Unendurable climate swings is setting in and with all due respect to the raging global pandemic, this is a crisis. Death rates from the coronavirus will be rendered moot if the planet is uninhabitable, so hats off to Scientific American for spelling it out: “Heat and Humidity Are Already Reaching the Limits of Human Tolerance,” the magazine warns. It’s the heat and the humidity: When both (the wet-bulb temperature) rise beyond a threshold, even healthy people sitting in the shade with access to water will die. Their sweat can’t evaporate and cool them. Such spikes are already happening, for instance, in locales such as Pakistan – and the Persian Gulf.
Among the nations most at risk for unsurvivably high wet-bulb temperatures today, not some time in the future, are Israel’s new friend, the United Arab Emirates, and potential future friends Saudi Arabia and Qatar too. What, you say: Deadly heat is one thing but deadly humidity in the desert? Yes: “There, unlike at the equator, heat and humidity are able to build up without triggering tropical storms that release humidity from the air in the form of precipitation,” Quartz explains.
How hot is too hot? A wet-bulb temperature of 35 degrees Celsius (95 Fahrenheit) is considered the most humans can tolerate, and incidences of that very condition have doubled in the last few decades. But one can die at lower wet-bulb temperatures too, as happened to tens of thousands of people in Europe in 2003. Considering how much people like to grouse about the weather it’s perhaps remarkable that if anything, reports of unsurvivable stretches of heat are under-reported, scientists report, because the hot spots are very localized and the extreme conditions there tend to last hours, not days. But they’re spreading and lengthening.
Throughout the process of becoming woke to global warming, many have assumed that the ramp-up would be gradual, slowly nuzzle at our awareness and enable us to progressively and painlessly switch from bad habits to benign ones with the help of “future” technological advances. Or not: A paper published last week connects abrupt climate swings in Greenland during the last glacial period (115,000 to 11,700 years ago) to abrupt climate swings in more southerly latitudes. In other words they identified a near-synchronous connection of climate events spanning Earth’s hemispheres.
Apropos the global interconnectedness of weather, a study of Laotian stalagmites reveals that end of the “Green Sahara” epoch (featuring rivers and hippos and crocs gamboling in their waters) around 5,000 to 4,000 years ago led to cataclysmic monsoon failure in Southeast Asia. As the Sahara dried out and plants died, increasing airborne dust cooled the Indian Ocean, which massively reduced monsoon moisture across Southeast Asia – for more than 1,000 years.
Speaking of aridification, as wildfires rage in California yet again, scientists warn that rising sea levels are raising water tables along the state’s coast. One upshot is potential flooding inland where none had been anticipated; damage to infrastructure such as roads; inability to drain sewage; “and the potential for mobilizing contaminants in soils currently above the water table,” an Arkansas University team reports in Nature Climate Change.
No, this problem of “shoaling,” as flooding due to rising groundwater is called, isn’t unique to California. But the researchers working there identified the Port of Los Angeles and airports in Santa Barbara and San Francisco to be at risk. By the way, they already knew this in Florida. They have known about this for a long time.
developed at the University of Bern demonstrated that the CO2 concentration in the atmosphere is higher now than it has been for the last 800,000 years (previous knowledge was that it’s higher than in the last 400,000 years). The scientists identified abrupt non-anthropogenic changes in CO2; they happen. Buuuuuuuuut now it’s happening 10 times faster. We are causing CO2 changes at a pace the Earth never experienced before. Warming correlates with rising CO2 concentrations at a lag. Ergo, even though we are already experiencing bouts of intolerable heat, we aren’t yet feeling the effects of the highest CO2 in millions of years. Stay tuned.
Plants are good, trees are good, no question about it. Now a study of 23-million-year-old fossil leaves in New Zealand concludes that high levels of CO2 and heat do result in increased plant growth as photosynthesis rates increase. But the scientists also warn against complacency – not all plants do this; the ramp-up in CO2 absorption isn’t even close to compensating for the CO2 we’re pumping into the air; and it seems the super-charged plants will actually be poorer in the nutritive minerals we need, such as zinc.
Originally published at haaretz