Monday, November 14, 2016

Climate of 2016 to date

No, I'm not talking about the recently concluded US election that saw a scientific illiterate ascend to the presidency. Given the lack of details about Donald Trump's intended policies, it's impossible to say what, exactly, his election means for science in the US although I have doubts that it means anything good given his stated antithesis toward science, particularly climate science. I will instead focus on some significant events that have been eclipsed in the media frenzy around the presidential campaign.

First up, global temperature. Has it been hot enough for you? Here are January through September temperatures for every year in the GISS record.
 So far, 2016 has obliterated the previous record for January - September global temperature anomaly set in 2015, 1.03ºC to 0.80ºC. Not only is the average for the first nine months hotter but eight of those months are the hottest respective months on record, with only June 2016 (in third place) the lone non-record-setter. That streak of hot months won't continue, however. The last quarter of 2015 was extremely hot thanks to El Niño. We're now in neutral conditions, so the last quarter of 2016 is unlikely to be hotter than the last quarter of 2015.

Now the president-elect of the US may not believe that the world is getting hotter but science is true regardless of personal opinion.

What are the chances that 2015 will retain its crown as hottest year in the GISS record? Short answer: Slim to none. The annual temperature anomaly in 2015 was 0.87ºC above the baseline. So far, 2016 has an eye-popping anomaly of 1.03ºC. For 2016 to miss being the hottest year on record, the last quarter of the year would have to have an average temperature anomaly of 0.39ºC.

Simply put, that's not going to happen. The probability of the three month average dropping that low in 2016 is 0.26%. There's a chance that 2015 will retain its crown, yes, but there's no way I'd bet against the 99.74% chance 2016 takes the crown away.

Also obscured by the hyperventilation over the US presidential election? The monthly atmospheric carbon dioxide crossed the 400 ppmv barrier in November 2015—and has not dropped back below that level as of September 2016. It's unlikely to do so since September usually sees the lowest CO2 levels of the year. Welcome to a world where CO2 is permanently above 400 ppmv, a world last seen in the Pliocene. Oh, in case you're wondering, the 12-month centered moving average has been above 400 ppmv since March 2015, now standing at 403.3 ppmv.
Finally, Arctic sea ice slipped to its third-lowest September extent on record, with a monthly average of just 4.51 million square kilometers of permanent sea ice in the Arctic Ocean this past September. The only years in which there was less permanent sea ice? The record lows of 2012 and 2007.
In short, global warming has continued in 2016 thanks to the continuous rise in CO2. As it has for the last century, as it will for the foreseeable future regardless of political opinion.

Monday, May 30, 2016

1996 versus 2016 in a Facebook meme

Recently, a right-wing cousin of mine shared a meme claiming that global temperatures were unchanged between 1996 and 2016, specifically that global temperatures were 14.83ºC (58.7ºF) in both 1996 and 2016.


I call BS and here's why.

First and most obviously, 2016 isn't even half over.  Stating that the mean temperature in 2016 was 14.83ºC (58.7ºF) is a bit premature.

Second, whoever came up with that meme has extreme difficulty with basic statistical terms. Here's a hint: "Average mean temperature" is nonsense.  As used in everyday speech, it's essentially the same as saying "average average temperature" or "mean mean temperature." Now, for those who understand statistics, I know that the mean is technically a specific method for calculating the average but in general usage, mean and average are interchangeable—and whoever came up with that meme was abjectly ignorant of that fact.

Third, the meme author had even more difficulty with facts and mathematics.  For one, the mean global temperature in 1996 was not 14.83ºC (58.7ºF). According to NASA GISS, the average global temperature was 14.34ºC (57.8ºF).  For another, the year-to-date mean global temperature for 2016 is not 14.83ºC—it's 15.25ºC (59.45ºF).  So the anonymous author has both their start point and their end point wrong.  Really wrong.



It's not just NASA that shows that 1996 is cooler than 2016. The satellite temperature records show the same.

So, if both surface and satellite temperature records agree that 2016 is far warmer than 1996, where is that meme author getting the lie that 1996 and 2016 have the same mean temperature?

Fourth, that meme displays a gross ignorance in what makes up a trend by implying that if the start and end points are the same, there cannot be a trend.  In reality, it wouldn't matter even if 1996 and 2016 did, in fact, have the same mean temperature.  A trend is far more than just its start and end points.  Even if you altered the end point, there would still be a warming trend.  It may not be as large but the trend would still exist.  Here's an example using the NASA GISS data I displayed above.  I just altered the end point of the second graph so that it would have the same value as 1996 before I calculated the trend.


As you can see, the warming trend still exists in the lower graph despite altering the end point.  It's not as large ("only" 0.102ºC/decade versus 0.221ºC for the original data) but it is still statistically significant (p = 0.0257).

So in summary, whoever made up that meme 1) lied about their numbers, 2) is ignorant of the actual temperature data, and 3) abjectly ignorant of basic statistical concepts.  And then they had the balls to call Al Gore and progressives liars.  How quaint.

Monday, May 16, 2016

Hottest start to a calendar year on record

NASA updated their global temperature data for April and it's hot.  Really hot.  As in the last time it was this hot may well be the Holocene Climatic Optimum.  April 2014 shattered April 2010's record by a full 0.24ºC, coming in at 1.11ºC above the 1951-1980 baseline.  That is, simply put, jaw-dropping.

Saturday, May 14, 2016

Climategate—Seriously??

It's hard to believe that anyone at this point takes the so-called Climategate seriously.  Yet I have encountered several individuals recently who appear to sincerely believe that Climategate was a real scandal that somehow disproves all the scientific evidence for climate change/global warming accumulated over the past 150+ years.

Thursday, May 12, 2016

A taste of 2049

Long time, no see.  Sorry for the lengthy time between entries.  Real life has gotten quite complicated of late.  So, let's hit one major topic that has been in the news of late: The absolutely sizzling start to 2016.  Just how sizzling has it been?  Take a look:

Sunday, August 30, 2015

What are the odds that 2015 will not be the hottest year on record?

Let me be upfront with you: I think it's a foregone conclusion that 2015 will beat out 2014 as the hottest year on record. However, I decided to test that idea, just to be certain.

The way I did it was simple: I first calculated the year-to-date average (January - July) and then calculated what the August — December average would have to be to keep the 2015 average temperature at or below that of 2014. I then calculated the August — December average for each year since 1970, fitted a trend, and calculated the standard deviation of the residuals. Last, I calculated the expected August - December average for 2015 given the trend and the difference between the expected August - December average and what that average would have to be to keep 2015 from setting a new record.  I then used z-scores to calculate the probability that the remainder of 2015 would fall to that level or below.

Annual global temperature according to NASA GISS since 1970




Year to date, 2015 sits at +0.82ºC above the 1951-1980 baseline.  The average for 2014 was "only" +0.75ºC above the baseline.  Keeping 2015 at or below the standard set by 2014 would require an average temperature of at most 0.652ºC for the remainder of the year.  So, how likely is that average temperature for the August - December period?
Average August - December temperatures since 1970.
The predicted average for August - December 2015 based on the trend would be 0.772ºC, more than enough to make 2015 the hottest year on record.  With a standard deviation of 0.0981ºC, there is only an 11.05% chance that the August - December 2015 average would be at 0.652ºC or below.  This means that right now, 2015 has at least an 88.95% chance of breaking 2014's record.  Pretty good odds but not quite a foregone conclusion.

There is one important caveat that means that I overstate the chance that 2015 will not break the record: I did not account for El Niño years.  That was done deliberately.  I wanted to be conservative with my estimate.  With a strong and strengthening El Niño event in the Pacific that might rival the 1983 and 1998 El Niños, I personally believe that 2015 has a nearly 100% chance of smashing 2014's record baring a major volcanic eruption.

Saturday, August 8, 2015

Global warming, The Wall Street Journal, and John Gordon

John Steele Gordon published a commentary in The Wall Street Journal on July 30 that, on its face, sounds reasonable.  Gordon makes the case that we should be cautious about calling climate science settled as science is always changing.  No real quibbles there, as science has shown that nothing is ever truly "settled" science.  Unfortunately, that's as close to reality as Gordon comes.  The rest of the commentary simply shows off Gordon's simplistic view of history, science, and, especially, the current state of climate science.