TCS Daily

Global Warming, Global Scepticism

By Hans H.J. Labohm - August 21, 2002 12:00 AM

In the 1970s and 1980s climate experts started to worry about the measured increase in the carbon dioxide (CO2) content of the atmosphere. On the basis of the known principle of the greenhouse effect, it could be expected that the temperature on the earth would rise. It seemed likely that the change was the result of the sharp increase in the use of fossil fuels (coal, mineral oil and natural gas). In 1988, under the auspices of the United Nations (UN), the Intergovernmental Panel on Climate Change (IPCC) was set up with the object of interpreting and reporting on developments in climate research around the world. These reports were intended to serve as advice for the participating governments. The main task was to examine whether there was indeed any question of climate change and in particular of global warming. If that were to be the case, international agreements might be needed to limit the use of fossil fuels.

The principle of the greenhouse effect is as follows. The earth is heated by solar radiation. This penetrates the earth's atmosphere and warms the earth's surface. The surface of the earth reaches a certain temperature, and incoming radiation is compensated by outgoing radiation. The atmosphere plays an important role in this interchange, because it retains a portion of the outgoing heat radiation. As a result, the average surface temperature of the earth has a pleasant value of around 15°C. Incidentally, this is not caused by the air itself, but mainly by the water vapour it contains and also by traces of a number of other gases, of which CO2 is the most important (alongside methane, nitrogen oxides and others). These allow the sun's rays to pass through but retain a portion of the outgoing heat radiation. Because of the similarity with a greenhouse, this effect of the atmosphere is known as the greenhouse effect. The greenhouse gases, such as water vapour and CO2, act like the glass panes in a greenhouse. If the CO2 content increases (through human agency), it can be expected that the surface temperature of the earth will also rise. This is known as the extra greenhouse effect.

"Precisely because the media and politicians generally announced the predictions of calamity as certainties, many scientists were prompted to voice their criticism loud and clear."
What we need to do is establish whether climate change is currently under way, whether there is already any global warming, and what can be expected for the future. It should be borne in mind that the climate cannot be predicted owing to its capricious behaviour, but that we can at most give projections for the future. And these are always based on a range of assumptions that will always be open to discussion. However, even if uncertainties remain about the possible consequences of an extra greenhouse effect, many people find it necessary to limit the use of fossil fuels on the basis of the precautionary principle. Another argument advanced for this is the inevitable future scarcity of fossil fuels.

Alarmist Standpoint of the IPCC

IPCC's reports contain three sections (drawn up by Working Groups): projected climate change; consequences of projected climate change; and possible measures to limit climate change.

Projected climate change has been examined by climate experts in several ways: first of all on the basis of worldwide measurements and additionally on the basis of models.

The CO2 content of the atmosphere is measured continuously. This fluctuates with the seasons, but the average value increased from 285 ppm in 1900 to 365 ppm in 2000, a relative increase of almost 25% (ppm = parts per million by volume). Temperature measurements have been used to see whether the average temperature on earth has in fact increased. To that end, the measurements collected at all weather stations around the world are averaged in a particular way (day and night, every day of the year, across the earth's entire surface). The IPCC reports a significant increase of 0.6°C during the twentieth century. This comprises an increase of 0.45°C in the period 1900-1930, a fall of 0.2°C in the period 1930-1975, and an increase of 0.35°C in the period 1975-2000. This last increase, which corresponds to 0.15°C every ten years, coincides with an observed increase in the CO2 content

Apart from surface measurements, temperature measurements have also been taken since 1959 using weather balloons and since 1979 using satellites. The latter measure temperatures across the earth's entire surface, something which is not possible with ground measurements. According to the IPCC, these show an average temperature increase of 0.05°C over ten years, which does not differ significantly from zero and falls within the inaccuracy range.

It has been observed that the length of most of the world's glaciers has shrunk significantly over the last fifty years, but this is related to a long term natural climate change (see below). Also a large number of local climate changes have been reported, but it is not certain that these are linked to climate change on a global scale.

"The almost blind trust that scientists have in advanced computer models, even when they are based on inadequate experimental data, is a phenomenon that has spread rapidly to almost all branches of science."
In addition, there has been very extensive work in the area of modeling, i.e. mathematical descriptions of the processes that occur in the earth's atmosphere. These encompass the phenomena which determine the local climate in each part of the world, combined with models for air circulation, interaction between atmosphere and oceans, and sea flows. Great progress has been made in this area over the last two decades in the sense that an ever larger number of effects have been incorporated in the models. The result of these developments is that there is increasing confidence in the predictive value of these models, despite the fact that they have become much more sophisticated. It should be noted that the IPCC very correctly does not speak about predictions but about projections. These projections are based partly on a number of assumptions regarding factors about which there is still uncertainty.

The IPCC has so far issued three major reports, the first in 1990, the second in 1996 and the third in 2001. With the successive reports, the warnings about possible temperature increases have become more serious. The IPCC assigns a probability to its projections for the future. For instance, the third report assigns a probability of 66-90% to the projection that the average temperature of the earth will increase by between 0.1 and 0.2°C every ten years over the coming decades. However, for the entire 21st century, a larger temperature increase is projected, of between 1.4 and 5.8°C for the hundred-year period. This difference arises from certain assumptions about future CO2 content (see below). Thus, there would appear to be a prospect of considerable global warming. On the basis of these projections, a significant rise in sea level is predicted, with the danger that low-lying countries would be submerged.

The way that the IPCC works has important consequences for the final reports. First of all, results of scientific research are collected, but these are then interpreted by the Working Groups. This means that a personal viewpoint is unavoidable. It is striking that the IPCC reports' Summaries for Policymakers make constant reference to the uncertainties surrounding the projections, whereas they also give explicit warnings about the unfavourable consequences of the climate changes that are depicted as being probable. In fact, the IPCC takes a clear stand in this respect, which can be summed up as follows: future catastrophes are inevitable unless there is drastic action by man.

Sceptical Standpoint of a Number of Scientists

The fairly uncompromising stand of the IPCC prompted criticism from scientists outside IPCC circles as long ago as 1990. After the second report in 1996, the criticism increased considerably. Nevertheless, the pronouncements of the IPCC were still quite cautious at that time: "The balance of evidence suggests a discernible human influence on global climate". Yet statements were issued that could be interpreted as dramatic predictions. After the third report in 2001 the criticism increased further. Precisely because the media and politicians generally announced the predictions of calamity as certainties, many scientists were prompted to voice their criticism loud and clear. In America this took the form of a public debate, initiated to a large extent by S.F. Singer and R.S. Lindzen. In Europe the criticism was until recently mostly ignored by the media. Apparently, in political circles it is regarded as "politically incorrect" to doubt the doom scenarios (see below).

The most important points of the scientific criticism of the IPCC's assertions are as follows. Determination of an increase in the average temperature of the earth from surface measurements is insufficiently reliable. Satellite measurements, which point to an unchanged temperature, seem more reliable. In addition, it is still not possible to distinguish clearly between possible short-term climate changes and long-term climate changes such as the warming after the last ice age. Moreover, the predictions of future developments in the CO2 content of the atmosphere are based on assumptions that may turn out to be wrong. The greatest uncertainties concern the rate of CO2 absorption by plants and oceans. Finally, the climate models that are used to make projections about the future are insufficiently reliable since they fail to take adequate account of certain effects, in particular the influence of variations in solar activity, changing cloud cover and aerosols (very fine dust particles).

These points of criticism are examined in more detail below. Temperature measurements taken at weather stations around the world are carefully averaged, taking account of the uneven distribution of such stations across the earth's surface. However, here there might be a question of various distorting effects which all point in the same direction. In the first place, temperatures are measured primarily on land, whereas more than 70% of the earth's surface consists of water. This can create significant distortions. Furthermore, the majority of the weather stations are in inhabited areas, with only a few in the thinly populated regions that form a large portion of the world's surface. Although temperatures can be measured everywhere with an accuracy of 0.1°C, there are such large holes in the measurement network that it is not easily possible to determine with the same accuracy the average temperature of a large country such as Australia, which has only a few small and densely populated regions alongside very large, almost unpopulated areas. This applies to an even greater degree for the world as a whole. It has also emerged that the temperature is significantly higher in urban areas than in the countryside, with an even more marked difference in large agglomerations (up to 2°C). In the course of the last twenty years urban areas have expanded almost everywhere and some of the more remotely located weather stations have been closed. This in itself ought to lead to a measured temperature increase. For determination of the average temperature of the earth's entire surface, enormous local differences of as much as 100°C have to be taken into consideration (e.g. between Verchoyansk and Jeddah). The further apart the extremes of temperature, the less accurate the average. Something similar applies for differences between day and night, and between the seasons. When these aspects are taken into consideration, it must be concluded that satellite measurements offer the only possibility for determining a real average world temperature accurately.

With regard to the distinction between short- and long-term changes, geophysicists in particular warn us for premature conclusions. Over the last millennium the temperature has moved up and down, and we are now on the upward curve that started about 300 years ago at the end of the so-called Little Ice Age. There are reasons to expect that the temperature will start to fall again in future centuries.

The behaviour of carbon dioxide is the key to assessing what extra greenhouse effect can be expected. The CO2 content of the atmosphere is the result on the one hand of emissions, largely from micro-organisms and animals, and on the other hand absorption, primarily by plants on the land and in the sea. Man adds about 4% to natural emissions. It has been observed that natural absorption increased by about 2% in the 20th century, mainly in the second half, which means that almost half of human emissions is now absorbed. The non-absorbed portion caused an increase in the CO2 content of the atmosphere of about 25% as compared with the level in 1900. It is expected that human emissions will increase further. For this, several scenarios can be envisaged. It is also expected that absorption will increase, because it is roughly proportional to the concentration in the atmosphere. The IPCC is very pessimistic about the extent to which this will happen. The IPCC assumes that absorption into the oceans will fall in relative terms, whereas not much is expected from the effect of plant growth (these two assumptions form the most important basis for the projected warming). However, this is expressly contradicted by a wide range of experts. If there is more plant growth, absorption by plants must increase even progressively (i.e. more than proportionally to the increase of the CO2 content of the atmosphere). If absorption were indeed to increase by a few percentage points, human emissions in the future would be completely absorbed. However, there are still insufficient scientific data in this area.

But the most serious criticism concerns the models. We now have supercomputers that can handle highly complicated models, but the climate is so complex that we will always have to employ models that are a simplification of reality. As a result, the accuracy of the predictions is necessarily limited. An important complication is that the climate behaves chaotically, reducing the accuracy of predictions as the length of the period covered increases. Some people argue that predictions can never be made for a period of more than a few years, even with the best models and the largest computers. Another important point of criticism relates to insufficient knowledge of various processes which play an essential role in the climate. This relates in particular to the influence of changing solar activity, variations in cloud cover and the effect of aerosols deriving from human activities. Cloud behaviour is perhaps the most important factor. It is clear that higher temperatures generally lead to more evaporation, generating more clouds which keep solar heat at bay. Of course, this effect is widely known, but due to great local variations it is not yet possible to model it adequately. Similar effects seems to play a particularly important role over the Pacific Ocean, but a great deal more research needs to be done (see Lindzen).

The problem is that, when such phenomena are inadequately incorporated in the climate models, the modelling results may be completely wrong. This means that probabilities attached to the IPCC's pronouncements lose their significance. These only make sense if we are certain that the best possible account has been taken of all relevant effects.

"If we view Kyoto as an insurance policy, it is a policy where the premium appears to exceed the potential damages, and where the coverage extends to only a small fraction of the potential damages."
Another important point is the question why the clear increase in CO2 content has not led to markedly higher temperatures. It should be remembered that surface temperatures went up and down in the course of the 20th century, whereas the temperatures measured by satellites since 1979 have been virtually constant (see above). According to the greenhouse theory, temperatures should have risen continuously since 1930. No satisfactory explanation has been found for this discrepancy, which in itself implies a criticism of climate models.

The almost blind trust that scientists have in advanced computer models, even when they are based on inadequate experimental data, is a phenomenon that has spread rapidly to almost all branches of science. When using complicated models it is of the greatest importance to indicate explicitly the assumptions and simplifications on which those models are based. The IPCC has neglected to do this in its Summaries.

Lastly, it should be pointed out that, even if there were no general temperature increase (global warming), there may still be climate change. In the first place, climate change has been continuous in the geological history of the earth. But, in principle, it is conceivable that the increasing CO2 content of the atmosphere may still lead to unforeseen effects. After all, if the projected extra greenhouse effect of CO2 were to be fully offset, for instance through more cloud formation or increasing emissions of aerosols, these may in turn have other unforeseen effects. Not enough is yet known about this.

Social Consequences

As indicated above, the sceptical standpoint is regarded as "politically incorrect", certainly in the Netherlands. Many people believe that the western economy is excessively based on squandering raw materials and energy, which means that we are heading for a future shortage, while we spoil nature irrevocably with the resulting waste products. In addition, many have the idea that we live in a world that can be completely controlled by man, a world in which human behaviour can in principle be steered, preferably by democratic means. People with this basic position are antipathetic to the sceptical scientific standpoint regarding climate change summarised above. But, in our view, these points of view are open to separate discussions. Another important effect is a widely expressed doubt about the integrity of sceptical scientists demonstrated by the media and politicians. When certain scientists announce a standpoint, it is all too readily assumed that this standpoint was dictated by industry that pays their research. It is silently assumed that a scientist who expresses the sceptical view is paid by the oil industry. He is also automatically a proponent of wasteful behaviour and thus partly responsible for exhaustion of raw materials and degradation of the environment. Needless to say, this is lacking in logic.

The assumption of a controllable world is also an important point for debate. Hitherto there are no indications that the world is in a position to steer population growth and the associated economic growth effectively.

From Kyoto to Bonn

Nevertheless, the United Nations Framework Convention on Climate Change should be regarded as an attempt to manage one element, namely emissions of greenhouse gases. Agreements have been reached in this framework, enshrined in the so-called Kyoto protocol dating from 1997. In this protocol the developed countries committed themselves to reduce their combined emissions of greenhouse gases by at least 5% in the period 2008-2012 as compared with the level in 1990. It was the original intention that the sixth conference of the parties to the climate convention, held in The Hague in November 2000, would see years of negotiations on reducing emissions of greenhouse gases crowned with specific commitments on the measures to be taken by countries in order to realise the objectives of the convention. But this conference turned into a fiasco. The same was true of the subsequent attempts made in April 2001 by Minister Pronk, in his capacity as chairman of the conference, with the particular aim of convincing the Americans to join the convention The new Bush administration had initially restricted itself to rejection of certain technical implementing measures in the convention. But the American position had in the meantime hardened into what many saw as a rejection of the principles of the convention, a point that was later denied by the American administration.

The American refusal to take part also led countries such as Japan, Canada and Australia to change their position, as became clear at the climate conference in Bonn and the G-8 summit in Genoa (both in July 2001). The fact that the climate conference in Bonn ended at the last minute with an agreement that these countries could endorse must be regarded as a minor miracle. There can be no doubt that this should be ascribed to the determination of the chairman of the conference, Minister Pronk. For this, he has rightly won respect and admiration. Nevertheless, it was a Pyrrhic victory. After all, the outcome of Bonn implies a considerable dilution of the commitments initially proposed: the agreed (but not yet ratified) reduction in emissions of greenhouse gases is now equivalent to roughly one third of the original objectives. As a result, the formal framework of Kyoto remains in place but the content, in terms of substantial emission reductions, has been substantially diluted.

What does a cost-benefit analysis of Bonn show? Without contributions from countries that are responsible for a considerable portion of CO2 emissions such as the US, the beneficial effect is zero. Incidentally, that would already have been the case if the US were to participate. In a letter to the editor of the New York Times 27 March 2001, Klaus Heiss wrote on this subject: "... there is little chance of reducing energy consumption in the United States by 30 to 40 percent within a decade. But beyond this, Kyoto is also ineffective. Even if the mandatory targets for emission reduction were enforced and one were to accept the computer simulations underlying the IPCC speculations as to the next 100 years, global temperature in 2050 would be reduced by only 0.05 degrees Celsius, an amount too small to measure with standard thermometers". According to some authors, the diluted compromise of Bonn would further reduce the benefit to 0.02°C. The supporters of Kyoto counter that the agreed measures still represent a political breakthrough: it is a first step which should be followed by further steps, the idea being to reduce use of fossil-based energy by 60-80% in 50 to 100 years.

There is also great uncertainty about the costs of Kyoto. The IPCC gives a range of (model) outcomes averaging from 0.2 to 2% of GDP (gross domestic product) in 2010 without CO2 emissions trading and from 0.1 to 1.1% of GDP in 2010 with emissions trading. In the literature we find higher estimates of around 4% of GDP in 2010 for the US, but these studies are based on extreme and unrealistic assumptions about emission reductions.

How should we weigh these costs and benefits against each other? Richard Lindzen, a meteorologist of the Massachusetts Institute of Technology and a (critical) member of the IPCC, once said: "If we view Kyoto as an insurance policy, it is a policy where the premium appears to exceed the potential damages, and where the coverage extends to only a small fraction of the potential damages".

Tradable CO2 Emission Rights

If we suppose that the IPCC is right, the question remains as to whether an effective global policy to reduce emissions of greenhouse gases, in particular CO2 , is at all possible. Many economists hold the view that, if something is to be done to reduce emissions of greenhouse gases, this can be achieved better in a market-based way via trade in emission rights than exclusively via regulation.

There is support for such an approach even among greens. Large portions of the business community object, but there are also companies, in particular a small number of large energy producers, who see advantage in clear rules for emissions of greenhouse gases, so that they know where they stand. They advocate ceilings, linked to a regime of tradable emission rights in line with the Kyoto convention. Although the American administration has rejected this convention, it is still considering introduction, at national level, of a system of voluntary measures to reduce CO2 emissions, including tradable emission rights. However, the Americans Robert Crandall and Fred Smith have expressed doubts over this approach. If the American administration believes that the scientific basis for the Kyoto convention is too meagre to justify far-reaching measures, why should it now be thinking about introduction of such a system? Conversely, if the Bush administration believes that the current CO2 concentration in the atmosphere is already too high, why should it make it easier for companies to emit more greenhouse gases than would otherwise have been allowed, by buying emission rights? The logic is flawed somewhere.

In a system of emission rights governments create an artificial shortage of energy and subsequently allocate rights to use this energy to individual companies. These companies then have a sort of monopoly. As a result, they have an interest in preventing any reversal of the artificial shortage, for instance as a result of technological breakthroughs or new climatological insights which show that man-made emissions of greenhouse gases have hardly any influence on the climate. After all, in that case, their emission rights, which they may have bought for a great deal of money, would have no value.

How should emission rights be shared out? Some companies have already invested heavily in clean technology. How can we avoid these companies being put at a disadvantage vis-à-vis competitors that emit more CO2? In addition, an international system of tradable emission rights requires monitoring of implementation and, if necessary, enforcement of contracts. For instance, who decides how much new forest should be planted somewhere in the world in order to offset a given quantity of emissions? The amounts involved will probably be considerable and the temptation to cheat will be great. All this will require a large international bureaucracy.

Furthermore, such a system runs the risk of conflicts, in the form of sanctions to compel enforcement. That could lead to trade wars or, at the very least, increasing international tension and accusations of eco-imperialism. It is also conceivable that purchase of emission rights by western companies in the Third World will place a brake on local industrialisation in those countries because the CO2 emissions quota have already been sold.

There are also dangers outside the material sphere. Granting power to politicians to determine who in society may use energy forms a major threat to the individual freedom of the citizen. In countries that practice "crony capitalism", this could strengthen the position of those currently in power and their followers, resulting in discrimination against companies that do not enjoy close relations with the local strongmen. It is also conceivable that minority groupings will be the losers under politicised distribution systems.

Accordingly, CO2 emission rights should be traded via the market. What supporter of free markets could object to that? But appearances are deceptive. After all, elements of central planning would be incorporated in our market economies under the banner of market conformity, which would represent a clear change in the development trend of our economic order towards more market and less government over the last twenty years.

All in all, it can be said that there is still great uncertainty about the question whether the earth is warming and, if it is, whether this can be ascribed to man-made emissions of CO2 and other greenhouse gases. It is also uncertain whether any global warming has harmful effects or even positive effects (e.g. stimulation of plant growth as a result of higher temperatures and CO2 concentrations). With regard to the cost-benefit analysis of measures to reduce man-made greenhouse gas emissions in line with the Bonn agreement, it can be pointed out that the beneficial effect is zero, whereas the costs will probably run to trillions of dollars worldwide over a period of ten years. Those who attach great value to the precautionary principle regard this insurance premium as justified. But critics point out that mankind is also confronted with a range of other risks. Rich and affluent societies are better able to adjust to changes of all kinds, and can protect themselves against various types of risk. For that reason, they regard the loss of well-being that flows on from large-scale measures to prevent (supposed) global warming as a waste of money. Finally, there are major political, economic and technical objections to the proposed mechanisms to reduce man-made emissions of greenhouse gases, in particular tradable CO2 emission rights. A solution is not in sight.

Dr H.H.J. Labohm is a senior visiting fellow at the Nederlands Instituut voor Internationale Betrekkingen Clingendael. Dr Ir D. Thoenes is a former professor of chemical processes studies at the Technische Universiteit in Eindhoven.


S.F. Singer, Hot Talk, Cold Science. Global Warming Unfinished Debate, The Independent Institute, Oakland CA, 1997

S.F. Singer, The National Academy of Sciences Issues a Distorted Report.

R.S. Lindzen,
Global Warming: The Origin and Nature of the Alleged Scientific Consensus

R.S. Lindzen,
Testimony before the US Senate Commerce Committee, 1 May 2001.

R.S. Lindzen, Scientists Report Doesn't Support Kyoto, The scientific report you've heard about does not say what you have heard, says one of its authors, Wall Street Journal, 12 June 2001.

A version of this article was first published in the Internationale Spectator.

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