PH, rest of the world, feeling deadly heat not expected until end of century

By: Tony S. Bergonia, Philippine Daily Inquirer, 10 May 2020

The Philippines, along with much of the rest of the world, is experiencing unprecedented levels of heat and humidity that came decades earlier than scientists predicted these to be the new normal at the end of the century yet, according to a new science report.

Extreme heat and humidity rarely experienced by humans are becoming normal now, tens of years ahead of predictions by scientists that such phenomena would be regular occurrence by the end of the century, said the report in The Earth Institute of Columbia University.

These are sending heat indexes, or the heat that a human body feels, soaring past records around the globe, said the report.

The report, released last May 8, said thousands of previously rare or unprecedented bouts of extreme heat and humidity had been found in Asia, Africa, Australia, South America and North America.

“Most everyone knows that humid heat is harder to handle than the ‘dry’ kind,” the report said.

“And recently, some scientists have projected that later in the century in parts of the tropics and subtropics, warming climate could cause combined heat and humidity to reach levels rarely, if ever, experienced before by humans,” said the report.

“The projections are wrong: Such conditions are already appearing,” the report by The Earth Institute said.

In the Philippines, monitoring by the weather bureau showed heat index averaging 40 degrees Celsius almost daily for the past several weeks already.

An INQUIRER.net report said just last Saturday (May 9), the Philippine Atmospheric Geophysical and Astronomical Services Administration (Pagasa) recorded a heat index of 50 degrees Celsius, half the boiling point of water, at Sangley Point in Cavite province.

In 2019, still according to an INQUIRER.net report, Pagasa recorded a heat index of 52.2 degrees Celsius in the province of Catanduanes.

Last April 6, according to multiple media reports, Pagasa recorded a heat index of 53 degrees Celsius in Butuan City.

The study being cited by The Earth Institute report from the journal “Science Advances” said temperatures across the globe had been measured by scientists using a method called “wet bulb,” or a method akin to thermometers wrapped in moist cloth that are able to measure temperature of the air and the moisture in it.

A wet bulb measurement in a country or region that reaches 35 meant the place is near lethal or uninhabitable for human beings. The measurement in the Philippines, according to an interactive map in The Earth Institute report, ranged from 29 to 30, which is in “dangerous” territory.

The report cited past climate studies as saying “even the strongest, best adapted people cannot carry out normal outdoor activities when the wet bulb hits 32 C.”

“Most others would crumble well before that. A reading of 35 is considered the theoretical survivability limit,” the report said.

It said wet bulb readings of 31, which had been believed to be rare, reached 1,000 during the study period. “Readings of 33, previously thought to be almost nonexistent, totalled around 80,” said the report.

Citing the Science Advances study, the report by The Earth Institute said “extreme, sometimes potentially fatal, mixtures of heat and humidity are emerging across the globe.”

It said in the Persian Gulf, scientists saw more than a dozen outbreaks of heat “surpassing the theoretical human survivability limit.”

The report said while the outbreaks had been confined to specific areas and lasted just hours, “they are increasing in frequency and intensity.”

“Previous studies projected that this would happen several decades from now, but this shows it’s happening now,” the report by The Earth Institute cited Colin Raymond, lead author of the study.

“The times these events last will increase, and the areas they affect will grow in direct correlation with global warming,” Raymond said, according to The Earth Institute report.

It said the scientists who worked on the study analyzed data from more than 7,000 weather stations around the world between 1979 and 2017 and “found that extreme heat and humidity combinations doubled over the study period.”

“Not surprisingly, incidents tend to cluster on coastlines along confined seas, gulfs and straits where evaporating seawater provides abundant moisture to be sucked up by hot air,” the report said.

“In some areas further inland, moisture-laden monsoon winds or wide areas of crop irrigation appear to play the same role,” it said.

Earlier climate studies, it added, failed to quickly detect the emergence of deadly heat-humidity combinations “because climate researchers usually look at averages of heat and humidity measured over large areas and over several hours at a time.”

Raymond, the lead author of the study, and his fellow scientists “drilled directly into hourly data from 7,877 individual weather stations.”

This, the report said, allowed them “to pinpoint shorter-lived bouts affecting smaller areas.”

“Humidity worsens the effects of heat because humans cool their bodies by sweating,” the report said.

“Water expelled through the skin removes excess body heat, and when it evaporates, it carries that heat away,” it said.

“The process works nicely in deserts, but less well in humid regions, where the air is already too laden with moisture to take on much more,” it added.

In already humid areas, the report said, “evaporation of sweat slows” and “in the most extreme instances, it could stop.”

“In that case, unless one can retreat to an air-conditioned room, the body’s core heats beyond its narrow survivable range, and organs begin to fail,” the report said.

“Even a strong, physically fit person resting in the shade with no clothes and unlimited access to drinking water would die within hours,” it added.

“We may be closer to a real tipping point on this than we think,” said the report, citing Radley Horton, research scientist and coauthor of the heat-humidity report.

Horton had co-authored a 2017 paper that projected current levels of heat and humidity taking place later in the century yet, according to The Earth Institute report.

It cited Horton as saying if people were forced indoors by the heat for prolonged periods of time, agriculture, trade and other human activity could grind to a halt.

It would be “a lesson already brought home by the collapse of economies in the face of the novel coronavirus.”

“In any case, many people in poorer countries most at risk do not have electricity, never mind air conditioning,” the report said, still citing Horton.

“There, many rely on subsistence farming requiring daily outdoor heavy labor. These facts could make some of the most affected areas basically uninhabitable,” Horton said as cited by the report.

“These measurements imply that some areas of Earth are much closer than expected to attaining sustained intolerable heat,” Steven Sherwood, climatologist at University of South Wales, was cited as saying in the report.

“It was previously believed we had a much larger margin of safety,” Sherwood’s comment went on.

“Such conditions would ravage economies, and possibly even surpass the physiological limits of human survival,” said the report by The Earth Institute.