Fairly reasonable worst-case scenarios for
global warming could lead to deadly temperatures for humans in coming
centuries and the need to build polar cities to house survivors of climate chaos in order to continue the human species after 2300 AD, according to research findings from Purdue University and
the University of New South Wales, Australia, and additional polar cities ideas from Danny Bloom. (http://pcillu101.blogspot.com). Sadly, only a few people grasp all this, and most people could not be bothered. So go back to your fun and games, people of Earth. The future? You don't really care. That's the truth. But read the truth below, too:
Researchers for the first time have calculated the highest tolerable
"wet-bulb" temperature and found that this temperature could be
exceeded for the first time in human history in future climate
scenarios if greenhouse gas emissions continue at their current rate.
Wet-bulb temperature is equivalent to what is felt when wet skin is
exposed to moving air. It includes temperature and atmospheric
humidity and is measured by covering a standard thermometer bulb with
a wetted cloth and fully ventilating it.
The researchers calculated that humans and most mammals, which have
internal body temperatures near 98.6 degrees Fahrenheit, will
experience a potentially lethal level of heat stress at wet-bulb
temperature above 95 degrees sustained for six hours or more, said
Matthew Huber, the Purdue professor of earth and atmospheric sciences
who co-authored the paper that will be published in the Proceedings of
the National Academy of Sciences.
"Although areas of the world regularly see temperatures above 100
degrees, really high wet-bulb temperatures are rare," Huber said.
"This is because the hottest areas normally have low humidity, like
the 'dry heat' referred to in Arizona. When it is dry, we are able to
cool our bodies through perspiration and can remain fairly
comfortable. The highest wet-bulb temperatures ever recorded were in
places like Saudi Arabia near the coast where winds occasionally bring
extremely hot, humid ocean air over hot land leading to unbearably
stifling conditions, which fortunately are short-lived today."
The study did not provide new evaluations of the likelihood of future
climate scenarios, but explored the impacts of warming. The challenges
presented by the future climate scenarios are daunting in their scale
and severity, he said.
"Whole countries would intermittently be subject to severe heat stress
requiring large-scale adaptation efforts," Huber said. "One can
imagine that such efforts, for example the wider adoption of air
conditioning, would cause the power requirements to soar, and the
affordability of such approaches is in question for much of the Third
World that would bear the brunt of these impacts. In addition, the
livestock on which we rely would still be exposed, and it would make
any form of outside work hazardous."
While the Intergovernmental Panel on Climate Change central estimates
of business-as-usual warming by 2100 are seven degrees Fahrenheit,
eventual warming of 25 degrees is feasible, he said.
"We found that a warming of 12 degrees Fahrenheit would cause some
areas of the world to surpass the wet-bulb temperature limit, and a 21-
degree warming would put half of the world's population in an
uninhabitable environment," Huber said. "When it comes to evaluating
the risk of carbon emissions, such worst-case scenarios need to be
taken into account. It's the difference between a game of roulette and
playing Russian roulette with a pistol. Sometimes the stakes are too
high, even if there is only a small chance of losing."
Steven Sherwood, the professor at the Climate Change Research Centre
at the University of New South Wales, Australia, who is the paper's
lead author, said prolonged wet-bulb temperatures above 95 degrees
would be intolerable after a matter of hours.
"The wet-bulb limit is basically the point at which one would overheat
even if they were naked in the shade, soaking wet and standing in
front of a large fan," Sherwood said. "Although we are very unlikely
to reach such temperatures this century, they could happen in the
Humans at rest generate about 100 watts of energy from metabolic
activity. Wet-bulb temperature estimates provide upper limits on the
ability of people to cool themselves by sweating and otherwise
dissipating this heat, he said. In order for the heat dissipation
process to work, the surrounding air must be cooler than the skin,
which must be cooler than the core body temperature. The cooler skin
is then able to absorb excess heat from the core and release it into
the environment. If the wet-bulb temperature is warmer than the
temperature of the skin, metabolic heat cannot be released and
potentially dangerous overheating can ensue depending on the magnitude
and duration of the heat stress.
The National Science Foundation-funded research investigated the long-
term implications of sustained greenhouse gas emissions on climate
extremes. The team used climate models to compare the peak wet-bulb
temperatures to the global temperatures for various climate
simulations and found that the peak wet-bulb temperature rises
approximately 1 degree Centigrade for every degree Centigrade increase
in tropical mean temperature.
Huber did the climate modeling on supercomputers operated by
Information Technology at Purdue (ITaP), Purdue's central information
technology organization. Sherwood performed the wet-bulb calculations.
"These temperatures haven't been seen during the existence of
hominids, but they did occur about 50 million years ago, and it is a
legitimate possibility that the Earth could see such temperatures
again," Huber said. "If we consider these worst-case scenarios early
enough, perhaps we can do something to address the risk through
mitigation or new technological advancements such as building polar cities in the northern regions for climate refugees and Earth holocaust survivors in 2300 AD that will allow us to