Apart from a bunch of apparently deranged sceptics (The Dragon Slayers) everyone involved in the science of The Great Climate Debate accepts the general principal that carbon dioxide in the atmosphere absorbs photons (energy) emitted by the Earth’s surface and re-emits them, some of which inevitably return to the Earth’s surface. Despite the protestations of the Slayers, photons have no idea which direction they are to travel in (bar a God who cares about such things). This leads to the Earth’s surface being warmer than it would be if there were no carbon dioxide in the atmosphere. CAGWers have a nasty habit of claiming that all sceptics of imminent Thermageddon refuse to accept this well-tested property of carbon dioxide. For those unfamiliar with atmospheric physics, Science of Doom made an educational (and quite technical) series of posts some time ago if you feel the need to come up to speed with the underpinnings.
As The Git pointed out in an earlier post, most accept the calculation of MODTRAN5 that a doubling of CO2 level in the atmosphere leads to ~1°C of temperature increase. However, this is ceteris paribus (all other things being equal). And where the real world is concerned, things are only very rarely ceteris paribus. An increase in CO2 inevitably leads to an increase in the amount of plant food available to plants.
Net Primary Productivity (NPP) is described in the article:
When scientists talk about productivity they are specifically talking about how much carbon ends up stored in the living biomass—roots, trunks, and leaves of plants—after they tally up carbon gains through photosynthesis and carbon losses through respiration. This tally of gains minus losses is called “net primary production.” Scientists estimate net primary production by observing how leafy vegetation is and how much sunlight it is absorbing, which can both be measured by satellite. Combined with climate data on rainfall, temperature, and available radiation, the satellite observations reveal where carbon intake increased—and biomass grew—across the globe.
The article further states:
Lack of sufficient water limits the growth of 40 percent of Earth’s vegetation, temperature limits 33 percent, and lack of sufficient sunlight limits the remaining 27 percent.
While the article (elsewhere) deprecates the effect of CO2, it is because the scientists involved only take into account the fertilisation effect of CO2. What they ignore here is the effect of increased CO2 on water availability. Plants respond to increased CO2 by reducing both the number and size of the stomata that allow the plant to respire. This reduction leads to a decrease in expired moisture.
To examine the effects of a doubled atmospheric CO2 concentration and other aspects of global climate change on a common CAM species native to the Sonoran Desert, Agave deserti was grown under 370 and 750//mol CO2 mol-1 air and gas exchange as measured under various environmental conditions. Doubling the CO2 concentration increased daily net CO2 uptake by 49% throughout the 17 months and decreased daily transpiration by 24%, leading to a 110% increase in water-use efficiency
The question then immediately arises: is this increase in NPP a Good Thing, or a Bad Thing? One might even suppose that it’s possible to be entirely neutral on the issue. If it’s a Bad Thing, one then wonders why farmers have ever bothered to irrigate, or why greenhouse growers regularly go to the expense of introducing additional CO2 into their greenhouses, or ensuring that there is adequate ventilation to ensure the depletion of CO2 by the crop doesn’t impact on productivity.
An additional biological effect on climate occurs in the oceans. This so far little investigated effect was initiated by James Lovelock of GAIA fame (or notoriety). Phytoplankton in the oceans emit not only most of the oxygen needed by animal life, they also emit dimethylsulfide (DMS). Some of the DMS gasses off from the surface of the oceans and molecules of DMS in the atmosphere act as cloud condensation nuclei (CCN), thus increasing the amount of cloud cover. The increase in cloud cover reduces the amount of sunlight reaching the Earth’s surface thus having a cooling effect. However, the decrease in sunlight inhibits the growth and reproduction of the phytoplankton and leads in turn to decrease in DMS production. The decrease in DMS production leads to a decrease in cloud generation allowing more sunlight to reach the Earth’s surface. You can read more about DMS here. Such negative feedback loops are abundant in Earth’s biosphere.
Of course the CAGWers deny the importance of negative feedbacks and claim that the Earth is dominated by positive feedbacks and has been in a completely unstable state for billions of years just waiting to turn into Thermageddon. Or is it?
Twice now The Git has been told that the Paleocene–Eocene Thermal Maximum (PETM) was a Mass Extinction Event. The wiki-bloody-pedia agrees with The Git’s geology texts that it was neither a major mass extinction event, nor even a lesser extinction event. The PETM occurred ~55.8 million years ago and lasted for ~0.2 million years. While 35–50% of benthic foraminifera became extinct over a period of ~1,000 years planktonic foraminifera diversified, and the population of dinoflagellates bloomed. The mammals also increased their share of Earth-pie at this time. One explanation for the depletion (not extinction) of the benthic forams is the disposition of the continents at that time. This led to much reduced oceanic circulation and likely the forams’ demise was caused by anoxic conditions.
The Following is from La Marguerite
Green Advocates Failing in Climate Debate
April 12, 2008 by lamarguerite
From highly respected fellow blogger, Mark Seal, here is a thought provoking post on why we greenies may need to sharpen our debating skills . . .
When I launched the TalkClimateChange forums last year, I was initially worried as to where I would find people who didn’t believe in global warming. I had planned to create a furious debate, but in my experience global warming was such a universally accepted issue that I expected to have to dredge the slums of the internet in order to find a couple of deniers who could keep the argument thriving.
The first few days were slow going, but following a brief write-up of my site by Junk Science I was swamped by climate skeptics who did a good job of frightening off the few brave Greens who slogged out the debate with. Whilst there was a lot of rubbish written, the truth was that they didn’t so much frighten the Greens away – they comprehensively demolished them with a more in depth understanding of the science, cleverly thought out arguments, and some very smart answers. If you want to learn about the physics of convection currents, gas chromatography, or any number of climate science topics then read some of the early debates on TalkClimateChange. I didn’t believe a word of it, but I had to admit that these guys were good.
In the following months the situation hardly changed. As the forum continued to grow, as the blog began to catch traffic, and as I continued to try and recruit green members I continued to be disappointed with the debate. In short, and I am sorry to say it, anti-greens (Reds, as we call them) appear to be more willing to comment, more structured, more able to quote peer reviewed research, more apparently rational and apparently wider read and better informed.
And it’s not just TalkClimateChange. Since we re-launched the forums on Green Options and promoted the “Live Debate“ on Nuclear Power, the pro-nuclear crowd have outclassed the few brave souls that have attempted to take them on (with the exception of our own Matt from TalkClimateChange). So how can this be? Where are all these bright Green champions, and why have I failed to recruit them into the debate? Either it’s down to poor online marketing skills, or there is something else missing. I’ve considered a range of theories as to the problem, none of which seem to fit – such as:
Greens are less educated? Nope.
Greens have less time? Nope.
Greens are a little reticent? Nope.
Greens are less intelligent? Definitely nope.
Greens are less passionate? Absolutely nope.]
Greens have less at stake? Clearly not.
The only feasible explanation that I can come up with so far is that perhaps Greens are less invested in the status quo, and therefore less motivated to protect it? The other possibility is that we are all completely wrong and we’re deluded – please tell me this isn’t so. So I am hoping that La Marguerite, with its insightful host and enlightened readership may be able to help shed some light on this peculiar phenomenon?
Mark Seal wrote: “I didn’t believe a word of it, but I had to admit that these guys were good.” And there’s the rub! Do you believe the physics and geology, or do you believe politicians? He also makes the mistake of lumping all sceptics together, when they are possibly the most heterogeneous group I’ve come across. For an excellent read about Why We Disagree About Climate Change, by Mike Hulme. “Climate change is not ‘a problem’ waiting for ‘a solution’.” Therein lies the problem; politicians galore are offering us (expensive) solutions to something that may only be an imagined problem. We shall look at some of those “solutions” next time.
Thought for the Day
The government solution to a problem is usually as bad as the problem. – Milton Friedman