(MODIS satellite shot of the epic storms that drenched Texas on Tuesday. Extreme rainfall events of this kind are more likely in a warming atmosphere. Image source: LANCE-MODIS.)
For the US, it (global warming + El Nino) means an increasing likelihood of heavy precipitation events from the southern plains states through the desert southwest. Storm track intensification through the Pacific to North America means that extreme rainfall events are a distinct possibility for states like Texas, Oklahoma, Colorado, Arizona, Nevada, and New Mexico. — robertscribbler blog’s El Nino + Global warming forecast posted on May 15, 2015.
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It’s a summer of El Nino. And it’s a summer when human-caused global warming is now hitting new record hot extremes. A combination that spells big trouble for severe weather in various regions around the globe, including in the center mass of the United States.
If it was only a summer El Nino, the Central US wouldn’t have too much to be concerned about. Sure, the added Pacific Ocean heat would amplify the subtropical jet stream and assist in trough development over the region. Both factors that would somewhat intensify rainfall events during a typical summer.
But this is not a typical summer El Nino.
This summer El Nino is happening in conjunction with record low sea ice extents in the Arctic (see Baked Alaska graphic below) and record hot global temperatures in the range of +1 degrees Celsius above 1880s averages. The record low sea ice levels aid in ridge and trough development — spurring the formation of hot-cool temperature dipoles that feed storms. Extreme weather firing off in an essentially changed atmosphere. An atmosphere heated to levels likely not seen in all of the current Holocene interglacial and probably at least since the Eemian 150,000 years ago. It’s an extra level of heat that loads the atmosphere with a substantially greater amount of moisture (amplifying the hydrological cycle by 7 percent for each 1 degree C of warming). So when the storms do fire, they are now likely to dump much higher volumes of rain than we are used to.
(Extraordinary hotter north, cooler south dipole anomaly pattern that helped to feed instability and storm development over the Central US this week. The extreme warming in the Northwest Territory, Alaska and near Arctic Ocean region is a signature of global warming related polar amplification and sea ice loss in the Northern Hemipshere polar zone. It also likely has a teleconnection with both the current El Nino and the warm ‘blob’ of abnormally hot water in the Northeast Pacific. Image source: Earth Observatory — Baked Alaska.)
Such was the case with Texas on Tuesday and Wednesday where hundreds of homes were flooded, numerous lives lost, and hundreds of water rescues performed. In some regions, all-time record rainfall amounts were shattered. In Houston on Tuesday, hourly rainfall accumulations exceed 4 inches per hour (11+ inches daily accumulation for that city) — an extraordinary rate of rainfall no drainage system is designed to accommodate. Residents were stranded in cars for hours due to washed out roads or watched on in horror as the first floors of their homes were turned into strange flood-fueled washing machines.
It was a deluge that many compared with past record rainfall events spurred by hurricanes. But this was no hurricane, just a wave of intense storms rippling down an extreme trough in the Jet Stream and encountering an equally extreme atmospheric moisture loading.
Make no mistake, it was climate change and related human heating of the atmosphere that provided the steroids that pumped what would have been garden variety moderate to strong storms into the monsters witnessed on Tuesday and Wednesday. A billion dollar flood that, without climate change, would almost certainly have just been another summer shower.
Most news coverage of the event was decidedly narrow — focusing only on the extreme instances of weather and not on the clear global warming context. On Tuesday, Bill Nye, who’s been acting as a climate gadfly to an otherwise climate-change mum media posted the following tweet:
Billion$$ in damage in Texas & Oklahoma. Still no weather-caster may utter the phrase Climate Change. — Bill Nye
And as we’ve come to see time and again, the related climate change deniosphere led by the likes of Fox News and National Review had an epic meltdown as a result. Either denying climate change is happening at all or, as was the case with National Review, denying that policy action could have any impact to help what is an already worsening situation.
But the critical elements of the current event appear to have been lost in all the fuzz. The first is that it was predictable, if we just look at current weather (El Nino, insane trough development, and atmospheric moisture loading) in a climate change context. And the second is that if we continue to ignore climate change, people will not be warned in advance of events like the one that occurred last week. Events that we have proven are indeed predictable see here if looked at in the climate context (and if weather forecasters simply do the same).
Whether we respond rapidly through responsible policy action (which will certainly help to reduce the harm we are now causing, but not prevent all of it), or whether we listen to the voices of nonsense that helped get us into this mess in the first place and continue to delay action, there is certainly a degree of far worse weather in the pipe. And failing to report on climate change, as the media has largely done, increases risks for loss of life, property damage, and overall disruption.
So far, the flood death count for this week is 30 souls. If you’re a weatherman who’s ignoring climate change, or if you’re a media organization that’s preventing weather forecasters from talking about climate change, this should weigh heavily on your conscience.
Hat-Tip to Bruce