Hansen et. al. 2008 - are they all mad?

Every now and then you have one of those "just a minute..." moments. I've just had one, while reading "Climate target is not radical enough - study", in where else but the UK Guardian. They quote from James "75 metres" Hansen and also his co-authored 2008 paper "Target atmospheric CO2: Where should humanity aim?".

One of the world's leading climate scientists warns today that the EU and its international partners must urgently rethink targets for cutting carbon dioxide in the atmosphere because of fears they have grossly underestimated the scale of the problem.

In a startling reappraisal of the threat, James Hansen, head of the Nasa Goddard Institute for Space Studies in New York, calls for a sharp reduction in C02 limits.

Hansen says the EU target of 550 parts per million of C02 - the most stringent in the world - should be slashed to 350ppm. He argues the cut is needed if "humanity wishes to preserve a planet similar to that on which civilisation developed". A final version of the paper Hansen co-authored with eight other climate scientists, is posted today on the arXiv.org website. Instead of using theoretical models to estimate the sensitivity of the climate, his team turned to evidence from the Earth's history, which they say gives a much more accurate picture.

As an aside, I corrected the arXiv.org link in the quote myself. The article didn't give the report title, nor a specific link to it; you'd have to search on the archive site for it. I've never yet found a link to a journal paper in a Guardian article. One might think they don't want you to read the originals. One might be right....
Clearly, this is the origin of the 350.org campaign, the so-called "safe limit". Hold onto that "much more accurate picture" while you read on.....

The team studied core samples taken from the bottom of the ocean, which allow C02 levels to be tracked millions of years ago. They show that when the world began to glaciate at the start of the Ice age about 35m years ago, the concentration of CO2 in the atmosphere stood at about 450ppm.

"If you leave us at 450ppm for long enough it will probably melt all the ice - that's a sea rise of 75 metres. What we have found is that the target we have all been aiming for is a disaster - a guaranteed disaster," Hansen told the Guardian.

So the "much more accurate picture" tells us that the Earth began to glaciate at a CO2 level of 450 ppm, and Hansen et. al. want to ensure levels stay well below that figure, in fact no higher than 78% of it? Surely the Grauniad's got it wrong? Apparently not - this is the abstract to the supporting material for the paper (My bold):

Abstract: Paleoclimate data show that climate sensitivity is ~3°C for doubled CO2,

including only fast feedback processes. Equilibrium sensitivity, including slower surface albedo feedbacks, is ~6°C for doubled CO2 for the range of climate states between glacial conditions and ice-free Antarctica. Decreasing CO2 was the main cause of a cooling trend that began 50 million years ago, large scale glaciation occurring when CO2 fell to 450 ± 100 ppm, a level that will be exceeded within decades, barring prompt policy changes. If humanity wishes to preserve a planet similar to that on which civilization developed and to which life on Earth is adapted, paleoclimate evidence and ongoing climate change suggest that CO2 will need to be reduced from its current 385 ppm to at most 350 ppm. 

The largest uncertainty in the target arises from possible changes of non-CO2 forcings. An initial 350 ppm CO2 target may be achievable by phasing out coal use except where CO2 is captured and adopting agricultural and forestry practices that sequester carbon. If the present overshoot of this target CO2 is not brief, there is a possibility of seeding irreversible catastrophic effects. 

When I read this stuff, and I regard it as stuff, rather than reasoned analysis, I though "I must be missing something here, surely?". It seems it's Hansen his co-authors, the Guardian journalist, 350,org and all its shrill "born again" followers, especially "Weepy Bill" McKibben who're missing something. Their brains can't be firing on all synapses.

BTW, the journalist Ed Pilkington is the Guardian's New York correspondent, a political correspondent at that, so just the guy to report on a scientific paper about the world's climate. Mind you, it makes a welcome change from failed sports reporters doing the job.

IMHO the "seeding irreversible catastrophic effects" bit is right - onward to the next ice-age. Those wind turbines won't be much good - no convection on an ice-planet to drive the winds. Still, we'll all have a "low-carbon footprint" then - no footprint at all. We'll be dead, gone to meet our maker, (not) pushing up the daisies (no daisies) .

The Guardian shows its naked bias

The Himalayas and nearby peaks have lost no ice in past 10 years, study shows

"Meltwater from Asia's peaks is much less then previously estimated, but lead scientist says the loss of ice caps and glaciers around the world remains a serious concern"

The Grauniad (an affectionate, or otherwise, nickname for the Guardian, which in the days of movable type was prone to side-splitting typos) may sometimes display an apparent lack of bias in its reporting of environmental and climate science, but a sceptical eye can often spot the face behind the mask. It's so with the above article. Those worried or even alarmed about apparent (I choose the word with care) ice-loss worldwide should rejoice in the news about Himalayan ice. I see no rejoicing here; indeed there's a whiff of disappointment throughout.

There's an obligatory picture of a an (apparently) melting glacier with this caption:

Hopar glacier in Pakistan. Melting ice outside the two largest caps - Greenland and Antarctica - is much less then previously estimated, the study has found.

That only interpretation I can put on that is that ice loss in Greenland and Antarctica is not "much less then previously estimated", but must be the same or more than previously estimated. However, the article, by omission, implies that the study didn't cover Greenland and Antarctica. The Grauniad agonises over melting icecaps, so why didn't they mention that the study was global? Perhaps it's that the study also revised estimates for Greenland and Antarctica - downwards from IPCC estimates, but similar to more recent estimates. Was the Grauniad disappointed?

Here's where their bias is revealed. We have what is being widely acknowledged as the most reliable estimates to date for the Himalayas

However, the scientist who led the new work is clear that while greater uncertainty has been discovered in Asia's highest mountains, the melting of ice caps and glaciers around the world remains a serious concern.

Are they really saying that the study reveals "greater uncertainty"? Check it out -

Recent contributions of glaciers and ice caps to sea level rise
Thomas Jacob John Wahr W. Tad Pfeffer Sean Swenson
Nature (2012)

Here's the abstract:

Glaciers and ice caps (GICs) are important contributors to present-day global mean sea level rise. Most previous global mass balance estimates for GICs rely on extrapolation of sparse mass balance measurements representing only a small fraction of the GIC area, leaving their overall contribution to sea level rise unclear. Here we show that GICs, excluding the Greenland and Antarctic peripheral GICs, lost mass at a rate of 148±30 Gt/yr from January 2003 to December 2010, contributing 0.41±0.08 mm/yr to sea level rise. Our results are based on a global, simultaneous inversion of monthly GRACE-derived satellite gravity fields, from which we calculate the mass change over all ice-covered regions greater in area than 100 km2. The GIC rate for 2003–2010 is about 30 per cent smaller than the previous mass balance estimate that most closely matches our study period. The high mountains of Asia, in particular, show a mass loss of only 4±20 Gt/yr for 2003–2010, compared with 47–55 Gt/yr in previously published estimates. For completeness, we also estimate that the Greenland and Antarctic ice sheets, including their peripheral GICs, contributed 1.06±0.19 mm/yr to sea level rise over the same time period. The total contribution to sea level rise from all ice-covered regions is thus 1.48±0.26 mm/yr, which agrees well with independent estimates of sea level rise originating from land ice loss and other terrestrial sources.

"Most previous global mass balance estimates for GICs rely on extrapolation of sparse mass balance measurements representing only a small fraction of the GIC area, leaving their overall contribution to sea level rise unclear" - that's where the uncertainty was. I hope the Guardian writers' disappointment doesn't last - there's bound to be some natural disaster or extreme weather event soon soon to give an opportunity to wheel out and polish their now time-worn and expected phrase "while it's not possible to ascribe any particular event to [global warming|climate change|rising sea levels] (choose one)" ..... and go on to effectively do just that. Good old Grauniad - at least they're predictable, unlike climate or weather.

So predictable, in fact, that they have to wheel out a Bristol University glaciologist, Prof Jonathan Bamber:

"I believe this data is the most reliable estimate of global glacier mass balance that has been produced to date," said Bamber. He noted that 1.4 billion people depend on the rivers that flow from the Himalayas and Tibetan plateau: "That is a compelling reason to try to understand what is happening there better."

He added: "The new data does not mean that concerns about climate change are overblown in any way. It means there is a much larger uncertainty in high mountain Asia than we thought. Taken globally all the observations of the Earth's ice – permafrost, Arctic sea ice, snow cover and glaciers – are going in the same direction."

Notice that? He says that "the most reliable estimate of global glacier mass balance that has been produced to date" means that "there is a much larger uncertainty in high mountain Asia than we thought". Silly me thought that reliable estimates reduced uncertainty. It just proves that I'm not cut out to be a glaciologist, especially one who clearly thinks that the "rivers that flow from the Himalayas and Tibetan plateau" rely almost exclusively on glacier melt. See the end of my post A Cool Look at Glaciers for a published refutation of that myth.

The study clearly supports what many have been saying for years - that studies of (at most) a few hundred of the estimated 150,000 glaciers worldwide are almost worthless, like attempting to assess population health by visiting hospitals. Few glaciologists (at least the vocal kind) seem to be interested in other than "sick" glaciers. That's what's wrong with so-called "mainstream" environmental and climate science (and reporting) - accentuate the unusual and ignore the normal.