Is Recent Greenland Ice Sheet Melting ‘Unprecedented’? Absolutely. Is It ‘Worrisome’? You Bet It Is.
"Is Recent Greenland Ice Sheet Melting ‘Unprecedented’? Absolutely. Is It ‘Worrisome’? You Bet It Is."
“Greenhouse gas emissions are overwhelming the [Arctic] system,” explained the coauthor of a 2009 Science article, “Recent Warming Reverses Long-Term Arctic Cooling.” The blue line is the estimate of Arctic temperatures over the last 2,000 years, based on proxy records. The green line is the long-term cooling trend. The red line is the observed warming in recent decades.
Another day, another bad New York Times headline:
The New York Times then launched into a critique of:
- NASA — for what they asserted was an “inaccurate headline” in its press release, “Satellites See Unprecedented Greenland Ice Sheet Surface Melt”;
- Most of the media coverage — for supposedly “hyperventilating” by accepting NASA’s use of the word “unprecedented”;
- Me — for using James Hansen’s term “reticent” for one of the NASA scientists who said, “if we continue to observe melting events like this in upcoming years, it will be worrisome.”
I interviewed one of the country’s top climatologists, Michael Mann, by phone, and another, Gavin Schmidt, by email. The bottom line is:
- People who live in greenhouses definitely should not throw stones
- Not. Mann explained to me that “it’s absolutely worrisome” what’s happening in Greenland already.
Before I elaborate on all three, let me make a point about headlines, which I discuss at length in my forthcoming book “Language Intelligence.”
Headlines are important because research shows that most newspaper readers don’t get much beyond them. And NY Times headlines sweep across the internet through twitter, facebook, news aggregators and search engines. Probably 10 to 50 times as many people see the headlines as read any substantial portion of the story.
I would define a flawed headline as one that, standing alone, is inaccurate or misleading or, as in this case, both. Indeed, this headline is so bad I’d urge the NY Times to change it. I write virtually all of the headlines on Climate Progress, and since I’ve had several thousand posts, I’ve had to change a few headlines over the years.
There’s nothing wrong with fixing a headline — most major news outlets do it on a regular basis. The only thing that would be wrong would be to leave a wrong headline unchanged.
Let’s run through why the NASA headline is fine and why the NY Times headline is not.
The NY Times asserts that “the space agency badly blew it earlier this week with this headline,” claiming:
Unprecedented means “never done or known before.” Yet the news release beneath the headline directly undercuts that description of this melting event, saying that it is rare — the last wide surface melt was in 1889, recorded in separate ice cores at the Greenland ice-sheet summit and in the northwestern part of the vast frozen expanse — and has happened roughly every 150 years over a long stretch of centuries, as recorded deeper in the ice. (Here’s a figure from a 1994 Science paper pointing to a series of such melt layers, reflecting summer warmth. Please see the postscript below for the key reference, provided by Lora Koenig of NASA.)
And yet Dr. Jason Box, a leading Greenland expert with “19 expeditions to Greenland since 1994, more than 1 year camping on the inland ice,” used the following headline on his blog, Meltfactor.org, “Greenland ice sheet record surface melting underway.” Hard for something to be a record if it isn’t unprecedented.
The most thorough response comes from NASA’s own Gavin Schmidt in a comment posted on the NY Times story (one he confirmed with me):
The NASA results are clearly unprecedented in the satellite record (and this is obviously what was being referred to), and come at the tail end of a strong increasing trend in summer surface melt area (as seen in data from the Steffen and Tedesco groups).
However, we know Greenland was warmer than today at many intervals in the past – the Early Holocene (from isotopes and borehole temperatures), the last interglacial, the Pliocene etc. so there is no claim that this is something that has never happened in the history of the planet.
Furthermore, the ‘every 150 years’ quote is very strange. The data on Summit melt layers – (discussed in the paper you reference http://www.igsoc.org/annals.old/21/igs_annals_vol21_year1995_pg64-70.pdf ) and more easily visible here:http://www.gisp2.sr.unh.edu/DATA/alley1.html – indicates that the  event was actually the only event in the last ~700 years, and there have only been 6 in the last 2000 years (4 of which were associated with the Medieval Climate Anomaly btw 750 and 1200AD). Hardly a frequently recurring ‘cycle’!
The all-Holocene average that Koenig is referring to includes the warmer Early Holocene where orbital variability was driving warmer northern high latitude summers — and which is not relevant to the expected frequency in today’s climate.
The point is that, as the top graph shows, the Arctic was in a long-term cooling trend until human emissions reversed that trend (and yes, Arctic warming isn’t precisely the same as Greenland warming). Multiple, independent studies make clear that “recent global warming is unprecedented in magnitude and speed and cause.”
The NYT is simply wrong when it says “the space agency badly blew it earlier this week with [its] headline.”
And that means the media coverage wasn’t flawed, either.
I discussed the surface melt with Dr. Mann. Here is what he told me:
Ablation is occurring at an unprecedented scale as far as modern observations are concerned. To try to make a statement about how unusual this event in the longer term context, we are forced to turn to more tenuous evidence from ice cores. And that only gives us spotty evidence, information from a small number of locations, and it’s very difficult to determine from that sort of information alone, whether there is in fact a precedent inrecent centuries for the remarkable spatial extent of the melt we are witnessing.
The NY Times cites as evidence in support of its assertion that the NASA headline was incorrect, this part of the full release:
“Ice cores from Summit show that melting events of this type occur about once every 150 years on average. With the last one happening in 1889, this event is right on time,” says Lora Koenig, a Goddard glaciologist and a member of the research team analyzing the satellite data. “But if we continue to observe melting events like this in upcoming years, it will be worrisome.”
The NY Times then launches into a critique of my post that is not sustained by the facts:
But subtlety and reality don’t play well in some circles. Koenig’s careful description of the science and the uncertainty about what the future holds prompted a public spanking from the Center for American Progress climate blogger Joe Romm, who charged her with “scientific reticence” — alluding to NASA scientist James Hansen’s paper criticizing sea-level researchers for being overly cautious in 2007 conclusions about the possible rate of sea rise in this century.
It is hard for me to see how what I wrote qualifies as a metaphorical act of physical violence. In my post — ABC News On Stunning Greenland Ice Melt: ‘Scientists Say They’ve Never Seen Anything Like This Before’ — I quote Koenig’s line and wrote:
That statement is a classic example of what James Hansen called “scientific reticence.”
The scientific literature and recent observations — along with our ongoing lack of climate action — have long passed the worrisome stage (see the post last month “Greenland Ice Sheet Melt Nearing Critical ‘Tipping Point’ ” …).
That is the full extent of my supposed flogging of the good doctor. Seriously, “reticent” is perhaps the mildest word one could possibly use, which is no doubt why Hansen used in the first place to describe some of his colleagues. Since the NYT likes definitions, “reticent” means “the quality or state of being reticent : reserve, restraint.” Ouch! Stop it! You’re hurting me!
I stand by statement, which clearly referred to our entirety of knowledge about what’s going on in Greenland. Mann told me when I asked him whether recent Greenland melt was ‘worrisome':
It’s absolutely worrisome. Some of the statements that scientists have made on this are a classic example of scientific reticence, understating to some extent what we know.
Finally, the NYT headline appears to echo Fred Singer’s lame denier treatise, Unstoppable Global Warming: Every 1,500 Years (see “Unstoppable disinformation every 15 minutes from Fred Singer“).
Hundreds of thousands of people will see nothing more than this one line: ” ‘Unprecedented’ Greenland Surface Melt – Every 150 Years?” Many will interpret that to mean the NY Times is mocking or downplaying what is happening in Greenland.
The semantic questions raised by the NY Times do not appear to be a productive use of their considerable resources. It appears that NASA’s headline was quite reasonable. It also appears that the New York Times‘ headline was quite unreasonable. They should fix that, especially since it is now becoming a bad habit:
- “Crappy Headline” Ruins New York Times Story on Link Between Climate Change and Extreme Weather
- Bad Headline Mars Good NY Times Story Debunking Lindzen’s ‘Discredited’ Cloud Theory.
- Sorry, NY Times, The Filibuster, The Polluter-Funded Campaign, and The Feckless Media Don’t Make Us All ‘Climate Idiots’. Well, Maybe The Media Do.
This post has been updated.