Extreme weather points to man-caused global warming

There still seems to be considerable confusion and misunderstanding today concerning whether or not the extreme weather events being experienced around the world and throughout Montana provide evidence of man-caused global warming. While no individual weather events can be ascribed to global warming, increases in the frequency and intensity of these definitely can be.

This is because weather is driven primarily by two factors. One is the energy of the sun and the other is water. Water vapor is the only major component of our atmosphere that is condensable under the conditions of our planet. When water vapor condenses to either droplets in clouds, rain, or snow, huge amounts of energy can be released into the atmosphere. Thus, water vapor provides a means of transferring the energy of the sun throughout the Earth via its atmosphere.

This is related to global warming because a warmer atmosphere will hold more water and will increase the rate of evaporation. This, in turn, will increase the amount of energy available for release wherever precipitation does occur. Thus, as the Earth continues to get warmer, we can expect the intensity and frequency of extreme weather events to increase on a decadal, if not annual basis. In general, we can also expect dry places to get drier and wet places to get wetter. In addition, water is also the most powerful greenhouse gas. Therefore, we can expect this additional water vapor to further increase the average temperature of the Earth.

I regularly ponder the question of what future outcomes of man-caused global warming will be severe enough and obvious enough for essentially all human beings to clearly see what is happening to our planet. Apparently the loss of our glaciers in our own back yard here in Northwest Montana has not been enough to do that. Perhaps this level of recognition will require large rises in sea levels to the point where our major coastal regions and cities are clearly threatened (as New Orleans already is). Because the oceans are so large, however, sea levels are not expected to exceed a foot in the next decade. Therefore that alarm will be going off too slowly to cause immediate and forceful action. I do hope, however, that our rapidly changing weather patterns will “do the job” in a more timely manner.

Unfortunately, the forces for denial and apathy concerning man-caused climate change are still strong and successful. We currently celebrate the explosive development of our region’s abundant fossil fuel resources — even as all of the professional scientific organizations of our country tell us that our increasing levels of atmospheric CO2 will lead to increased temperatures which will lead to more water vapor which will lead to increased severity of weather and then to worse global changes after that.

If we could recognize the bit about the severity of weather now, maybe we could avoid some of those worse changes later — just a thought for your consideration — as we observe our 100-year flood plains being repeatedly inundated.

Eric Grimsrud, of Kalispell, is a retired atmospheric scientist.