Debate

Is the burning of fossil fuels causing climate change?

RAPID CLIMATE change caused by the burning of fossil fuels has become a major social and political issue internationally.

A number of attempts to cut greenhouse gas emissions - such as the Kyoto protocols - have been an abject failure as the biggest emitters, China and the US, refuse to accept internationally binding targets.

Even willing signatories to Kyoto etc, such as Britain, will miss their 2012 targets. But sections of capitalist industry, especially the big energy giants, and some scientists, have questioned whether the burning of fossil fuels is actually responsible for global warming.

One reader of The Socialist, Tony Simmons, is a climate change sceptic and has challenged the Socialist Party's position on the issue. Below left we print his contention that the world may be cooling instead.

In reply, Pete Dickenson, author of the Socialist Party's pamphlet Planning Green Growth, takes up Tony's arguments.

Although the argument rests on the weighing of scientific literature on the subject and can be somewhat technical in nature, we welcome readers' views on this debate (in not more than 200 words please).

Global cooling instead?

MANY PEOPLE will not be aware of this, but there are two competing theories of climate change. While the prevailing anthropogenic theory based on greenhouse gas emissions continues to hit the headlines with predictions of catastrophic global warming, some proponents of the alternative theory based on solar activity are predicting a period of global cooling.

The juggernaut of conventional greenhouse gas theory has run into problems in recent years. Global warming peaked in 1998, the IPCC in their latest report have downgraded man's impact on global temperatures, revising their predictions of sea level rise down, and the famous hockey stick graph has been utterly discredited.

Climate models continue in their inability to reliably model past climate or consider other potential variables, so we get predictions which are simply not valid. Jim Renwick, a lead author of the IPCC working group 1 report admitted as much, "Climate prediction is hard, half of the variability in the climate system is not predictable, so we don't expect to do terrifically well"1.

At the same time, another theory pioneered by Henrik Svensmark of the Danish National Space Centre has been making strides in peer reviewed literature. The theory argues that changes in the magnetic activity of the Sun modulate the intensity of cosmic rays reaching the Earth. This in turn causes changes in the amount of low cloud cover, which regulates average global temperatures.

This theory has had problems of its own; the Sun's output varies by less than 1%, not enough to cause such large temperature changes as observed on Earth, but cosmic rays in this case act as an amplifier.

The recent paper by Lockwood and Frohlich2 concluded that "Our results show that the observed rapid rise in global mean temperatures seen after 1985 cannot be ascribed to solar variability, whichever of the mechanisms is invoked and no matter how much the solar variation is amplified."

However, in December, a new peer reviewed study by David Douglas et al has argued that recent temperature trends are better explained by the solar factor3. Svensmark's upcoming CLOUD experiment should clarify matters within a few years.

Looking to the future, many solar physicists, including those at NASA, are predicting that solar cycle 24 will be weak and for solar cycle 25 to be the weakest in centuries. The effect on our climate could be a net cooling of round 1.5oC peaking around 2030 according to some at the Russian Academy of Science.

Which of these two climate theories will prevail? We should know within a decade.

1. Carter B, James Cook University, 07/07/2007.

2. M. Lockwood & C Frohlich, 2007. 'Recent oppositely directed trends in solar climate forcings and the global mean surface air temperature' Proceedings of the Royal Society, www.publishing.royalsociety.org/media/proceedings_a/fulltext.pdf

3. D. H. Douglass, J. R. Christy, B. D. Pearson, S. F. Singer, 2007. 'A comparison of tropical temperature trends with model predictions' International Journal of Climatology, www3.interscience.wiley.com/cgi-bin/abstract/117857349/ABSTRACT?CRETRY=1&SRETRY=0

Action can't be delayed

TONY SIMMONS raises many highly contentious points in his article that challenge much of what has been written in The Socialist on global warming over the past ten years.

The first is a possible implication that the competing theory on climate change that he refers to, which predicts global cooling rather than warming, is comparable in scientific credibility to the accepted theories of human-induced global warming. This is emphatically not the case, contradicting the impression that could be given by Tony's remarks that scientific opinion is balanced on this question.

The research of Hendrik Svensmark that he mentions has not established an accepted theory of global cooling, since the little evidence that Svensmark or his co-workers have produced to support their claim has been promptly refuted in the scientific press. Again, Tony's contribution, by quoting one article for and one against Svensmark, could imply that the balance of scientific opinion is even, which would be misleading.

A recent paper of Svensmark in Proceedings of the Royal Society reported that cosmic rays cause tiny particles to form in the atmosphere, a finding which he claimed in a press release showed that variation in cosmic radiation drives climate change.

However, even assuming this result is subsequently corroborated which is open to doubt given his past record, a link between particle formation and cosmic radiation would do no more than provide a small initial piece in the jigsaw needed to support a possible theory and it was totally irresponsible to claim otherwise.

It is significant that this claim was not made in the Royal Society paper itself, which is peer reviewed to check for scientific veracity, but in an attached press release. (These criticisms have been taken up in more detail by George Monbiot, see www.monbiot.com/archives/2007/03/13/channel-4s-problem-with-science/).

In contrast to the cosmic ray model, the theory of human-induced global warming is almost universally accepted and is backed up by an increasingly vast and persuasive empirical literature.

Other points or implications made by Tony are equally contentious, for example, it is stated without amplification that global warming peaked in 1998, possibly implying that the trend is now downwards and the worst is over. Such an implication would be unjustified however, because although the hottest year to date was in 1998, since then temperatures have remained close to record levels, and the highly respected Hadley Centre is predicting that from 2010 onwards every year has a 50% chance of exceeding the record year of 1998.

Another point made to support the cooling theory is that the IPCC has lowered its prediction of increased sea levels due to global warming. In my opinion however, this is just a sign of the extreme conservativeness of the UN body, which wants to maintain the maximum political consensus on the issue in the face of the climate-sceptic attack by George Bush and 'Big Oil'.

Recent articles in the highly respected journals Environmental Research Letters and Nature Geoscience have taken up this issue and concluded that the IPCC estimates could be massively understating the problem. Also, as discussed in the latest edition of Socialism Today, some of the data used by the IPCC was ten years old, since which time there is evidence that the situation has deteriorated.

Hockey stick

The next point Tony makes is to question the 'hockey stick graph' that claimed that the 20th Century was the hottest in history. Whether the hockey stick data can be challenged is not decisive in the debate however, since it is recognised by all concerned that the temperature of the earth fluctuates naturally, producing significant shifts in global temperatures throughout history. The issue now is that a new phenomenon has arisen that is human-driven, that acts over and above natural fluctuations.

It is a mere hypothesis that there could be a natural downturn in global temperatures that may counteract the effects of human induced warming, since there is no significant evidence to back it up, contrary to the prediction in Tony's article that variations in solar activity are driving cooling. In fact, in theory, the opposite could happen with natural fluctuations reinforcing warming effects due to fossil-fuel burning.

Another issue raised is how useful are models to predict climate change, since, as a member of the IPCC working group is quoted as saying, half the variability of the climate system is unpredictable.

As mentioned above, there has always been a naturally occurring variation in global temperatures, whose presence builds in some uncertainties, but models can now discriminate between these and human induced factors, meaning that predictions of anthropomorphic warming are not undermined. Therefore, there is no reason to delay taking action on human-driven global warming, as implied by Tony's wait and see conclusion, not least since the consequences of inaction are potentially catastrophic.

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In The Socialist 17 January 2008:

Fight for a living wage