Some climate scientists clamber across Arctic icefields or measure drought-stress in western forests. But much of what scientists do is behind a computer screen, creating global computer models that meld together the laws of physics with field data and various scenarios of choices that humans make.
Two new reports released this falls paint a few pictures of possible climate futures for Montana and the U.S. as a whole. Predictably, the future is much rosier if we all buckle down to quickly make the transition to a clean energy economy. The picture is much darker if we continue down the path of pollution that we currently are on.
We already knew that, however, and the new reports just fill in the details. Global climate models (GCMs) are good at projecting increases in average annual temperatures or shifts in seasonal precipitation totals. Powerful computers are now able to downscale those global models to local regions.
The first-ever Montana Climate Assessment, released in September by the Montana universities in Bozeman and Missoula, indicate that average temperatures across Montana could increase 3-8 degrees Fahrenheit by mid-century, depending on how much greenhouse gases are emitted in coming decades.
But more ominous than long-term temperature and precipitation trends, the new reports suggest a future of increasingly weird and extreme weather. Picture a popcorn popper. The more heat is applied to the popper, the more frenetic goes the popping. A warmer atmosphere is like that, with air molecules bouncing around harder and faster, creating more collisions with greater impact. In some places that will mean huge rainfall events and megastorms that cause widespread flooding. In other places, it will mean hotter, drier winds that drive wildfires before it.
Those frenetic molecules are the linkage between long-term climate trends and short-term weather events.
The Montana report warns of several trends in weird weather that we’re already experiencing and are expected to get worse. I’ll note two here.
Wildfire: Montana is expected to have hotter, drier summers with up to 35 more days each year reaching above 95 degrees. Even though winters and spring may be wetter, the onset of summer increasingly will create “flash drought” conditions that quickly parch farm fields and launches intense fire seasons. This won’t happen every year, but severe seasons that were rare in the past will become more common. Montana scientists say that the 2017 summer is an indicator of fire seasons to come.
Hail: North American climate models indicate that hailstorms are expected to become more frequent and more severe, with larger-diameter hailstones, especially in eastern and southwestern Montana. This will increasingly damage crops, livestock, building roofs and vehicles, which will mean higher insurance premiums and economic impacts. Montana insurance companies report a big uptick in damaging hail over the past decade.
But scientists are quick to note the difficulty of projecting extreme weather events, which by definition are difficult to predict. As the new National Climate Assessment reports, recent trends of severe heat waves and extreme precipitation events are consistent with the laws of physics, but climate models tend to underestimate the frequency and severity of observed trends.
There’s a lot we can do to reduce the risk of global weirding, beginning with collective action to reduce carbon pollution. We can also adapt to the changes that already are in the pipeline, such as by building soil carbon to retain moisture and reversing the trend of building new homes in the forested wildland-urban interface.
But the first ingredient for resilience is to acknowledge the gravity of the situation, speak about it with our neighbors and elected officials, and begin taking action one small step at a time.