There are many ways to die. Everyone has to do it. But as climate change has become the new norm, there have been some alarming developments. With increasing frequency, powerful superstorms are destroying our communities. Forest fires are ravaging forests, transforming entire towns into cinders. Our buildings are being swept away by floodwaters.We can now add: Deadly heat is keeping us alive.The deadly heat wave that swept the western half North America in June killed many people in the Pacific Northwest, and Canada experienced its highest ever recorded temperatures. It was not a fluke. India and Pakistan both experienced record-breaking heat at this time. Another heat wave will bring more than 100 degrees to most of the U.S. next week.AdvertisementAdvertisementAdvertisementWhat gives? Every summer it gets hotter. These new heat waves are so dangerous and different.Temperatures around the world will rise multiple times per year if we continue to use oil in our SUVs and power plants, as well as coal and gas, limestone in our cementkilns and tropical forests in the stomachs (in the form Brazilian hamburgers and Indonesian palm oil), and keep burning oil in our SUVs.Imagine Portland, Oregon experiencing Death Valley temperatures every summer.However, Death Valley says it's a dry heat.Palm Springs is located just a few minutes south of Death Valley in a desert. Humans can survive in extreme heat for hours if they have enough water and shade to avoid sunstroke. This is not a recommendation from a doctor.AdvertisementIt's a different story if you go to Palm Beach, Florida. Because Palm Beach is located in the tropics and in one of the most humid areas of the Western Hemispheres, even a single day of 120 degree temperatures in Palm Beach could result in a large number of deaths. The morgues would be filled with bodies of victims of heatstrokecooked or hyperthermia.AdvertisementWhat is the answer? What is the difference between 120 and 120 degrees in Palm Beach?It turns out that there is some truth to the old cliche, it's not the heat, but the humidity. Understanding this temperature is essential for surviving and mitigating the climate crisis.AdvertisementThe human body can maintain a constant temperature between 97 and 99 degrees in moderate heat. Our bodies produce sweat when it gets hot. When the sweat evaporates, it transforms from liquid water on our skin to water vapour in the air. Your body's heat is what gives you that energy, and as the sweat evaporates your body cools.Dry heat is comfortable as the sweat evaporates so quickly that it doesn't even register on your skin. Dehydration can be dangerous in desert climates. While you may feel that the dry air is making it easier to tolerate the heat, you are actually losing water. Hydrate or die isn't just a clever slogan, it's good science.AdvertisementImagine that you are in the same heat but in Palm Beach where the air is extremely humid. The air already holds all the water vapour it can. Your sweat remains on your skin and heat from the sweat you are supposed to expel stays in your body.AdvertisementYour body is no longer able to heat itself, so your core temperature begins to rise to the same temperature as the air around it. If this continues for too long, your body temperature will rise from a comfortable 98 to a dangerous 108.It is not enough for the temperature to tell if the body can survive. It is necessary to know the temperature of the wet bulb. This term is derived from the mercury thermometer's bulb. Wrap a thermometer bulb in a wet cloth and place it in a warm room. The temperature will drop to a point below the room temperature. However, if the humidity in the room is high enough, the temperature of water vapour in the air will equalize with that on the cloth. At this point, heat loss is no longer possible. The mercury will rise even though the bulb is now sweating.AdvertisementThe wet bulb temperature is similar in that it captures heat and humidity. It is not the same. The Heat Index attempts to describe how a combination of heat/humidity feels. However, it is not exact. A feeling like 113° could feel like 90 degrees with a 72 degree dew point, or it could feel like 113° with zero humidity. To be able unpack the item and, most importantly, to assess risk, you would need to know all these numbers. The temperature of the bulb when it is wet communicates precisely what risk you are taking. This risk is increasing.AdvertisementThe best climate models predict that large areas of the United States will see several weeks of hot, wet bulb temperatures before the middle of the century. This is in the next 30 years. ProPublica reported that parts of the Midwest, Louisiana, and Mississippi could experience conditions that make it hard for the body to cool down for almost every 20 days by 2050. Shade and hydration are not enough to save you from the heat. Without reliable air conditioning, any human being is at risk of death.AdvertisementPreparing for climate change requires provisions against dangerous wet bulb temperatures.We know one thing for certain: Growing cities up is better than spreading our suburbs out. Denser areas produce significantly less carbon than rural and suburban developments. It is also more cost-effective and efficient to provide energy and cooling services to those who live close to each other, rather than spreading out.Despite NIMBYs railing against shadows from tall structures, cities need more shadows from trees, tall buildings and more housing to alleviate urban heat island effects, and offer shade from the midday sun.The No. The No. 1 intervention is to reduce climate pollution. That means cars and SUVs. Cities will become cooler if they reduce their car use and replace it with land that is used for housing, trees, transit, or other uses. No matter what clean technology achieves, it is essential to end the 75-year-old failed experiment with sprawling and car culture.It is dependent on our ability to survive heat waves in the future and present.Future Tense is a collaboration between Slate, New America and Arizona State University. It examines emerging technologies and public policy.
