Challenges for global warming

Fri, Apr 5, 2013, 05:54

Sir – In his criticism of a recent article by David Robert Grimes (Opinion, April 1st), Christian Schaffalitzky writes, “I wish he and his colleagues would make up their minds. Previously we were told that our children would be lucky to ever see snow again” (Letters, April 3rd). Mr Schaffalitzky also states that “it appears that . . . the theory of man-made global warming cannot be challenged by any evidence from weather, such as the last 17 years of flat global temperatures”.

First, I seriously doubt that any physicist or climate scientist made such a claim on snowfall. The prediction makes the elementary error of confusing short-term regional weather patterns with long-term trends in global climate. As Dr Grimes points out, a cold spring in Europe is not inconsistent with global warming.

Second, Mr Schaffalitztky’s assertion that global temperatures have been flat for 17 years is wildly inaccurate. Perhaps he is thinking of the spike that occurred in global surface temperature in 1998 due to a strong El Nino: that one event has little bearing on the overall trend, which is upwards. In any case, surface temperatures do not tell the whole story, as ocean temperatures have also been rising steadily, not to mention the ongoing melting of land and sea ice. – Yours, etc,

Dr CORMAC

O’RAIFEARTAIGH,

Lecturer in Physics,

Waterford Institute of

Technology.