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Monbiot–Hamilton debate

An engaging debate has followed a review of George Monbiot's "Heat" by Clive Hamilton in "New Left Review", especially in regard to targets and timelines.

Hamilton's review: "Building on Kyoto"
http://www.newleftreview.org/?page=article&view=2671
New Left Review 45, May-June 2007
"Monbiot has decided that his task in Heat is to achieve emission reductions that might prevent the globe warming by more than two degrees: a more ambitious target than most" .

Monbiot: "Environmental feedback- a reply to Clive Hamilton"
http://www.newleftreview.org/?page=article&view=2672
George Monbiot,  New Left Review 45, May-June 2007
"Hamilton says that seeking to prevent two degrees of warming above pre-industrial levels is ‘a more ambitious target than most.’ That is not correct. An upper limit of 2°C is the European Union’s stated target, which informs the carbon reductions planned by the UK and most of the governments making serious efforts to tackle climate change.

David Spratt: More ambitious than most? (18 June 2007)
A response to Clive Hamilton's review
"At a time when the ALP, following Stern, is (unofficially) focussed on a 3 degree target, reading a leading climate change researcher and commentator appearing to say that 2 degree target is "more ambitious than most" and that 440ppm is based on the work of amateurs will make the heart race."

Hamilton: Fear of Climate Change: A rejoinder to George Monbiot (6 July 2007)
http://www.tai.org.au/documents/downloads/WP103.pdf
"If the scientists are right, the consequences of a three-degree increase in global temperature are almost too horrible to contemplate, but contemplate them we must. "

David Spratt: Is our silence consent? (9 July 2007)
"So what do we say about Labor's 3-degree target? Should we say what Hansen says about 3 degrees? Should we say it means the end of the planet as we know it, the loss of a fair proportion of the human population and most species? Or should we follow the lead of the ACF and many of the peak green organisations in simply being silent about Labor's horrible policy shortcomings till after the election?"

More ambitious than most?

Dear Clive,

Your review says in one complete sentence that "Monbiot has decided that his task in Heat is to achieve emission reductions that might prevent the globe warming by more than two degrees: a more ambitious target than most".

I read this at face value that your view is that 2 degrees is a "more ambitious target" than "most" (presumably governments, climate change scientists, etc) say is necessary. I am not sure how else this statement can be read. The implication to me is that being "more ambitious than most" means it is beyond the mainstream debate, which as a target it clearly is not, and that some less ambitious target may be reasonable.

My understanding is that the serious (non-sceptics) scientific community, various UN bodies, the EU and a number of European states amongst others have all adopted the 2 target, so I am not sure who "the most" in the public arena are, except those who have gravitated to Stern's 3 degree target. Who are "the most"?

Monbiot's emission reduction's scenario and it's timeline may be more more ambitious than others, but this not what the statement in question says. If you had said his timeline is "more ambitious" than most, than would be generally true, but that is not how I or I think most readers would understand your words, which unambiguously relate to the 2 degree target.

And rather than being "more ambitious than most", I believe many researchers view it as a political compromise, are far from safe. As Simon Retallack of the IPPR notes: "It is important to understand that a 2°C rise itself is not ‘safe’, and does not represent an ideal to be reached, but rather an upper limit which must not be exceeded. A 2°C warming would be a magnitude of warming greater than any that human civilisation has ever experienced. We would need to return to the Milocene era, some 5–25 million years ago, to find a climate that is warmer than today’s by more than 2°C. Modern man, meanwhile, is only thought to have entered into existence about 120,000 years ago."

On the issue of stabliization levels, you write: "That this target requires stabilizing greenhouse gas emissions at the equivalent of 440ppm of carbon dioxide is suggested to Monbiot in an unpublished paper, sent by a man who—he concedes—‘is not a professional climate scientist but [who] appears to have done his homework’, with supporting evidence from the Potsdam Institute for Climate Impact. My understanding is that Meinshausen from Potsdam did much of the emissions trajectory work for Stern, so to suggest that 440ppm relies for authority on an unpublished paper is somewhat colourful and suggestive, as if Monbiot is outside the mainstream on this.

I am not clear whether this is 440 CO2 or CO2e, but in either case I believe there is a wide body of research that would support this as being a reasonable view and certainly not relying on amateurs.

For example, Retallack in "Setting a long-term climate objective" for the International Climate Change Taskforce in which you participate, says: "To have an 80% chance of keeping global average temperature rise below 2°C, this paper concludes that greenhouse gas concentrations would need to be prevented from exceeding 450-500ppm CO2-equivalent in the next 50 years and thereafter should rapidly be reduced to about 400ppm CO2-equivalent. If, in attempting to achieve that, non-CO2 emissions are as significantly constrained as CO2, levels of CO2 alone would probably need to be stabilised at about 360ppm."

Meinshausen says that ""The results indicate that a 550ppm CO2 equivalent stabilization scenario is clearly not in line with a climate target of limiting global mean temperature rise to 2°C above pre-industrial levels. Even for the most ‘optimistic’ estimate of a climate sensitivity PDF, the risk of overshooting 2°C is 68% in equilibrium. Second, there is also a substantial risk of overshooting extremely high temperature levels for stabilization at 550ppm CO2eq. Assuming the climate sensitivity PDF, which is consistent with the conventional IPCC 1.5°C to 4.5°C range, the risk of overshooting 4°C as a global mean temperature rise is still 9%. Assuming the recently published climate sensitivity PDF by Murphy et al., the risk of overshooting 4°C is as high as 25%. Third, risks of overshooting 2°C can be substantially reduced for lower stabilization levels. In this paper, two emission pathways that lead to stabilization at 450ppm and 400ppm CO2eq are presented and analyzed. In the latter case, seven out of eight climate sensitivity PDFs suggest that the chance of staying below 2°C warming in equilibrium is “likely” based on the IPCC Terminology for probabilities. For stabilization at 450ppm CO2 equivalence, the chance to stay below 2°C is still rather limited according to the majority of studies, namely “medium likelihood” or “unlikely”. (“On the risk of overshooting 2 degrees Celsius”).

And "To have a ‘very low to low risk’ (calculated as a nine to 32% chance) of exceeding the 2°C threshold, global emissions of carbon dioxide (CO2) would need to peak between 2010 and 2013, achieve a maximum annual rate of decline of four to five% by 2015-2020, and fall to about 70 to 80% below 1990 levels by the middle of the century. This would need to be matched by similarly stringent reductions in the other greenhouse gases. These calculations are based on scenarios in which atmospheric concentrations of CO2, which stand at 380 parts per million (ppm) today, peak at between 410-421ppm mid century, before falling to between 355- 366ppm by 2100. This in turn is based on the understanding that CO2 concentrations can be reduced by lowering annual emissions below the level of CO2 which is absorbed by global carbon sinks, which currently take up approximately half of the CO2 emitted annually by human activity.' (Baer and Mastrandrea ""High Stakes: Designing emissions pathways to reduce the risk of dangerous climate change", IPPR).

My axe to grind... my reading of your article was that you characterised 2 degrees and 440 ppm as being too ambitious and not credible respectively. You have said this is not so and I accept that of course. But I hope you will see how your words will be read, despite your intention. I am not alone in reading it this way.

At a time when the ALP, following Stern, is (unofficially) focussed on a 3 degree target, reading a leading climate change researcher and commentator appearing to say that 2 degree target is "more ambitious than most" and that 440ppm is based on the work of amateurs will make the heart race.

Sincerely

David Spratt
18 June 2007

------

David

Thanks for your considered reply. My objection was to the demanding tone of your original piece rather than the content the argument.  I can see that my words on the 'ambitious target' were poorly chosen and very much open to being taken in a way I had not intended. I am writing a response to the Monbiot reply, trying to clarify my position. I will send it to you.
 
Cheers
Clive
25 June 2007

Is our silence consent?

Dear Clive,

You write in "Fear of Climate Change: A rejoinder to George Monbiot": "A concentration target of 400 ppm CO2-e equates to a target of around 350-375 of CO2.   The current concentration is 380 ppm. In short, we are already past the two degree  threshold, and will without question go well beyond it." 

This statement is, I believe, incorrect and unnecessarily pessimistic because it confuses short-term (peak) and long-term (decline) trajectories and targets, and does not take fully into account the time lags due to thermal imbalance. We are not "already past the two degree  threshold", though we are getting close. All the "safe" emissions trajectories of Baer, Meinshausen, Hansen etc incorporate  "initial peak" and the "long-term" stablisation level that you appear not to have not taken into account in your comment. 

As I understand it, of the forcings produced by rising CO2 levels, only about half are manifested as rising temperatures within 25 years,  another quarter takes 150 years, and the last quarter many centuries to manifest. James Hansen says: "The climate system has inertia. Nearly full response to a climate forcing requires decades to centuries".

Paul Baer in "High Stakes" (IPPR 2006) notes: "because of the time lag between the increase in GHG concentrations and the increase in temperature – what we call 'thermal inertia' – the atmosphere need never reach the maximum level of temperature 'implied' by the GHG concentration peak (the long-term temperature that would be reached if CO2-equivalent concentrations were held at that peak level indefinitely). The faster and further that GHG concentrations can be lowered below their peak, the lower will be the peak temperature increase that is eventually reached."

Meinshausen makes this explicit in " KyotoPlus - Papers  <2°C Trajectories – a Brief Background Note": "Fortunately, the fact that we are most likely to cross 400ppm CO2eq level in the near-term, does not mean that our goal to stay below 2°C is unachievable . If global concentration levels peak this century and are brought back to lower levels again, like 400ppm, the climate system's inertia would help us to stay below 2°C. It's a bit like cranking up the control button of a kitchen's oven to 220°C (the greenhouse gas concentrations here being the control button). Provided that we are lowering the control button fast enough again, the actual temperature in the oven will never reach 220C."

Thus for 70-90% chance of staying below 2 degrees Meinshausen talks of an "initial peak at 475ppm CO2eq " for the long-term return to "400ppm CO2eq stabilization scenario".  Meinshausen in "On the Risk of Overshooting 2°C"  notes: "Due to the inertia of the climate system, (which is generally thought to be greater, the higher the real climate sensitivity is [24, 25]) the peak of  3.14W/m2 in radiative forcing before the stabilization at 450ppm CO2eq (2.58W/m2) does not translate into a comparable peak in global mean temperatures. However, for the presented 400ppm CO2eq stabilization scenario, the initial peak at 475ppm CO2eq seems to be decisive when addressing the question of whether a 2°C, or any other temperature threshold, will be crossed (see Figure 5)."

James Hansen's "alternative scenario" first published in 2000*  seems similar to Meinshausen: he aims to keep warming to under 2 degrees by holding ghg levels below 450ppm CO2 [approx 70ppm ABOVE their present level]  by limiting the CO2 increase between 2000 and 2050 to 75ppm CO2 in total, and then allowing a quick decline emissions so that the long-term stablisation is under 2 degrees. 
* ["Global warming in the twenty-first century: An alternative scenario" by James Hansen, Makiko Sato, Reto Ruedy, Andrew Lacis, and Valdar Oinas]

Likewise, Paul Baer in "High Stakes" notes that "The research concludes, based on a reasonable set of assumptions, that to have a 'very low to low risk' (calculated as a nine to 32 per cent chance) of exceeding the 2C threshold, global emissions of carbon dioxide (CO2) would need to peak between 2010 and 2013, achieve a maximum annual rate of decline of four to five per cent by 2015-2020, a nd fall to about 70 to 80 per cent below 1990 levels by the middle of the century. This would need to be matched by similarly stringent reductions in the other greenhouse gases...  These calculations are based on scenarios in which atmospheric concentrations of CO 2, which stand at 380 parts per million (ppm) today, peak at between 410-421ppm mid century , before falling to between 355- 366ppm by 2100. This in turn is based on the understanding that CO2 concentrations can be reduced by lowering annual emissions below the level of CO2 which is absorbed by global carbon sinks, which currently take up approximately half of the CO2 emitted annually by human activity. "

ONE OTHER QUESTION: You write that "Even three degrees is looking very hard to avoid" and that "If the scientists are right, the consequences of a three-degree increase in global temperature are almost too  horrible to contemplate, but contemplate them we must."  Some people will interpret this as meaning that "we" should consider 3 degrees as a policy target. I presume from your unambiguous statements about the 2-degree target that this is not the case. 

But in does raise an important issue. The ALP, following Stern, has unofficially adopted the 3 degree target. What should we as climate activists say about this?

My view is that a 3-degree  target is a death sentence, partly because it cannot be  a target, but only a sign-post on the way to something much worse. As James Hansen told the SOLAR 2006 Conference on Renewable Energy in Denver on 10 July last year: "An important point is that there is a clear dichotomy between the (Hansen's) Alternative Scenario, which keeps additional global warming under 1°C, and warmer scenarios. If warming is less than 1°C, within or near the range of the warmest interglacial periods, we know that feedbacks such as release of methane hydrates from melting tundra or from the continental shelves are only moderate positive feedbacks. But if global warming becomes larger than that, all bets are off. In past large warming events in the Earth’s history at least half of the warming was probably caused by such a positive feedback. To achieve the Alternative Scenario, with warming of less than 1°C, requires that methane and tropospheric ozone decrease. But if warming exceeds that, we are likely to get substantial positive feedbacks and these gases will increase. So there seems to be a dichotomy. We either keep the warming small or it is likely to be quite large."

Many times, Hansen has warned that  two-to-three degrees would produce a planet without Arctic sea ice, a catastrophic sea level rise in the pipeline, and super-drought in the American west, southern Europe, the Middle East and parts of Africa: "Such a scenario threatens even greater calamity, because it could unleash positive feedbacks such as melting of frozen methane in the Arctic, as occurred 55 million years ago, when more than ninety per cent of species on Earth went extinct".

Despite this, three degrees is fast being adopted as the new target, the relative safety of the two-degree limit put aside.  In his 2006 report to the British government,  Stern declared keeping the rise to two degrees as "already nearly out of reach" because it meant emissions "peaking in the next five years or so and dropping fast", which he judged to be neither politically likely nor economically desirable. Three degrees was a more practical target, and Stern nominated the appropriate emissions reduction plan a limit of 550ppm CO2e, and 60 per cent by 2050. In his 3-degree footsteps file Kevin Rudd and Ross Garnaut, appointed by Rudd to do a Stern report for Australia, but saddled with the answer before he has researched the question.  I don't think anybody now doubts that Stern's target of 550 ppm and 60/2050 target for  a high polluting nation is a 3-degree target. And for Rudd. 

This view is shared by Dr Brian Fisher, Australia's lead delegate to the May 2007 IPCC meeting, who says the two-degree target, with emissions peaking by 2015, "is exceedingly unlikely to occur... global emissions are growing very strongly... On the current trajectories you would have to say plus three degrees is looking more likely."

The shift is plain in the most recent IPCC report. Of the 177 research scenarios assessed for future emissions profiles, only six dealt with limiting the rise to the range of 2 to 2.4 degrees. By contrast, 118 covered the range of  3.2 to 4 degrees, which suggest that the IPCC researchers have also largely shifted focus from two degrees.  

We know that two degrees is already disastrous.  Today, at less than one degree, the floating ice at the north pole is disappearing fast, likely to be gone within a few decades; and we are close to the tipping point when the Greenland ice sheet starts the irreversible melting that will lift sea levels by five to seven metres, in as little as a 100 years according to Hansen. At two degrees it will be too late for Greenland, and over a third of species will be committed to extinction.  

The peer-reviewed research suggests that in a three-degree world vast amounts of dead vegetation stored in the soil – more than double the entire carbon content of the atmosphere – will be broken down by bacteria as soil warms. The carbon cycle will be thrown into reverse so that vegetation and soils start to release carbon dioxide instead of absorbing it, boosting global warming by another 1.5 degrees. Three degrees becomes four to five.

We all agree that it was right to criticise the government for its lack of target, for Howard's comment that it is "crazy and irresponsible.... to commit to a target when you don't know the impact " and for Howard's revealing answer on Lateline earlier this year when he said that 5 degrees would be "less comfortable for some than it is now".

So what do we say about Labor's 3-degree target? Should we say what Hansen says about 3 degrees? Should we say it means the end of the planet as we know it, the loss of a fair proportion of the human population and most species? Or should we follow the lead of the ACF and many of the peak green organisations in simply being silent about Labor's horrible policy shortcomings till after the election?

I was discussing this matter with my companion over dinner recently. Her academic field is music, not politics or climate change. After patiently listening to my exposition on the great quietness from the peak greens on ALP policy, she simply responded:  "If you don't get decent policy commitments out of a party before an election, is anyone still naive enough to believe that after the election they will deliver more than they promised ?"

Indeed. That really is the question.  On Labor's policy, is "our" silence consent to a policy which if implemented would produce catastrophe?

David Spratt
9 July 2007