Published on November 14th, 20121
Climate Change – What are the Facts, What are the Myths?
By Steinar Jakobsen
Despite that the government and traditional media (newspapers, radio, and TV) alike inform us that the debate about climate change is long since concluded, this is at best a truth with some modifications. In the following I will explicate why one should not take at face value the claim that “the science is settled”, at least not in the way we are told by the governments and most of the mass media.
Firstly, a vivid debate is still ongoing among scholars belonging to relevant areas of the natural sciences. There the discussion to a significant extent centers on the relative impact on the climate of a range of different possible independent variables or factors. To be sure, CO2 is but one of many such factors that may have a measurable impact.
Secondly, the debate about the trustworthiness of the processes and conclusions of the Intergovernmental Panel on Climate Change (IPCC, or the Climate Panel) is also fierce and ongoing. Many of the conclusions of IPCC are relying on the output from climate models (i.e. Computer simulations predicting future climate developments). Evidence suggests that the Climate Panel’s methods are far from infallible.
The Natural Sciences
As for the natural sciences, a sensible starting point would be to identify areas in which there really are agreement – as well as areas in which disagreement exists. Before we proceed with that review, however, it would be worthwhile taking a quick glance on what is arguably the most widely recognized graphical representation of the global temperature development of the last 2000 years:
All serious scientists with some knowledge of this topic concur that we have indeed witnessed a small increase in global average temperatures since the “Little Ice Age,” which reached its nadir around the turn of the 17th century.
Furthermore, one can also agree that greenhouse gases contribute to the earth being significantly warmer than it otherwise would have been. Many put forth the estimate that this effect represents a temperature differential of around 33 degrees centigrade. The CO2 contribution of this is usually considered to be about 0.5 degrees centigrade.
Scientists are also in agreement that water vapor – H2O – is the most prevalent of all individual greenhouse gases; it is therefore also the one with the largest impact on the world’s climate.
Neither do scholars disagree that people, to a certain extent, can affect the local climate. This is referred to as the “urban effect,” and it is caused by, among other things, deforestation, asphalting, heating, air-conditioning, changes in plantation, and urban expansion. In some cases this will increase the local average temperature; in other cases, though, local temperature will decrease (e.g., with the increase in sunlight-reflecting plantation).
Obviously, there is also agreement that human-induced CO2 emissions (the standard label is “climate gas emissions,” by which one first and foremost mean CO2) have increased significantly after the Second World War. Since CO2 is a greenhouse gas, many concur that such a rise should affect global temperatures somewhat. However, it is exactly on this point that the disagreement really commences. Scientists point to three alternatives:
- The amount of CO2 emissions, relative to other factors, is so small that no increase in global temperatures as a result of these emissions will be discernible.
- A small increase in temperatures might be discernible and measurable, but this increase will be so small that it likely does not really warrant much concern.
- Some point to larger possible impacts on temperatures – with estimates typically ranging between 2 and 6 degrees centigrade – given a doubling of today’s atmospheric concentration of CO2. If this third scenario carries some truth, the consequences, according to many, could be quite unpleasant or even catastrophic.
Considering that alternatives 1 and 2 are irrelevant in the context of a discussion of the “end of the world as we know it,” I will instead dwell a little bit on the third scenario. What makes some scholars believe that alternative 3 is likely?
Many (though not all) researchers agree, at the outset, that a doubling of the atmospheric concentration of CO2 will yield a 1-degree centigrade increase in global temperatures. In itself, this is not menacing. But cue what the whole debate is really about: A common conjecture is that such a temperature rise will lead to an accumulation of water vapor in the lower part of the troposphere (the troposphere stretches upward from an altitude of 10 to 18 kilometers, depending on one’s location on the earth). The effects will, of course, be greatest around the equator (where temperatures are the highest and the sunshine is most intense). This water vapor will allegedly, given that it constitutes a powerful greenhouse gas, yield an above-ground rise in temperatures that far exceeds the temperature increase on the ground, though it will of course also affect ground temperatures. This high-temperature area in the troposphere is called the “hot-spot”. At this point one usually introduces the concept of feedback. A few of the scientists claim that the main feedback comes from the water vapor, and that it amplifies the effects of any temperature increase resulting from a doubling of the atmospheric concentration of CO2 by a factor of +3 to +6. This can be graphically illustrated (see the first causal figure).
Nevertheless, those atmospheric physicists who conduct satellite and balloon measurements provide less dramatic estimates. They typically state that, based on what until now – i.e. since the satellite age – has been possible to measure, the scenario depicted in the second causal figure is the most likely one.
Their explanation is that the water vapor does not, of course, remain only as such, but is instead transformed into clouds. Some of the clouds, for their part, will normally work as a cooling device considering that they reflect incoming sunshine.
This, to be sure, is the central point of deliberation of that part of the climate-change debate that proceeds among those scientists who have really tried to grasp what the issue is all about. How large is the feedback?
Measurements from balloons and satellites confirm that the temperatures in the troposphere are not rising at the rate predicted by the climate models. Satellite data also confirm that the outgoing, infrared (heat) radiation from the earth is not diminishing. That is contrary to what the climate models tell us.
The “father of global warming”, Dr. James Hansen, presented these predictions to the US Congress in 1988.
We see that his climate model predictions clearly exaggerated the future temperature rises.
The greatest bulk of heat in the climate system is in the oceans. It is therefore of outmost importance to get temperature data from the seas all over the world. Since mid-2003 the Argo system has been operational. The system consists of 3000 (± some) buoys distributed around all the oceans of the world. A typically Argo buoy is capable of diving down to a depth of about 2000 meters, measuring temperatures (and salinity) as it slowly ascends, and radioing the results back via satellite when it surfaces. And the results so far are illustrated in the figure “Climate Models vs Argo Data”.
In the natural sciences the operating modus is to test the hypothesis against measurements and/or laboratory experiments. If the measurements/experiments don’t confirm the hypothesis, you have to revise or scrap the hypothesis.
“It doesn’t matter how beautiful your theory is, it doesn’t matter how smart you are. If it (your theory) doesn’t agree with experiment, it’s wrong.”
Richard Feynman, Nobel laureate in physics
This is what is measured:
|Air temperatures from 1988||Over-estimated rise, even if CO2 is drastically cut|
|Ocean temperatures from 2003||Greatly over-estimated trend rise|
|Predicted atmospheric hot-spot||Completely missing –> water vapor feedback not amplifying|
|Outgoing radiation||Opposite to reality –> water vapor feedback not amplifying|
The climate models are fundamentally flawed. Their assumed 3- to 6-fold amplification by feedbacks does not exist. We therefore have no reason to believe that human caused CO2-emissions will have any adverse effect on the climate.