Wet Bulb at 33 C — Human Hothouse Kills Nearly 800 in Pakistan

Human-forced warming of the global climate system is pushing sea surface temperatures in some areas to a maximum of 33 C. Extreme ocean warming that is increasing the amount of latent heat the atmosphere can deliver to human bodies during heatwaves. And near a 33 C sea surface hot zone, the past few days have witnessed extreme heat and related tragic mass casualties in Sindh, Pakistan.

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For Pakistan, the heat and humidity has been deadly. Temperatures over Southeastern Pakistan hit 100 to 113 Fahrenheit (40 to 45 degrees Celsius) during recent days. Night time lows dipped only into the 80s and 90s (30s Celsius). Relative humidity throughout this period has remained above a brutal 50% even during the hottest hours of the day.

Wet bulb temperatures (the wet-bulb temperature is the temperature air has if it is cooled to saturation — 100% relative humidity — by evaporation) climbed into a dangerous range of 30 to 33 degrees Celsius. This greatly reduced the ability of evaporation at skin level to cool the bodies of human beings exposed to such oppressive temperatures. As a result, people working outdoors, the elderly, or those without access to climate-controlled environments fell under severe risk of heat related injuries.

The Hospital Morgue is Overflowing

According to reports from Al Jazzera, thousands of heat injuries and hundreds of deaths have occurred across the region since Saturday. Karachi’s largest hospital — Jinnah Postgraduate Medical Centre (JPMC) — has been flooded with over 5,000 patients suffering from heat injuries since the weekend. At some points, the hospital was receiving one heat injury patient per minute — a pace that nearly overwhelmed the facility. By earlier today, more than 380 of those patients had died.

Dr Seemin Jamali, a senior official at JPMC noted to Al Jazeera:

“The mortuary is overflowing, they are piling bodies one on top of the other. We are doing everything that is humanly possible here. Until [Tuesday] night, it was unbelievable. We were getting patients coming into the emergency ward every minute.”

Across Sindh, Pakistan the story was much the same with the total official heat death toll now standing at 775 and climbing as calls were raised for more government support for people impacted by the worst heat wave to hit Pakistan in at least 15 years.

Killing Heat and Unprecedented Rains

This extreme and deadly heat is a feature of a boundary zone between a hot, high-pressure air mass over the Persian Gulf region abutting against a very moist and El Nino-intensified monsoonal system over India. The result is a combination of high heat and high humidity — factors that, together, are very hard on the human body (wet bulb temperatures above 30 C are considered dangerous, while a blanket measure of 35 C [never reached yet on Earth] is considered rapidly deadly even in the shade).

During late May and early June, similar conditions resulted in hundreds of heat related deaths in India. When the heat finally abated, the subsequent influx of monsoonal moisture set off torrential downpours. In some places, rates of rainfall exceeded typical June monsoonal accumulations by nearly 50 percent with Mumbai already having received 32 inches of rainfall (normal June rainfall is 23 inches). With Mumbai showing daily rainfall accumulations of 1-3 inches, it is possible that June totals could be double that of a typical year.

A Ramping Oceanic Heat/Moisture Pump — Feature of a Record Warm World

The high heat, high humidity and related extreme rainfall events are all features of a warming world. At issue, primarily, is the impact of human forced global warming on the ocean system and how this heating then impacts the atmosphere — making it harder for humans to remain alive outdoors during the most extreme heating events even as it pushes a tendency for more and more extreme droughts and deluges.

This warming related heat and moisture flux is most visible out in the Pacific, where record global atmospheric and ocean heat is pushing maximum sea surface temperatures into the lower 30s (typically between 30 and 31 degrees Celsius). These high sea surface temperatures in a record warm world are now dumping an extreme amount of moisture into the atmosphere through an El Nino amplified evaporation rate. A subsequent amplification of the equatorial storm track due to extreme moisture loading has already seen extraordinary record rainfall events in places as widespread as India, China and the Central U.S.

image

(Sea surface temperatures climb to near 33 C in the Ocean region near Pakistan — supporting wet bulb temperatures [high heat and high humidity] that generate a heightened risk of heat injury and death. Image source: Earth Nullschool.)

Maximum global sea surface temperature is a good proxy measure for how much moisture the atmosphere can hold, a measure that also likely determines the maximum wet bulb temperature (implied latent heat) at any given point on the globe. And particularly, near Pakistan, we find ocean surface temperature readings in the range of 30 to 33 C running through the coastal zone of the Indian Ocean and on into the Persian Gulf. Readings that increased the amount of moisture the atmosphere could hold at high temperature, increased relative humidity readings as temperatures entered the 100s Fahrenheit (40s C), and forced wet bulb temperatures into deadly ranges which in turn reduced the ability of the human body to cool by evaporation at skin level.

This is how human-forced global warming kills with direct heat — by basically increasing latent heat to the point that evaporation can no longer cool the human body to a natural maintenance temperature of 98.6 (F) or 37 (C). And once wet bulb temperatures start hitting 35 C, then the heat casualty potential really starts to get bad — essentially rendering heat wave regions temporarily uninhabitable for human life outdoors. With maximum sea surface temperatures now running near 33 C, we’re probably just within about 2 C of hitting that deadly boundary.

The Pakistan and Indian heat deaths this year, though extraordinarily tragic and probably preventable without current level of human forced warming of the atmosphere, serve as a warning. Keep warming the globe through fossil fuel emissions and there are many far, far worse heatwaves to come.

Links:

Pakistan Heatwave Death Toll Edges Toward 800

Pakistan Heatwave Death Tool Rises to 750

Heavy Rain Soaks India as Monsoon Advances

Flash Floods Pelt China

Earth Nullschool

An Adaptability Limit To Climate Change Due to Heat Stress

Hat Tip to Colorado Bob

China Falls Under Suspicion of Covering Up Deaths as Ocean Heat Dome Expands to Blanket Korea and Japan

US Weather Fatalities by Type

US Weather Fatalities by Type

(Image source: NOAA)

According to recent reports from NOAA and the CDC, heat is the most lethal form of weather in the United States. Death and injury rates have been on the rise as human-forced temperature increases have expanded, surging northward into major metro areas such as New York City. The CDC report showed a growing number of heat deaths and injuries for this northern region, with the New York Metro area seeing an average of 13 deaths and over 440 heat injuries each year during the period from 2000 to 2011. Nationwide, the average number of heat fatalities surged to 117 during a period from 2003 to 2011.

Heatwaves have hit the NYC region time and time again over the past decade, driving the death and injury rate inexorably higher. However, the heat impacting that area is paltry when compared to the extreme and deadly temperatures that have broiled southeastern China since late July. For more than three weeks, the Shanghai region of China has experienced almost daily temperatures in excess of 100 degrees Fahrenheit and sweltered under very high humidity for such hot conditions. This combination has pushed wet bulb temperatures (a measure that simulates the temperature of human skin) into a range of 29 to 32 degrees Celsius, very close to the lethal human limit of 35 degrees C.

On Sunday, an extreme heat pulse sent thermometers soaring to 109 degrees Fahrenheit in the city of Shengxian — its hottest temperature ever recorded and a scorching 32.3 degree wet bulb temperature. Meanwhile, on the same day, Hangzhou had hit a new all time record high temperature of 105.8 degrees Fahrenheit, the twelfth time since July 24th that Hangzhou has tied or broken its old all time temperature record which, in some cases, was set just the day before.

High heat and humidity of this kind is deadly to humans because as temperatures approach 35 degree C wet bulb readings, it is nearly impossible for the human body to carry away the excess heat it generates through evaporation. Never has a wet bulb temperature of 35 degrees C been recorded by humans. However, climate scientists such as James Hansen have asserted that it’s just a matter of time under the current regime of human-caused warming before we hit that ominous mark.

So have thousands died?

Road Sing Burns in Shanghia Region

Road Sign Burns Under Record Heat in Shanghai Region

(Image source: Shenzhen Daily)

As reports of vehicle fires and sporadically smoldering infrastructure in the massive Chinese heatwave flared, suspicions emerged that Chinese officials are covering up what are potentially thousands of heat-related deaths.

According to Chinese news agencies, the official report is that about two dozen have died so far in Shanghai’s record-shattering heatwave. But similar heat in Europe and Russia resulted in tens of thousands of deaths over the past decade. At issue is the fact that China’s current record heat and humidity are at levels never before experienced in its weather history and that this event is even more intense than the deadly heatwaves of Europe and Russia. Add to this extraordinarily dangerous event the fact that more than 400 million people live in the region of China currently being socked by record heat and the vague reports coming out of China seem highly incongruent.

Never before has such high wet bulb temperatures hit a region of so dense a population. Yet China has only continued to report the vague ‘dozens’ estimate.  It was this discrepancy that caused WeatherUnderground Historian Christopher Burt to speculate that China may be covering up a catastrophic rash of fatalities:

Eastern China, where about 30% of the population of the country and 5% of the global population reside (approximately 400 million people) has undergone a heat wave unprecedented in its history. No one really knows how many have died as a result of the heat wave (Chinese news sources claim ‘about two dozen’), but statistically it is almost certain that many thousands must have perished as the result of the heat over the past month.

If Christopher Burt’s, quite rational, analysis ends up proving true, we can expect reports of fatalities to begin to slowly trickle out of China. Misreporting and under-reporting of Chinese heatwave casualties would also be yet one more instance of government officials and mainstream media downplaying and under-reporting the effects of catastrophic events related to human-caused climate change. Such under-reporting is yet one more manifestation of a dangerous and paralyzing denial that has so hampered an effective response to these increasingly dangerous and self-inflicted events.

Making such a call, however, is possibly premature as residents of this region are more acclimated to excessive heat than Europeans or Russians. As Burt notes:

One thing to keep in mind, however, is that it is ALWAYS hot and humid in eastern China during the summer (unlike Russia and Western Europe), so perhaps the population has learned to adapt to extreme heat.

The Ocean Heat Dome Expands to Cover Korea and Japan

Ocean Heat Dome

Ocean Heat Dome Over China, Korea and Japan

(Image source: NASA/Lance-Modis)

A sprawling heat dome high pressure system that has scorched a region stretching from coastal China to a large expanse of the Pacific Ocean shifted eastward into Korea and Japan over the weekend. Southern Japan saw temperatures surge into the 100s with Shimanto recording the highest temperature ever measured in Japan of 105.8 degrees Fahrenheit (41 degrees Celsius). Tokyo, meanwhile, broke the record for its hottest minimum temperature at 86.7 degrees Fahrenheit (30.4 C).

South Korea, over the same period, reported 8 deaths as temperatures soared to 102.2 degrees Fahrenheit (39 C) in Busan. Temperatures in Seoul hit the still hot, but more moderate, 90s (32 C +).

Both South Korea and Japan are surrounded on multiple sides by water. This geographic feature would usually provide a cooling effect as ocean temperatures are typically many degrees cooler than land temperatures. But, in this case, a massive heat dome is baking the ocean itself to unprecedented high surface water temperatures. As a result, a large area of open ocean now shows readings above 30 degrees Celsius ( 86 Fahrenheit). This extremely hot, near 90 degree water, has formed the central pulse of the current heatwave even as it has pumped extraordinarily humid air for such hot conditions over adjacent land areas. A shift to the north of this large and still growing region of extraordinarily hot ocean water led to the record steamy conditions over Japan and Korea during the past few days — both of which can expect little relief from the now, very hot, water.

Asia in Hot Water

Ocean Heat Dome Puts Asia in Hot Water

(Image source: Weather Online)

Forecasts for Shanghai, Korea, and Japan call for slightly less sweltering temperatures in the upper 90s with more isolated readings in the 100s as clouds are expected to move in and increase chances of rainfall by later this week. A slight improvement but a welcome change, nonetheless. Meanwhile, hot ocean conditions create a risk for continued very hot temperatures for much of this coastal region.

(Hat Tip to Colorado Bob for the head’s up)

Ocean Heat Dome Steams Coastal China: Shanghai to Near Very Dangerous 35 Degree Celsius Wet Bulb Temperatures This Week

Shanghai Under Ocean Heat Dome

Shanghai, southeast China swelter under Ocean Heat Dome.

(Image source: NASA/Lance-Modis)

An ocean heat dome that formed over a broad area of the Pacific Ocean, the South and East China seas, and a large stretch of coastal China during late July continues to create a dangerous combination of record hot temperatures and high humidity.

According to reports from AccuWeather, the sweltering coastal China town of Shanghai hit a new all-time record high temperature of 105.8 degrees Fahrenheit (41 degrees C) on Tuesday. But this marker may just be a milepost to what is predicted to be a 107-108 degree scorcher on Wednesday and Friday. With humidity predicted to be around 50% and barometric pressure readings expected to hit 1005 millibars, these represent extraordinarily dangerous conditions.

The human wet bulb limit: 35 C

Recent climate papers by former NASA scientist James Hansen have issued warnings of the potential for wet bulb temperatures on the surface of the Earth to start to exceed levels that are lethal for humans at 35 degrees C  for longer and longer periods as humans continue to warm the atmosphere. Hansen notes:

One implication is that if we should “succeed” in digging up and burning all fossil fuels, some parts of the planet would become literally uninhabitable, with some time in the year having wet bulb temperature exceeding 35°C. At such temperatures, for reasons of physiology and physics, humans cannot survive, because even under ideal conditions of rest and ventilation, it is physically impossible for the environment to carry away the 100 W of metabolic heat that a human body gene rates when it is at rest.

Different from direct air temperature, wet bulb readings measure what air feels like on the surface of the skin. The measure simulates the cooling effect caused by human sweat evaporating from the skin surface. In very dry, hot conditions, human skin temperature can remain below this lethal level as the rate of evaporation increases due to dryness. Since most of the world’s hottest regions are very dry, humans can withstand air temperatures of 120 degrees (Fahrenheit) and above. Thankfully, it is very rare that extraordinarily hot and humid conditions occur in the same locations. This is generally due to a cooling affect provided by an adjacent ocean mass — as most damp regions are also near or surrounded by cooler ocean air.

The Ocean Heat Dome

Enter the weather conditions forecast for Shanghai tomorrow and Friday…

A massive heat dome high pressure system has settled, not just over land areas of China, but directly over a large region of the Pacific Ocean and adjacent China seas. The result is that sea surface temperatures are now ranging 1-4 degrees Celsius above the already warm 1971-2000 average with a large area showing temperatures above 30 degrees Celsius (86 Fahrenheit). This large region of hot water and corresponding hot ocean air is pumping both heat and humidity into the Shanghai region. Hot ocean air is being pumped over Southeast Asia where it mixes with the already baking land mass air to form a brutal brew of very high heat and high humidity. The clockwise flow of the heat dome then pulls this mixture of record hot and humid air over the highly populated regions of Shanghai.

These ocean-based heat dome conditions are not normal, with typical heat dome conditions usually forming over land. The danger in this particular set of conditions is that very high heat combines with higher than usual humidity to result in much greater heat injury risks for humans.

Ocean heat dome

Sea surface temperatures under Ocean Heat Dome

(Image source: Weather Online)

Forecasts for tomorrow and Friday are showing Shanghai temperatures will probably reach at least 107-108 degrees Fahrenheit (42 C) in an area where relative humidity is forecast to be 50% and where barometric pressures are forecast to remain around 1005 millibars of mercury. This brings us to the extraordinarily dangerous high wet bulb temperature of 33 degrees Celsius.

Please do your best to stay safe

In such instances, the best defense is to find a cool, shaded location and limit exposure to heat during the hottest times of the day. Drinking cold fluids can also aid in reducing core body temperatures. A common heat mitigation aid is freezing a bottle of water and carrying it in a pocket next to your thigh. The cold bottle will contact the skin near the femoral artery, cooling blood there and transporting this cooler blood throughout the body. If extreme heat is still too much, placing the bottle in direct contact with the large veins in the neck will provide even more efficient cooling. This simple cooling pack also doubles as a means to replenish vital fluids.

Under such conditions, it is also important to be alert for signs of heat exhaustion and heat stroke to include:

  • Confusion
  • Dark-colored urine (a sign of dehydration)
  • Dizziness
  • Profuse sweating
  • Weakness
  • Muscle cramps
  • A lack of sweating

China has also activated emergency operations facilities and is providing information and aid in the hardest hit regions.

Unfortunately, record heat is expected to continue over Shanghai through at least next Wednesday with only one day expected to see below 100 degree (F) readings. With so many already dealing with heat stress, our best hopes are that all there will have the means to remain safe.

Hat Tips and People I Just Feel Like Promoting:

Colorado Bob

Prokaryotes

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