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The fuss about the hacked emails from researchers at the Climate Research Unit, University of East Anglia, the misinformation of the disappearance of Himalayan glaciers and, maybe the most important, the cold spells in much of Europe in January and December 2010 have been meat and drink to climate change sceptics. I will try to put matters into perspective.

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Informed comment

I am not a climate scientist but I am a meteorologist who knows something about the arguments and who has had responsibility for maintaining climatological data sets. What follows is my take on the situation.

To see some rather more informed comments on the science from a respected scientist with an international reputation, I can do no better than refer to Professor Slingo, Chief Scientist at the Met Office. She has used the Met Office YouTube Channel to answer queries. Or, you can read the transcript as a PDF file (355 kb). For more extensive information on all aspects of climate change theory and observations the Met Office Hadley Centre has produce much information of high quality. The Hadley Centre was set up by Mrs Thatcher and charged with studying all aspects of climate change in a thouroughly scientific manner

Observations from weather stations

There has been much discussion about the use of records from weather stations and the University of East Anglia has done much research into the evaluation of data sets. It is a thorny problem and few good long term records exist. One is the Met Office Central England Temperature series. This dates back to 1659 and is a composite of records from a number of sites.

Compiling and maintaining the series involves some advanced statistical methods in order to adjust records from different stations to provide a best endeavours homogeneous record. Those wishing to criticise the use of such data have plenty of opportunity because instruments have changed over the past 350+ years and, together with changes in land use and urbanisation, have to be taken into account. This is not an exact science.

Because it is all too easy for the sceptics to pick holes in data and the use of any particular observing site, I can well understand the nervousness of the University of East Anglia Climate Research Unit to divulge their data sources. They were wrong to do so, that is clear. As a reputable group with long experience in the field I am sure that they can defend their analyses. However, the climate change deniers, as was the case in the long running tobacco smoking and cancer controversy, will pick on any weakness, apparent or real, in data. The Royal Society examined all the facts in the cold light of day and gave a clean bill of health.

Glaciers

The statement that the Himalayan glaciers would disappear by 2035 seems to be an incorrect deduction from the observations and the climate model data. However, the retreat of glaciers is well documented and cannot be denied and the rror in that paragraph of the latest International Panel on Climate Change report is not a serious shortcoming.

The cold spell of 2010 and 2011

It must seem paradoxical to the lay-person that we are in a period of global warming but can have abnormally cold weather. That is easily explained as the difference between day to day weather and long term climate. In fact, one of the predictions of the climate scientists is that weather will become more variable and more extremes are likely. Our cold January in 2010 has been put into a global context by NASA announcing that, globally, January 2010 was the warmest over the past 30 years.

The science of climate change

There are three approaches to the problem using -

  1. Instrumental data systematic records
  2. Surrogate data from paleontological records
  3. Modeling of the atmosphere.

Taking these in turn

Data and data records

These are always going to be subject to criticism but the sceptics and climate change deniers should make an effort to study the data and provide reasoned suggestions when they are used uncritically. They should not just say that data are invalid because of site changes. They should query how instrumental, site and other changes are taken into account.

Surrogate data

This includes tree ring data, ice cores, fossil data on vegetation and animal behaviour - where they exist or not as the case may be. Again, there can be uncertainties that sceptics can attack. Those on both sides should be able to justify their assertions and deductions; it is not sufficient for sceptics to say simply that the data are not reliable. Such statements should be subject to critical review.

Modelling of climate

This is where there has been much development mainly over the past 30 or so years in line with modelling for numerical weather prediction. The atmosphere is inordinately complex in its interactions with the oceans and the earth. Physical, chemical, biological effects have to be assessed and calculated; this includes the effect of human activity. As more people of different disciplines get involved, as computers become more powerful, as more studies of the various processes are made, so the models become more and more complex. There are no easy or straightforward answers.
What we do have is a vast effort by scientists, mathematicians and computer scientists of high calibre. There are uncertainties, as in many fields of science, and as those working in the field are only too willing to agree. All that can be done is for the modellers to make their best assessments and give error bars for their results. It is significant that those doing the modelling come up with broadly similar answers. I have yet to hear about such modelling indicating otherwise.

Impacts

On curren trends, assuming that effects such as the observed glacier melting continues, there is likely to be considerable hardship for many. With the expected acceleration due to the possible release of methane from the thaw of the Siberian tundra and the reduction in absorbtion of carbon dioxide by the oceans it could get far worse.

One of the many uncertainties is the variation from region to region and some areas may well benefit. However, sea levels are certain to rise as ice caps melt further and sea water expands with higher temperatures. Some islands will disappear as will low lying coastal areas. Extremely worrying for those living in temperate latitudes is the increased desertification with many millions of already poor nations and people placing greater demands on diminishing resources.

My conclusions

It is a difficult subject with many uncertainties but we have to weigh up the evidence. Sceptics, if they are to be taken seriously, should make reasoned cases where they believe the science is wrong. Hand waving, emotional statements do nobody any good and do not advance our knowledge in any way. They simply cause the scientists to go on the defensive with the unfortunate effects of the UEA Chinese station data as a salutary example.

I do not think that we should play Russian roulette with the future of the planet and, until such time as the best science suggests otherwise, we must plan for the worst knowing that the worst might not happen. In any case, we must recognise that fossil fuels are a diminishing resource and will become increasingly costly to extract. For the sake of future generations we must push on and develop alternatives.


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