Hurricane Florence, downgraded to a tropical storm, continues to dump massive quantities of rain on South Carolina, with more to come. She looks like a rerun of Harvey, which flooded Houston last year, cost $125bn. Are these “Acts of God or of the Queen’s enemies”, in the picturesque language of old British insurance contracts?
A bit of both. IPCC 4th Assessment Report, 2007, WG1:
A synthesis of the model results to date indicates that, for a future warmer climate, coarse-resolution models show few consistent changes in tropical cyclones, with results dependent on the model, although those models do show a consistent increase in precipitation intensity in future storms. Higher-resolution models that more credibly simulate tropical cyclones project some consistent increase in peak wind intensities, but a more consistent projected increase in mean and peak precipitation intensities in future tropical cyclones.
We’ve known for at least a decade, for the subset of “we” capable of wading through IPCC prose or reading more popular transcriptions of the science, which should include the press, TV weathermen and policymakers. In this case, the science is extremely simple in outline:
Warmer tropical seas → warmer and wetter air above them → conversion of extra heat energy into rotational energy by the cyclone mechanism → bigger and wetter hurricanes.
Sandy, Harvey, Irma and Florence have been hurricanes modulated by the modest global warming of 0.8 degrees C since 1880, the period with a full and accurate instrumental record. To be generous with the earlier uncertainties, let’s say at most 1 degree C above pre-industrial (say 1750). There is quite certainly more warming to come. Jerry Brown’s recent executive order, aiming at zero net emissions in California in 2045, was rightly hailed as brave political leadership (grandstanding to opponents). Sweden was there first, with the same date. These are the cutting edge of real policy commitments; most countries have done nothing to translate into action their vague Paris Agreement commitment to zero carbon “in the second half of this century” (Article 4(1)).
Suppose by a miracle everybody else joined Jerry Brown tomorrow. We would, it seems, be on track to the more ambitious 1.5 degrees aspirational goal of the Paris Agreement. Meeting the main 2 degree cap only calls for moderate optimism, not a miracle. The range of good outcomes – never mind the bad ones – lies between doubling global warming from the pre-industrial level, and only increasing it by half.
More storms like Harvey, Irma and Florence are certainly on the way.
Some will be even bigger and more destructive. You have to wonder how many coastal cities in the hurricane and typhoon zones will survive in anything like their current form. I’m glad I’ve seen New Orleans, it may not be there for my grandchildren.
- Miami is not on my must-see list, which is just as well as its fate is even more certain. The city sits on a thick bed of porous limestone, permeable to water. Osmotic pressure ensures that water levels will be the same on both sides of any sea wall. It’s Venetian stilts or evacuation. That’s just from sea level rise, which will be supercharged by storm surges and deluges of rain from future mega-hurricanes. I fear that Miami will be given the same advice as the parents of Belloc’s Henry King :
Physicians of the Utmost Fame
Were called at once; but when they came
They answered, as they took their Fees,
‘There is no Cure for this Disease.
Henry will very soon be dead.’
It won’t sound better in Dutch – see endnote.
Will Florence shift the political obstacles to effective climate action in the USA? Not by deathbed conversion of denialists. There is a popular myth among greens that US policy is held back by a denialist hold on public opinion. In fact, a very substantial majority of Americans (67%) accept the reality of global warming, and over half (53%, trending up) correctly attribute it to human action. Even larger majorities (70%) support a decisive shift to 100% renewable electricity, the key policy measure: the climate hawks are joined by other hawks on urban air pollution, on energy independence at the national and local levels, and on economic arithmetic like Iowan farmers and Warren Buffett. It’s true that electricity is now responsible for less than a third of US carbon emissions, but electrification powered by renewables is the key to the decarbonisation of transport and heating.
The political problem is not that Americans disbelieve the science, but that they don’t give the problem high priority. In the latest Pew survey, climate change clocked in at 18 out of 19 issues, well behind jobs, the economy, and healthcare (fair enough) but also the utterly insignificant dangers of terrorism (first position, God help us). This half-heartedness has allowed a handful of oil and gas billionaires like the Koch brothers, and their useful idiots like Scott Pruitt, to seize the initiative and bind one of the two historic political parties of the United States entirely to their nihilism.
Having a major hurricane pass over your house is a shock; more if you are ordered to evacuate by panicky authorities, or find your home feet-deep in a sea of dilute pig manure and toxic coal ash sludge. [Update: you may also enjoy a neighbourly visit from a floating colony of fire ants.] Convinced denialists have strong mechanisms to keep their beliefs in the face of the strongest evidence; but the lukewarm realists will surely become less receptive to a soothing delayist message that “it’s not so bad, we’ll keep coping with this, and doing what the alarmists propose will cost a fortune.” The apathetic may become activists, or a least turn out to vote for candidates who appear to take the problem seriously.
The trends to bigger hurricanes and rising sea levels are good news only to one small group: professional water engineers, many of them Dutch. In an earlier life working on higher education policy, I was told a story about a shiny new quality assurance programme set up by Ministry of Education technocrats. The inspectors visited the Technical University of Delft and pored over its performance indicators. They then demanded to know why the Department of Water Engineering had such a poor record of publications in peer-reviewed foreign journals. The embarrassed professors explained that in the sub-discipline, sadly the Delft department held a de facto world monopoly, and the major research periodical was their own. This story has a whiff of self-serving legend to it, but it’s very likely that there are few real experts to turn to in the field, and Delft is on the list. You do not want to save money by seeking second-best consultants, let alone cheaping on the dikes and sluices.