Madam, - James G. Lacy (March 13th) appears to have garnered his entire understanding of climate change from the content of a much-discredited documentary aired last week on British television.
He cites two "facts" broadcast in that programme to build his own case against others' misuse of facts. He is thus skating on very thin ice.
No climate scientist of any standing will deny that, for most of the historical record, a rise in global temperature has indeed preceded a rise in atmospheric CO2. But to claim that this therefore implies that the current rise in atmospheric CO2 cannot force a further rise in temperature is scientific naivety of the worst kind.
Under conditions of natural climatic variability, temperature often takes the lead. Climatic conditions will then oscillate within a generally non-threatening range. If, on the other hand, large amounts of greenhouse gases are suddenly injected into the climate system, whether naturally (by volcanoes, for example) or, as is currently the case, by ourselves, a potentially highly dangerous instability can result. This, regrettably, is the case at the moment.
Prof Lacy also claims that polar bears survived the Holocene. We are, in fact, still very much in the Holocene, and have been since around 10,000 BC. He is actually referring to a very temporary period of local warming in north-east America around 1,000 years ago, when parts of Greenland were, indeed, somewhat warmer than today. However, Arctic conditions at that time were radically different from today. Warming was local, moved from south to north, and in any case, soon halted. Today's warming is not local, but global, is most intense in high latitudes, and is not projected to end any time soon unless we rapidly mend our ways.
Unless we do so, polar bears may, indeed ultimately not survive the Holocene. So let's, for their sakes as much as our own, please get our facts straight. - Yours etc,
PAT FINNEGAN, Co-ordinator, Grian, and member of the Intergovernmental Panel on Climate Change, Blackrock, Co Dublin.