Tag Archives: climate science

No man-made global warming in Ireland, thank you

My letter on global warming in The Irish Times (see post below) got a response from an Irish lobby group called Turn 180. The sub-title of their blog is ‘Humans are not causing global warming’, top marks for clarity there. You can read their objections in their own words here.

The Turn 180 blog got me thinking about why there is so much resistance to the whole idea of an enhanced greenhouse effect. Below are some favourite points:

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Q1. Why do climate scientists keep banging on about recent changes over the last few decades, when everyone knows that, by definition, it is only meaningful to talk about climate over extremely long timeframes?

A. Studies of past climate changes (yes, climate has certainly changed in the past) suggest that once started, climate change tends to happen quite quickly due to feedbacks – with noticeable effects over decades rather than hundreds of years.

Q2. If climate change has occurred in the past, clearly not linked to human activity, why are the boffins so sure it’s different this time?

A. The fact that climate change has had natural causes in the past doesn’t mean it can’t have a man-made cause now. We know greenhouse gases (GHGs) in the atmosphere such as C02 play a major role in regulating the heat of the earth and we know we have increased the GHG concentration by over 40%. It would be very nice to show that this has had no effect on climate, but the evidence points the other way. In particular, measurements of infra-red radiation emerging from the atmosphere into space show it has been steadily decreasing over recent decades. This matches the rise in temp measurements, ice melt and sea-level rise measured worldwide. At the same time, there is no matchup between the recent temp rise and natural cycles  (e.g. studies of sun cycles, earth orbit cycles etc suggest we should be in a cooling cycle).

Q3. Isn’t it true that C02 rise has followed temp rise in past climate change, not vice versa?

A. Yes, but the data also show that once started, a rise in C02 leads in turn to further temp rise. Ouch.

Q4. What’s all this about consensus, hasn’t scientific consensus been wrong in the past?

A. Yes; Scientists like evidence, not ‘he said, she said’. However, if a serious threat to society is perceived (think meteor or alien invasion) the first thing is to find out if the experts are agreed amongst themselves. The IPCC was set up for precisely this purpose, to collate and make sense of the many hundreds of diverse scientific studies of various aspects of global warming. The most striking aspect of the IPCC reports is how closely the studies agree – all this from scientists who like nothing better than proving each other wrong.

On consensus in science, it’s quite hard to find examples in modern science where the consensus was wrong, from the dangers of tobacco to the ozone layer. Examples quoted usually predate the rise of the scientific method.

Q5.Ok, so what is the principle at work in the current climate change?

A. The physics of the greenhouse effect is quite straightforward. The earth’s heat balance is regulated by certain gases in the atmosphere that trap emerging heat, known as greenhouse gases. Given the sensitivity of the earth’s heat balance to greenhouse gases, and given that we have increased their concentration by 40%, one would expect a gradual increase in trapped heat and temperature. This is exactly what we measure, in many different ways.

Q6. Any good news?

A: There’a a Nobel prize waiting for anyone who can show that carbon emissions don’t matter i.e. that greenhouse gases created by human activity quietly disappear instead of clogging up the atmosphere (about 50% currently gets absorbed by the oceans, but that is also causing problems and cannot last). Drinks on me if you do prove this.

Update

There is a reference to a really interesting paper in the comments section, thanks Justin! The paper, by Tony Dorlas of the Dublin Institute of Advanced Studies, takes a most unusual and simple approach; in the complex system that is climate, take the one parameter that is varying in a systematic way  (C02), explore from first principles what variation in average temperature this parameter could lead to, and compare the results to the measured warming. The result is pretty thought-provoking, see here

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Where is the global warming?

A few days ago, the letter below was published in The Irish Times, Ireland’s most respected newspaper:

Sir, – I’ll believe in global warming when I don’t have to turn on my central heating in mid-June. – Yours, etc,

PETER STAPLETON,

Drumshanbo,

Co Leitrim.

As the short statement contains three common misunderstandings, I thought it worthwhile to respond. My response is published in The Irish Times today :

Sir, – Peter Stapleton writes “I’ll believe in global warming when I don’t have to turn on my central heating in mid-June” (June 16th). This short statement contains three classic errors:

1. Weather is not climate. Mr Stapleton has confused a wet summer in Ireland with longterm trends in global climate.

2. There is now a great deal of evidence pointing towards a gradual increase in the average surface temperature of the earth and its oceans, an increase that is strongly linked to carbon emissions. Recent data from MET Éireann show a warming in Ireland in line with this global trend.

3. Climate change is not a question of belief, it is a question of science. The overwhelming consensus among climate scientists is that global warming has the potential to affect the lives of many millions of people, from widespread flooding in some countries to permanent drought in others.

Sadly, one suspects Mr Stapleton’s misapprehensions are shared by a great many political leaders worldwide. – Yours, etc,

CORMAC O’RAIFEARTAIGH,

Lecturer in Physics,

Waterford Institute of Technology.


All in all, I think the two letters sum up the challenges of communicating climate science. Could it be that mankind will one day face devastating cimate change, all because we couldn’t distinguish between weather and climate?

Flooding in Bangladesh: soon to be permanent?

Drought in Africa: more frequent and severe?

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Tyndall conference in Ireland

This weekend, I caught the last day of a climate conference honouring the memory of the great Irish scientist John Tyndall. Born in County Carlow, Tyndall became a key member of the Royal Society around the time of Charles Darwin. He studied under Robert Bunsen in Germany and did much to promote the idea of experimentation in science. Among his many contributions are the discovery of the Tyndall effect (an explanation for the colour of the sky in terms of the scattering of light) and pioneering works in optics.

Tyndall’s most important contribution was his experimental demonstration of the greenhouse effect. He was the first to show that certain gases – notably carbon dioxide and water vapour – absorb radiation of infra-red wavelength, thus trapping heat reflected from the earth. This discovery forms the bedrock of the modern climate science. Today’s phenomenon of global warming (measured as an increase in global temperature, glacier-melt and sea level rise over the last few decades) has been attributed to an increased concentration of greenhouse gases in the atmosphere caused by the burning of fossil fuels.


The 2011 Tyndall climate conference was sponsored by the EPA and the Royal Irish Academy

The conference celebrated the 150th anniversary of the publication of Tyndall’s landmark paper On the Absorption and Radiation of Heat by Gases and Vapours and took place in Dublin castle, a superb venue in the heart of Dublin’s vibrant city center (and the seat of British rule in Ireland only a century ago). Day one was an overview of Tyndall’s life and work, with a keynote lecture by eminent climatologist Richard Sommerville. The next two days featured slightly more technical talks on climate science. You can find the conference program and book of abstracts here.

I caught several excellent talks on Friday, including a talk on climate sensitivity and feedback mechanisms by John Mitchell of the UK Hadley Centre, and a talk on tipping points and their predictability by Peter Ditlevensen of the Center for Ice and Climate at the Niels Bohr Institute in Copenhagen. Another talk, by George Moore of the University of Toronto, suggested that we may already have passed such a tipping point. The lecture  ’20 years of IPCC projections’ by Ulrich Cubasch of the Free University of Berlin, demonstrated how well IPCC projections have stood the test of time. This is a point often overlooked in discussions of climate science in the media. The public are wary of theoretical models, and climate scientists sometimes forget to point out that we have had twenty years to test predictions – so far, the projections have turned out to be all too accurate.

Possibly the most advanced talk of the day was by Professor Ray Bates of the Meteorology and Climate Centre at University College Dublin, a former professor of meteorology at the Neils Bohr Institute. In his talk, Ray presented a new global climate model, contrasting it with the recent model of Dick Lindzen. The Lindzen model is quite controversial as it suggests that conventional climate models overestimate the contribution of an enhanced greenhouse effect on climate. In good scientific fashion, Ray outlined the basic physics underpinning the two models, steering clear of polemics and concentrating on the science. You can Ray’s paper on his, and other, models here .

All in all, a great conference, I was sorry to miss the first two days. One of the aspects the increased teaching workload in the Institute of Technology sector is that there is almost no time left over for conferences – someone’s idea of increased productivity.

Update

Richard Sommerville did a very nice interview on the Pat Kenny show, a flagship radio show on RTE radio 1. Pat raised almost every point favoured by climate skeptics, while Richard provided clear and cogent answers to each. Well worth a listen, you can download a podcast here.

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Filed under Global warming, History and philosophy of science