******************** POSTING RULES & NOTES ********************
#1 YOU MUST clip all extraneous text when replying to a message.
#2 This mail-list, like most, is publicly & permanently archived.
#3 Subscribe and post under an alias if #2 is a concern.
*****************************************************************
Every time I see a new report, surprise is registered at how much
reality exceeds expectations. And mass migration emerges more urgently
with each successive pile-on.
["...researchers were surprised to find such sharp increases in moist
heat waves in part because computer model projections don’t show these
occurrences becoming common for a few more decades"...it is disturbing
to see it happening in real time. It will only get worse and more
widespread from here." "The computed heat index [in Bandar Mahshahr, a
city in southwest Iran] for this brutal combination was 165 degrees (74
Celsius), among the highest recorded. However, the National Weather
Service cautions such conditions are so extreme that they are beyond the
limit the heat index was designed to calculate..."“Of all of the climate
risks coming this century, the thing I am most concerned about is
excessive heat in the tropics,” said Ken Caldeira, senior scientist
emeritus at the Carnegie Institution for Science at Stanford University,
in an email. “Rich countries have brought much of their economy indoors
where air conditioning is a possibility, but many developing economies
rely on labor-intensive outdoor agriculture,” he wrote. “The combination
of poverty and extreme temperatures can be lethal...would make
agriculture that relies on outdoor picking impossible. ”]
Unsurvivable heat extremes have emerged earlier than expected: study
Andrew Freedman, Jason Samenow - The Washington Post - Friday, May 8, 2020
Welcome to “Steambath Earth,” featuring sauna-like temperatures and
humidity too high for humans to tolerate.
Extremely humid heat that is more intense than most Americans have
experienced — approaching a crucial, immovable human survivability limit
— has more than doubled in frequency in some coastal subtropical regions
of the world since 1979, according to a new study published Friday.
The study is the first to find that wet bulb temperatures of 95 degrees
(35 Celsius), which renders ineffective the human heat response of
sweating to shed heat through evaporation, leading to hyperthermia, are
already occurring for short periods of time at a few weather stations.
These tend to be located in parts of the Persian Gulf shoreline and
coastal southwest North America, where sizzling lands border sultry
seas, as well as in northern South Asia, where extreme heat and humidity
combinations overlap just before the annual monsoon begins.
With computer model projections showing the world will continue to warm
rapidly in response to increasing amounts of greenhouse gases in the
atmosphere, the study, published Friday in the journal Science Advances,
warns that highly populated regions of the world will be rendered
uninhabitable sooner than previously thought for parts of each year.
This will come to pass unless people take wide-ranging and costly steps
to adapt to the heat during the next few decades, while nations
undertake measures to slash emissions of greenhouse gases.
The study depicts a world steadily marching toward a future in which
many locations approach or reach that survivability threshold, as well,
a trend that could throw a spotlight on the divide between rich nations
that are able to adapt to this new reality and poor countries that
suffer productivity losses and deaths.
The heat in the subtropics constitutes a threat to global stability,
some researchers say, since they could prompt millions to become climate
migrants, searching for more temperate conditions elsewhere.
For the research, scientists at NASA’s Jet Propulsion Laboratory and
Columbia University examined surface temperature data around the world
on land and sea. They detected, for the first time, the arrival of what
some scientists have called “Steambath Earth,” with heat waves that
humans cannot survive after prolonged exposure.
The threshold for survivability occurs when the wet bulb temperature
hits 95 degrees (35 Celsius).
Meteorologists measure wet bulb temperatures by wrapping a wet wick
around the bulb of a thermometer. While it may seem to be an esoteric
figure, it’s highly significant in heat wave situations, since the
higher the wet bulb temperature gets, the more difficult it becomes for
the human body to shed metabolic heat into the air through the
evaporation of sweat.
In fact, mortality increases during heat waves when wet bulb
temperatures reach temperatures of 88 to 91 degrees (31 to 33 Celsius),
the study states.
According to study co-author Radley Horton of Columbia University, the
combination of high temperature with high humidity is, “Maybe the most
underappreciated of the direct climate hazards.” In an interview, he
said for too long, attention has mainly focused on increasing global
temperatures and heat extremes overall.
“People are late to the game in thinking about these multiple variate
risks, such as heat plus humidity,” Horton said.
Horton said the researchers were surprised to find such sharp increases
in moist heat waves in part because computer model projections don’t
show these occurrences becoming common for a few more decades.
However, models often miss local-level interactions between coastal
regions and hot seas, for example, or hot inland regions of South Asia
and moist air flowing northward from the Indian Ocean, just as the
monsoon season begins.
Matthew Huber, a heat extremes researcher at Purdue University, not
involved in the study, said excessive combinations of heat and humidity
are not a widespread health concern yet, but they likely will be as
global warming progresses.
“We expect these extreme wet bulb values to be rare, but to become more
common as the world warms,” he said in an email. “That this is observed
to be happening is therefore exactly as we would predict from standard
models of global warming, but it is disturbing to see it happening in
real time.
“It will only get worse and more widespread from here."
In the Washington region, which is notorious for its hot and humid
summers, study co-author Colin Raymond of NASA said the results show
moderate levels of heat and humidity have increased significantly since
1979, although extremely high wet-bulb temperatures are not yet
commonplace.
The region’s all-time maximum wet-bulb temperature is 87.2 degrees (30.7
Celsius) set at Newington, Va., on July 18, 2013.
Middle East, South Asia are among the first regions to see such deadly
heat emerge
Parts of the Middle East have endured suffocating levels of heat and
humidity in recent years, producing off-the-chart heat index values,
which is another metric showing the combination of heat and humidity.
In July 2015, Bandar Mahshahr, a city in southwest Iran registered an
air temperature of 115 degrees (46 Celsius) and a dew point of 90
degrees (32 Celsius). The computed heat index for this brutal
combination was 165 degrees (74 Celsius), among the highest recorded.
However, the National Weather Service cautions such conditions are so
extreme that they are beyond the limit the heat index was designed to
calculate.
The highest known combination of heat and humidity occurred in Dharan,
Saudi Arabia according to weather extremes expert Christopher Burt,
author of “Extreme Weather: A Guide & Record Book.” On July 8, 2003, the
temperature hit 108 (42.2 Celsius) with a dew point of 95 (35 Celsius).
Both the Dharan and Bandar Mahshahr temperature and humidity pairings
equate to wet-bulb temperatures readings around 35 Celsius, at the
theoretical survivability limit. The two cities lie adjacent to the
Persian Gulf, where water temperatures can soar into the 90s.
As another recent example of extremely humid heat at a Middle East
location adjacent to water, on June 26, 2018, the coastal city of
Quriyat, Oman, never dropped below 108.7 degrees (42.6 Celsius) over the
course of a calendar day. This was most likely the highest minimum
temperature observed on Earth.
With the intensity of humid heat escalating, wealthy countries in the
Middle East are pursuing innovative but expensive strategies to bring
their people indoors, and even to air-condition the outdoors. Qatar, for
example, is air conditioning its outdoor markets, sidewalks and outdoor
malls, for example.
However, these are not steps that rapidly-warming but comparatively poor
nations in the subtropics can take in the face of global warming.
“Of all of the climate risks coming this century, the thing I am most
concerned about is excessive heat in the tropics,” said Ken Caldeira,
senior scientist emeritus at the Carnegie Institution for Science at
Stanford University, in an email.
“Rich countries have brought much of their economy indoors where air
conditioning is a possibility, but many developing economies rely on
labor-intensive outdoor agriculture,” he wrote. “The combination of
poverty and extreme temperatures can be lethal.”
For Jonathan Buzan, a climate scientist at the University of Bern in
Switzerland, the new study doesn’t just contain extreme heat warnings
for the Middle East and South Asia, but for the United States, too. His
research has found that wet-bulb temperature extremes in the Midwest
increase by about 1.8 degrees (1 Celsius) for every 1.8 degrees of
global warming.
This means that warming of 3.6 degrees (2 Celsius) would bring periods
of wet-bulb temperatures of 95 degrees (35 Celsius) for a limited amount
of time. With global warming on course to exceed 3.6 degrees, that could
bring “a few days per year” with unsurvivable heat “sustained for a few
days per year.” This would make agriculture that relies on outdoor
picking impossible.
_________________________________________________________
Full posting guidelines at: http://www.marxmail.org/sub.htm
Set your options at:
https://lists.csbs.utah.edu/options/marxism/archive%40mail-archive.com