our intention, which is to offer a wide range of interesting, if controversial, views and in doing so, to represent a diversity of expert opinions over time. News travels fast in the blogosphere, however, and our somewhat unclear beginnings did not go unnoticed. As a result we found that some researchers who had previously offered themselves as willing bloggers no longer wished to make that offer, leading us, as William noted, to revise our “core contributors” list to “recent contributors”, just listing those who had posted on the site to date.

This change also reflects our intention to broaden our blogging base; in addition to our regular bloggers, those many contributors we initially invited remain welcome to post, as do others. We will be encouraging our contributors to write about things seen elsewhere rather than to focus solely on their own research, though their particular fields of expertise will of course continue to show through.

Although we had considered it, we will not be taking “right to reply” posts in response to the initial post on the hockey stick, though the comments threads remain open. We feel this has been discussed widely elsewhere and that continuing to post on it will not serve our readers well. For those who are interested in the most recent official statement on the topic, we suggest reading the IPCC Working Group I report. In the future, we may, however, structure debates between proponents of opposing views on certain issues. In the case of a contributor posting on a specific piece of work by another author, we will notify that author of the posting and invite a response.

We strongly encourage readers to comment, though comments will be moderated – personal or offensive material will not be posted.

We remain open to suggestions from you all about how to make the blog a useful addition to one of the world’s most pressing conversations. We look forward to many fruitful discussions on climate change in our journals and others, in the news, and in the world at large.

Olive Heffernan

Posted by Olive Heffernan on May 16, 2007
Categories: Communicating Climate Change, Olive Heffernan | Permalink | Comments (2) | TrackBacks (0)

Posted by Olive Heffernan on behalf of Roger Pielke Jr.

Today I am testifying before the House Committee on Science and Technology of the U.S. Congress. In my testimony I argue that we should pay attention to development paths in addition to the mitigation of greenhouse
gases. You can see my testimony in full here.

Continue reading "The Importance of the Development Pathway in the Climate Debate" »

Posted by Olive Heffernan on May 16, 2007
Categories: Climate Science, Roger Pielke, Jr | Permalink | Comments (4) | TrackBacks (0)

Olive Heffernan

Warnings that switching to biofuels as a ‘clean’ energy source could threaten food security and increase deforestation have become increasingly stark this week.

A UN report, released last Monday concluded that, despite offering considerable benefits such as clean energy for millions and the creation of wealth and jobs in poorer countries, biofuel production also has the ability to cause real destruction.

The report warned that increasing production of liquid biofuels, such as ethanol and biodiesel, could increase the price of agricultural commodities with negative economic and social impacts, especially for the world’s poor who spend a large proportion of income on food. It also raised the issue that, where forests are cleared to make way for energy crops, GHG emissions may actually be higher overall from biofuels than from fossil fuels. The report states:

Unless new policies are enacted to protect threatened lands, secure socially acceptable land use, and steer bioenergy development in a sustainable direction overall, the environment and social damage could in some cases outweigh the benefits

Today, BBC News reports on new study by the UK based Co-op Insurance Society that reiterates some of these concerns. The CIS report warns of the potentially severe environmental impacts of increased biofuel production. According to the BBC, the study found that as much as nine per cent of the world's agricultural land could be needed to replace just 10% of the world's transport fuels. The land needed for energy crops could encroach on what little land is available for food in countries threatened by famine.

Though not the first time these concerns have been raised, the reports, in particular the UN study, represent significant efforts to investigate the pros and cons of bioenergy production. For previous discussions of these issues, see George Monbiot’s series of articles on the ills of biofuels, in particular his recent piece in The Guardian in which he argues that we need a five year freeze on biofuels if we are to save the planet

The recent boom in the bioenergy sector looks set to continue. Worldwide biofuel production fdoubled in the last five years and will double again in the next four years, says the UN report. The latest IPCC Working Group III SPM, projects that biofuel use for transport will grow to 3% of total transport energy by 2030. Growth could reach up to 5-10% of total transport energy, depending on future oil and carbon prices, improvements in car efficiency and technological advances.

In the meantime, the EU and the UK have set a target of 10% of all car fuel to come from biodiesels by 2010. At the start of the year, the EC made proposals for a new EU-wide energy policy, which includes a binding target of 10% of biofuels in petrol and diesel in all member states. The public consultation on how this could be achieved – and sustainably – is open until June 4.

Posted by Olive Heffernan on May 13, 2007
Categories: Climate Policy, In the News, Mitigation, Olive Heffernan | Permalink | Comments (2) | TrackBacks (3)

Posted by Olive Heffernan on behalf of Paty Romero Lankao

It does make sense to compare the per capita CO2 emissions of Mexico City and Los Angeles (see figure below) to illuminate the debate on shared but differentiated responsibilities on greenhouse gases emissions and show that just as urban centers register different levels and paths of economic development, cities do not contribute at the same level to global warming. For instance, the real GDP per capita of Los Angeles (US$40,031) is almost 3 times that of Mexico City (US$13,470). The paradox here is that many of those urban centers with almost negligible contributions to the greenhouse gases in the atmosphere are more vulnerable to the negative impacts of climate change are. One reason of this relates to the local level of expenditures per capita in Mexico City, which are similarly tiny when compared with those of Los Angeles. In such conditions, the binding constraint for this and other cities of the developing world is the lack of economic resources from peoples’ taxes and of economic growth to deal with any component of the climate agenda.

Continue reading "Does it make sense to compare cities’ per capita emissions?" »

Posted by Olive Heffernan on May 12, 2007
Categories: Climate Science, GHG emissions, Paty Romero Lankao | Permalink | Comments (2) | TrackBacks (0)

I wrote a longish feature for Nature this week on geoengineering. It goes into various details perhaps a little deeper than some accounts have, and of course also leaves out stuff that in an ideal world it would have got in. The bottom line is that lowering the earth's average temperature by putting long-lived particles of some sort into the stratosphere is, as has long been known, technologically feasible, and would alter the course of, but not completely stop, climate change. Crucially, as yet we cannot predict with any confidence what the net changes under a warming+cooling regime would be, and though there are signs they might be a little smaller than was once thought they could easily be large enough to be complete showstoppers. The article gives, I think, full voice to the uncertainties and risks involved (though I suspect some will differ, especially since the article has served as a springboard for the AEI, which makes this comment peculiarly ironic).

There are some things it doesn't do: it doesn't go into the fact that we have no way of deciding, as a world, whether to do this, nor of setting up reliable systems for managing a century long geoengineering strategy. (I say century long because the people I was talking to all seemed to be thinking about geoengineering as either a time-limited stop-gap to buy time for mitigation to get into full swing or as a way to take the edge off the worst of the warming that would accompany an "overshoot" in greenhouse gas levels before they settled down to a stabilisation plateau. No one, as I understood it, was talking about an open ended commitment that would allow emissions to go unchecked forever.) Nor does the article explore the fact that it would be conceivable for a country to embark on such a scheme unilaterally. It certainly doesn't advocate doing anything along these lines, unilaterally or multilaterally. (It also doesn't know its history, and lamentably gave Ralph Cicerone a Nobel prize that he doesn't have. I am a fool.)

What I did try and do, at least a little, was explore the reasons why many researchers don't even want to look at this issue. There's a fairly widespread feeling that even studying it lends it a certain legitimacy, and that that legitimacy could be used as a rhetorical tool -- or even as a basis for real-world programs -- by people who have no interest in reducing CO2 emissions. I can understand this as a position; people obviously have a right to avoid doing research that they believe will be misappropriated. But that said I think that this view is at least somewhat on the wane. One reason is Paul Crutzen's intervention last year (see further discussion in the journal Climate Change). Another, I think, is increasing consciousness of ocean acidification, though this is speculation on my part, and didn't as I recall make it into the finished article. Ocean acidification provides a really strong argument for cutting carbon dioxide emissions that geoengineering can do nothing about. Its acknowledgement may thus, in a strange way, provide people with a license to speculate about such ideas, since it allows all such speculation to carry the firm proviso that even if you did try geoengineering, you'd have to cut emissions anyway -- that there's no either/or.

Continue reading "Sunshades" »

Posted by Oliver Morton on May 12, 2007
Categories: Oliver Morton | Permalink | Comments (14) | TrackBacks (1)

Via Gary at Muck and Mystery, various reports on the conference on biochar/agrichar/terra preta nova/what-you-will that just ended down in Australia. If you're not up to speed on this, the general idea is that people could help solve a great many problems by enriching soils with reduced carbon in charcoal-like form. This gets rid of the carbon for a long time (charcoal is very refractory) and improves the soil in various not yet fully understood ways. My colleague Emma wrote a lovely feature on the subject last year. There's what seems to be a thriving discussion board on the subject at Hypography. And we have an article on the subject in Nature this week (see below).

The conference was opened by Tim "Weather Maker" Flannery, which is a pretty big name for a new field to manage to attract, I'd have thought. Here's an overview of the conference by Kelpie Wilson of the Energy Bulletin. One interesting aspect is the idea of tying this issue to the issue of crappy stoves that drive indoor air pollution and waste a lot of energy.

Transect points, a blog by soil scientist Philip Small who, like Gary, is tracking this issue, has more reports in a round-up. As one of the people quoted says, the great thing about this field is that it opens up in so many different directions. Its also low tech enough to be of real use globally. The flip side of that is that different techniques will be needed in different places -- this is unlikely to be a one-size-fits-all technology.

As I mentioned we've a look at the subject in Nature this week, too -- a commentary (pdf) from one of the field's main men, Johannes Lehmann of Cornell, which takes things forward nicely, I think. One of the advantages he points out for biochar sequestration -- as opposed, say, to sequestration of carbon in aquifers -- is that once the carbon is in the soil "it is difficult to imagine any incident or change in practise that would cause a sudden loss of stored carbon". And he also argues that this sort of practise could be carried out at a serious scale:

I have calculated emissions reductions for three separate biochar approaches that can each sequester about 10% of the annual US fossil-fuel emissions (1.6 billion tonnes of carbon in 2005). First, pyrolysis of forest residues (assuming 3.5 tonnes biomass per hectare per year) from 200 million hectares of US forests that are used for timber production; second, pyrolysis of fast-growing vegetation (20 tonnes biomass per hectare per year) grown on 30 million hectares of idle US cropland for this purpose; third, pyrolysis of crop residues (5.5 tonnes biomass per hectare per year) for 120 million hectares of harvested US cropland. In each case, the biochar generated by pyrolysis is returned to the soil and not burned to offset fossil-fuel use. Even greater emissions reductions are possible if pyrolysis gases are captured for bioenergy production.

Similar calculations for carbon sequestration by photosynthesis suggest that converting all US cropland to Conservation Reserve Programs — in which farmers are paid to plant their land with native grasses — or to no-tillage would sequester 3.6% of US emissions per year during the first few decades after conversion; that is, just a third of what one of the above biochar approaches can theoretically achieve.

Posted by Oliver Morton on May 11, 2007
Categories: Mitigation, Oliver Morton | Permalink | Comments (9) | TrackBacks (0)

Posted by Olive Heffernan on behalf of Paty Romero-Lankao

Cities play key and diverse roles in the climate change arena. Regarding mitigation, a high proportion of energy, industrial and transportation emissions is generated by urban areas. Although most of the electricity and fuels are produced outside cities, they are aimed at satisfying cities’ “thirst” of energy. Therefore, urban areas place a huge burden not only on the absorptive capacity of the local environment; they also influence wide patterns of energy and land use in the surrounding and more distant areas, in the livelihoods and quality of life of people living outside cities’ boundaries.

As of vulnerability and adaptation, urban centers concentrate a large proportion of coastal and other populations most at risk from the effects of climate change (IPCC Summary for Policy Makers). The need for urban and local authorities and civil groups to develop actions to reduce greenhouse gases is part of the agenda of several cities in United States, Europe, Asia and Latin America (www.iclei.org). Yet, the need to act to increase cities’ capacity to adapt to climate change and to understand the mechanisms to increase their resilience is not so well established, especially in developing countries. The irony here is that many of the urban areas more vulnerable to the negative impacts of climate change are those with almost negligible contributions to the greenhouse gases in the atmosphere. For instance, each citizen of Los Angeles emits an average of 15.6 tons CO2 e. These amounts are huge when compared to amounts in Mexico City, where each inhabitant releases four times less than in Los Angeles (3.6 tons CO2 e). If we multiply the per capita numbers by the total population, then Los Angeles and Mexico City emit 234 and 64.8 million Tons per year respectively (See footnote 1).

At the same time, cities are centers of diverse kinds of innovations (including technological innovation) that may contribute to de-carbonizing our societies and making them more sustainable and resilient. Only through the transformation of the infrastructure, especially transport, and the use of power in cities’ buildings, in the behavior, and in the production and consumption patterns of their residents, will it be possible to reduce greenhouse gases. Furthermore, urban centers might cope with the impacts of climate related events by introducing changes in the availability of water and other natural resources, in environmental conditions, and in buildings characteristics. There are examples of well governed cities, which have introduced actions to ensure the provision of infrastructure and services, and urban planning and management that reduces the vulnerability of people, industries and infrastructures. Yet, those cases are exceptional, and adaptation practices which increase cities’ resilience are taking place on a very limited basis (IPCC Summary for Policy Makers).

Further reading:
Romero Lankao, P. 2007: “Are we missing the point? Particularities of urbanization, sustainability and carbon emissions in Latin American cities”, Environment and Urbanization Volume 19, No. 1, pp.159-175

Hunt, J. (2004), “How can cities mitigate and adapt to climate change?, Building, research and information 32(1), p.55

Posted by Olive Heffernan on May 09, 2007
Categories: Mitigation, Paty Romero Lankao | Permalink | Comments (6) | TrackBacks (0)

(Posted by Oliver on behalf of Roger)

Our research suggests that the answer to this question is a clear "No!"

With the IPCC reporting that greenhouse gas concentrations can be stabilized at an extremely small cost relative to global GDP, why should advocacy press right up to the scientific frontier where claims are most vigorously contested and knowledge most uncertain? The case for mitigation is already strong without invoking hurricane damages.

And consider this: even if we simply assume that greenhouse gases have a large and immediate impact on hurricane intensities, there is little that mitigation efforts can do anyway to stem the ever-growing economic toll associated with hurricanes.

Continue reading "Should Hurricanes be Part of the Mitigation Debate?" »

Posted by Oliver Morton on May 07, 2007
Categories: Mitigation, Roger Pielke, Jr | Permalink | Comments (13) | TrackBacks (0)

This week in Nature we have a news story on an attempt to follow up Frank Keppler's work on methane produced aerobically by green plants which we published early last year (news story | paper). The Keppler piece, which suggested that methane emissions from green plants were a significant but previously unappreciated factor in global methane emissions, caused quit a lot of fuss, understandably, in the media -- since methane is a greenhouse gas which, over short time horizons, is about 75 times more powerful than carbon dioxide -- and quite a lot of befuddlement among plant scientists. If it were true, it would have significant implications for the way that people model methane production, and the levels of production that one might predict in a warming world. The debate rumbled on last year (another news report, this time by my colleague Quirin).

The new work that Tom Dueck and colleagues have published in New Phytologist (paper), though , finds no methane emissions from plants at all.

Obviously, not necessarily the last word. As Mike Hopkin reports:

Both groups have criticized the other's choice of experimental method. Dueck says that Keppler's group kept plants in sealed plastic containers instead of flow chambers, and exposed them to sources of stress such as bright sunlight and high temperature, which could have produced methane as an artefact. Keppler retorts that the use of ¹³C is an artificial piece of chemical trickery with unknown effects on plant metabolism, and also argues that methane production can vary by up to three orders of magnitude between species.

What Mike doesn't mention, because an evil news editor (me) wouldn't give him the space, is that various people in the community have pointed to an interesting contrast between the way plant scientists responded to the discovery of isoprene emissions and the Keppler work. With isoprene people said oh that's interesting, replicated, and got on with it. This work has had a far frostier welcome.

On isoprene, this is as good a place as any to mention an interesting perspective by Manuel Lerdau in Science a few weeks ago on a possible isoprene-ozone positive feedback (paper). Isoprene within leaves protects the plants that produce it against ozone. But when isoprene gets out into the air, as it will, it can react with nitrogen oxides to make ozone. Only some species produce isoprene, and so these isoprene-producing plants both protect themselves against ozone and, in Nox-rich environments, increase the ozone stress on their non-isoprene-producing neighbours.

If this effect is real, it might have significant effects on forest composition over the next century.

One last thing to note on the Keppler story: it led to Carl Zimmer saying something nice about us, and that is always a good thing. As of course is Carl.

Posted by Oliver Morton on May 04, 2007
Categories: Biosphere feedbacks, Oliver Morton | Permalink | Comments (8) | TrackBacks (0)

(Posted by Olive on behalf of Roger)

Even the venerable New York Times is prone to completely botching a discussion of the science of climate change. In a front page article today, the NYT reports on how the National Arbor Day Foundation has updated plant hardiness maps to reflect recent changes in climate. (A plant hardiness map presents the lowest annual temperature as a guideline to what plants will thrive in what climate zones.) The NYT misrepresents understandings of variability and trend and in the process confuse more than clarify.

The new map updates a 1990 USDA map based on 1974-1986 data, and replaces it with data from 1990-2006. In most places the range of increased average minimum temperature has moved north as can be seen from a difference map between the two time periods. The difference map, shown here, has the horizontal lines because the zones used are so broad -- 10 degrees -- that the differences are only noticeable at the margins of the zones.

The New York Times reports that these differences can all be attributed to human-caused climate change, using the case of Atlanta as an illustration:

Using data from the National Oceanic and Atmospheric Administration, the Arbor Day map indicates that many bands of the country are a full zone warmer, and a few spots are two zones warmer, than they were in 1990, when the map was last updated.

Atlanta, which was in Zone 7 in 1990, is now in Zone 8, along with the rest of northern Georgia. That means that areas in the northern half of the state where the average low temperature was zero to 10 degrees Fahrenheit are now in a zone where the average low is 10 to 20 degrees. A scientific consensus has concluded that this warming trend has largely been caused by the human production of heat-trapping gases.

Because the zones span 10 degrees (or 5 degrees in the case of the 1990 USDA map) and the largest change shown on the difference map is 2 zones (i.e., >10 degrees!, now corrected), then clearly no location has jumped 2
zones! This is just an error.

More important than this simple mistake is the claim in the NYT that the changes in temperature observed in Atlanta can be attributed to human-caused greenhouse gases. In fact, the IPCC argues that it needs 30 years of records to detect trends, much less make attribution. In fact, the IPCC report just out has reported that the U.S. southeast has actually cooled over the period of record as shown below.

The underlying issue has to do with understanding the role of human-caused climate change in the context of climate variability on long time scales.

Continue reading "Confusion on Climate Variability and Trends" »

Posted by Olive Heffernan on May 03, 2007
Categories: Climate Science, Communicating Climate Change, In the News, Roger Pielke, Jr | Permalink | Comments (35) | TrackBacks (2)

(Posted by Olive on behalf of Hans)

In October 2004 we were lucky to publish in Science our critique of the ‘hockey-stick’ reconstruction of the temperature of the last 1000 years. Now, two and half years later, it may be worth reviewing what has happened since then.

The publication in 2004 was a remarkable event, because the hockey-stick had been elevated to an icon by the 3rd Assessment Report of the IPCC. This perception was supported by a lack of healthy discussion about the method behind the hockey-stick. In the years before, due to effective gate keeping of influential scientists, papers raising critical points had a hard time or even failed to pass the review process. For a certain time, the problem was framed as an issue of mainstream scientists, supporting the concept of anthropogenic climate change, versus a group of skeptics, who doubted the reality of the blade of the hockey stick. By framing it this way, the real problems, namely the ‘wobbliness’ of the shaft of the hockey-stick, and the suppressing of valid scientific questions by gate keeping, were left out.

Hopefully, sociology of science will later study this unfortunate period of climate science, but we may conclude now that science itself has indeed corrected claims of premature knowledge. We see now a healthy and broad discussion of the issue. We had the opportunity to respond to no less than four comments on our 2004 Science paper, but unfortunately only two comments were published. Similarly, Michael Mann and his coworkers had to respond to at least 2 comments to their Journal of Climate article in 2005.

At the EGU General Assembly a few weeks ago there were no less than three papers from groups in Copenhagen and Bern assessing critically the merits of methods used to reconstruct historical climate variable from proxies; Bürger’s papers in 2005; Moberg’s paper in Nature in 2005; various papers on borehole temperature; The National Academy of Science Report from 2006 – al of which have helped to clarify that the hockey-stick methodologies lead indeed to questionable historical reconstructions. The 4th Assessment Report of the IPCC now presents a whole range of historical reconstructions instead of favoring prematurely just one hypothesis as reliable.

When looking back we are satisfied with what has been achieved – namely an open, open-minded exciting discussion about the merits and problems related to different methods; an atmosphere where mere claims about the informational content of proxy-data meet a more critical response; an evolving practice of testing the skill of reconstruction methods in the laboratory of millennial forced global climate model simulations, where the formation of proxy-data is simulated in - so far too simplified - models.

Hans von Storch and Eduardo Zorita

Posted by Olive Heffernan on May 03, 2007
Categories: Climate Science, Hans von Storch, Palaeoclimate | Permalink | Comments (36) | TrackBacks (1)

(Posted by Olive on behalf of Heike)

The week before last, I was one of an army of geoscientists travelling to Vienna from Europe and the world for the General Assembly of the European Geophysical Union (EGU). And of course, we are all aware of climate change. There was a talk on “The carbon footprint of academic travelling – assessing the sustainability of different ways of travelling to the EGU Assembly”. Too late, since most of us had already come by plane.

There also was a debate with the title “The carbon footprint of EGU is bigger than necessary”. I didn’t go. I suspect the potentially interesting question in this debate — “What is necessary?” — was not addressed.

Is the EGU assembly itself necessary? Of course it is nice to meet colleagues in person. Yes, when people chat over a glass of wine at the poster session, chances are that new science emerges that would not have come into the world without that poster session (or without that wine). And for me personally, talking to people informally about the launch of my new Journal, Nature Geoscience, is very helpful.

In the end, do 4,200 oral presentations and 6,700 posters justify 8,000 participants’ travel emissions? The bottomline of EGU sounds reasonable. But necessary? No. Necessary it is not.

Heike Langenberg
Chief Editor, Nature Geoscience

Posted by Olive Heffernan on May 03, 2007
Categories: Climate Science, Conferences and Meetings, Heike Langenberg | Permalink | Comments (3) | TrackBacks (0)