Winds of dissent

Will Irma persuade Donald to change his mind about global warming? Or, in the style of certain Scottish politicians, will need to save face prevail? WILLIAM DURWARD South Erskine Park Bearsden, Glasgow Recent events raise two questions: are tropical cyclones getting more frequent and are they getting fiercer?

The answer to the first is No. The UN’S Climate Change Panel reports “Current datasets indicate no significant observed trends in global tropical cyclone frequency over the past century.”

The fact is, Harvey and Irma ended an unprecedented 12-year hiatus in which not a single category 4 or 5 hurricane came ashore.

The question of ferocity is more complicated. Irma is the strongest Atlantic storm outside the Gulf of Mexico to make landfall in recent times rivalling Allen in 1980. It is wider than Charley (2004) or Andrew (1992). But we simply don’t know the strength of the 1935 Labor Day Hurricane or the terrible 1780 Barbados hurricane.

The US Geophysical Laboratory found greenhouse gases have had “no detectable impact on Atlantic hurricane or global tropical cyclone activity”. In fact Irma devel- oped over cool Atlantic waters (26C) when the rule of thumb is 28.5C for a major hurricane. So it wasn’t “global warming” but exceptionally low wind shear (high-altitude wind) that led to Irma.

The temptation for the BBC and other climate alarmists to blame Irma on fossil fuels will be irresistible. But that’s as silly as blaming the Syrian civil war on climate change rather than human bestiality, though that hasn’t silenced Prince Charles, Barack Obama or the Greens. (REV DR) JOHN CAMERON

Howard Place, St Andrews