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Wild Weather Swings May Be a Sign of Climate Change

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For a political candidate, being labeled a “flip-flopper” can be a career killer. Just ask Secretary of State John Kerry, who lost his 2004 presidential race in part because of his reputation for voting against bills before he voted for them. Increasingly, though, the label also applies to North American weather, which has been lurching from one extreme to the next in a pattern that is consistent with global warming.

Flooding on Grand Avenue in Chicago after heavy rains struck the city in mid-April. 
Credit: NWS via John Trillik.

Climate studies have warned us to expect more frequent and intense extreme events, such as heavy rain and snow storms, along with heat waves. While weather variability is nothing new, the wild swings in weather — termed "weather whiplash" and that have recently occurred across the Midwest and South Central states during the past few years, from record flood to record drought and back to record flood — may be an example of what’s in store as global warming continues to alter the atmosphere.

As exhibit A, consider what is going on right now in the nation’s heartland.

Chicago has already had its wettest April on record, with nearly 9 inches of precipitation, and its wettest start to the year, with a little more than 17 inches of precipitation so far. That compares to the 26.91 inches of precipitation that fell during all of 2012 (weather records in Chicago date back to 1871).

Chicago had a bout of especially heavy rainfall on April 17-18, which set a record for the heaviest two-day rainstorm there, and which led to major urban and river flooding.

The wet and cool conditions in Chicago this spring are a sharp reversal of fortune compared to last year, when the city experienced its warmest March on record, and severe drought conditions were taking hold starting in April.

“This year, of course, we cannot buy any spring warmth,” said a report from the National Weather Service in Chicago. 

The heavy rains in the Midwest have helped to raise Great Lakes water levels from record lows set during last year’s drought to more average levels. According to WGN-TV meteorologist Tom Skilling, the U.S. Army Corps of Engineers has found that Lake Michigan's level had risen by 9 inches during April alone.

“Each inch increase on Lake Michigan is the equivalent of 390-billion gallons of water, so we're talking about a whole lot of water there,” Skilling wrote on his Facebook page. “We've more than halved the deficit in Lake Michigan's water level between this year and last. Lake Michigan — only a month ago 17 inches lower this year than last — is now just 7 inches lower than a year ago. And the other Great Lakes have posted water-level increases since April 1 as well,” Skilling wrote.

In August 2012, drought had left runoff in the Upper Mississippi River Basin in the bottom 10 percent. Now, water levels are in the top 95 percent. 
Click image to enlarge. Credit: Climate Central.

Other areas have also been experiencing sudden shifts in the weather, particularly the Ohio and Mississippi River Valleys. Record rains in the Ohio Valley in 2011 caused the Mississippi River to reach record to near-record crests downstream from the intersection with the Ohio River. At New Madrid, Mo., the crest of 48.35 feet on May 6, 2011 was the highest recorded, forcing the Army Corps of Engineers to blow up levees along the river to lower water levels. That flooded farmland, but saved more heavily populated areas.

Yet just 15 months after the record flooding, on Aug. 30, 2012, the river dropped to the lowest level on record at New Madrid. That forced the Army Corps to reverse tactics, this time dredging the river to try to ensure the river remained navigable for barge and ship traffic.

Now the river is back in flood, with record highs noted in some locations along the Mississippi River’s tributaries.

“The recent flooding is due to an inordinately wet April,” said NWS climate services program manager Victor Murphy. “Portions of northern and central Illinois and eastern Iowa have received from 200 percent to 400 percent of normal precipitation over the past 30 days," Murphy said. 

While spring flooding is typical in the Midwest as snow cover melts and heavy spring rainfall occurs, the recent extreme swings between record dry conditions and record flooding are anything but normal.

Trend in 1-day precipitation extremes through 2012 for the lower 48 states.
Click image to enlarge. Credit: NCDC.

The swings may be connected in part to climate change, since the atmosphere is now carrying more moisture than it used to due to warming air and ocean temperatures. Climate studies have projected that precipitation extremes will become more frequent and severe. Some studies have already found an increase in heavy precipitation events across the Northern Hemisphere and in North America, including in the Midwest.

The proximate cause for the floods and the drought have had to do with sharp and extended variations in the jet stream, which in the case of flooding means storms were steered into the Midwest, or in the case of drought means they were steered away from the region. However, the long-term increase in water vapor due to manmade global warming acts to worsen both extremes by providing more water for storms to work with, therefore dumping heavier rains, or making temperatures hotter than they otherwise would be during a drought, thereby drying soils out even more.

Some recent studies have also linked increased variability in the jet stream itself to rapid Arctic climate change, and this is an area of ongoing scientific research.

According to a draft federal climate assessment released in 2012, heavy precipitation events in the U.S. have increased during the past half-century. Managing increased variability, with the climate lurching from dry to extremely wet and back again, is already putting a strain on businesses and municipalities that have to manage the consequences, from shipping companies trying to move their products along a shrunken or swollen Mississippi River to cities trying to prevent flooding of entire neighborhoods.

Another area that has suddenly reversed its fortunes is the state of Georgia, which got rid of its two-year drought in just two months. As recently as February, 81 percent of the state was in drought. But heavy rainfall that began late in February and continued through April has slashed the portion of the state in drought conditions down to a measly 2 percent.

“This is due largely to Georgia having its wettest February on record, with a statewide average precipitation of 9.92 inches, or more than double the 100-year average of 4.5,” Murphy said in an email conversation.

So yes, when it comes to the atmosphere, the flip-flopper label certainly applies, at least lately. And we better get used to it.

Related Content:
Scientists Identify Human Connection to Precipitation Extremes
A Year After Flooding, Commerce on Mississippi Imperiled
Historical Context of the Mississippi River Floods
From Heat Waves to Snowstorms, March Goes to Extremes
'Strong' Links of Manmade Heat, Rainfall Extremes
Extreme Weather and Climate Extremes: The Midwest

Comments

By Dave (Basking Ridge, NJ 07920)
on April 26th, 2013

The predicted trend towards enhanced climate instability as a consequence of climate change doesn’t get much ‘air time’ in the media. But this is one of many disturbing implications of uncontrolled climate change. Maybe, as suggested here, this current flood / drought flip-flop is among the first mild indications of that happening in the US.

Compared with that, the term “climate flickering” has been used to describe acute instability due to climate change as temperatures rise closer to climate tipping points. That extreme case is envisioned as being highly severe. Zon & David, 2013, describe it as “…characterized by recurring abrupt climate changes, switching back and forth at high frequency between spatially uncorrelated bouts of pronounced warming and cooling.” 
UNU Merit Working Paper, January 2013, Zon & David, page 2:
http://www.merit.unu.edu/publications/wppdf/2013/wp2013-009.pdf

Hopefully, high emissions nations will switch from a business as usual energy policy in time, etc., and it won’t quite come to anything like that.

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By Camburn (North Dakota)
on April 26th, 2013

The graph indicates that within statistical norms, the trend is very hard to pick out.

Also, taking 3 months out of annual data doesn’t show much.

The trend in humidity is down, on a short term basis,  contrary to what climate models have projected.

http://hockeyschtick.blogspot.com/2013/04/new-data-falsifies-basis-of-man-made.html

Lot’s of things we don’t know with any degree of certainty.

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By Dave (Basking Ridge, NJ 07920)
on April 27th, 2013

Camburn, I agree that any trend towards instability is difficult to discern in the data shown. But I would also suggest that assumes that we know what we are looking for. Early stage instability is technically a tough measurement to pin down in anything.

Right now there are people in the US who previously had come to terms a drought, and then looked out of the window and seen a river where it shouldn’t be… I think it is fair to consider that and similar real life experiences as cause to pause and wonder about climate stability, especially if things like that keep happening and if experienced weathermen seem to start using the term “unprecedented” more than usual.

Atmospheric water content, as you mentioned, is another tough measurement. We could all probably argue about the past few decades data trend for that until the cows swim home.  See for instance Trenberth, 2005: http://www.cgd.ucar.edu/cas/Staff/Fasullo/my_pubs/Trenberth2005FasulloSmith.pdf

Reply to this comment

By Camburn (North Dakota)
on April 28th, 2013

Dave:
I guess I am old, well I don’t feel old but have been around awhile.  Weather has always swung one way or the other.  At least in the upper Great Plains.  Proxy data shows such a huge variation that unless something really changes, that variation is actually the norm.

The 1980’s thru the early 2000’s produced a period of absolutely tranquil weather.  Now that dry bulb temps have paused rising, the weather seems to be getting back to its normal self.

Up here we have a well established 80 year wet/dry cycle. This is embedded within a 400 year wet dry cycle.  I am only talking central corridor of North America.  This does stretch from Texas through Manitoba.

The main point is, that using normalized numbers, there does not seem to be an increase in “unprecedented events”.  Might be if you only want to go back 50 years, but take in longer proxy data’s, and this appears 100% within the confines of normal.

I agree on the water column content.  Altho, one would have expected it to rise somewhat with warmer temps, and it does not seem to be doing that.  But then, that is a very weak area of understanding via climate science as of yet.  And an extremely complicated one to boot.

Just my old opinion here, but I really do not see anything out of the ordinary at present.

Reply to this comment

By Dave (Basking Ridge, NJ 07920)
on April 29th, 2013

Camburn, thanks, that’s interesting. Globally, the frequency of weather extremes has been increasing. There seems to be no doubt about that. However the regional distribution of impacts around the world is uneven. From my perspective in faraway NJ, this “wild” flood / drought / flood instead subjectively looks severe and unusual in terms of not just the depth of the drought especially, but also thus sudden high frequency of those extremes. Of course, that’s a superficial subjective take, whereas you actually live there. Technically it may be the case that just like you say it isn’t unusual when considered from a multi century perspective… at least yet. But also technically, I would seriously caution that we have to be patient about drawing conclusions about what is unusual and what isn’t in this context and wait to see if there is a significant trend. Only once a trend is clearly established and correctly identified is it obvious, but of course that’s always in hindsight and here could be after years and years of misery. That’s possibly also a weather statistician’s nightmare.

Thankfully that’s not all we have to go on though. We also have open access to regional climate projections which provide objectively derived warnings. This official US 2009 one talks a lot about water supply with respect to what’s in store for the Great Plains this century. It doesn’t look comfortable. I imagine that you have probably read it before, here or elsewhere in one form or another. But in case not and in case others are interested:

http://downloads.globalchange.gov/usimpacts/pdfs/climate-impacts-report.pdf
Great Plains, pp.123 - 8.

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By Tucker (princess anne md .21853)
on April 30th, 2013

GOD is in control of His world not man. Just look around you . GOD made it He can take it back. Just be ready.

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By Robin (Hudson, NY 12534)
on June 30th, 2013

I have lived in upstate NY for 45 years and within the past few years a hurricane came to my home to destroy my basement requiring Fema help.,  Wind sheers, tornadoes, and multiple hail storms damaged our siding.  This is not part of a normal weather flux for us.  We are experiencing increasingly wilder weather.  Our weather is changing where I live and our status as a D climate zone will soon have to be changed to a C climate or North Carolina weather because we are barely sustaining the temperature requirements to maintain a D.

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