It's Not Just the Heat

It's also the humidity, among other things. The planet is getting more humid as well as hotter, according to a new study. "This humidity change is an important contribution to heat stress in humans as a result of global warming," said Nathan Gillett of the University of East Anglia in the United Kingdom, a co-author of the study. According to this AP story:

The finding isn't surprising to climate scientists. Physics dictates that warmer air can hold more moisture. But Gillett's study shows that the increase in humidity already is significant and can be attributed to gas emissions from the burning of fossil fuels.

And that's just One More Thing. This same story says that climate scientists have now seen the man-made fingerprint of global warming on 10 different aspects of Earth's environment: surface temperatures, humidity, water vapor over the oceans, barometric pressure, total precipitation, wildfires, change in species of plants in animals, water run-off, temperatures in the upper atmosphere, and heat content in the world's oceans.

The Climate Crisis will continue to offer surprises to nonscientists and scientists alike, because one big shift like this leads to consequences that result in other changes. Some, like drought, are big and obvious. Others, like excessive pressure on plants (including trees) and animals, play out over time, but when plants and animals leave an ecological niche, a cascade of effects can follow fairly quickly. And then there are more prosaic problems: for instance, U.S. retail clothing sales had a bad September, partly because it was a warm one and people weren't buying fall or winter clothes. That's likely to happen again for October, and also likely to happen more regularly in autumns to come, so there will be changes in the shopping mall.

But let's get back to the humidity. High humidity causes physical stress to humans, but as we all know it also shows up in behavior---people get short-tempered and miserable, and their judgment is often impaired. The Nobel committee officially recognized the part that the Climate Crisis can have in causing warfare over resources. But it is also likely to cause other stresses that can make warfare an impulsive choice, when cooler heads don't prevail, because there might not be any.

Right now humidity isn't rising everywhere. Australia, South Africa and the western U.S. are getting very dry. There's drought in the American southeast and now in the Great Lakes region (although that is probably caused by warmer winters and less ice melt.) But the humidity is getting higher in the eastern U.S.--you know, where New York and Washington are.