UPDATE: Despite Doubling Down, Climate Change Article Still Very Misleading

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Sept. 18 2013 1:04 PM

UPDATE: Despite Doubling Down, Climate Change Article Still Very Misleading

Over the weekend, the Mail on Sunday posted a highly misleading article on climate change. In it, author David Rose made a number of errors, some fundamental, downplaying the reality of climate change. I, along with many others, pointed out the numerous mistakes made, including his comparing two numbers that are not at all comparable, as well as a grossly inaccurate misquote of a climate scientist, making it seem he was saying something he really wasn’t.

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Phil Plait writes Slate’s Bad Astronomy blog and is an astronomer, public speaker, science evangelizer, and author of Death from the Skies! Follow him on Twitter.

On Tuesday, the Mail "corrected" the article. Except not really. The headline, which had originally said “World's top climate scientists confess: Global warming is just HALF what we said” was changed to “World's top climate scientists confess: Global warming is just QUARTER what we thought - and computers got the effects of greenhouse gases wrong.”

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This, of course, has caused some ripples among the people who keep track of climate-change denial nonsense. It’s actually a rather masterful use of distraction: It has some truth in it but doesn’t tell you the biggest thing you need to know to understand the real situation. And it’s important to note that none of the other really obvious errors in the article were changed.

global temperatures
The global land-sea surface temperature "anomaly" (deviation from an average determined from 1951 - 1980). The flat part over the past few years is the cause of this kerfuffle, and is due to a temporary cooling of ocean surface tempeatures. Note that this sort of short-term flattening has happened many times in the past, but the overall trend is up.

Graph from NASA/GISS

In 2007, the Intergovernmental Climate Change Panel released their Assessment Report 4 (AR4) about the state of the climate. In it, they said that for the period 1991–2005, the average measured increase in land surface temperatures was 0.2 degrees Celsius per decade, much larger than the 0.12 degrees Celsius per decade that had been found for the period of 1951 on. Given that computer models, which use physics to independently simulate climate conditions, matched observations (and trends) pretty well, the model predictions of a 0.1–0.3 degrees Celsius per decade rise over time seemed reasonable.

However, over recent years, that increase has flattened considerably. This is almost certainly due to the extra heat being absorbed by deep ocean water; measurements have confirmed that. Apparently, the rate that heat from the ocean's surface could be transported to lower depths was not well determined at the time. But bear in mind, that extra heating exists. It's real. It's in the water, not the air, and so surface temperatures over land have not increased as fast as the models initially predicted. Rose doesn’t mention this.

But that heat is still there, building up. At the same time, the ocean surface has a natural oscillation in temperature, up and down, over timescales of a decade or more. This affects land surface temperatures on short time scales like a few years. We're in a downswing right now, which is another reason temperatures over land have flattened.

But that won't last forever. The ocean surface will warm once again, the heat inside will be released, and temperatures will go up again. It's difficult to say exactly when, but it won’t last forever.

Pacific Decadal Oscillation
The Pacific Decadal Oscillation, the cooling and warming of surface temperatures in the north Pacific. The index is a measure of the amount of temperature change; we are currently in a temporary cool trend, which acts to suppress land temperatures.

Graphic by NCDC/NESDIS/NOAA

But for the moment, though, this works in the favor of deniers, who claim that temperatures are dropping and the Earth is cooling. That's not the case. It's just the temporary downward swing of the ocean cycle masking the long-term upward trend of land temperatures.

In either case, what we know is that in the Northern Hemisphere, the last 30 years (from 1983–2012) were certainly the warmest in the last 800 years and likely to be the warmest for the last 1,400 years. The updated AR5 report, due out very soon, confirms this. Not only that, but Arctic sea ice is declining, global average upper sea level temperatures are going up, and sea levels are still rising … all as they have been for decades.

Rose ignores all this, focusing on details while missing the bigger (and much more important) picture. What he says on the surface—so to speak—is true, but leaves off the rest of the story you need to know to understand what's really going on.

I'll note, too, that while the Mail updated their article doubling down (or really, halving down) on warming, they did nothing to change the grievous misquotation of scientist Myles Allen, nor corrected any of the other egregious errors in the article (like propagating the old and long-debunked “Medieval Warming Period was warmer than today before CO2 levels were as high as they are now” gambit). I find it fascinating that they updated the article about one particular error (without actually fixing it) while not correcting the other mistakes.

And remember, this type of nonsense does have an impact. It gets picked up all over the media, who in many cases parrot this type of thing without doing even the most minimal amount of investigation … and of course there are other venues that repeat it because denial is what they do. I’ve already seen this in other newspapers, blogs, and of course on Twitter.

These folks may call themselves skeptics, but they’re nothing of the sort. An actual skeptic looks into the matter, digs deeper, looks for the evidence and weighs it fairly. My own agenda is simply science. I would love for global warming to go away; it terrifies me. We’re already seeing its effects, and things are bound to get worse. But we cannot wish it away and we cannot bluster it away. The most important thing we can do is face it squarely, accept the evidence, and do what we can do to mitigate the effects. Otherwise, we’re fiddling while the world burns.

Tip o' the birdcage liner to Peter Sinclair (the first of many who pointed out the updated Mail article) and to climate scientist Michael Mann for some useful advice.

Correction (Sep. 18, 2013): In the original article, I wrote that the computer models used current conditions to predict future temperatures. In fact, the models make predictions independently of current conditions; that's why when they match observations closely it increases confidence in their output. Also, I initially wrote that the amount of heat transported to ocean depths wasn't well known; in fact it is the rate of transport that's the issue.