There's an interesting discussion at Crooked Timber accusing critics of global warming theories of interest and bias, and disparaging net commentary as "actually largely written by bloggers of a libertarian and/or conservative cast of mind to provide easy, prejudice-congenial op-ed-like material."

The discussion isn't interesting in the sense of being informed or insightful on the issues, it's interesting in the sense of revealing the lack of scholarship and analytic skills of the participants, and their own lack of self examination for interest and bias. Chris Bertram, the author of the original post, has some suspicions that his own bias in favor of the theories, formed from political and popular advocacy in the media, just might be unsound. Chris, more than most others at Crooked Timber, has episodes of self examination and doubt which help him be open to new information and understanding.

Most of the comments in the thread fell far, far short of the standard Chris set for open debate but there was one interesting exchange. Chris Geneovese wrote an informed and insightful comment that included a fair accounting of the shameful treatment of Bjorn Lomborg by the media as well as an analysis of the quality of the truth claims made by supporters of global warming theory.

Bertram responded with a link to some comments made by Brad DeLong that essentially support Lomborg's work but states that it isn't enough.

It's not my field of expertise, but as a card-carrying economist I can't help but think that Lomborg is probably right when he condemns Kyoto as a worthless waste of the world's wealth--as something that will be ineffective at fighting global warming and so expensive as to foreclose options to do other things that would be more useful. Lomborg's flaw, however, is that he doesn't spell out what the "other things" we should be doing are. And that's what he needs to do if he wants to advance the ball.

DeLong is right that Lomborg hasn't provided a counter policy to Kyoto but it doesn't seem a fair criticism of Lomborg. It has been a huge effort taken at great personal risk for Lomborg to do so much in helping the world snap out of the Kyoto trance that finding fault that he didn't provide an alternative plan seems stingy.

Climate change cannot be stopped. If there were no humans climate would still change. All living things change the climate. It is thanks to cyanobacteria that we have the oxygen rich reducing environment that makes human life possible. It is thanks to animals and other bacteria that there is any CO2 in the atmosphere at all though it can only be measured in parts per million. Without CO2 there would be no plant life. Similarly, atmospheric methane, another green house gas, is mostly a result of anaerobic bacteria living in swamps, including human made swamps such as rice paddies. The carbon cycle, which is a continuous exchange of carbon in its various forms (CO2, methane etc.) between air, land and seas, is a complex system we only have the dimmest understanding of at present.

Each aspect of the cycle is a complex system in itself. Atmospheric chemistry - the reactions between carbon, nitrogen, hydrogen and oxygen compounds - is hideously complex and varies markedly with changes in everything from relative concentrations to cyclical cosmic ray bombardment. Biological uptake - the temporary or permanent sequestration of carbon by life forms - is even more complex. Worse, we only have the dimmest understandings of how any of it works, what life forms actually fix the carbon and how their activity is affected by cyclical changes.

An interesting example of this is glomalin, a durable form of carbon found in undisturbed soil. It is produced by Vesicular Arbuscular Mycorrhizal fungi (VAM) as a byproduct of their lives and deaths. VAM also play a key role in enabling plant life. They barter phosphorous, an otherwise immobile essential soil nutrient, to plant roots in exchange for carbohydrate secretions. Glomalin wasn't discovered until 1996 since it is destroyed by plowing and most soil research was done on farm fields. In unplowed land glomalin is extremely durable and accumulates over time to improve soil texture, water holding ability, cation exchange capacity and nutrient uptake by plants. The amount of the earth's total carbon budget sequestered as glomalin in uncultivated soils is huge and we didn't even know it existed until recently.

We know so little. We don't understand the carbon cycle, we don't even know which factors are significant. Carbon is a tiny, tiny fraction of the atmosphere yet it is in extremely high demand by every living thing. Life on earth is made of carbon. We are just beginning to understand how the low concentration of atmospheric carbon inhibits life.

For example, plants breath in CO2 through openings in their leaves, stomata, which open and close (using hydraulic pressure) depending on activity. When there is no light the systems shut down since they lack the energy needed to synthesize plant flesh. Stomata close when not needed to breath since they allow water to escape and make plants wilt. The more CO2 there is in the air the less stomata must be opened to breath and the lower the water loss. Experiments growing plants in elevated CO2 environments indicate that soil moisture can be as much as 10% higher under these conditions, an extremely important consideration since the vast majority of the earth's biosystem is limited by soil moisture during all or part of the year.

The water plants lose while breathing affects the atmosphere as well as the biosphere. Water vapor, the most potent green house gas, cycles between land, sea and atmosphere in a cycle as complex as carbon's. It isn't just evaporation - the change from liquid to gaseous form on exposure to warm air - it is also evapo-transpiration - water vapor emitted by plants when they breath. Rain forests evapo-transpire so much water they create their own rain. In dryer areas plants, especially trees, evapo-transpire so much water that they dry up rivers and create a thick atmospheric haze. One of the environmental restoration projects in S. Africa involves sending crews with chain saws into mountain parks to cut down European tress planted by settlers and gone feral since they evapo-transpire so much water that permanent water courses have become seasonal and withered lowland ecosystems...and cities.

Though it would take a library of books to document what we know and an army of scholars to comprehend it all the most important fact of them all is that we only have the vaguest glimmerings of the entities and their relationships in this complex planetary system of complex systems. It is sheer hubris for politicians to make any claims at all about intentional control of climate change. We have no idea what the consequences of elevated atmospheric CO2 will be. We have no idea whether it is fossil fuel burning, disturbance of soil for agriculture, or some other unsuspected human behavior that has caused increased CO2 concentrations.

We can't trust our measurements of global temperature. Even if we had reliable temperature data we don't understand natural climate cycles related to cyclical ocean current oscillations such as ENSO and PDO (as well as NAO, AO etc. etc.). Some of these oscillations occur over years, some over decades and it is likely that some occur over centuries but we haven't yet identified them since we are just beginners. There are atmospheric oscillations similar to ocean oscillations that cause large changes in the path of high altitude, high speed air flows (jet streams). The planet as a whole oscillates on its axis. The sun oscillates in many ways, has its own weather cycles which affect its planets in myriad ways. The solar system oscillates as it orbits the galactic core. Which of these factors are important? How important? Are the trends we think we see really trends or are they rises and falls that are part of long wave oscialltions?

It's silly to think that we know what the result of global acts will be. But that is not license to do as we wish with no thought for consequences. Spewing various smokes and stinks into the air is never something we should do when avoidable. Plowing up the land, spewing into rivers and setting off nuclear explosions should also be avoided. They are destructive acts done in bad taste. They fail aesthetic, ethical and biological constraint tests in ways we can immediately perceive whether they perturb major systems such as climate or not. We can't stop spewing wastes or digging the land, not yet, but we shouldn't do such things more than necessary to live and we should seek methods to reduce spew.