written 26 May, 2024
published 2 June 2024
Humans are warm blooded mammals, which means our metabolism runs faster, allowing us to eat more varied foods, supports a larger brain, and allows life in more varied regions.
However, when external temperatures increase above 97°F, our bodies have to shed heat. We can dilate the blood vessels below our skin, increasing the blood flow, allowing heat to escape, as we have very little hair on our bodies, reducing skin insulation. However, our primary system is the evaporative cooling from our extensive sweat gland system.
The evaporation of water requires significant energy, which is pulled from our skin, cooling it. However, air always contains some amount of moisture: the "relative humidity". When humidity is low, the air can absorb more moisture, and evaporative cooling is possible. As the humidity increases, cooling becomes less possible. When the air holds as much moisture as possible at that temperature (100 percent humidity), no cooling is possible. This is why we can survive 115°F here in Ukiah, with a humidity of maybe only 30 percent, while 104°F with 99 percent humidity can be lethal.
When our cooling systems fail, our body begins to die. As more blood is shifted to the skin, central organs (kidneys, liver, and brain) become blood deprived, and begin to shut down. Symptoms of heatstroke include: body temperature over 104° F, flushed skin, rapid breathing, racing heart rate, nausea, vomiting, fatigue, headache, agitation, irritability, slurred speech, confusion, delirium, seizures, and unconsciousness.
With increased heat, our cells "denature", and melt. Proteins begin to come apart, kidneys and intestines begin leaking toxic waste into the blood stream, triggering systemic clotting of the blood. Once all the clotting proteins are consumed, we hemorrhage everywhere, as our bodies disintegrate. The only remedy, if applied in time, is to cool down our core, by drinking cool water, moving into cool shade or buildings, or being immersed in cool or icy water.
After thousands of years of relatively stable climate and temperatures, we now live in a climate hotter than the one we were born into, and heat death is increasing. A 2003 European heatwave killed over 70,000 (more than all US deaths in Vietnam). A 2010 104°F heatwave in Russia killed more than 55,000. In 2017, Pakistan experienced record heat of 129°F. In 2021, Antarctica saw an extra 70°F, a heatwave in the Pacific Northwest killed more than 1,000, and 126°F heat hit Pakistan again. 2022 brought a 104°F heatwave to London, killing more than 3,000, and Phoenix set a heat record of 122°F.
For those that can afford it, air conditioning has allowed human civilization to survive in increasingly lethal heat conditions. But this technological fix has limitations. To cool a building, the heat is shifted to the outside environment, making the outside even more lethal. A more serious concern is the availability of electricity. Last September, record heat, and record use of air conditioning, nearly crashed the California electrical grid. Rolling blackouts were avoided by massive voluntary customer load shedding. In places where electricity is less secure, people die when the power goes down. 2023 was the hottest year on record, and 2024 is already hotter.
Despite growing awareness that the climate crisis is real, humanity is adding increasing amounts of CO2 into the atmosphere every year. The wealthy few who are profiting from the existing energy system are doing everything they can to keep people ignorant of the problem. People seem to deny a situation until it affects them personally. So, for the foreseeable future, we will have to deal with what we are creating.
Here in Ukiah, the City Council, the City manager, and the head of the City electrical utility should begin planning for power resilient cooling centers, because the grid is unstable in times of high heat. Traditional use of diesel or propane power not only adds to the underlying climate problem, but these expensive systems are rarely used, and might not work when needed.
The City has been told by NCPA, our power provider, they need to add 15 percent more power produced locally. In addition to designing local systems to power essential City services, a creative plan would install renewable power for cooling centers, which could be of use all the time, while being ready for emergencies. Furthermore, an effort should be made to help other groups build resilient cooling systems, as the entire community will be in need.
