I hear a lot of people saying that the weather is getting more extreme as a result of climate change. Fair enough. However I’ve heard this view stated as an opinion that the we are also witnessing more and more hurricanes too, an opinion which is often presented as direct proof of the negative effects humans are having on the planet. In fact I heard this very opinion repeated several times only last week on a recent BBC Radio 4 program discussing the environment and climate change.
Take this example too from the recent Earth Hour project homepage: “Our towns and cities are already facing the staggering costs of weather driven to extremes by climate change, and the resulting power outages, flooded roadways, shuttered businesses, and damaged homes are becoming more and more frequent” (my emphasis).
There’s no denying the terrible havoc caused by hurricanes and big storms. But check that end phrase they’ve thrown in. Hmmmm.
So if the consensus says that we are getting more frequent hurricanes as a result of climate change, I want to ask a simple but disruptive question: is that true?
Where to start?
To be honest, I had absolutely no idea. I had half-baked opinions, but no facts. I didn’t want to just search the internet randomly either – who knows what kind of weird stuff and crackpot ranting is out there on blogs (and yes, pot-kettle-black, let’s move on), so I decided to start off by seeing what the IPCC itself has to say on the subject.
Here are the surprising statements I found. As ever, the truth is more nuanced than the headlines might suggest.
What follows are the key findings taken from the 2012 IPCC summary report for policymakers on “Managing the Risks of Extreme Events and Disasters”.
- Models project substantial warming in temperature extremes by the end of the 21st century.
So the temperature range of hot spells and cold snaps will increase at both ends of the scale. Worrying as this is, it is not about hurricanes. Next.
- It is likely (by which they mean more than a 66% probability) that the frequency of heavy precipitation or the proportion of total rainfall from heavy falls will increase in the 21st century over many areas of the globe.
So if I understand that correctly, it’s going to rain more in some places. OK, this is not about hurricanes either, next.
- Average tropical cyclone maximum wind speed is likely to increase, although increases may not occur in all ocean basins.
Right, here we go. So maybe some storms might be stronger, but possibly not everywhere. So if there are storms which hit land (those on the sea bother no one) they might be stronger than normal. Not good. Keep going.
- It is likely that the global frequency of tropical cyclones will either decrease or remain essentially unchanged.
So climate change is predicted (> 66%) to have no effect on the frequency of big storms. In fact, the frequency of big storms might even decrease. See that? Decrease. Isn’t that interesting! Let’s see if there’s anything else in here.
- There is medium confidence that there will be a reduction in the number of extratropical cyclones averaged over each hemisphere.
Notice the word reduction here again, as in less, not more. Next.
- There is medium confidence that droughts will intensify in the 21st century in some seasons and areas, due to reduced precipitation and/or increased evapotranspiration.
So if it’s not raining more where you are (see above), it’ll probably be raining less. Again, not about hurricanes. Next.
- Projected precipitation and temperature changes imply possible changes in floods, although overall there is low confidence in projections of changes in fluvial floods.
“Imply possible changes” is a bit wooly, but that’s because it seems they don’t really have any reliable data on this subject. Chances of river flooding remain the same however. As interesting as this is, it is not about hurricanes. Next.
- It is very likely (meaning more than 90% probability) that mean sea level rise will contribute to upward trends in extreme coastal high water levels in the future.
The world is getting warmer so sea levels are going to rise. This makes total sense but has nothing to do with hurricanes. Next.
- There is high confidence that changes in heat waves, glacial retreat, and/or permafrost degradation will affect high mountain phenomena such as slope instabilities, movements of mass, and glacial lake outburst floods.
Interesting, but not relevant to storms affecting people. Next.
- There is low confidence in projections of changes in large-scale patterns of natural climate variability.
This refers to weather patterns like monsoons, so isn’t relevant.
That’s it. We’re at the end of the line.
So what’s the conclusion here regarding the consensus that hurricanes are becoming more and more frequent?
Well, as ever, there’s both good and bad news. On the downside the storms we get might be more intense and damaging by a small degree, but on the upside there may well be less of them.
Given that, how come so many people still seem to think that big storms (meaning hurricanes / cyclones / typhoons etc.) are getting more frequent as a result of climate change, when even the IPCC itself says that this isn’t the case? Is it lazy journalism, or what?
The point of this enquiry is not to deny the obvious effects of climate change, or that man isn’t having an effect on the climate, it’s just to show that sometimes it’s worth digging down to the facts and asking those disruptive questions in order to challenge commonly held assumptions. If we are to have a sensible debate about climate change, then it has to be one based on facts and current scientific consensus, not fantasy. The alternative of an assumptions-led debate doesn’t do anyone any good in the long run.
As a friend of mine once said, we need more constructive disruption, and less corrosive assumption.