2021 Blog Climeaggedon

This blog will begin where we are: July 27, 2021

We are in the moral equivalent of WWIII. The enemy is our own pollution and reduction of wilderness - wherein today humans and their domesticated animals now outweigh all wild mammals by 10 to 1, a complete reversal of where we stood 100 years ago. As we look across the N Hemisphere when in a year historically around 138 americans supposedly die of heat exposure a year 2000-2020, we had 400 people die from heat in British Columbia alone. Oregon is burning the country is convulsed with drought flood and fires. Moving to Europe the entire continent is in climate chaos, N Africa, the Middle East India Russia Siberia and China. The olympics in Japan are being performed under extreme heat and humidity events - the Olympics in Qatar 2024 will need to be conducted indoors or off season. And the marine heatwaves may be worse. There are no excuses left. As George H.W. Bush said "We are in deep doo-doo".

The most immediate threat is the wet bulb event.


Humans’ ability to efficiently shed heat has enabled us to range over every continent, but a wet-bulb temperature (TW) of 35°C (95 F) marks our upper physiological limit, and much lower values have serious health and productivity impacts. Climate models project the first 35°C TW occurrences by the mid-21st century. However, a comprehensive evaluation of weather station data shows that some coastal subtropical locations have already reported a TW of 35°C and that extreme humid heat overall has more than doubled in frequency since 1979. Recent exceedances of 35°C in global maximum sea surface temperature provide further support for the validity of these dangerously high TW values. We find the most extreme humid heat is highly localized in both space and time and is correspondingly substantially underestimated in reanalysis products. Our findings thus underscore the serious challenge posed by humid heat that is more intense than previously reported and increasingly severe.

Note- my Grandparents above

Wet Bulb Events Heat and Humidity are lethal within one hour outdoors in sun at a adj wet bulb temperature of 35C or 95F

wet bulb temperature of 35 degrees Celsius, people’s bodies can’t dissipate metabolic heat, they then suffer from hyperthermia, overheating.

A wet bulb temperature is measured with a standard thermometer covered in a wet cloth while well ventilated, indicating the temperature at 100% humidity. Wet bulb or Temperature Wet TW is a measure of temperature and humidity combined.

Humans maintain an internal body temperature of 37 degrees Celsius, with a skin temperature kept at 35 degrees C or below. With the skin cooler than the internal core temperature heat can be lost to the skin. Heat from metabolism is lost from the body and skin by heat conduction, evaporative cooling and infrared radiative cooling (Sherwood & Huber, 2010).

The wet bulb temperature of 35 degrees Celsius is the temperature and humidity at which humans and mammals will become overheated, with potential death at 42 to 43 degrees internal body temperature. Conduction and evaporation cooling can’t occur as a result of the temperature and humidity respectively being too high (Sherwood & Huber, 2010).

Wet Bulb Globe Temperature, WBGT, is another index for measuring heat stress, it is often used in industry and includes the other factors of the amount of physical activity, the environment characteristics eg sun angle, cloud cover, and the clothing worn. Tw has been chosen here because it establishes a limit at which these other factors included in WBGT are ineffective (Sherwood & Huber, 2010; Willet & Sherwood, 2012).

The highest wet bulb temperature reached anywhere on earth is about 30 degrees C, this is probably because of a convective instability mechanism, that can occur with high temperature and humidity, which result in storm activity that cools air near the surface, but many areas of the earth have very low storm activity and low rainfall.

A climate change increase in air temperature of 7 degrees is possible by 2100, pushing the wet bulb temperature to 35 (Sherwood & Huber, 2010) while Sokolov, et al. (2009) projects 5.4 degrees air temperature rise by 2091 to 2100. Warming will continue to increase past 2100 if emissions of carbon dioxide continue.

We are 3 degrees below that condition this weekend in North Carolina tommorow and at what were maximums globally are being broken all over the US (30-32C Wet Bulb Global Temperature WBGT)

Heat Index of 130 would lead to heat stroke

Heat stroke can kill or cause damage to the brain and other internal organs. Although heat stroke mainly affects people over age 50, it also takes a toll on healthy young athletes.

Heat stroke often occurs as a progression from milder heat-related illnesses such as heat cramps, heat syncope (fainting), and heat exhaustion. But it can strike even if you have no previous signs of heat injury.

Heat stroke results from prolonged exposure to high temperatures -- usually in combination with dehydration -- which leads to failure of the body's temperature control system. The medical definition of heat stroke is a core body temperature greater than 104 degrees Fahrenheit, with complications involving the central nervous system that occur after exposure to high temperatures. Other common symptoms include nausea, seizures, confusion, disorientation, and sometimes loss of consciousness or coma.

Climate change

How hot is too hot for the human body?

Climate change is bringing extreme heat and testing the limits of what people can tolerate.


July 10, 2021


Climate change is making extreme heat more common and more severe, as we've seen in the heat waves that have swept the western US for the past two weeks. Some climate models predict that swaths of the globe will become inhospitable to humans in the next century.

But what makes a place unlivable isn’t as straightforward as a specific temperature, and even accounting for humidity doesn’t fully explain the limits of the human body in extreme heat. Tolerance can vary from person to person, and someone’s ability to withstand heat can change. Understanding our limits and what determines them will be more important as global temperatures creep upward and extreme weather events become harder to predict.

“You would think that, at this moment, we will have choices between the good and the bad,” says Camilo Mora, a climate researcher at the University of Hawaii. But now, when it comes to extreme heat, “the choices are more of this or a lot more of this.”

Related Story

Climate change made the record-shattering Northwest heat wave 150 times more likely

The event burst some all-time highs by nearly 5 ˚C, raising troubling questions.

For a study published in Nature Climate Change in 2017, Mora and his team analyzed hundreds of extreme heat events around the world to determine what combinations of heat and humidity were most likely to be deadly, and where those conditions were likely to occur in the future.

They found that while today around 30% of the world’s population is exposed to a deadly combination of heat and humidity for at least 20 days each year, that percentage will increase to nearly half by 2100, even with the most drastic reductions in greenhouse-gas emissions.

Other researchers have found that climate change is making extreme heat waves up to hundreds of times more likely and causing over a third of heat-related deaths. We’re changing our planet—what are the limits of what we can endure?

Cooling off

As warm-blooded mammals, humans have a constant body temperature, around 98 °F (37 °C). And our bodies are designed to work pretty much right at that temperature, so there’s a constant balance between heat loss and heat gain.

Problems start when our bodies can’t lose heat fast enough (or lose it too fast in the cold, but let’s focus on heat for now). When your core temperature gets too hot, everything from organs to enzymes can shut down. Extreme heat can lead to major kidney and heart problems, and even brain damage, says Liz Hanna, a former public health researcher at the Australian National University, who studies extreme heat.

Your body works to maintain its core temperature in hot environments mostly by using one powerful tool: sweat. The sweat you produce evaporates into the air, sucking heat from your skin and cooling you down.

Humidity cripples this cooling method—if it’s so humid that there’s already a lot of water vapor in the air, then sweat can’t evaporate as quickly, and sweating won’t cool you down as much.

Extreme heat can lead to major kidney and heart problems, and even brain damage.

Researchers like Mora and his team often use measures like heat index or wet-bulb temperature to consider how excessive heat and humidity interact. This way, they can focus on a single number to identify unlivable conditions.

Heat index is an estimate that you’ve probably seen in weather reports; it factors in both heat and humidity to represent how the weather feels. Wet-bulb temperature is literally what a thermometer measures if a wet cloth is wrapped around it. (The temperature in the forecast is technically a dry-bulb temperature, since it’s measured with a dry thermometer.) Wet-bulb temperature can estimate what your skin temperature would be if you were constantly sweating, so it’s often used to approximate how people would fare in extreme heat.

A wet-bulb temperature of 35 °C, or around 95 °F, is pretty much the absolute limit of human tolerance, says Zach Schlader, a physiologist at Indiana University Bloomington. Above that, your body won’t be able to lose heat to the environment efficiently enough to maintain its core temperature. That doesn’t mean the heat will kill you right away, but if you can’t cool down quickly, brain and organ damage will start.

The conditions that can lead to a wet-bulb temperature of 95 °F vary greatly. With no wind and sunny skies, an area with 50% humidity will hit an unlivable wet-bulb temperature at around 109 °F, while in mostly dry air, temperatures would have to top 130 °F to reach that limit.

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Some climate models predict that we’re going to start hitting wet-bulb temperatures over 95 °F by the middle of the 21st century. Other researchers say we’re already there. In a study published in 2020, researchers showed that some places in the subtropics have already reported such conditions—and they’re getting more common.

While most researchers agree that a wet-bulb temperature of 95 °F is unlivable for most humans, the reality is that less extreme conditions can be deadly too. We’ve only hit those wet-bulb temperatures on Earth a few times, but heat kills people around the world every year.

“Everyone is susceptible—some more than others,” says Hanna, the Australian public health researcher. Children and elderly people usually can’t regulate their temperature as well as young adults, and people on certain medications have a decreased ability to sweat.

People’s heat tolerance can also change over time—your body can become more acclimatized to heat with exposure, sort of like the way it can acclimatize to lower oxygen levels at high elevations.

Heat tolerance

Heat acclimatization builds up over time: It can start in as little as a few days, and the whole process can take six weeks or longer, Hanna says. People who are more acclimatized to heat sweat more, and their sweat is more diluted, meaning they lose fewer electrolytes through their sweat. This can protect the body from dehydration and heart and kidney problems, Hanna says.

Acclimatization is why heat waves in cooler places, or heat waves early in summer, are more likely to be deadly than the same conditions in hotter places or later in summer. It’s not just that places like Canada and Seattle are less likely to have air conditioning, although infrastructure is another big factor in how deadly heat waves will be. Residents of cooler places are also just less acclimatized to the heat, so wet-bulb temperatures below 95 °F can be deadly.

There are limits to acclimatization, Hanna points out. We won’t be able to evolve past the conditions that climate change is likely to bring in the coming decades. She also says that while physiological limits are important, we must also consider other factors, like behavior and infrastructure.

If you’re moving around or working outside, the temperature doesn’t have to get nearly as hot to be deadly, Hanna says. Of the total energy you use to do a task, whether that’s running a race or washing dishes, 20% goes to actually moving your muscles, and the other 80% turns into heat. So more movement means more heat for your body to get rid of, which means that if you’re exerting yourself, you won’t be able to handle temperatures you could endure if you were just lying around.

Living in Australia, Hanna is especially attuned to how extreme heat affects people and communities. Australia is one of the hottest countries on Earth, with some places already pushing the limits of human tolerance. Helping people understand the dangers of heat is more urgent to her than ever as the extremes become the norm.

“The world is warming,” Hanna says, “and it’s going to go beyond what normal physiology can cope with.”