Melting ice and picking cherries

I don't usually like to post multiple times on the same topic only a few days apart, lest I be seen as constantly ringing the changes on the same idea, but sometimes circumstances demand that I do.

Last week I wrote a piece about the discovery that climate change denier Wei-Hock (Willie) Soon had financial ties to the petroleum industry and the Koch brothers that he had not disclosed in his academic papers, an omission that clearly contravenes standards of scientific ethics.  Although Dr. Soon's transgressions surprised no one, it was worth noting from the standpoint of doing what the deniers themselves demand, that is, "following the money."

Shortly thereafter we had Senator James Inhofe telling a bunch of his fellow senators that because it was cold outside, climate change wasn't occurring.  He demonstrated his entire knowledge of climatology by holding up a snowball, thus simultaneously proving that your skull can be filled with cobwebs and dead insects, and you can still get elected to public office.

But what brings this topic back to my attention is the release of information from the National Snow and Ice Data Center that shows that the Arctic Sea ice is already thinning rapidly (it's March, folks) and is set to go into a melt this year that climatologists are calling "catastrophic."

Here's how the trend was described by science blogger Robert Marston Fanney:

(T)he March 4 measure finds NSIDC values sliding below previous records for the date set just 8 years ago. 

Ever since Monday, extent values have been falling by an average rate of 10,000 square kilometers each day. A steady progression of warm air fronts through the Barents coupled with well above average temperatures in the Bering and near Alaska region have generated heat pressure along the ice edge and well into the Central Arctic. 

As of today, we have extreme temperature departures in the range of +20 degrees Celsius above average in the Barents northward through to the polar zone. From the Bering through Alaska and into the Southern Beaufort near the Mackenzie Delta departures are in the range of +5 to +20 C above average. 

These two hot spots, together with another warm pool over Greenland have shoved the Arctic, as a whole, into the +2 C range. A rather high departure that is only forecast to worsen in the GFS model summary over the coming days. 

The added warmth, wind, and waves in these ice edge regions drove these extent losses and now, as of Wednesday, values had fallen to 14,383,000 square kilometers. By comparison the previous record low for the day in 2006 was 14,411,000 square kilometers, so the new record is 28,000 square kilometers lower. An area approximately the size of the State of Maryland. 2011 now comes in as third lowest for the day at 14,451,000 square kilometers or 68,000 square kilometers above the 2015 value.

I don't want to quote anything further from Fanney's post, because it deserves to be read in its entirety (please go to the link I posted above to read it), but you get the picture.  Record high temperatures for the Arctic, including many regions above the freezing point of water -- and we haven't even hit the Vernal Equinox yet.

Sea ice coverage in 1980 (bottom) and 2012 (top), as observed by passive microwave sensors on NASA’s Nimbus-7 satellite and by the Special Sensor Microwave Imager/Sounder (SSMIS) from the Defense Meteorological Satellite Program (DMSP). Multi-year ice is shown in bright white, while average sea ice cover is shown in light blue to milky white. The data shows the ice cover for the period of 1 November through 31 January in their respective years. [image courtesy of NASA and the Wikimedia Commons]

The frightening part of all of this is that once you start opening up gaps in the ice sheet, there's a risk of a positive feedback effect.  Open water absorbs heat from insolation far better than snow and ice do.  This will accelerate the warming, opening up further gaps, and so on.  Storing vast amounts of heat in the Arctic Ocean will also affect the weather; the Northeastern deep-freeze this winter, and the repeated snowstorms that slammed the mid-Atlantic states and New England, were caused by a meander in the Polar Jet Stream that brought a blob of Arctic air far south of where it should have been, this time of year.  So Inhofe's snowball is actually consistent with climate models -- not that I expect him to have the intelligence to understand that.

In fact, the whole climate-denier mindset depends on three things; confirmation bias, the power of money, and a sly ability to cherry-pick your facts.  This last one is particularly insidious; that game involves publicizing like hell any specific data points that seem to support your claim, and not mentioning anything else.

You have to wonder how the deniers would explain away the latest from the NSIDC.  My guess is that what we'll hear from them is the following:

*sound of crickets chirping*

It puts me in mind of a quote from linguist Alice Kober:  "Facts are slippery things.  Almost anything can be proved with them, if they are selected correctly."

Climate change, sea ice, and regression to the mean

One of the least-recognized statistical phenomena, at least by your average layperson, is called regression to the mean.

Let me give you two examples.  Let's say that I gave some American, English-speaking students a true-or false test in Swahili, and told them to fill it in.  Their results, in other words, would be random, and you would expect (with a large enough sample size) that the average score would be right around 50%.

That doesn't mean, of course, that everyone got 50%.  Again, with a large enough population of test-takers, the scores would very likely fall on a normal distribution (also known as a "bell curve").  So far, nothing surprising here.

But suppose you took the top 5% of the test-takers -- the ones who scored well above the mean score of 50% -- and asked them to take a second test, this one written in Latvian.  What would happen to their scores?

The answer, of course, is that virtually all of them would fall -- not because they suddenly got stupider, but because their first scores were so far outside the norm that their second is extremely likely not to be.  If you gave all of the original students the test in Latvian, there would once again be that 5% who got anomalously high scores -- but it almost certainly wouldn't be the same students.

It doesn't need to be a random process to generate a regression to the mean.  I see this happening all the time with my students, who (I hope) aren't simply guessing answers randomly.  As a second example, let's say we have a kid who usually scores around 85%, and then she scores a 65% on a twenty-point quiz.  Her next score is pretty likely to rise -- even assuming that she studied the same amount on both of them.  The 65% was simply an anomalous low score.  Bouncing back up to 85% could just be a regression to the mean, especially given (1) how many factors can be involved in missing questions on quizzes, and (2) the fact that the difference between a 65% and an 85% on a twenty-point quiz is only four additional questions correct.

It's the reason why so many people expect "lucky streaks" (or unlucky ones) to keep going -- and they almost never do.  You're much more likely to see a regression to the mean sooner rather than later (or a "correction," as they call it in the stock market.)

So, the question I'm sure you're all asking by this point is: how does this relate to climate change?

Some of you may have seen recent articles, mostly in conservative media outlets, that have headlines like this one from The Daily Caller:  "Global Warming? Satellite Data Shows Arctic Sea Ice Coverage Up 50%!"  The author, Michael Bastasch, writes:

The North Pole is still there, and growing.  BBC News reports that data from Europe’s Cryosat spacecraft shows that Arctic sea ice coverage was nearly 9,000 cubic kilometers (2,100 cubic miles) by the end of this year’s melting season, up from about 6,000 cubic kilometers (1,400 cubic miles) during the same time last year... 

This is good news for the Arctic, but presents somewhat of a tough problem for environmentalists and some climate scientists who have been pummeled with evidence this year contradicting the theory of man-made global warming.

Scientists have been struggling to explain away the 15-year pause in rising global temperatures. Some have turned to solar activity or natural climate cycles to explain the hiatus in warming.

Oh, those poor scientists, always "struggling to explain away" stuff.  Well, sorry, Mr. Bastasch, but no climate scientist I've ever heard of has trouble understanding regression to the mean -- which is what you and your climate-denier friends, in your apparent ignorance, are referring to as a "pause."

Amusing, too, that The Daily Caller chose to illustrate their article on Arctic sea ice with a photograph of ice... that includes a penguin:

Be that as it may, let's see what an actual climate scientist has to say about this year's miraculous rebound, okay?  Here's what Andrew Shepherd, climatologist at University College London, has to say about the situation (quoted in an article in The Independent):

"The 9,000 cubic kilometres we measured in October is still very much smaller than the 20,000 cubic kilometres we estimate for the same time in the early 1980s. So today's minimum still ranks among the lowest for the past 30 years," Professor Shepherd said.  "The October figure is still a significant result and it's not to be underestimated, but it's not an unexpected result. We do see year-to-year variations in the sea ice due to changes in weather patterns."

Oh, and then there's this quote, from David Kennedy, deputy undersecretary for operations at the National Oceanic and Atmospheric Administration:  "The Arctic caught a bit of break in 2013 from the recent string of record-breaking warmth and ice melts of the last decade. But the relatively cool year in some parts of the Arctic does little to offset the long-term trend of the last 30 years: the Arctic is warming rapidly."

In other words: the previous years' ice coverage was so low that sooner or later, there was bound to be a cooler year.  It's just regression to the mean, even if the overall trend is still obvious to anyone who is not willfully blind.

Scientists look at patterns, not at cherry-picked data points that happen to support their favorite biases -- unlike the agenda-driven climate deniers who are (with luck) decreasing in number as the data piles up.  And the data is piling up.  NOAA's National Climatic Data Center just released November's Global Climate Report, and reported that the globally-averaged sea and land temperatures for November were the highest for that month since record keeping began in 1880.  "Aha," the deniers might say.  "Couldn't this just be an anomalously high number, just like our kid who got a 90% on a Swahili test that he couldn't read?  Aren't you committing just what you said was a statistical fallacy, in your opening paragraphs?"

Sure, could be.  Until you add the second thing that this month's report announced; that this is the 37th consecutive November, and 345th consecutive month, with an average temperature higher than the 20th century mean.

That, my friend, is a trend.  Show me a kid who can score higher than the mean on a test in Swahili 345 times in a row, and I'll show you a kid who is lying about the fact that he can actually read Swahili.

So, yeah.  Slam dunk.  Not that I expect that this will change the minds of the climate change deniers, any more than the retraction of the Seralini study will change the minds of the anti-GMO crowd, or the retraction of the Wakefield study will change the minds of the anti-vaxxers.  But it is becoming clearer and clearer that the people who are denying the existence of anthropogenic climate change are deliberately misinterpreting the data, or else ignoring it entirely.  The scientists, however they are portrayed as "struggling," seem to have a pretty good consensus about what is happening.

But unfortunately, nobody much seems to be explaining all of this to the layperson, leading lots of them to believe what the media is claiming -- that the climate is yo-yoing all over the place, and no one knows why, not even the scientists.  But what started out as legitimate questioning, back in the 1980s when the alarm bells on climate change first began to sound, has now turned into nothing more than "la-la-la-la-la-la-la, not listening."  Agenda-driven political organizations like the Heartland Institute are, at this point, no longer simply pointing out uncertainties in the data and analysis; they are lying outright.

To buy that this regression to the mean in the Arctic pack ice coverage is significant, and means that climate change isn't happening, requires you simultaneously to ignore a mountain of other data.  Meaning that you are coming to that conclusion for some other reason than science.  But the deniers don't want you to know that -- because a confused populace, who thinks that no one can know what's causing climate shifts and that (anyway) we couldn't do anything about it even if we did, is much more likely to vote to keep doing what we've always done.

Convenient for the powers-that-be, isn't it?