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This extreme cold is just weather but all heat waves are climate change

Posted By Jo Nova On January 2, 2018 @ 5:25 am In Global Warming | Comments Disabled

There is a deep asymmetry in science. Don’t take it from me, take it from the former President of American Meteorological Society (AMS) and a current Director of the University of Georgia’s (UGA) Atmospheric Sciences Program. Marshall Sheppard would know, he has written over “80 peer reviewed papers” which gives him secret weather knowledge. It’s a kind of smarts that people who analyze MRI scans, design aerofoils or find minerals 3,000m underground can only aspire to.

He’s worried that people are mocking climate change, just because snap-frozen sharks are washing up on the beach, and it’s hitting minus 50C in Canada.  In the last twenty years mankind has put out more than a third of all the CO2 homo sapiens has ever made since Homo Erectus lit their last fire. Despite that whole extra blanket on the planet, the last time it was this cold was, like 1917.

So to help train believers Marshall Sheppard has written a handy retort to skeptical cynics:

Step One: It’s only cold where you are:

Girls and boys, global weather is hills and valleys. You are in a valley, but the crest of the wave is coming (or something like that).

Global Temperature graph, Map.

Near surface temperatures on December 28th as generated by the Climate Reanalyzer online software tool

The neat-o graph covers a whole 24 hour period.  Don’t look now, but according to Sheppard that’s meaningless weather. See Step Two, or not.

The global pause, on the other hand, lasted for years. It wasn’t supposed to be possible. Sheppard doesn’t seem to want to discuss that kind of climate right now. Next time there is a heatwave, lets send a graph of anomalies to Sheppard so he can tell the world why heatwaves don’t matter.

Step Two: Weather is not climate

This, we can all agree with (in a sort of vague “statisticky” way over an undefined period):

 Weekly or daily weather patterns tell you nothing about longer-term climate change (and that goes for the warm days too). Climate is defined as the statistical properties of the atmosphere: averages, extremes, frequency of occurrence, deviations from normal, and so forth.

What we are seeing right now in the United States is just,………well……wait for it……”winter”…..

And name one occasion Marshall Sheppard, when you said:

What we are seeing right now in the United States is just,………well……wait for it……”SUMMER…..

How many journalists and scientists have you corrected?

Likewise, if this is true:

The other thing to point out is that because one part of the world is cold (in that valley), there is likely another part of the world experiencing abnormally warm conditions (in the hill part of the wave pattern).

Tell us which heat wave you claimed the mirror converse for. Swap the warm for cold. Which heatwaves did you warn people were being used to distract us with “pesky climate communication” when the warm peaks were only the random bumps?

Hypocrites United?

Apparently some are even using the word “hypocrite” because Sheppard has done an update on Forbes, raising just that point:

A distracting narrative is emerging. There have certainly been some misinformed tweets, posts, and innuendo about the cold weather and the global warming narrative. One thing that I have observed is a narrative in certain circles that some people are being hypocrites by pointing out that cold weather doesn’t refute climate change but not making a similar point during the warm season.

I wonder who they could be talking about?

So what’s he got? Not much:

I make that point all of the time and as recently as my aforementioned article. I also cautioned during Hurricane Harvey and other 2017 hurricanes that there may be climate change DNA in those storms, but it is important to let peer-reviewed attribution studies confirm. Attribution studies are a generation of scientific analyses that investigate potential connections between current extreme events and climate change. I was one of several experts on an in-depth National Academy of Sciences study that provided the most robust understanding of where the science is on the topic.

Don’t cringe now, but these are not equal and symmetrical. Saying that a hot spell “may contain climate change DNA” is not the same as saying “cold spells are weather”. If a hot spell could contain DNA, (we molecular biologists don’t think so) then so can a cold one. If hot DNA can spell “manmade global warming”, then cold DNA can spell “the models are wrong”.

Sheppard creates a diversion: Don’t look here!

The question he can’t answer is apparently the wrong question to ask.

Sheppard says:

I pointed out this cliche dance that often plays out in social media,

Person X: “This event is clearly caused by climate change…..blah blah blah”…..Person Y: “See they say every extreme event is caused by climate change, but the climate changes naturally and there were always extreme events…..blah blah blah”

is important to discuss events from the proper perspective. “Was that event caused by climate change?” is an ill-posed question because natural variability almost always plays some role. However, this does not mean that an anthropogenic signal is not sitting on top of the natural variability.

An anthropogenic signal can be “sitting on top of natural variability”. And natural variability could equally be sitting on top of the anthropogenic signal and crushing it flat.

The question “ “Was that event caused by climate change?”” is not ill-posed, it is mindless, undefined agitprop with an ambiguous vocabulary, loaded meanings and no role in a scientific conversation.

Step Three: Pretend Models are Reality

Marshall goes on to claim that peer reviewed studies calculate the percentage of attribution:

MIT’s Professor Kerry Emanuel is one of the top climate scientists in our field. He recently published a study suggesting that Harvey-scale rain events have and will likely continue to increase in likelihood as climate warms. Another peer-reviewed study found that chances of the 2016 Louisiana flooding were likely increased 40% due to climate change. So while I do agree that consistency has to be applied when discussing each extreme event, the graphic below from the National Academy Attribution study summarizes some of the findings. It is clear that “lack of cold events” ranked high on confidence list based on physical understanding, data records, and climate model reproduction (three criteria the panel used).

Climate Models, dot graph of attribution, understanding.

So consistency “has to be applied” everywhere except for in situations where scientists can draw four-color graphs claiming otherwise.

Sheppards inconsistent use of cold and warm imply that cold is not just a lack of heat, it’s something fundamentally different. Heat, after all, can prove human attribution, but cold cannot prove the opposite.





Cold extremes don’t prove climate change wrong Marshall Sheppard

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