Tuesday, September 5, 2023

'There are Still Some Deniers Out There in Terms of Whether or Not Climate Change Had Anything to Do With Any of This.'

Thus spoke President Joe Biden referring to Hurricane Idalia on Thursday afternoon. I realize that tying global warming to things is red meat for his party's base. 

Only one problem: the facts don't support his position.

It is impossible for climate change to "cause" hurricanes. 

Can climate change "contribute" to hurricanes? Theoretically, yes, but the evidence is weak. 

Hurricane Strength and Duration
The peer-reviewed "ACE Index" (Accumulated Cyclone Energy) is the gold standard as to hurricane frequency and intensity (wind speeds). It is available back to 1970, when we first had worldwide weather satellite coverage. There is no upward trend whatsoever -- it is flat. There is no increase due to climate change! Hurricanes are not getting stronger.

What about disaster costs? Of course, those are rising but it is because so many are building expensive homes and businesses in high risk areas. Let's look at what causes losses.

Let's start with hurricane landfalls. In order to have a loss, a hurricane has to come ashore. 
The black line in the graph above is all hurricane landfalls. They are down. Hurricane landfalls are less frequent in the Atlantic and Pacific Basins. The red line (bottom) is major hurricanes -- Cat 3 or stronger. They are flat. 

Normalized Economic Losses
Going back to 1900, there is a very slight positive trend. Meteorologists have long discussed a hurricane "cycle" and it seems to be present in this graph with slow periods 1901-14 and 1971-90. Will the recent uptick last as part of climate changes or will it decrease again as part of the cycle? I don't know. Stay tuned.

The bottom line is the evidence of stronger hurricanes doesn't exist and the evidence for increased economic loss is weak. 

Part Two
Again: Climate change/global warming cannot "cause" hurricanes. While it is theoretically possible it can make them worse, global warming doesn't "cause" weather events. 

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