Deadly Heat and Humidity Emerging Decades Ahead of Forecasts

Scientists tweak sea level rise forecasts, upward, and could the Indian Ocean develop its very own El Niño storms? Oh yes, it’s time for the Haaretz climate change briefs

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A smoggy sunrise, Mexico City, May 8, 2020.
A smoggy sunrise, Mexico City, May 8, 2020Credit: Marco Ugarte,AP
Ruth Schuster
Ruth Schuster

Lethal heat and humidity combination isn’t futuristic, it’s already here 

Unsurvivable heat and humidity conditions are already emerging worldwide decades ahead of expectations. A study published Friday in Science Advances identified thousands of unusual or unprecedented bouts of extreme heat and humidity in all the continents except Antarctica. In the Persian Gulf, the researchers spotted “more than a dozen” incidents in which the temperature and humidity surpassed the theoretical human survivability limit (your sweat can’t evaporate if it’s “too” humid, so your body can’t cool down and then your organs fail). So far, the outbreaks lasted only hours. But they’re increasing in frequency and intensity – and are projected to affect wider areas. The most prone areas are the Indian subcontinent; Saudi Arabia, Qatar and the United Arab Emirates; and parts of the United States as well. Under these conditions: “Even a strong, physically fit person resting in the shade with no clothes and unlimited access to drinking water would die within hours,” the researchers observe.

Why didn’t climatologists spot this before? Because they usually look at average heat and humidity over large areas: this study was based on hourly data from 7,877 individual weather stations. Climatologist Kristina Dahl warns that the conditions may be worse than the study suggests in some cities because weather stations don’t necessarily “notice” hot spots with heat-trapping concrete and pavement. Our margin of safety is disappearing very fast.

Climate change to revive ‘Indian Ocean El Niño’ 

The rising temperature of the Indian Ocean could revive an ancient weather pattern akin to the El Niño system, which is caused by unusually warm surface water in the Pacific off Peru and Ecuador, and which causes weather anomalies from storms to drought throughout the southern hemisphere. Now scientists show that even minor surface temperature increases in the Indian Ocean – which are happening – could cause a similar pattern within decades (or less: many models seem a tad optimistic timewise). The outcome could be exacerbation of storms, floods and droughts around the Indian Ocean, possibly by 2050. The last time this sort of thing happened there was during the last ice age, 21,000 years ago.

The Great Salt Lake in Utah. Coming soon: unsurvivable heat and humidity.Credit: Rick Bowmer / AP Photo

Sea level forecasts rising as warming accelerates

As humankind collectively fails to even consult on, let alone adhere to, emission goals – sea level estimates looking forward are rising. Now a vast international group publishing in Nature Climate and Atmospheric Science has raised its forecast for global mean sea level rise to more than 1 meter (over 3 feet) by 2100 and more than 5 meters (16 feet) by 2300 “if global targets on emissions are not achieved.” Specifically: if we curb global warming at 2 degrees Celsius, which seems increasingly unlikely, the group projects sea level rise by “a mere” 50 centimeters by 2100. At 4.5 degrees, they project rise of 1.3 meters. The team saw the Greenland and Antarctic ice sheets as the greatest sources of uncertainty; it bears adding that average temperatures there are rising faster than anywhere else. Science doesn’t know why. Last December, scientists warned that Greenland is less stable than had been thought and is approaching a tipping point.

Plant a tree, achieve nothing

Some hail large-scale reforestation (“Planting a trillion trees”) as a solution to climate change. Wouldn’t that be lovely if it were true. It could and should be part of the solution, says ecologist Karen Holl, but people can’t just stick baby trees in the ground and drive away in their SUVs hoping it will work. Reforestation has to be PLANNED, Holl explains: For one thing, the trees could deplete the water table; cause other environmental or ecological disruption; and dismay business interests … really. “Planting trees doesn’t ensure they will survive; a review of mangrove forest restoration efforts in Sri Lanka following the 2004 tsunami showed fewer than 10 percent of trees survived in 75 percent of sites,” reports the UC Santa Cruz on Holl’s work. Sure, plant a tree. But you have to do more than that: curb emissions and not cut down other trees.

Heat to beat coronavirus? Or us?

By the way, hear ye hear ye all you who think summer heat will save us from the coronavirus. We remind of a study in February 2019,  which found that the higher the ambient temperature, the more enfeebled were the immune responses of mice infected with viruses, including the flu. Sure, it’s mice not men, but there is a reason the hapless rodents are used as models for studies on human health. Seriously, wear your mask wherever you go – even if it’s uncomfortable, and even if the cops aren’t wearing theirs.

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