With huge floods in Colorado, fires in California, twin hurricanes on the two coasts of Mexico, and all the other weather catastrophes of the summer season, we’re already way beyond the question of what’s happening and why. The big questions now are how rapidly is the climate catastrophe unfolding, and what regions are going to be hit worst.
Colorado, it turns out, is in a kind of anti-Goldilocks zone.
The weather system that hit Colorado last week had already visited the Southwest states of Arizona, Utah and Nevada, but with nothing like the force of what happened in Colorado, where it dumped up to 20 inches of rain in parts of the region – almost a foot of rain in one day alone. Two hundred people are still unaccounted for, and more than 18,000 homes have been damaged so far – 1,600 totally destroyed.
So, why the extraordinary flooding there – especially in Boulder?
According to Rebecca Anderson of the Alliance for Climate Education, while some parts of the country, particularly the north and northeast, can expect more floods (and are getting them), and other parts, particularly the southwest, can expect more drought, Colorado lies uncomfortably between these two zones:
Colorado, however, is on the border between the desert Southwest, which is expected get drier from climate change and the northern states that are supposed to get wetter. Instead of making the state less impacted by climate change, however, it’s been the opposite. Colorado has been getting the worst of both worlds: drought and wildfires plus flooding.
How? More heat in the atmosphere means evaporation and drought, while at the same time warm air holds more moisture and makes individual storm events worse. This means that Colorado can still be experiencing drought conditions, but get hit by a major storm at the same time.
In some ways, drought and wildfire damage can make a flood like this worse, by removing trees whose roots soak up water and parching soil, so that it’s too dry to absorb runoff. In this case, those factors may have worsened the flooding, but the more than half a year’s worth of rain that fell was plenty to do the damage on its own.
No one knows exactly how all this is going to play out But climate change is currently speeding up. And with 40 percent more CO2 in the atmosphere than in pre-industrial times, with methane gases now being released from the ground as Arctic tundra begins to melt, and with 4 percent more water vapor in the atmosphere than 40 years ago, we’re already into a runaway effect.