C4’s debate on global warming boils over

Two eminent British scientists who questioned the accuracy of a Channel 4 programme that claimed global warming was an unfounded conspiracy theory have received an expletive-filled tirade from the programme maker.

In an e-mail exchange leaked to The Times, Martin Durkin, the executive producer of The Great Global Warming Swindle, responded to the concerns of Dr Armand Leroi, from Imperial College, and Simon Singh, the respected scientific author, by telling them to “go and f*** yourself”.

The tirade has caused Dr Leroi to withdraw his cooperation from another Channel 4 project with Mr Durkin on race, The Times has learnt.

The programme, broadcast by Channel 4 last Thursday, featured a number of scientists who disputed the consensus on the causes of global warming.

Dr Leroi was particularly concerned about a segment that featured a correlation between solar activity and global temperatures, which was based on a 1991 paper in the journal Science by Eigil Friis-Chris-tensen. He was surprised that the programme failed to mention that while these findings look convincing superficially, they have been revealed as flawed by subsequent research by Peter Laut.

Dr Leroi e-mailed Mr Durkin about his use of data, concluding: “To put this bluntly: the data that you showed in your programme were . . . wrong in several different ways.” He copied Mr Singh into the exchange.

Mr Durkin replied to both later that morning, saying: “You’re a big daft cock.” Less than an hour later, Mr Singh, who has worked for the BBC, intervened to urge Mr Durkin to engage in serious debate. He wrote: “I suspect that you will have upset many people (if Armand is right), so it would be great if you could engage in the debate rather than just resorting to one-line replies. That way we could figure out what went wrong/ right and how do things better/ even better in the future.” Mr Durkin replied nine minutes later: “The BBC is now a force for bigotry and intolerance . . . Since 1940 we have had four decades of cooling, three of warming, and the last decade when temperature has been doing nothing.

“Why have we not heard this in the hours and hours of sh*t [edited by poster] programming on global warming shoved down our throats by the BBC?

Last night Dr Leroi said that he was amazed at the rudeness of Mr Durkin’s reply.

“It was rather a shocking response,” Dr Leroi said. “It was my intention to make a film with Martin Durkin and [the production company] Wag, but that is something I am seriously reconsidering now. I am no climate scientist, but I was very concerned at the way that flaws in these data were brushed over.”

He said that the global warming film had glossed over flaws in data that it used to make its case, and that it was critical that a documentary about a subject as controversial as race and biology did not make similar mistakes.

“As the subject of our proposed film was race, it is such a sensitive topic that it requires great care and great balance. That he has shown so little respect for scientific consensus and such little nuance is a cause for great concern. I cannot imagine it will go ahead now.”

The film would have addressed Dr Leroi’s thesis that race is a biologically meaning-ful and medically valuable concept, a view that is highly controversial among scientists.

Last night Mr Durkin apologised for his langauge. “As far as I was concerned these were private e-mails. They arrived when I was quite tired having just finished the programme in time for transmission,” he said.

“Needless, to say, I regret the use of intemperate language. It is so unlike me. I am very eager to have all the science properly debated with scientists qualified in the right areas and have asked Channel 4 if they will stage a live debate on this subject.”

Claim: Ice core data shows that carbon dioxide levels rise after temperatures go up, not before

Fact: This is correct, but climate scientists have a good explanation. There is a substantial feedback effect – initial small rises in temperature lead to substantial release of carbon dioxide from natural reservoirs in the oceans, which then produce much steeper warming later on

Claim: Temperatures in the troposphere, the lower part of the atmosphere, have not risen as predicted by the models

Fact: This was once the case, but it has been resolved now that initial measurement errors have been corrected

Claim: Temperatures rose for the first part of the century, then cooled for three decades before warming again. There is no link to carbon dioxide

Fact: Temperatures did follow this pattern, but again there is a good explanation. The mid-century effect fall came about chiefly because of sulphate aerosols – particles that have a cooling effect on the atmosphere. These are no longer produced so heavily by industry because of environmental regulations to combat other problems, such as acid rain

"Other positive feedbacks, mainly increased water vapor, account for the rest."

This positive feedback thing is generally where I see the exaggeration in temps comes from. The amount of increased water vapor can be obtained from humidity tables, and is not significant for these tiny increases in temp. It doesn't amount to much. As far as any increases in temp go, that I've ever calculated, they appear to be the same as the lower numbers that appear in the IPCC reports. I made no mistake about using equilibrium numbers. It is only equilibrium numbers, that are any good. That eq. I gave is what IPCC uses for the CO₂ component and did result from curve fitting.

You can not have any positive feedback that results in averages that exceed the equilibrium values calculated for a simple configuration of the components representing the 2 states. In order to find the change in energy content, between any 2 states of a system, the energy along the path is minimized. It is not allowed to wander, as these computer simulations do. The bounds found for simple configurations of components representing the states are the references, which no simulation, which is said to be real, can go beyond.

As far as that ocean solubility link goes. It is correct. The oceans are roughly saturated, and the 8-10^oC temp changes do in fact represent the given changes in solubility, and the resulting change in atmospheric conc. Note, that to get that kind of temp change from CO₂, it must be raised by almost an order of magnitude, not a jump from 190ppm to 270ppm.

"Note that ancient_geezer disputes that the important effect is atmospheric warming; he has a counter-position that the surface warming for doubling CO2 won't be the same as the whole atmosphere warming."

I don't know what this means. He did just look at one layer and the resulting temp increase given was too small. All layers warm, and the real numbers are generally on the low side of the range given by the IPCC.

A doubling of CO2 will account for about 0.8-0.9 C rise directly. (I suspect that you didn't use the equilibrium blackbody temperature, a very common error, because when that error is made, the result is ...... 0.3 C!!!). Other positive feedbacks, mainly increased water vapor, account for the rest.

Equilibrium relative to top of atmosphere measures (at tropopause) may see 0.8-0.9^oC arising from upward directed Longwave radiation of ~4w/m2 absorption at the wavelengths as which CO2 is active in the atmosphere.

OTOH, downward directed radiative forcing from emission by CO2 are much less due to intervening water vapor aborbing across much broader spectrum and overlapping CO2 at its IR active spectral bands.

As a consequence heating at the surface due to CO2 is severely restricted and limited in what it can contribute to surface temperatures.

Kiehl, J. T. and V. Ramanathan, 1982: Radiative Heating Due to Increased CO2: The Role of H2O Continuum Absorption in the 12-18 mm Region . J. Atmos. Sci., 39: 2923-2926.

Introduction:
Within the 12-18mm region, both H2O and CO2 absorb and emit radiation giving rise to the so-called "overlap." This study examines the role of this H2O-CO2 overlap in the CO2-climate proble. The H2O absorpotion, within the 12-18mm region, that has been traditionally included in climate models (Manabe and Wetherald, 1980; Ramanathan, 1981) is the line absorption due to the pure rotational band of H2O. In addition to the pure rotaional band, there is very strong "continuum" absorption by H2O in the 12-18 um region (Roberts et al., 1976). The few climate model studies which include the effect of this continuum (e.g., Wang et al., 1976) have not examined its rl in the increased CO2 radiative effects. In order to isolate the overlap effects of various H2O radiation processes in the 12-18mm region, we comput the radiative heating of the surface/troposphere system due to double CO2 with and without the H2O overlap effects.
*** SNIP ***
[p. 3] We consider three cases in which CO2 is doubled and the changes in longwave fluxes are computed for no overlap between water vapor and CO2. This is achieved by setting the transmissivity of H2O in the 12-18mm region to be equal to 1. In the second case, the H2O overlap due to the rotaional band is included. Finally we include the H2O continuum and calculate the flux changes using both continuum and line transmissivity (for the pure rotation band) described in the previous section. These cases illustrate the most important aspects of the water vapor overlap.
*** SNIP ***

Table 1. The effect of CO2 increase on the hemispherically
averaged net radiative heating (wm^-2). DF_T^N is the change
in the net outgoing longwave flux (at the tropopause) due to
doubling of CO2; negative values of this quantity denote
heating of the joint surface/troposphere system. DF¯_s is the
is the change in the downward longwave flux at the surface.

Case Comments -DF_T^N DF¯_s

1 Without H2O absorption in
12-18 mm region 4.69 3.65

2 H2O line absorption 4.18 1.56

3 Line plus continuum absorption 3.99 0.55

The overlap graphically represented in the following:

IR absorption overlap between Water Vapor and Carbon dioxide
http://earthobservatory.nasa.gov/Study/ArbitersOfEnergy/

Using the more commonly accepted and conservative value of downward directed LW radiation based on line absorption only, CO2 flux is constrained to roughly 1/3 of its TOA upwared directed value.

http://www.eia.doe.gov/cneaf/alternate/page/environment/appd_d.html

"Carbon dioxide adds 12 percent to radiation trapping, which is less than the contribution from either water vapor or clouds. By itself, however, carbon dioxide is capable of trapping three times as much radiation as it actually does in the Earth's atmosphere. Freidenreich and colleagues[106] have reported the overlap of carbon dioxide and water absorption bands in the infrared region. Given the present composition of the atmosphere, the contribution to the total heating rate in the troposphere is around 5 percent from carbon dioxide and around 95 percent from water vapor."

Using the NOAA measure for direct radiative flux at TOA due to CO2,

DF = 5.35 ln(C/C₀) wm^-2 [Myhre et al. 1998, Geophys.Res.Lett., 25:2715-2718].

We can calculate the downward directed longwave flux adding to surface heating as a consequence of CO2 doubling in the atmosphere.

Given a doubling of CO2 flux at tropopause is DF = 5.35 ln(2) = 3.70wm^-2 . Due to water vapor spectral overlap CO2 the direct radiative force of CO2 is reduced to approximately 3.70/3 = 1.2wm^-2. Which compares well with the range of values estimated by other researchers:

Re-cycling of Infra-Red Energy

According to Dr Hugh Ellsaesser's IPCC submission, "The direct increase in radiative heating of the lower atmosphere (tropopause level) due to doubling CO2 is 4 wm^-2. At the surface it is 0.5 - 1.5 wm^-2". Schlesinger & Mitchell (1985), estimated this surface flux at 2 wm^-2. Thus, depending on the model, or modeler, the estimates for increased surface flux following a CO2 doubling, varies between +0.5 and +2 wm^-2.

To determine the effects on temperature measurement at the surface from the back radiation of 2XCO₂ (1.2w/m²), the calculation proceeds as follows:

Starting with 288K initial surface temperature @ current atmospheric conditions.

One applies the Stefan-Boltzman relation:

F=esT⁴
where:
F = total amount of radiation emitted by an object per square meter (Watts m^-2)
e is emissivity, the ratio of the radiation emitted by a surface to that emitted by a black body at the same temperature.
http://www.electro-optical.com/bb_rad/emissivity/emisivty.htm

s is a constant called the Stefan-Boltzman constant = 5.67 x 10^-8 Watts m^-2 K^-4
T is the temperature of the object in K

to determine the total radiative forcing necessary to maintain the atmosphere/surface greenhouse temperature at the current 288^oK surface temperature of the earth.

Flux (F₂₈₈) at the Earth's surface with atmosphere = 5.67*10^-8(288^oK)⁴ = 390.08 w/m²

To which we add the increment of 2XCO2 direct radiative forcing at the surface DF = 1.2w/m² (i.e bottom of atmosphere as opposed at tropopause at the top.)

F = 390.08 + 1.2 = 391.28 w/m²

And solve for the resultant equilibrium blackbody temperature at the surface for the doubling of CO2 concentration in the atmosphere.

T = (E/s)^0.25 = (391.28/5.67*10^-8)^0.25= 288.22K

Final step we determine our result in terms of change in temperature (DT) by subtracting our initial state temperature 288K for the resulting increment of temperature do (2 CO²) direct radiative forcing alone.

DT = 288.22-288 = 0.22K

A value that agrees well with the value cited by Ramanathan for direct effects of CO2 on surface temperature:

"the direct radiative effects of doubled CO2 can cause a maximum surface warming [at the equator] of about 0.2 K, and hence roughly 90% of the 2.0-2.5 K surface warming obtained by the GCM is caused by atmospheric feedback processes described above.
--- "Increased Atmospheric CO2: Zonal and Seasonal Estimates of the Effect on the Radiation Energy Balance and Surface Temperature"
(V. Ramanathan and M. S. Lian), J. Journal of Geophysical Research, Vol. 84, p. 4949, 1979.

All layers warm, and the real numbers are generally on the low side of the range given by the IPCC.

All layers warm certainy and cool as well through re-radiation and reflection, very notably so in the case of water vapor and clouds which dominate in the lower atmosphere.

The net is to reduce the effect of CO2 downward directed flux through intervening interaction with water vapor and clouds such that at the surface CO2 is reduced to an effective flux heating the surface of only 1/3 of the flux value at top of atmophere.

Increase water vapor indeed inhibits and limits the efficacy of CO2 even more in acting as a GHG. The dominant drivers are those affecting cloud cover and evaporation from the ocean surface which control the hydrological cycle, that definitely is not CO2.

"The surface of the earth does not cool primarily by infrared radiation. It cools mainly through evaporation.⁷ Most of the evaporated moisture ends up in convective clouds (clouds with strong vertical currents carrying the air and its contents upward, as opposed to layered clouds, which form and stay at a particular level) where the moisture condenses into rain. Just as evaporation cools, the condensation of watervapor heats, and the atmosphere realizes most of this heat at altitudes >5km. It is at these heights that the atmosphere must balance the heat deposited by convection from the surface through cooling by thermal radiation. It is worth noting that, in the absence of convection, pure geenhouse warming would lead to a globally averaged surface temperature of 72^oC given current conditions (Moller and Manabe 1961). Our current average temperature, 15^oC, is actually much closer to the black body temperature temperature (-18^oC), than to the pure greenhouse result.⁸ The relative ineffectiveness of the greenhouse effect is due to convection which carries heat past the bulk of watervapor (which has a characteristic scale height of about 2km), and to large-scale meridional heat transport which carries heat from the moist tropics to the less moist higher latitudes. Because of this transport, it is primarily the distribution of infared absorbers above 5km (rather than below 5km) that is important for containing the heat carried away from the earth's surface (Lindzen et al. 1982)."
*** SNIP ***
"In the meantime greenhouse effect is not nearly as straight forward as is commonly stated."
--- Richard Lindzen (1990) Some coolness concerning global warming. Bulletin, American Metorolological Society, 71, 288-299.

"Even if all other greenhouse gases (such as carbon dioxide and methane) were to disappear, we would still be left with over 98 percent of the current greenhouse effect." Cato Review, Spring issue, 87-98, 1992;

I, of course, believe Dr. Ramanathan.

So we all do, especially in his statements concerning what is the primary hypothesis on which climate models are based.

Water vapor and clouds are the kingpin to how the atomosphere operates, and simultaneously the Achille's heal of climate models, overstating the role of CO2 as opposed to solar effects controlling both cloud cover and thereby solar heating of the ocean surface.

Obviously, the modelers do not hide the dependance of there models on water vapor and clouds:

http://www.meteor.iastate.edu/gccourse/model/direct/direct_lecture_new.html

Water-vapor/greenhouse feedback.
Relative humidity is reasonably constant despite variations in absolute humidity. That is, an increase in temperature leads to more evaporation and increase in the absolute amount of water vapor in the air (increase absolute humidity). But since the warmer air has a higher saturation vapor pressure (can hold more water vapor), the relative humidity stays approximately constant. The increased absolute humidity, however, increases absorption of infrared radiation by the atmosphere and hence increases the greenhouse effect. Note that this increased greenhouse effect raises the surface temperature, which further increases evaporation. This feedback mechanism is not self-regulating, so we call it a positive feedback.
Cloudiness / surface-temperature feedback.
As temperature increases, evaporation and absolute humidity both increase leading to more cloudiness. But the increase in clouds leads to increased reflection of solar energy and also leads to more trapping of infrared energy from the surface of the earth. The net effect (which depends on the altitude of the clouds) is thought to lead to a cooling, which makes this a negative feedback process.

as quantified by Ramanathan:

"the direct radiative effects of doubled CO2 can cause a maximum surface warming [at the equator] of about 0.2 K, and hence roughly 90% of the 2.0-2.5 K surface warming obtained by the GCM is caused by atmospheric feedback processes described above.
--- "Increased Atmospheric CO2: Zonal and Seasonal Estimates of the Effect on the Radiation Energy Balance and Surface Temperature"
(V. Ramanathan and M. S. Lian), J. Journal of Geophysical Research, Vol. 84, p. 4949, 1979.

But we do seem to have a bit of disconnect going on at the empirical side of science, seems that water vapor and cloud cover are going the wrong direction for CO2 to explain the current changes going on in the atmosphere across the last couple of decades:

http://isccp.giss.nasa.gov/JPEG/zD2ATMOSCLIM/B128B129glbp.anomdevs.jpg

http://isccp.giss.nasa.gov/zD2BASICS/B8glbp.anomdevs.jpg

http://isccp.giss.nasa.gov/zD2CLOUDTYPES/B32glbp.anomdevs.jpg

Seems something other than CO2 may be driving the show as far as flux reaching the surface of the earth to heat things up.

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Case	Comments	-DF_T^N	DF¯_s
1	Without H2O absorption in 12-18 mm region	4.69	3.65
2	H2O line absorption	4.18	1.56
3	Line plus continuum absorption	3.99	0.55