The following is the text of a letter prepared by Prof. John Sweeney, Ireland's foremost climate scientist. The letter was originally submitted to the Irish Times on 5th July 2015. It was not accepted for publication. Nonetheless, in response to ongoing commentary in that newspaper, Prof. Sweeney submitted a revised and updated version on 13th July 2015. Again, it has apparently not been accepted for publication (as of 16th July 2015). Given these circumstances, and with Prof. Sweeney's permission, An Taisce now publishes the full letter here (with minor final updating), in the interests of fully informed public debate on Ireland's proper and ethical contribution to promoting (as opposed to undermining) climate justice in the 21st century.

To: The Editor, The Irish Times.

Date: 13th July 2015


I congratulate the Irish Times for its enlightened editorial of Friday 3rd July, particularly as it offered a rebuttal of some of the opinions expressed earlier that week by Professor Ray Bates. Unfortunately, in a further letter from Professor Bates, which you chose to publish on 10th July, he took the opportunity to congratulate himself on a presumed absence of disagreement with the specifically scientific views he expressed in his original opinion piece. That presumption is seriously misplaced. In fact, and not for the first time, Professor Bates sought to espouse his contrarian views regarding the seriousness of climate change by a selective ‘cherry picking’ of the recent IPCC Assessment Report and a misinterpretation of current climate science.

There are many aspects of the various contentions made by Prof. Bates which lack robustness, too many to reply individually to. However what is most disappointing from an academic perspective is the selective quoting of only that part of a paragraph from the IPCC Fifth Assessment Report which appears to suit his arguments. He states that recent warming has been confined to two periods (supposedly ending in 1998), and contends that the human contribution to this warming is comparable to the ‘natural’. The sentence cherry picked from the IPCC was as follows: “It is extremely likely that more than half of the observed increase in global average surface temperature from 1951 to 2010 was caused by the anthropogenic increase in greenhouse gas concentrations” [IPCC AR5-WG1-SPM, 2013, p. 17]. Had he wished to accurately report the paragraph concerned he would have emphasised the immediately following sentence in the Report also. This clarifies that the “more than half” attribution is effectively a minimum; in fact the current best scientific estimate is that essentially all of the warming over the last 60 years is due to human activity (“The best estimate of the human-induced contribution to warming is similar to the observed warming over this period”).

There are a number of other scientific inaccuracies which permeate the article. The claimed increased uncertainty regarding causes of future sea level rise is just one. Far from increased uncertainty in attributing causes to sea-level rise, the recent IPCC Report provided a closed budget for the first time, the very opposite of increased uncertainty. Similarly, the preoccupation with the rate of warming since 1998 is also at variance with what has actually been observed. Warming has continued since 1998 and 2014 was the warmest year on record, with early indications that 2015 will exceed even this. While short term variations occur in where the heat of the planet is being stored, its continuing, rapid, and accelerating warming, due primarily to human activity, is not in any significant scientific doubt whatsoever.

Despite Professor Bates’ complacent contention to the contrary, it is absolutely valid to describe the problem of climate change as a ‘planetary emergency’. Earlier this month in southern Germany over 30 science Nobel Laureates gathered to make a declaration on climate change. They made a similar declaration nearly 60 years ago about nuclear arms. Their considered opinion is that “our world today faces another threat of comparable magnitude”.

Professor Bates cites an unidentified conference to substantiate his alternative arguments. Perhaps if he had attended the Climate Justice conference in Maynooth two weeks ago that he refers to, and listened to UN Special Envoy Mary Robinson, or heard the poignant case made by the Prime Minister of Tuvalu at the recent conference on the Papal Encyclical in Rome which I attended, he might reconsider his blind acceptance of the ‘national interest’ as the message Ireland wants to send the world on this issue.

Yours etc.

Emeritus Professor John Sweeney, Maynooth University