It is not news that climate change is expected to usher in extreme heat waves, most markedly in North Africa and the Middle East. Some cities in the Middle East are already experiencing briefly unbearable bouts of heat – but in the future they could last weeks. Reporting in npj Climate and Atmospheric Science, a team headed by George Zittis of the Cyprus Institute warns that without mitigation, the business-as-usual pathway should lead to “unprecedented super- and ultra-extreme heat waves” in the second half of this century, 56 degrees Celsius (132.8 degrees Fahrenheit) and up, especially in the cities. Nobody can take heat like that, even “heat-tolerant camels” – and may we note that air-conditioning may be a necessity but it isn’t a solution. You may breathe easier for an hour, but it just makes the Earth’s situation worse.
Here is a nice article in Slate succinctly explaining how heat kills you.
Southern hemisphere on fire? It’s happened before
Modeling future climate is tricky because so many parameters are involved. Just one of the parameters is particles in the air from wildfires, volcanic eruptions and the like. We can estimate preindustrial emissions, but we had no clue about smoke aerosol in the preindustrial atmosphere. Now, a study of soot deposits in Antarctic ice cores shows that in the century preceding the industrial revolution, the southern hemisphere was fiery: producing up to four times more smoke than had been thought. Why? Mostly because of “widespread and regular burning practiced by indigenous peoples in the precolonial period.”
Smoke particles cause cooling by blocking sunlight – so what do we have here? Apparently, we have underestimation of the preindustrial cooling effect of soot. Since the industrial revolution, vast swaths of land have been converted to farming and industry, which are producing greenhouse gases. What does this mean for the future? Climate models may have failed to factor in a cooling effect of the smoke and may be overestimating the warming effect of greenhouse gases.
So are we off the hook? No.
Oops, forgot the snow
Au contraire: The sea ice in the Arctic may be melting twice as fast as had been thought, warns a new model led by UCL that factors in snow as it is now. Excuse us? The thickness of an ice floe is estimated by measuring the height of the ice above the water, the researchers explain in The Cryosphere. But snow weighing the ice down distorts this measurement and the map the scientists have been using of snow depth in the Arctic is 20 years out of date. When they factored snow as it is now, they calculated that the ice on the Arctic’s coastal regions is thinning 70 percent to 100 percent faster than previously thought.
Also, the Arctic is warming at three times the global average, if not more. This does not augur well for coastal dwellers, especially in cities where the ground is subsiding due to the sheer weight of construction and aquifer depletion. The city sinking fastest, experts say, is Jakarta: one study says it’s sinking by 25 centimeters (10 inches) a year and has already lost 40 percent of its land to the sea.
Monsoon: Carbon dioxide beats Earth’s orbit
Apropos flooding, a study of monsoons in the Indian subcontinent in the last million years found a correlation between carbon dioxide concentrations (among other things) and the strength of the monsoon season. The research published in Scientific Advances suggests the monsoon season will grow stronger as the globe heats. Yes, cyclical changes in Earth’s orbit, changing the amount of sunlight each hemisphere receives, affected the monsoon. But the researchers detected that peaks in atmospheric CO2 and low points in global ice volume were found to correlate with more intense monsoon winds and rainfall. The monsoon is essential to agriculture and the economy, but there can be too much of a good thing.
