CRISISBOOM

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Extreme weather events occur every year in various parts of the earth, but the United States — and Missouri — have seen natural disasters strike its ground this year seemingly more often than not.The jury is still out as to what has caused these extreme events, pending major climatology studies that often take years to complete. Some say it’s due to a naturally variable earth, others argue it’s due to a changing climate, one that’s getting warmer and more intense, leading to weather events we’ve never seen, before calming down again.

Recent devastationMany scientists argue that 2010 was the most extreme year ever in terms of natural disasters across the globe. Devastating worldwide events made the headlines during what the National Oceanic and Atmospheric Administration said was the world’s warmest year on record (it tied with 2005).Among the most devastating were Pakistan’s flood, the most expensive natural disaster in its history, Russia’s deadliest heat wave in recorded history, and Tennessee’s 1-in-1,000-year flood that killed 30 people.And it hasn’t stopped in 2011, specifically in North America.

In the United States, the year has been impacted by four major weather events — snowstorms, tornadoes, record floods and heat waves — all of which are unprecedented in such a short time frame and are most likely due in part to climate change, said Dr. Jeff Masters, director of meteorology for the Weather Underground, a company that tracks weather developments around the globe.“I don’t think you can get that many extreme events compressed into that amount of time without some powerful climate-altering force at work — and the most likely explanation for that is human-caused emissions of heat-trapping gasses,” Dr. Masters said.According to NOAA’s National Climatic Data Center, 2011 represents the highest damage cost-to-date from natural disasters in the United States since 1980, when the organization began tracking damage in dollars.

The United States has experienced $32 billion in damage costs this year, with a normal disaster year totaling $6 billion.In Missouri alone, major natural disasters have contributed to that amount, including the Joplin and St. Louis tornadoes, the February blizzard, as well as the Mississippi and Missouri River flooding events.Conflicting viewsDr. Masters argues that floods and heat waves are the primary indicators of a warming climate. He says heat, especially extreme heat followed by extreme cold, is one of the primary indicators of a changing climate, as evidenced by 2010’s “Snowmaggedon,” occurring during the warmest year on earth’s record.But Dr. Pat Guinan, Missouri state climatologist, disagrees.“People can say (the two extremes) is unprecedented, but that’s not true,” he said. “I can go back to the historical record and find periods of more extreme temperature changes between one winter and the following summer.”A perfect example, Mr. Guinan said, is 1936, which had the hottest summer, followed by the fifth coldest winter on record.

And while a major heat wave has broken records across the United States this year, Missouri hasn’t seen any temperatures reach high enough to shatter records. Evan Bookbinder, meteorologist for the National Weather Service, said although the heat indices have felt extremely high recently — four days this month have reached 100 degrees — the Kansas City reporting station “hasn’t even come close” to reaching its highest of highs.Temperatures are, on average, four degrees above normal for July, which is significant. But a relatively cooler June evens out the averages for the summer months, Mr. Bookbinder said.Dr. Masters also argues that floods are a major indication of a changing climate. He said Missouri’s precipitation levels are up 5 percent over the past 50 years, which is made more likely due to a warming climate and — pending studies — has contributed to this year’s devastating floods.“When you have a warmer atmosphere, you can evaporate more water vapor into it. That means you’ve got more moisture available to fuel heavy rains and flooding events,” Dr. Masters said.Tornadoes, however, are an anomaly in the climate-change argument, as there is no real explanation as to why more deadly tornadoes have struck various places this year.

Interestingly enough, however, the same storm system that spawned the Joplin tornado dumped 8 inches of rain over the Missouri River watershed, which, among other things, contributed to the ongoing flood system, Dr. Masters said.No easy answersNot all scientists agree that extreme weather events can be specifically attributed to climate change, as weather is a naturally variable machine.The first half of the year started with a La Niña event, which has a natural cooling effect on Pacific Ocean waters. According to NOAA’s State of the Climate report, La Niña presents typical warmer and drier-than-normal conditions in typically dry areas, and cooler and wetter-than-normal conditions in typically wet areas.“The pattern of observed temperature anomalies for June 2011 and the last three months (April-June) is a very good match for the La Niña pattern,” the report states.

It’s also difficult to say for certain whether weather events are becoming more extreme, compared to hundreds of years ago, when data gathered wasn’t from as sophisticated measuring instruments as exist now. That, and ongoing weather events can’t be firmly attributed to climate change until a series of complicated studies are completed, which often takes years to analyze.“It’s tough to say, other than extreme events are common,” Mr. Bookbinder said. “Noteworthy events that make headlines do happen on a regular occurrence across the globe. It’s just the nature of weather on our planet.”Kim Norvell can be reached at kim.norvell@newspressnow.com.