Although international negotiations have made hardly any progress in the past few years – and the hoped-for binding international agreement remains a highly improbable prospect – the debate continues about the extent and attribution of global warming. It is sometimes difficult for a neutral observer (if there are any left) to make head or tail of the situation. On one hand, they hear that there has been no warming trend since 1998, but on the other hand reports continue to come out about the rapid rate of Arctic ice melting or greater extremes in the weather. The situation is like a pantomime, with one character continuing to say ‘oh yes it is’ while another shouts ‘oh no it isn’t’.
This week, the World Meteorological Organisation has made its own contribution to the ‘yes it is’ camp with a new report: The Global Climate 2001-2010 – a Decade of Climate Extremes (20 page summary, with the full report also available from the WMO website). The WMO, we should remember, is the co-sponsor of the IPCC, together with the UN Environment Programme. It is very much part of the mainstream of what we can rightly regard as the climate change industry. The premise on which the IPCC was formed was that human activities had become the main driver of climate change, its role being to gather the evidence and propose mitigation and adaptation actions.
Not surprisingly, then, the report has found evidence which supports its case, and the authors set out their stall very clearly via the title and the opening paragraph of the foreword from Michel Jarreau, the organisation’s secretary-general:
“The first decade of the 21st century was the warmest decade recorded since modern measurements began around 1850. It saw above-average precipitation, including one year – 2010 – that broke all previous records. It was also marked by dramatic climate and weather extremes such as the European heatwave of 2003, the 2010 floods in Pakistan, hurricane Katrina in the United States of America (USA), cyclone Nargis in Myanmar and long-term droughts in the Amazon Basin, Australia and East Africa.”
The two key take-away messages from the report are that the first decade of this century has been the warmest on record and that weather patterns are becoming more extreme. Let’s take these individually. The first message is summed up in their statement that “A pronounced increase in the global temperature occurred over the four decades 1971–2010”. However, it is well accepted that the period of general temperature increase only lasted from the mid-70s until 1998. Since then, there has been no trend in either direction. How long this plateau will last is anyone’s guess. In the meantime, the WMO statement is factually correct but somewhat misleading.
It is well established that the world has been emerging from the so-called Little Ice Age over the entire period for which modern records are available. The record also shows that this recovery has not been steady, with the decades from the 1920s to 1960s showing a very similar pattern to the period from the ‘70s until now. Going further back, the Roman and Medieval Warm Periods are further evidence of how climate can vary quite significantly with or without our help. That is not to deny that burning fossil fuels or clearing land for farming does not have an impact. It clearly must, but it has not been the dominant factor in the past. It is really for the WMO and others to offer proof that the positive feedback loop which supposedly reinforces the so-called greenhouse effect is real and having an impact. Just using modelled data and saying there is no other explanation is simply not a good enough reason to try to re-engineer the global economy.
Similarly, the statement that the Noughties have been the warmest decade since modern record-keeping began is factually correct but misleading. Since there has been a rising trend for pretty much the whole of that period, it is inevitable that later years will be among the warmest. The statement seems designed to reinforce the message that average temperatures are continuing to increase, whereas they have not done so since 1998.
It is tempting to suggest that the focus on extreme weather in this report is because the case for a dominant role of mankind in global warming has become weaker. The climate change industry would deny that, but it is nevertheless interesting to see the change of tack. In this case, the authors are being somewhat disingenuous. For example, they use the example of hurricane Katrina as evidence of increasing extremes, whereas Katrina was not particularly fierce by hurricane standards. The problem was that it made landfall in a densely populated area with unique flood hazards and inadequate defences.
Overall, there seems to have been a relatively quiet period for Atlantic hurricanes in recent years, certainly with no trend towards greater intensity. Numbers have increased to some extent in the last two decades, but they are known to follow a 50-70 year cycle. Numbers of tropical cyclones (the general term for such violent storms, which includes Atlantic hurricanes and Asian typhoons) has remained stable overall. Greater economic damage has resulted because of larger populations living in vulnerable areas, but loss of life is generally low in developed regions. Cyclone Nargis was a disaster for Burma and was in the top ten in terms of destructiveness, but not unprecedented.
The 2003 European heatwave is another often-quoted climate extreme, but such events are not rare and are caused by stationary areas of high pressure. The fact that this particular one covered much of France and caused significant loss of life, particularly among the elderly in cities such as Paris, certainly made the headlines, but was due in part to inadequate monitoring and medical backup for vulnerable people. The droughts in East Africa and Australia are in areas prone to regular periods of low or no rainfall and are by no means unusual.
This stream of correct, carefully-worded but misleading statements will doubtless continue. Those who already accept the IPCC view will see them as further vindication, while those who are more sceptical – including, I hope, most readers of this piece – will try to deconstruct them and come to their own view about the underlying reality. The pantomime has not yet reached the final act.
The Scientific Alliance
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