Friday, October 25, 2013

Colorado Floods - statistical certainty vs geophysical realities


Here is an article I wrote for November's Four Corners Free Press concerning last month's flooding in Colorado.  Should anyone find anything of value in it feel free to lift and use as you see fit.  Memes for the sharing.
{I have added many links that offer authoritative support for my claims along with basic educational sources}.
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Colorado experienced its most extreme weather event in memory between September 9th to the 15th. Golden, Boulder and Larimer counties received the worst of it with rain accumulations of sixteen/seventeen inches and more, some areas receiving nine inches on Thursday alone, resulting in massive flooding compounded by destructive run-off from mountainsides of burned-out forests that could no longer hold water.

Predictably folks are asking: Is this related to manmade Global Warming? It's an easy and tough question to answer.

Consider please, our climate system is a global heat distribution engine and our land, atmosphere, and the oceans have indisputably warmed, not only that, our atmosphere's moisture content has been measurably increasing. Given such geophysical realities, it is self-evident that all extreme weather events contain elements of this newly energized climate system.  And that much more of the same must be expected.

On the other hand,
it's an exceedingly difficult question to answer if the demand is to know precisely every attribution down to fine detail. Fortunately for interested citizens, scientists have been trying harder to convey their knowledge of those details.

For example, less than two weeks after the flooding, the Western Water Assessment (WWA) together with Cooperative Institute for Research in Environmental Sciences (CIRES) released a preliminary report during an hour and a half long videoed web news conference
(For more see: wwa.colorado.edu)

The CIRES/WWA event was a collaborative effort of many people and interconnected agencies, including NOAA's ESRL (Earth System Research Laboratory) Physical Science Division, and the Colorado State University's Climate Center. It was a good example of scientists stepping forward and personally sharing their data and discussing the state of their science.

Watching the September 25th presentation I was reminded what straight-forward conservative lot scientists are. They will say what they know for "sure" and stop. Then they will back-track and share every doubt they have in order to prove that they do indeed understand weaknesses and further questions regarding their area of study.

The report, "Severe Flooding on the Front Range" (Sept. 2013), explained that "the extraordinary rainfall in this event was due mainly to the unusual and persistent weather pattern that funneled abundant moisture towards the Front Range and enhanced the lift."

To understand what this means, you need to know about the Polar Jet Stream, a high speed ribbon of air that's driven by atmospheric temperature differentials between Earth's hot Tropics and cold Polar regions. It's been there for millennia whipping around the Northern Hemisphere pushing and pulling weather patterns with it.



You see, one result of our society "salting" our atmosphere with "greenhouse gases" is that it has increased its "insulating" ability. That's because these atmospheric gases catch Earth's heat waves as they rise towards frigid outer space.  More GHG molecules, means catching more heat, so the planet warms. {Link to more rigorous explanations.}
Since the industrial revolution society has increased that greenhouse gas component by about a third. Causing the Earth to retain more heat within our climate system than it used to.

One of the cascading consequences of this is that the Polar atmosphere is actually swelling and changing its relative elevation. This, in turn, causes a decrease in the differential between polar and tropical regions. This, in turn, has manifested itself in a slower and more meandering Jet Stream pattern. This, in turn, has been at the root of some very extreme events such as the September Colorado rains and floods.

What happened was that in mid-September Colorado got stuck between two such stalled Jet Stream loops for about a week before they moved on. Technically, and to quote the University of Wisconsin-Madison's Cooperative Institute for Meteorological Satellite Studies (CIMSS) -- what happen was that in the upper atmosphere above the Great Basin west of the Rockies, a "quasi-stationary upper-level cyclonic circulation" developed, while across the mountains, over the Great Plains, a "lower-tropospheric anticyclonic circulation" pattern set in.

While down south off Baja California tropical cyclone Lorena was dissipating and the two stalled circulation patterns started sucking up all that tropical moisture right into Colorado. It then got funneled up the mountain slopes, saturating the air to record breaking levels and then dropped out of the sky in a "biblical" deluge.

All this information was explained in wonderful detail. 

And then, disturbingly, when a reporter asked pointedly about the Jet Stream global warming connection, these geophysical facts suddenly became "speculation" subject to further study.

Using a freak, but similar, Colorado event back in September 1938 as justification, Dr. Hoerling rejected making any firm connection to global warming. We need further study. As I understood him, he also felt we needed a more accurate understanding of past extreme weather events.

I was left wondering, what good is a time consuming perfect understanding of past events, when that atmosphere's composition was radically different from today's? It's nice to know, but it is background information and not that relevant to our contemporary climate which has been and continues to be supercharged.

Beyond that I found it odd Dr. Hoerling used one 1938 freak event to warn against making premature assertions.  While not acknowledging the recent drum beat of "Jet Stream blocking pattern" driven extreme events such as the record shattering European killer heat waves of 2003, 2006, 2011 and the Russian heat wave of 2010, and the floods in Russia and Pakistan in 2010, and the recent Calgary floods and the extreme winters on the East Coast three and four years ago.

In fact I did write Professor Hoerling and asked why he seemed to rejected all the studies that have shown evidence for global warming driven Arctic Amplification influencing the Jet Stream, such as those being reported by Dr. Jennifer Francis and colleagues. Unfortunately, I didn't get a response, in fairness he is a very busy man. 

Still I find it disturbing when scientists, who are supposed to inform and advise leaders and the public about dealing with the world we have in front of us, slip into that professorial deep-thought mode and focus on minutia while ignoring the "big" picture. 

The professor is typical of many conscientious scientists, statistical certainty is their calling - but from my boots on the ground perspective, statistical certainty does not trump common sense, nor the laws of physics, nor the geophysical reality we are actively altering. Think about it, are the exact details really that important?

Doesn't a basic climatology outline tell us enough to know we need to stop denying and start collectively, all of us, getting real about what is happening out there?

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A visual tour of our global heat distribution engine.
The groundbreaking two-hour special that reveals a spectacular new space-based vision of our planet. Produced in extensive consultation with NASA scientists, NOVA takes data from earth-observing satellites and transforms it into dazzling visual sequences, each one exposing the intricate and surprising web of forces that sustains life on earth.

Earth From Space / Nova

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Weather and Climate Summit - Day 3, Dr. Jennifer Francis


Session 6: Dr. Jennifer Francis - Rutgers University
Topic: Wacky Weather and Disappearing Arctic Sea Ice: Are They Connected?

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Processes and impacts of Arctic amplification: A research synthesis 
Mark C. Serreze , Roger G. Barry
Global and Planetary Change 77 (2011) 85-96



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