Is global warming causing more severe storms in the American Midwest? Well, that depends on who you ask and what you consider a severe storm. Most of the studies that have been done don’t focus on the storm aspect, but rather on the increase in temperature in the region and how it will affect the economy – which shows their bias. But even in studies that do focus on the strength of storms in the region, the data is often skewed to play to a particular agenda.
Here’s the problem with asking a question like this. There isn’t a significant enough set of data to make any educated observation that has meaning. We have roughly 110 or so years of data on storms in the region. And the early data suffers from being thoroughly incomplete. The first really reliable data for the region comes in the 1960s when radar imaging and data collection stations reached a unified scientific standard. So, to make any actual observations for the entire region, we really only have 50 years of complete data.
What does this data say? Again, that depends on who you ask. Using the limited data set, the federal government issued the National Climate Assessment that said that the Midwest region would be, “subject to degrading air and water quality, an increased frequency of flooding, and potential public health risks,” due to increased storm activity in the spring and heat waves in the summer. This study claims that temperature increases in the Midwest could reach catastrophic levels by 2100. “Projections for the end of the century in the Midwest are about 5.6 degrees for the low-emissions scenario and 8.5 degrees for the high-emissions scenario,” according to the report. Of course, this report doesn’t talk about the severity of storms other than to mention that they will bring potential flooding in the spring and drought in the summer, which will significantly impact the production of food crops in the region.
According to the data that was provided by the federal study, heavy downpours are now twice as frequent in the Midwest as they were a century ago. This has been attributed to higher spring temperatures that bring in rain rather than snow. NASA also agrees with this position, but cautions that the severity of storms may not actually be affected, just the amount of rainfall.
In fact, the data on tornadoes suggests that the severity of storms will be unaffected by climate change. NASA officials point out that the cause of extremely strong storms is the meeting of warm, moist air at low levels and cold with drier air above and vertical wind shear, which provides the source of the rotation. Climate change increased the amount of warm, moist air while lowering the vertical wind shear equally. So, the overall effects counteract each other.
Now, if you were to ask the experts at Accuweather and Scientific American, you’d get this answer, “There is no strong evidence to support severe weather becoming stronger, more frequent or more widespread during the past 50 years in the United States as a result of climate change.” So, why are we so convinced that severe weather is getting more common? I’ll leave that to NOAA’s research meteorologist, Harold Brooks.
He says, “The big reason why we think that severe weather has gotten worse is our ability to communicate information about it. If you think back 100 years ago, a tornado that happened 10 or 20 miles away, you might not even be aware of it, if it didn’t affect where you live directly. Now, you can watch people chasing tornadoes online live,” Brooks explained. “So it’s the fact that we are more aware and able to communicate that information about events so much better than we used to be able to that it makes us think severe weather has increased.”
This is a classic case of the absence of enough empirical data to make a justifiable hypothesis. While there are plenty of supporters of climate change leading to more severe weather, the fact is that there isn’t a large enough data set to make that assertion. That doesn’t mean that the assertion is wrong, just that we will have to wait and see if it pans out that way. The biggest problem is that if we are actually creating the problem through burning of fossil fuels, by the time we have enough evidence to prove it; the damage will be so severe that it won’t matter.
That makes the course of action relatively clear – we should limit our greenhouse gas emissions just in case it is the cause of severe storms increasing in the Midwest, or at least put some type of policy in effect that helps the region deal with the potential problems that climate change may present.
What side of the issue do you come down on? Is climate change to blame for bigger and stronger storms in the Midwest?