Global Warming: A lesson in correlation vs. causation

On October 21 of this year a man by the name of Richard Muller published an Op-Ed in the WSJ to publicize his findings on global warming. He starts this article by laying out reasons that skeptics up to this point have been completely justified in skepticism of the global warming data. After he has proven himself to be sufficiently fair and just in his reasoning, he then states that it's not ok to be a skeptic anymore, because now he isn't one. Basically, he used to be a skeptic, then he tried some science out, and now he's not.

(Pictured: Muller trying science)

The science he tried, a 2 year study based out of the Marxist Recruiting Center known as Berkeley, shows that temperatures have in fact been rising for the past century or so. His data shows correlation between rises in CO2 and rises in temperature.

Our work covers only land temperature—not the oceans—but that's where warming appears to be the greatest.

We discovered that about one-third of the world's temperature stations have recorded cooling temperatures, and about two-thirds have recorded warming. The two-to-one ratio reflects global warming. The changes at the locations that showed warming were typically between 1-2ºC, much greater than the IPCC's average of 0.64ºC.

Naturally, since this is the case, catastrophic measures to bring down CO2 levels worldwide are now authorized, up to and including exterminating industrialists with extreme prejudice.

There is just one small catch: Correlation does not in fact equal causation.

As it is pointed out by Ed Morrissey from Hotair.com:

AGW skepticism doesn’t rest on the notion that global temperatures aren’t rising, but that the AGW crowd has yet to show causation between CO2 release and actual warming...Correlation only shows that two trends parallel each other; if one isn’t the cause of the other, then “solutions” designed to change one trend won’t impact the other anyway — and it will waste time, money, and perhaps lives while the perceived problem continues unabated.

Even more concerning is the fact that the correlation itself isn't as clear cut as we would be led to believe.

Prof Judith Curry, who chairs the Department of Earth and Atmospheric Sciences at America’s prestigious Georgia Institute of Technology, said that Prof Muller’s claim that he has proven global warming sceptics wrong was also a ‘huge mistake’, with no scientific basis...Prof Curry said, the project’s research data show there has been no increase in world temperatures since the end of the Nineties – a fact confirmed by a new analysis that The Mail on Sunday has obtained."

The graph that Muller published (because as we all know data is not official unless you have a brightly colored picture with which to communicate to the unwashed savages) shows a generally upwards trend since 1950 or so. This same graph then takes a sharp turn upwards into the sky after 1975, ending around the turn of the century with an exponential increase that is sure to consume the world in a ball of fire any day now. If you take their own data and follow it further, which The Daily Mail was kind enough to do...

Huh. This unwashed savage perceives no rise in global temperatures at all during the last decade, and this done using Muller's own published data. Also, Ed points out:

A closer reading of the top chart shows that, relative to the 1950-1980 average baseline BEST uses, temperatures didn’t actually warm at all until sometime during the Great Depression, so the entire first century of the Industrial Era apparently had no impact — in a period where the dirtiest of mass energy production processes was in widest use (coal). Temperatures then started to slowly rise during an era of significantly reduced industrial output, thanks to a lengthy economic depression that gripped the entire world. What we end up with is a 30-year spike that also includes a few years of reduced industrial output, starting in the stagnating 1970s where oil production also got restricted thanks to onerous government policies and trade wars.

In climate terms, a 30-year spike is as significant as a surprisingly warm afternoon in late October. Man, I wish we were going to have one of those today.

But then look what happens in the past 11 years in the bottom chart. Despite the fact that the world’s nations continue to spew CO2 with no significant decline (except perhaps in the Great Recession period of 2008-9), the temperature record is remarkably stable. In fact, it looks similar to the period between 1945 and 1970 on the top chart. If global temperature increases really correlated directly to CO2 emissions, we wouldn’t see this at all; we’d see ever-escalating rates of increase in global temperatures, which is exactly what the AGW climate models predicted at the turn of the century. They were proven wrong.

Prof Curry says that her colleagues are now forced to address the impact of other things on the climate, such as clouds, and you know, the SUN, little stuff like that. Of course, the idea that CO2 levels could be less important to temperature than the massive ball of hydrogen that gives off the energy that heats our little planet to something slightly above a ball of ice is something of an outlier. Still, gotta explore all the options, right?

Of course, nobody has even proven that rising temperatures are bad. There was a time when they used to grow crops in Greenland. Not much grows there now, on account of there being a glacier. Could be the planet used to be a lot warmer and this did not immediately result in every living creature spontaneously bursting into flames. I guess it might have, I mean I wasn't there, but I'd like to think we'd have found proof of that along the way somewhere.

Muller, naturally, fired back at his critics. He states strongly that while his own data shows no important increase in the last 13 years, this is might not be "statistically significant"...Of course, he added it was just as likely that it was significant. Then, you know, that might be important...and stuff...

Thanks for clearing that up, friend.