Tropical storm Ana in January, tropical cyclone Batsirai in February, then Dumako, Emnati and Gombe in quick succession: three cyclones and two “tropical storms” in six weeks hit the coasts of south-eastern Africa.
Then Cyclone Idai at the end of March, which practically destroyed the city of Beira in Mozambique, killing more than 750 people. Three weeks later, subtropical depression Issa hits the east coast of South Africa, killing 450 people in the greater Durban area.
And the fact is that just five years ago, there were only one or two of these storms a year in the region. Fifteen years ago, the average was not even one per year.
“It tells us that climate change is serious, it’s there,” said South African President Cyril Ramaphosa. Well seen, sir. A bit late, however.
Cyclones in the Indian Ocean, typhoons in the Western Pacific, hurricanes in the Caribbean – it’s the same beast, just different names. Similarly, “tropical storms” and “subtropical depressions”; again the same beast but with a lower wind speed.
What’s amazing is how surprised they all are when the future that scientists and activists have been predicting for years finally arrives. They didn’t get the memo?
It’s not rocket science. When the global temperature rises, it warms the surface of the ocean. When the sea surface is above 26.5 C, it has enough energy to power hurricanes/cyclones/typhoons. The western Indian Ocean is now above this temperature in late summer and early fall (January-April).
People say you can’t do anything about the weather, but it’s actually possible to weaken or even stop these storms. And maybe Southern Africa is the place to try it, as they haven’t yet gotten used to a constant procession of severe tropical storms.
Last year I interviewed a retired engineering professor called Stephen Salter who started working on a climate cooling project decades ago in conjunction with Professor John Latham, a renowned climatologist.
The idea is to build a fleet of unmanned, wind-powered, satellite-guided vessels that position themselves under the low, thin clouds that are very common in tropical oceans – “marine stratocumulus clouds” – and spray a fine mist of water which thickens. upwards so that they reflect more sunlight.
Reflect more sunlight and you cool the whole planet – but you especially cool the ocean surface below those clouds. There’s already a small team from Southern Cross University in Queensland experimenting with this technology as a way to cool the waters of northeast Australia and save the corals of the Great Barrier Reef.
Large “named” tropical storms usually form in well-defined areas of the Atlantic, Indian and Pacific oceans that are not too large for mobile fleets of spray vessels. All you have to do is drop the sea surface temperature by a degree or less, and most storms that form will never become large enough to deserve a name.
It’s worth a try, and maybe Southern Africa is new enough for this kind of weather to believe it could be stopped. South Africa should take the lead, because that’s where most of the funds and scientific and technical skills are, but it’s a problem that affects the entire east coast of the continent.
In fact, it is a technology that matters to the whole world. We will almost certainly need technologies to keep the global temperature down as we work to eliminate our greenhouse gas emissions, and that would be a relatively soft, controllable, and affordable form of geoengineering.
It would also be a project of global scientific and political significance led by Africans, which is long overdue.