Remember when they laughed at the fellow who said that trees make smog? And since then we have discovered that they emit methane as well. Ocean phytoplankton do too, and that may be significant.

Discovery of the new link between clouds and the biosphere grew out of efforts to explain increased cloud cover observed over an area of the Southern Ocean where a large bloom of phytoplankton was occurring. Based on satellite data, the researchers hypothesized that airborne particles produced by oxidation of the chemical isoprene – which is emitted by the phytoplankton – may have contributed to a doubling of cloud droplet concentrations seen over a large area of ocean off the eastern coast of South America.

Using complex numerical models, they estimated that the resulting increase in cloudiness reduced the absorption of sunlight by an amount comparable to what has been measured in highly polluted areas of the globe. If confirmed by field studies, this connection between clouds and biological activity could add a critical new component to global climate models. Many environmental scientists believe that increased cloud cover may be partially countering the effects of global warming by reducing the amount of energy the planet absorbs from the sun. . .

"Studies like this one may help reshape the way we think about how the biosphere interacts with clouds and climate," said Nenes, an assistant professor in Georgia Tech's School of Earth and Atmospheric Sciences. "One of the largest uncertainties right now in climate models is the ability to predict how clouds would respond to changing particle levels – whether they originate from humans with air pollution or from biological activity. We can now see very strongly the influence of marine biology on oceanic clouds."

Researchers had previously theorized that dimethyl sulfide (DMS) – which is also emitted by phytoplankton – affects the formation of clouds by increasing the number of sulfate particles, which can absorb moisture and form cloud droplets. When oxidized, isoprene may enhance the effect of DMS by increasing the number and size of the particles while helping them to chemically attract more moisture. The impact of isoprene on atmospheric particulate matter was previously thought to be important only for terrestrial plants, Nenes said. . .

In their paper, the researchers estimated that the isoprene emissions reduced energy absorption in the area by about 15 watts per square meter. "This is a huge signal," said Nenes. "You would normally expect to see a change of a couple of watts." . . .

Atmospheric scientists believe that by blocking sunlight, increased cloudiness has up until now partially mitigated the effects of global warming. The role of oceanic biology on cloud formation could therefore be a major factor in controlling global climate, and the new mechanism identified by Nenes and Meskhidze may make it even more important. This effect needs to be better understood, Nenes noted, because anything that can change global clouds can dramatically alter the impact of greenhouse gases on our changing climate.

The more I learn the more there is to learn. Each new discovery exposes a mountain of ignorance. I'm not complaining, this is phun for me. It just increases my contempt for politicized wankers that seek to limit inquiry and debate, preferring mushroom management of public perceptions.

Highlighting the gap, the two sides clash on how much the Earth would warm today if carbon dioxide concentrations double from preindustrial levels, as scientists expect. Many climatologists see an increase of as much as 8 degrees Fahrenheit. The skeptics, drawing on Phanerozoic data, tend to see far less, perhaps 2 or 3 degrees.

In the Phanerozoic (the term is Greek for visible life), complex organisms arose. If its countless ages were compressed into a single year, fish would have appeared in January, land animals in March, dinosaurs in June, monkeys in December and humans late on New Year’s Eve.

The Phanerozoic dispute, fought mainly in scholarly journals and scientific meetings, has occurred in isolation from the public debate on global warming. Al Gore in “An Inconvenient Truth” makes no mention of it.

Some mainstream scientists familiar with the Phanerozoic evidence call it too sketchy for public consumption and government policy, if not expert deliberations.

“In my view, the uncertainties are too great to draw any conclusions right now,” Michael Oppenheimer, a professor of geosciences and international affairs at Princeton, said. “It could be that when the dust settles some insight will emerge that will be germane to the current problem — how do we keep the climate from spinning out of control.”

Skeptics say CO2 crusaders simply find the Phanerozoic data embarrassing and irreconcilable with public alarms. “People come to me and say, ‘Stop talking like this, you’re hurting the cause,’ ” said Dr. Giegengack of Penn.

Pathetic. One of my hopes for ubiquitous ICT is that the public will become cynical about catastrophic visions whipped up by activists, and so immune to manipulation by elites. It isn't clear that this can happen - people have a distressing tendency to gather in echo chambers devoid of information and insight - but it may make such mobs smaller and shorter lived. It takes more energy to maintain ignorance in an information rich environment.