The best way to not look like an idiot is to shut up. Works every time. Why just a few minutes ago I said something really stupid because I confused UPS and USPS. Should have just kept my mouth shut, but I didn’t.

This time of year a lot of people start sounding like idiots, quite possibly because they are idiots (but see below for alternative explanations), when it comes to global warming. For example, someone who may or may not be a “global warming denier” (i.e. a person who does not believe in physics) sent me, out of the blue, this string of tweets:

First he tells me that the ice in the Northern Hemisphere in mid December is extensive. He says that I can see “the recovery” and points out how extensive the recovery is, and how much snow there is too.

This is the somewhat more elaborate version of, “It is cold out today therefore there is no global warming.”

This is December, which means we have data through last November for the last several year compiled on a monthly basis by NASA. Here’s the last several years of Novembers, showing that Novembers are getting warmer (for background click here):

Turns out it’s the hottest November in this extensive database of Novembers, globally. Still, though, November was very cold in the northern hemisphere compared to July! That, of course, is because July is pretty near the middle of the warm season, and November is getting close to the cold season, in that hemisphere. I predict that when the data come out, December will be even colder than November!

The “recovery” my twitteriffic friend points to is the idea that Arctic Sea ice has recovered after having a couple of bad years. Here’s the story on the sea ice (click here for background). First, let’s look at Arctic Sea ice as it melts and reforms every year, in surface extent, for something close to ten years in a row a bunch of years back. The thick like is for reference. All the thinner squiggly lines are each for one year, back in the day:

Then, a thing happened we call “Arctic Amplification” in which global warming caused the northern regions to get warm, just like the entire surface of the Earth is getting warm, but relatively more so. This includes reduced sea ice that forms and melts every year, like in the graph, as well as permanent melting of the thicker multi-year ice, decrease in overall snow cover, and increase in the temperature of the northern sea. The effects on sea ice is seen in the following graph, which shows through 2011. The thick line is still there for reference. Notice that the pattern from 2002 to 2011 is distinctly different from, with less ice all the time, than the pre-2002 pattern. This is because of global warming, and it is an excellent signature of “Arctic Amplification.”

Notice that the last chart only goes through 2011. One thing that happened last year, for the 2013 melt season, is that a lot of science denialists such as my tweety friend (see above) went on and on and on about how Arctic sea ice had “recovered” in 2013. They used this series of data to make their case. Look at this graph:

Notice that when we look at the march of melt and formation of Arctic sea ice for 2013, it looks like one of the worst years of the worst. Yet climate science denialists called this a recovery. They are still calling it a recovery, and now, apparently, they are even calling “Winter” a “recovery.” This, without a doubt, makes them look like idiots.

There is a reason that they do this. Not good enough of a reason to make them not look like idiots. Rather, if you look at this reason they look even more like idiots than you might have been thinking unless you want to give them the benefit of the doubt and call them dishonest instead. Either description seems to fit. Here’s the thing. If you add the year 2012 on to that last graph, it looks like this:

The year 2012 is the dotted line that is way way more intense in terms of melting than any other year ever seen. If we remove that year from consideration, we can see that Arctic sea ice has been melting more and more with every year being highly likely to be worse than any previous year at least for several months (but not always) right up to and including the present year. But if you add 2012 into the mix, we can easily say the same thing but then we also note that 2012 was an exceptional super-melty year.

Going back to all messed up and melty from an unbelievable extreme year is not a “recovery.” Not even a little.

Tweety Bird (the guy cited above) makes the mistake of thinking that if it gets cold or snowy during the Winter than global warming is over. But actually, the extreme snow cover we’ve seen in some areas, and some of the extreme cold, is probably due to global warming. Confused? It is, in fact, a little confusing but you can learn why this is and not look like an idiot! Let me show you.

We’re not completely sure of this, but here’s what climate scientists are currently thinking and all indications are that it is likely true. Normally the air around the Earth can be thought of as being in large rotating bands demarcated by jet streams, and weather patterns move along those bands bringing dry, wet, whatever, conditions as they do so. The bands and the jets form because the tropics are warm and the poles are cold and weather is all about the movement of tropical heat towards the poles. But if you change some of the key variables in this system, like the size of the planet or the amount of the atmosphere, for example, the system looks different; perhaps a different number of these big bands forms (Earth has several, Mars has two, for example) or some other attributes change.

It turns out that if you decrease the amount of difference from tropical and temperate regions vs. the poles, in terms of temperature, the jet streams get all wiggly and cause northerly air to reach far to the south in some places and southerly air to reach farther north in other places. This causes unexpected weather like snow in Egypt. It also may facilitate the formation of nasty storms. More importantly, perhaps, is that the wiggles in the jet stream stay in place for long periods of time, or move very slowly, and this causes storms to stall in place and we get weather events like the flooding we saw in Colorado, Calgary, Central Europe and other places over the last year. Or Sandy’s being steered int NY/NJ/Conn last year. That sort of thing.

So if it was Summer and it is now Winter, that does not mean that global warming isn’t real. If there is a strange weather event that causes snow in Cairo or a “500 year flood” in Boulder, that is an effect of global warming, not evidence that global warming is not real. For global warming to not be real some very basic physics need to not be real. The basic physics are real. Your idea that global warming is a fiction is not real. You might have good intentions (this is doubtful, more likely you are a jerk for wanting our children to suffer the consequences of your actions) or you might be misinformed (this is doubtful — if you know enough to use dog whistles such as “recovery” you can’t claim this honestly) or you might be economically motivated (there are those who are paid to deny global warming, millions have gone into this form of science denialism). Or maybe you really are an idiot. In any event, remember that there are consequences. Short term, you’re not going to be taken seriously. Long term you are helping to ruin the planet. Either way, please consider the advice given at the beginning of this post.

Here are a few related items from here and elsewhere on the internet:

<ul>

<li><a href="http://scienceblogs.com/gregladen/2013/09/28/global-warming-and-extreme-weather-climate-agw/">Global Warming and Extreme Weather – #climate #agw</a></li>
<li><a href="http://thinkprogress.org/climate/2013/12/09/3038631/arctic-warming-extreme-weather/">Arctic Warming Drives More Extreme Summer Heat Waves, Droughts And Deluges, Study Finds</a></li>