- Humans are currently emitting around 30 billion tonnes of CO2 into the atmosphere every year (CDIAC). Of course, it could be coincidence that CO2 levels are rising so sharply at the same time so let's look at more evidence that we're responsible for the rise in CO2 levels. Humans are emitting an increasing amount each year. CO2 levels are not rising sharply, they are rising steadily at around 1.9ppm p.a. That sinks adjust to increase take-up tells me that 2ppm remain in the air because that is what air/sea conditions dictate.
- When we measure the type of carbon accumulating in the atmosphere, we observe more of the type of carbon that comes from fossil fuels (Manning 2006). Oceans have been absorbing 13C depleted CO2 for mill-yuns of years - from the sea floor e.g. volcanoes, smokers, seepage. The ocean surface layer availability of 13C depleted CO2 may also be due to the great conveyor returning medieval CO2.
- This is corroborated by measurements of oxygen in the atmosphere. Oxygen levels are falling in line with the amount of carbon dioxide rising, just as you'd expect from fossil fuel burning which takes oxygen out of the air to create carbon dioxide (Manning 2006). The paper talks of estimates and possibilities. The scope of measurements is hardly conclusive.
- Further independent evidence that humans are raising CO2 levels comes from measurements of carbon found in coral records going back several centuries. These find a recent sharp rise in the type of carbon that comes from fossil fuels (Pelejero 2005). The curve also coincides with warming. It could as easily be due to the preference of algae chosen by the coral.
- So we know humans are raising CO2 levels. What's the effect? Satellites measure less heat escaping out to space, at the particular wavelengths that CO2 absorbs heat, thus finding "direct experimental evidence for a significant increase in the Earth's greenhouse effect". (Harries 2001, Griggs 2004, Chen 2007). (Also see point 1) That is a massive leap in assumption. We don't know whether humans have changed the balance or whether non human sources would merely replace the human contribution in its absence. That the atm. increase does not correlate with human emissions increase suggests that ocean and air T control what CO2 remains in the atm rather than human output.***
- If less heat is escaping to space, where is it going? Back to the Earth's surface. Surface measurements confirm this, observing more downward infrared radiation (Philipona 2004, Wang 2009). A closer look at the downward radiation finds more heat returning at CO2 wavelengths, leading to the conclusion that "this experimental data should effectively end the argument by skeptics that no experimental evidence exists for the connection between greenhouse gas increases in the atmosphere and global warming." (Evans 2006). The IR range of CO2 can barely be detected as sensible heat. If radiation is returning, the amount can be no more than negligible. I fail to see how emitted IR (CO2 range) is absorbed practically to extinction in under 100 mtrs yet down welling IR gets past this barrier. How does the IR manage to do this? More solar radiation reaching the surface would cause more IR to be emitted and so produce the claimed effect.
- If an increased greenhouse effect is causing global warming, we should see certain patterns in the warming. For example, the planet should warm faster at night than during the day. This is indeed being observed (Braganza 2004, Alexander 2006). And has been conclusively proved to be due to CO2 how? An increase in solar radiation reaching the surface would have an identical effect as would an increase in lower tropospheric humidity that has been evidenced.
- Another distinctive pattern of greenhouse warming is cooling in the upper atmosphere, otherwise known as the stratosphere. This is exactly what's happening (Jones 2003). Volcanoes cooled the stratosphere. Without them it would have been a lot less cold. Ozone is recovering probably due to the stratosphere drying. A warming factor for the stratosphere and poles and an increasingly cooling factor towards the tropics.
- With the lower atmosphere (the troposphere) warming and the upper atmosphere (the stratophere) cooling, another consequence is the boundary between the troposphere and stratophere, otherwise known as the tropopause, should rise as a consequence of greenhouse warming. This has been observed (Santer 2003). As a consequence of warming whatever the source.
- An even higher layer of the atmosphere, the ionosphere, is expected to cool and contract in response to greenhouse warming. This has been observed by satellites (Laštovika 2006). That one I can't comment on other than to say an expanding troposphere would cause layers above to thin. I suspect that is why the ionosphere would cool. As mentioned warming can be due to other factors.
Using a non-sequitur seems a bit of a strange way to prove a fingerprint.
As far as heat energy emitted to space goes, it is the total compared to incoming energy that is relevant. The "noise" in satellite outgoing IR measurements precludes a definitive comparison with incoming energy. No mechanism has yet been shown for the conveyance of energy in CO2's range from the upper atmosphere back to the surface.
Richard S Courtney: Aug 6, 2010 at 11:44 am
(comment to http://wattsupwiththat.com/2010/08/05/why-the-co2-increase-is-man-made-part-1)
It is time to refute the simplistic idea that a mass balance indicates anything concerning flows in and out of the atmosphere. It does not because the magnitudes of the flows and their variations are not known. And the system is complicated with many of the flows varying and interacting.
In one of our 2005 papers
(ref. Rorsch A, Courtney RS & Thoenes D, ‘The Interaction of Climate Change and the Carbon Dioxide Cycle’ E&E v16no2 (2005))
we considered the most important processes in the carbon cycle to be as follows.
SHORT TERM PROCESSES
1. Consumption of CO2 by photosynthesis that takes place in green plants on land. CO2 from the air and water from the soil are coupled to form carbohydrates. Oxygen is liberated. This process takes place mostly in spring and summer. A rough distinction can be made:
1a. The formation of leaves that are short lived (less than a year).
1b. The formation of tree branches and trunks, that are long lived (decades).
2. Production of CO2 by the metabolism of animals, and by the decomposition of vegetable matter by micro-organisms including those in the intestines of animals, whereby oxygen is consumed and water and CO2 (and some carbon monoxide and methane that will eventually be oxidised to CO2) are liberated. Again distinctions can be made:
2a. The decomposition of leaves, that takes place in autumn and continues well into the next winter, spring and summer.
2b. The decomposition of branches, trunks, etc. that typically has a delay of some decades after their formation.
2c. The metabolism of animals that goes on throughout the year.
3. Consumption of CO2 by absorption in cold ocean waters. Part of this is consumed by marine vegetation through photosynthesis.
4. Production of CO2 by desorption from warm ocean waters. Part of this may be the result of decomposition of organic debris.
5. Circulation of ocean waters from warm to cold zones, and vice versa, thus promoting processes 3 and 4.
LONGER TERM PROCESSES
6. Formation of peat from dead leaves and branches (eventually leading to lignite and coal).
7. Erosion of silicate rocks, whereby carbonates are formed and silica is liberated.
8. Precipitation of calcium carbonate in the ocean, that sinks to the bottom, together with formation of corals and shells.
NATURAL PROCESSES THAT ADD CO2 TO THE SYSTEM
9. Production of CO2 from volcanoes (by eruption and gas leakage).
10. Natural forest fires, coal seam fires and peat fires.
ANTHROPOGENIC PROCESSES THAT ADD CO2 TO THE SYSTEM
11. Production of CO2 by burning of vegetation (“biomass”).
12. Production of CO2 by burning of fossil fuels (and by lime kilns).
Several of these processes are rate dependant and several of them interact.
At higher air temperatures, the rates of processes 1, 2, 4 and 5 will increase and the rate of process 3 will decrease. Process 1 is strongly dependent on temperature, so its rate will vary strongly (maybe by a factor of 10) throughout the changing seasons.
The rates of processes 1, 3 and 4 are dependent on the CO2 concentration in the atmosphere. The rates of processes 1 and 3 will increase with higher CO2 concentration, but the rate of process 4 will decrease.
The rate of process 1 has a complicated dependence on the atmospheric CO2 concentration. At higher concentrations at first there will be an increase that will probably be less than linear (with an “order” <1). But after some time, when more vegetation (more biomass) has been formed, the capacity for photosynthesis will have increased, resulting in a progressive increase of the consumption rate.
Processes 1 to 5 are obviously coupled by mass balances. Our paper assessed the steady-state situation to be an oversimplification because there are two factors that will never be “steady”:
I. The removal of CO2 from the system, or its addition to the system.
II. External factors that are not constant and may influence the process rates, such as varying solar activity.
Modelling this system is a difficult because so little is known concerning the rate equations. However, some things can be stated from the empirical data, and the following assessment uses conservative estimates of values that exaggerate any possible anthropogenic effect.
At present the yearly increase of the anthropogenic emissions is approximately 0.1 GtC/year. At Northern latitudes where most anthropogenic emission occurs, the natural fluctuation of the excess consumption (i.e. consumption processes 1 and 3 minus production processes 2 and 4) is at least 6 ppmv (which corresponds to 12 GtC) in 4 months (see Ferdinand’s Figure 3). This is more than 100 times the yearly increase of human production, which strongly suggests that the dynamics of the natural processes here listed 1-5 can cope easily with the human production of CO2. A serious disruption of the system may be expected when the rate of increase of the anthropogenic emissions becomes larger than the natural variations of CO2. But the above data indicates this is not possible.
The accumulation rate of CO2 in the atmosphere (1.5 ppmv/year which corresponds to 3 GtC/year) is equal to almost half the human emission (6.5 GtC/year). However, this does not mean that half the human emission accumulates in the atmosphere, as is often stated (1,2,3). There are several other and much larger CO2 flows in and out of the atmosphere. The total CO2 flow into the atmosphere is at least 156.5 GtC/year with 150 GtC/year of this being from natural origin and 6.5 GtC/year from human origin. So, on the average, 3/156.5 = 2% of all emissions accumulate.
The above qualitative considerations suggest the carbon cycle cannot be very sensitive to relatively small disturbances such as the present anthropogenic emissions of CO2. However, the system could be quite sensitive to temperature. So, our paper considered how the carbon cycle would be disturbed if – for some reason – the temperature of the atmosphere were to rise, as it almost certainly did between 1880 and 1940 (there was an estimated average rise of 0.5 °C in average surface temperature).
And our paper showed that three different natural variations could each be used to model the observed rise in anthropogenic CO2 with a very precise match that required no ‘fiddle factor’ such as the 5-year smoothing of the data that is needed to get mass balance models to match the data.
John Cook's "10 fingerprints" effort is a heavily biased piece that takes non-sequitur statements and assigns them as CO2 fingerprints, takes warming effects and assigns them as CO2 fingerprints.That is a misrepresentation of science.
Regardless of the rights and wrongs of the above, scientists accept a doubling of preindustrial CO2 will lead to a small temperature increment ignoring any other factor. Less than 1C is the most commonly deduced value of which we have seen more than 70%. The scare comes from the unevidenced idea that CO2 drives water evaporation to higher levels and water vapour has a far greater capacity to actually warm the planet as it is a real GHG, i.e. it stores energy, CO2 doesn't. Satellite and radiosonde balloon measurements are the only evidence to date and within their range of error show a very small positive (warming) to larger negative feedback from increasing water vapour volumes in the lower troposphere air that could be attributed to CO2. At higher altitudes, as the distance between molecules increases CO2 transists to an anti GHG because it radiates to space. More CO2 increases upward radiation.
The CO2 action is logarithmic because each additional molecule absorbs less IR. The amount of IR available is finite. At around 800ppm, any effect of additional CO2 will be statistically indistinguishable from zero although a log curve never actually achieves the flatness necessary to achieve a true zero effect.
The problem with politicians, the misanthropic and fund hungry, the agenda driven and the likes of the IPCC is that it is against their interests to show the benefits of CO2 that include such as it is a free fertiliser, crop yield increases for a doubling have been found as high as 24% and 12% is believed to be a reasonable average. Plants require less water as the stomata (holes) that absorb CO2 need to be open less so less water is lost to evaporation. Some say this will be offset due to drying of the air although that counters the argument that CO2 increases water vapour.