Andrew Revkin and I had a brief exchange about the power of labels. Both of us object to the phrase "climate emergency." Even though it is an emergency that could escalate into an existential threat, people don't respond to labeling longer term threats as emergencies. I've been suggesting we've entered an adaptation epoch. Andrew, a much better communicator, is still searching.
The past two or three years have taught us short term temperature excursions can be dramatic. Last year the Pacific Northwest recorded previously unheard of temperatures - the highest in the area in at least 7,000 years and probably much longer. This Spring it was South Asia. Last week record heat came to England and parts of Europe. These events are probably going to be more common and time goes on and greenhouse gas levels continue increasing.
Wet bulb readings of 35°C (95°F at 100% humidity) have long been considered unsurvivable. A person in good physical shape would probably die in a few hours. Such events are extremely rare. Until the past decade they've only been recorded a few times and then only for an hour or so. They're increasing in frequency and length - mostly in the Indian subcontinent. Finding cooler spaces for people is a matter of life and death.
It's become clear the 35° number was something of a guess. Recent careful work shows it's more like 31° for young people in good physical shape. Older and compromised people have lower limits. The Tokyo Olympics had periods with wet-bulb temperatures in the upper twenties. Athletic performance during these periods was certainly compromised (I saw it happen to a friend).
What can be done? Cities suffer from heat island effects. All of the asphalt and concrete increases the local daytime temperature and holds them at higher levels at night. (hot nights may be harder on the body than hot days). Air conditioning helps, but it costs money and a power grid that not everyone has access to. Reducing the amount of asphalt and concrete while planting trees can make a big difference. It's a great justification for reducing the number of cars and roadways in cities (green spaces are a key motivating reason for the dramatic change currently underway in Paris). Unfortunately green spaces are usually linked to wealth. In many places racism and redlining have produced some of the worst heat islands.
There are other tricks that are easily implemented. White paint on roofs can make a difference. Paint that holds up to temperature and monsoons for the better part of a decade isn't cheap, but is becoming more popular. In Western countries more reflective shingles are appearing. Some of these look fairly normal, but are highly reflective in the infrared and can make a difference in cooling bills.
And you can send some of the excess heat directly to space.
If you're in a very dry area go outside on a clear night and look up. Feel the cooling on your face. Now hold a piece of cardboard between your face and the stars. You'll notice a warmer feeling. Remove the cardboard and your face gets cooler.
Your body glows - you've undoubtedly seen infrared photos and videos of people. We radiate photons at a variety of wavelengths, but it peaks around 9.5 microns - about twenty times longer than visible light. The atmosphere is transparent to visible light and also from 8 to 13 microns. Photons from our bodies can radiate to space. Deep space is really cold (a bit over 2° above absolute zero) so your face is radiating some of it's heat directly to space - enough that you can feel the cooling.
Clever material engineering has produced materials that are good at absorbing the heat around them and then radiating it into space. It's enough to reduce cooling requirements - at least in places with very dry atmospheres. There's still work lowering costs and making the surfaces last longer, but it's something else to try.
Back to the idea of an adaptation epoch. Many things will need to be tried and efforts will stretch for generations. There's enormous opportunity. It's both sad and dangerous there's so much 19th century political inertia, but I'm optimistic more clever people, organizations and governments will finally emerge. As a species we don't have a choice if we want to survive.
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