Jennifer Marohasy

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Archives for July 14, 2008

Climate Sensitivity Reconsidered

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Physics and Society, in its July 2008 quarterly edition, has published a paper by Christopher Monckton entitled Climate Sensitivity Reconsidered, which exposes the IPCC’s strange method of calculating the effect of CO2 on temperature and suggests that in response to a CO2 doubling global temperature may rise by as little as 0.6 C.

Abstract:

The Intergovernmental Panel on Climate Change (IPCC, 2007) concluded that anthropogenic CO2 emissions probably caused more than half of the “global warming” of the past 50 years and would cause further rapid warming. However, global mean surface temperature has not risen since 1998 and may have fallen since late 2001. The present analysis suggests that the failure of the IPCC’s models to predict this and many other climatic phenomena arises from defects in its evaluation of the three factors whose product is climate sensitivity:

1. Radiative forcing ΔF;
2. The no-feedbacks climate sensitivity parameter κ; and
3. The feedback multiplier ƒ.

Some reasons why the IPCC’s estimates may be excessive and unsafe are explained. More importantly, the conclusion is that, perhaps, there is no “climate crisis”, and that currently-fashionable efforts by governments to reduce anthropogenic CO2 emissions are pointless, may be ill-conceived, and could even be harmful.

Physics & Society: July 2008, Volume 37, Number 3

Full Paper at http://www.aps.org/units/fps/newsletters/200807/monckton.cfm

Physics and Society is the quarterly of the Forum on Physics and Society, a division of the American Physical Society. It presents letters, commentary, book reviews and reviewed articles on the relations of physics and the physics community to government and society. It also carries news of the Forum and provides a medium for Forum members to exchange ideas. Opinions expressed are those of the authors alone and do not necessarily reflect the views of the APS or of the Forum.

The Greenhouse Effect is a Myth: A Note from Jim Peden

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As a dissenting physicist, I simply can no longer buy the notion that CO2 produces any significant warming of the atmosphere at any rate.

I’ve studied the atomic absorption physics to death, from John Nicol’s extensive development to the much longer winded dissertation by Gerlich & Tscheuschner and everything in between, it simply doesn’t add up.

Even if every single IR photon absorbed by a CO2 molecule were magically transformed into purely thermal translational modes , the pitifully small quantity of CO2 in the atmosphere doesn’t add up to much additional heat. And if the aforementioned magical 100% transformation from radiation into “heat” were true, then all arguments concerning re-emission ( source of all the wonderful “greenhouse effect” cartoons with their arrows flying in all directions ) are out the window.

More and more, I am becoming convinced that atmospheric heating is primarily by thermal conduction from the surface, whose temperature is determined primarily by solar absorption. I get a lot of email from laymen seeking simple answers ( I’m sure you all do as well ). My simple reply goes like this:

1. The sun heats the earth.
2. The earth heats the atmosphere
3. After the sun sets, the atmosphere cools back down

With a parting comment: If we were to have 96 continuous hours without sunlight, temperatures would likely be below freezing over all the world’s land masses. The warmest place you could find would be to take a swim in the nearest ocean. There is no physical process in the atmosphere which “traps” heat. The so-called “greenhouse effect ” is a myth.

Jim Peden

Jim is Webmaster of Middlebury Networks and Editor of the Middlebury Community Network, spent some of his earlier years as an Atmospheric Physicist at the Space Research and Coordination Center in Pittsburgh and Extranuclear Laboratories in Blawnox, Pennsylvania, studying ion-molecule reactions in the upper atmosphere. As a student, he was elected to both the National Physics Honor Society and the National Mathematics Honor Fraternity, and was President of the Student Section of the American Institute of Physics. He was a founding member of the American Society for Mass Spectrometry, and a member of the American Institute of Aeronautics and Astronautics. His thesis on charge transfer reactions in the upper atmosphere was co-published in part in the prestigious Journal of Chemical Physics. The results obtained by himself and his colleagues at the University of Pittsburgh remain today as the gold standard in the AstroChemistry Database. He was a co-developer of the Modulated Beam Quadrupole Mass Spectrometer, declared one of the “100 Most Significant Technical Developments of the Year” and displayed at the Museum of Science and Industry in Chicago.

Bushfires, Prescribed Burning and Global Warming

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Two myths about climate change and bushfire management are often repeated in the media:

1. Because of global warming, Australia will be increasingly subject to uncontrollable holocaust-like “megafires”; and

2. Fuel reduction by prescribed burning must cease because it releases carbon dioxide into the atmosphere, thus exacerbating global warming and the occurrence of megafires.

Both statements are incorrect. However they represent the sort of plausible-sounding assertions which, if repeated often enough, can take on a life of their own and lead eventually to damaging policy change.

I’m paraphrasing from an important new report entitled ‘Bushfires, Prescribed Burning and Global Warming’ by Roger Underwood, Chairman of the Bushfire Front, David Packham, Senior Research Fellow at the School of Geography and Environmental Science, Monash University, and Phil Cheney, Honorary Research Fellow, CSIRO, Canberra.

The authors consider in detail at the carbon balance in relation to fire in the three most typical Australian ecosystems: tropical grasslands, tropical/subtropical savannahs and tall forests and conclude:

1. Although the situation is almost carbon-neutral, all fires in tropical grasslands actually sequester some carbon in the form of “black carbon” which is incorporated into the soil;

2. Over time, the carbon balance of fires in tropical and subtropical savannahs is also just about neutral. In some years more CO2 is emitted to the atmosphere from fires than is absorbed by post-fire regrowth, while in other years more carbon is taken up by regrowth than is lost to the atmosphere from fire (including prescribed burning and wildfires).

The management approach that will optimise storage of carbon in Australian savannahs is one of low-intensity, early dry-season burning under mild weather conditions. This protects the overstorey trees and woody shrubs which are consumed by hot late-season fires.

3. Tall forests store carbon in tree trunks, bark, branches and roots, in woody shrubs and mid-storey vegetation and in the litter and accumulated organic debris on the ground. Eventually all old trees begin to decay from within, and in the absence of fire, the accumulated litter on the forest floor begins to rot away. At this point, the rate of release of carbon through decay exceeds the rate of storage of carbon by new growth. Thus Australia’s “old growth” eucalypt forests eventually stop being a carbon sink and become a source of CO2.

Fuel reduction by prescribed burning employs low-intensity fires lit under mild weather conditions at a time when there is still some moisture in the fuel. This ensures that the flames are generally less than a metre high and the fire is confined to the surface layer of fine fuel and the green material in the low shrubs. A properly managed prescribed fire will be conducted at a time when organic matter (including charcoal) in the soil will not burn. The ideal prescribed burn consumes only the surface fuels, leaving behind a layer of ash protecting the soil and the heavy logs.

The amount of CO2 released by a low-intensity fire is small and the store of carbon on the forest floor is rapidly replaced as the fine fuels re-accumulate and the low shrubs regrow. By comparison, a hot summer bushfire burning under drought conditions will consume all of the surface fuels, including large logs and organic matter in the soil which may have accumulated carbon for thousands of years. An intense summer bushfire will even consume the canopies of the tallest trees. The amount of CO2 produced by a fire is directly proportional to the total amount of fuel consumed in the fire. Thus a hot summer bushfire [in Australia’s tall forests] will release massive amounts of carbon.

The authors conclude that from the point of view of carbon storage in grasslands, savannahs and tall forests, the best management approach is one in which large high-intensity wildfires are minimised by periodic prescribed burns carried out under mild weather conditions.

The authors also examine the alarmist concept that “global warming will lead to unstoppable megafires”. They observe that if the current climate change models are correct, there will only be an increase in average annual temperatures of between 2 and 4 degrees over the next 100 years. The effect of this on bushfire behaviour, by itself, will be trivial. Fire intensity is far more significantly affected by fuel quantity, fuel dryness and wind strength, than it is by temperature.

Some climate change computer models also suggest a significant reduction in rainfall, leading to increased fuel drying and increased fuel availability at lower temperatures. This is the same effect as that of drought, a phenomenon which is common in Australia. Drought does result in more intense fires…..but only if nothing is done to reduce fuels before the fire occurs.

The factor which “doomsday” commentators ignore is the opportunity for land managers to get in first, and reduce fuels before a potential megafire starts. In other words, the potential megafire can be forestalled, simply by the adoption of a program of fuel reduction prescribed burning under mild weather conditions.

Finally, the authors advocate that the Precautionary Principle must apply: this means playing safe while the research is being done. The safe approach is not to ban prescribed burning because of an unsupported assertion that it may increase atmospheric CO2 levels, but to promote prescribed burning because it reduces the size and intensity of wildfires.