Don't you think the joker laughs at you-oo-oo?

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 -- 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.

In an earlier post, Expertise, I launched a rant in response to Keppler's earlier paper, about how little is known about the world, how much is left to discover, and how this ought to temper our views, especially about the claims of experts and the concept of expertise in general. The idea was further developed in a series of updates pointing to supportive material.

"Obviously, not necessarily the last word."

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.

This is a politically loaded bit of plant science, and so it isn't surprising that it would be contentious. It is disappointing that it is contentious for scientists too since I have some residual childish expectations, including that of the ideal scientist who is overjoyed by discovery, even when it refutes one's own work, since the goal is truth and understanding of the natural world.

The Nature News article reveals a bit of the dynamics of the dueling investigations.

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.

Not the last word.

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.

Since isoprene oxidizes into organic aerosols there is also a climate connection involving clouds as well as an ozone connection.

In a study published last month, scientists from the Weizmann Institute, Rehovot, Israel, and NASA's Goddard Space Flight Center, Greenbelt, Md., document for the first time that air around clouds that was previously considered clear is actually filled with particles that are neither cloud droplets nor typical dry aerosols such as dust and air pollution. Worldwide, up to 60 percent of the atmosphere labeled as cloud-free in satellite observations is actually filled with this twilight zone of in-between particles, according to the study.

"With the highly sensitive Earth-observing instruments NASA has used since 2000, we can distinguish aerosols and clouds in greater detail than ever before," said Goddard's Lorraine Remer, a co-author on the study. "But the area around clouds has given us trouble. The instruments detected something there, but it didn't match our understanding of what a cloud or an aerosol looked like. What we think we're seeing is a transitional zone where clouds are beginning to form or are dying away, and where humidity causes dry particles to absorb water and get bigger."

Precisely accounting for everything in the atmosphere that can influence changes in global temperatures is critical to scientists' quest to accurately predict what Earth's climate will be in the future. The latest report from the Intergovernmental Panel on Climate Change, which assessed the potential risks of human-induced climate change, notes that the overall effect of clouds and aerosols on the amount of heat held in the atmosphere is still uncertain. Finding a previously unknown ingredient in the mix further complicates an already complex picture, but it also holds out the promise of resolving some nagging problems in climate change science.

"The effects of this zone are not included in most computer models that estimate the impact of aerosols on climate," said lead author Ilan Koren of the Weizmann Institute "This could be one of the reasons why current measurements of this effect don't match our model estimates."

And yet we hear from bureaucrats that "We can no longer make the excuse that we need to wait for more science, or the excuse that we need to wait for more technologies and policy knowledge".

The final report, from the Intergovernmental Panel on Climate Change, said prompt slowing of emissions could set the stage later in the century for stabilization of the concentration of carbon dioxide. Now at about 380 parts per million, the concentration has risen by more than one-third since the start of the industrial revolution, and could easily double from pre-industrial level within decades.

The report concluded that significant progress could be made toward halting the increase in the next 25 years using known technologies and policy changes, setting the stage for what would have to be a century-long transition to energy sources that have no impact on the climate.

Perhaps bureaucratic meddling could "set the stage later in the century", but it would have at best a negligible effect on climate change. The stage it would set would be for more meddling. Whether or not "significant progress could be made toward halting the increase in the next 25 years using known technologies and policy changes" depends greatly on the definition of "significant", and in any event seems not to grasp what progress will be made in technologies in the next 25 years both for limiting emissions and for air capture of existing GHGs. Others seem to have a better grasp of the issues.

Some of the experts and government officials involved in the final discussions said in interviews and e-mail messages that the costs could be substantially greater than those estimates, adding that the report used some very rosy assumptions.

The economic studies cited in the report, for example, assumed that a universal international policy would be adopted, that capital would flow immediately into developing and disseminating new, cleaner technology, and that consumers will not resist change, according to several experts and officials involved with the climate panel.

Other experts said the report underplayed the importance of an aggressively intensified research quest to make alternatives to coal and oil much cheaper.

Richard Richels, an author of the report and an economist at the Electric Power Research Institute, said a tax or cap on carbon dioxide emissions that was politically feasible would not be strict enough to propel research seeking big innovations.

“A carbon policy without an R. and D. policy is bankrupt,” he said.

I'm not convinced that we yet have a useful grasp of the climate system, or that we have technologies that will be effective, or that the ones we have can be widely deployed before they are obsolete. A rush to deployment would actually set us back in all areas, as well as saddling us with a massive bureaucracy that would be primarily devoted to self perpetuation and aggrandizement.

Worse perhaps, that bureaucracy would not even achieve its own stated goals due to a cavalier attitude about the turbulence of techno-social systems and a naive grasp of geopolitics. The idea of universal international policy adoption is fantasy, and the idea that populations will meekly conform is even more fantastic.

The only thing that would be achieved is the creation or enlargement of ineffective bureaucracies. Climate reality will not be affected.