The real budgetary emergency and the myth of "burnable carbon"

by David Spratt

How fast and how profoundly we act to stop climate change caused by human actions, and work to return to a safe climate, is perhaps the greatest challenge our species has ever faced, but are we facing up to what really needs to be done?

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Carbon budgets, climate sensitivity and the myth of "burnable carbon"
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No carbon left to burn (audio + slides, 17 minutes)

We have to come to terms with two key facts:  practically speaking, there is no longer a "carbon budget" for burning fossil fuels while still achieving a two-degree Celsius (2°C) future; and the 2°C cap is now known to be dangerously too high.


No Carbon Budget Left - David Spratt from Breakthrough on Vimeo.

For the last two decades, climate policy-making has focused on 2°C of global warming impacts as being manageable, and a target achievable by binding international treaties and incremental, non-disruptive, adjustments to economic incentives and regulations (1).

2 degrees hotter not an acceptable climate target but a disaster, say leading scientists

Countries round the world have pledged to try and limit the average global temperature rise to 2°C above pre-industrial figures. That’s way too high and would threaten major dislocations for civilization say a group of prominent scientists.

Lead author James Hansen

by Tim Radford, Climate News Network

Governments have set the wrong target to limit climate change. The goal at present – to limit global warming to a maximum of 2°C higher than the average for most of human history – “would have consequences that can be described as disastrous”, say 18 scientists in a review paper in the journal PLOS One.

With a 2°C increase, “sea level rise of several meters could be expected,” they say.  Increased climate extremes, already apparent at 0.8°C warming, would be more severe. Coral reefs and associated species, already stressed with current conditions, would be decimated by increased acidification, temperature and sea level rise.

Triggering permafrost meltdown is closer than we think

• Current levels of atmospheric carbon dioxide are probably sufficient to trigger large-scale permafrost carbon feedbacks and global warming that human effort would be unable to contain.

• The time to slash emissions was a long time ago but now is still much, much better than later, which may, as new studies suggests, simply become too late.

Thawing permafrost

Two future climate impacts above all others will overwhelm human efforts to mitigate global warming should temperatures and carbon dioxide levels reach critical levels, which in the latter case we are already close to achieving.
       The last time carbon dioxide levels were apparently as high as they are today — and were sustained at those levels — global temperatures were 3 to 6 degrees Celsius higher than they are today, the sea level was approximately 25 to 40 metres higher than today, there was no permanent sea ice cap in the Arctic and very little ice on Antarctica and Greenland.

What would 3 degrees mean?

David Spratt

The failure of international climate negotiations means that if all countries acted on ALL their commitments, the world would still warm by more than 3 degrees, according to Climate Tracker. 

So what would a world 3 degrees warmer llok and feel like? Scientists draw on a number of disciplines and methods to answer the question, including paleo-climatology (study of past climate history), complex mathematical models of the world's climate system tested and refined against past climate data, observation of current events and specific research testing hypotheses. Mark Lynas surveyed much of this research for his book "Six degrees: our place on a hotter planet" (Harper Collins, 2007). Drawing from his work and other sources, the following is an overview of some of the scientific projections as the world warms. These are not all certain events, but they are what scientific research thinks is likely. A full set of references on pp. 301-327 of "Six Degrees".

Three degrees of warming

Three degrees may be the “tipping point” where global warming could run out of control, leaving us powerless to intervene as planetary temperatures soar. America's most eminent climate scientist, James Hansen says warming has brought us to the "precipice of a great “tipping point”. If we go over the edge, it will be a transition to “a different planet”, an environment far outside the range that has been experienced by humanity. There will be no return within the lifetime of any generation that can be imagined, and the trip will exterminate a large fraction of species on the planet" ["Wild" magazine, April 2007].

A climate con: Analysis of the "Copenhagen Accord"

By David Spratt and Damien Lawson
21 December 2009
Climate Action Centre Briefing Note

''In biblical terms it looks like we are being offered 30 pieces of silver to betray our future and our people … our future is not for sale.'' Ian Fry, Tuvalu negotiator

"This is a declaration that small and poor countries don't matter, that international civil society doesn't matter, and that serious limits on carbon don't matter. The president has wrecked the UN and he's wrecked the possibility of a tough plan to control global warming. It may get Obama a reputation as a tough American leader, but it's at the expense of everything progressives have held dear. 189 countries have been left powerless, and the foxes now guard the carbon henhouse without any oversight." Bill McKibben, 350.org

Copenhagen reality check: 25% by 2020 isn't in the ball park

First published in Crikey, 4 November 2009

Climate policy analyst David Spratt writes:

Columnist David Roberts sees the Copenhagen climate change conference negotiating process so far as akin to "an aquarium full of hamsters connected to rudimentary motors. There's a lot of frantic running, a lot of sweat and heat, but in the end, very little light".

The dim light that does exists flickers on a target for Australia and the developed economies of reducing emissions by 2020 to 25% below the level of 1990.

In Bali two years ago, the European Union proposed a framework that included global emissions peaking in 10–15 years and for developed countries to achieve emissions levels 20–40% below 1990 levels by 2020. The United States, supported by Australia and others, strongly opposed this.

In a flood of tears and acrimony, the final Bali session sat through the night to produce a compromise that mandates "deep cuts in global emissions", with footnote references to the 2007 IPCC report which talks about the developed economies needing to reduce emissions 25 to 40% below 1990 levels to have a reasonable chance of holding warming to 2 degrees Celsius.

The Garnaut report quietly dropped the 40% end of the range and mischievously took 25% by 2020 as being a 2-degree target. The Rudd government followed in these footsteps and went for a 25% target, with highly conditional qualifications, in the revised CPRS in May, abetted by the ACTU-led Southern Cross Climate Coalition.

Now 2 degrees isn't the sort of target anyone with grandkids should aspire to. The research tells us that a 2-degree warming will initiate large climate feedbacks on land and in the oceans, on sea-ice and mountain glaciers and on the tundra, taking the Earth well past significant tipping points.

Likely impacts include large-scale disintegration of the Greenland and West Antarctic ice-sheets; sea- level rises; the extinction of an estimated 15 to 40 per cent of plant and animal species; dangerous ocean acidification and widespread drought, desertification and malnutrition in Africa, Australia, Mediterranean Europe, and the western USA.

You can bet your house that Copenhagen will not conclude with a 25% mandatory target for all the developed economies, but is it what we need to do, or is the whole of the Copenhagen process wrapped in an enormous delusion?

In September, researchers from Oxford and Germany's Potsdam Institute, produced figures on a carbon budget to 2050. In essence, they estimated how much carbon in total can be put in the air to 2050 if the aim is to not exceed 2 degrees.

From there it's not too hard to work out what each country needs to do, and that what's the Potsdam Institute Director Professor Hans Joachim Schellnhuber did in his recent presentation to the "4 Degrees and Beyond" conference in Oxford.

Assume the present population, and divide it into the total carbon budget and you get a budget per person to 2050. [This is based in the assumption that each citizen of the planet has an equal right to the budget, a proposition disputed by many in the developing world who rightly point to the historic carbon debt on which the developed world built their economies].



Nevertheless, by taking the per capita allocation to 2050 and comparing it to a nation's current annual emissions per person, you get a clear picture of national responsibilities, and that's what Schellnhuber did in a single chart.

Australia, like the USA, is top of the pops for per capita emissions.

If we maintain that rate, our carbon budget to 2050 runs out in five years. Five years!! Or put in another way, as the chart illustrates, Australia and the USA would need to be at zero emissions by 2020. Just follow the black line.

Not 25% by 2020, but 100% by 2020 for Australia. That's the science, unadorned. God forbid the politics.

Climate countdown

Last night, Monday 20 April 2009, I had an opportunity to debate the topic "Climate Change: What Should the Federal Government Be Doing?" with Kelvin Thompson, the Labor member for the federal parliamentary seat of Wills at a public meeting organised by the newly-formed Moreland Climate Group. The meeting was recorded and a DVD will be made available. Here are the comments I made in the opening half of the meeting. The two speeches were followed by almost an hour of energetic comments and Q and A. Thanks to Moreland Climate Group for putting on a great event, with more than 150 attending.

Thank you to Kelvin for engaging in this public conversation on climate between electors and their member of parliament. It is important to make this happen in electorates across the nation, for the conversations to be public rather than private.

The Intergovernmental Panel on Climate Change (IPCC) predicts a 2-to-6 degree Celsius temperature rise by 2100. But emissions are going up at an increasing rate and tracking on or above the IPCC's worst scenario, so we are headed for the high end if we keep on going as we are.

Yet neither major political party has a policy as to what the maximum safe temperature rise would be.

The Australian government has a "business as usual", high-emissions plan.
The Carbon Pollution Reduction Scheme outsources our responsibility, rewards the biggest polluters, and plans no sizeable reduction in national emissions in the next 40 years.

According to resources minister Martin Ferguson:

…although greenhouse gas reduction targets may be necessary, any frank review must conclude that the world’s greenhouse emissions are not going down in the short term: they are simply being shifted from one country to another.

Dr. Vicky Pope, head of climate change predictions at the UK Met Office’s Hadley Centre says that:

In a worst-case scenario, where no action is taken to check the rise in Greenhouse gas emissions, temperatures would most likely rise by more than 5 degrees Celsius by the end of the century.

So let's count down from 5 degrees.
.
5 DEGREES: In 2007, former PM John Howard told an ABC interviewer that an increase of 4–6 degrees Celsius would be "less comfortable for some than it is now" but "it's very, very hard for us... to sort of extrapolate what things might be".

Well, it's not that hard.

Five degrees of warming occured 55 million years ago: breadfruit trees grew on the coast of Greenland, while the Arctic Ocean saw water temperatures of 20 degrees Celsius. There was no ice at either pole (today that means a 70-metre sea-level rise), and much of the world would have been desertified.

Prof. Hans Joachim Schellnuhuber, Director of the Potsdam Institute and adviser to the European Union and to the German Chancellor, told the Copenhagen science conference in March that a rise to 5–6 degrees Celsius above preindustrial would reduce "the carrying capacity of the planet (to) below 1 billion people".

4 DEGREES: Sussan Ley, the federal liberal shadow for customs and justice told one of her constituents in a recent letter that "I agree with my colleagues that an acceptable increase in the mean temperature would be 1.8–4 degrees C." (see correction by Sussan Ley in comments)

At 4 degrees Celsius hundreds of billions of tonnes of carbon locked up in Arctic permafrost – particularly in Siberia – would melt, releasing methane and carbon dioxide in immense quantities, and make further human action to mitigate emissions futile.

In Europe, new deserts would be spreading in Italy, Spain, Greece and Turkey: the Sahara will have effectively leapt the Straits of Gibraltar. In Switzerland, summer temperatures may hit 48 degrees Celsius. The sort of climate experienced today in Marrakech will be experienced in southern England. Europe’s population may be forced into a “great trek” north.

3 DEGREES: 3 degrees Celsius is the cap effectively being advocated by Australia’s Labor government. Labor policy is a 60 per cent reduction in Australian emissions by 2050. Sir Nicholas Stern says explicitly that for developed nations this is a 3 degrees Celsius target, telling the National Press Club in Canberra it would be "a very good idea if all rich countries, including Australia, set themselves a target for 2050 of at least 60 per cent emissions reductions" and this would leave us with "roughly a fifty-fifty chance of being either side of 3 degrees above pre-industrial times".

This is the target that both Stern and Garnaut advocated, but Stern now says that “We haven't seen 3 degrees Celsius for a few million years, and we don't know what that looks like”. But from the Pliocene 3 million years ago we know what a 3 degrees Celsius world would likely be: a northern hemisphere free of glaciers and icesheets, where beech trees grew in the Transantarctic mountains, sea levels were 25 metres higher, and probably permanent El Nino conditions.

NASA climate chief Dr James Hansen (PDF) has warned that a 3 degrees Celsius warming "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 90 per cent of species on Earth went extinct".


2 DEGREES: I understand that Kelvin has suggested Australia should set a 2 degrees Celsius or 450ppm target.

2 degrees Celsius has been a target of convenience in international negotiations, but is now losing consensus as the politicians head to 3 and 4 degrees Celsius, and the scientists towards zero.

To have a 2 in 3 chance of holding to 2 degrees Celsius, atmospheric carbon needs to be held to 400ppm CO2e (carbon dioxide equivalent) and that requires a global reduction is emissions of 80% by 2050 (over 1990) and negative emissions after 2070. For Australia, a 2 degrees Celsius target means a more than 95% cut by 2050.

A rise of 2 degrees Celsius over pre-industrial temperatures will initiate large climate feedbacks in the oceans, on ice-sheets, and on the tundra, taking the Earth well past significant tipping points. Likely impacts include large-scale disintegration of the Greenland and West Antarctic ice-sheet; the extinction of an estimated 15– 40 per cent of plant and animal species; dangerous ocean acidification; increasing methane release; substantial soil and ocean carbon-cycle feedbacks; and widespread drought and desertification in Africa, Australia, Mediterranean Europe, and the western USA.

Hansen told the US Congress last year that: “We have reached a point of planetary emergency… climate is nearing dangerous tipping points. Elements of a perfect storm, a global cataclysm, are assembled… the oft-stated goal to keep global warming less than +2 degrees Celsius is a recipe for global disaster, not salvation.”

1 DEGREE: Today at just less than 1 degree Celsius of global warming we are witnessing of the destruction of the Arctic ecosystem. Eight million square kilometres of sea ice is disappearing fast each summer and may be entirely gone within a few years. Already 80% by volume of summer sea-ice has been loss, and regional warming of up to 5 degrees Celsius may have already pushed the Greenland ice-sheet (eventual sea-level rise of 7 metres) past its tipping point.

At less than 1 degree Celsius there is more frequent and intense heatwaves, ongoing drought in Australia, sub-Saharan Africa and the western US, and the swift retreat of river-feeding mountain glaciers. The eastern Amazon is drying (some tributaries ran dry in the 2005 drought), low-lying island states are on the edge of a precipice, as are coral reefs. Britain’s Hadley Centre calculates that warming of just 1C would eliminate fresh water from a third of the world’s land surface by 2100.

ZERO DEGREES: Yet we know that the present level of greenhouse gases is enough to increase temperatures by more than 2 degrees Celsius over time. We have already gone too far, there is already too much carbon in the air. At less than 1 degrees Celsius we are on the way to triggering a multi-metre sea level rise than will devastate coastal infrastructure, delta peasant–farming communities and some of the world's biggest cities.

Our only choice is to head back to zero degrees Celsius of warming, to halt all emissions and drawdown atmospheric carbon to return the planet to a safe-climate zone.



Schellnhuber, Europe's leading climate scientist, says that “we are on our way to a destabilisation of the world climate that has advanced much further than most people or their governments realise”, so “our survival would very much depend on how well we were able to draw down carbon dioxide to 280 parts per million”, compared to the present level of close to 390 parts per million.

Put starkly, we either keep warming under the range where carbon feedbacks become sufficiently pervasive as to make further human action futile, or we do not. We have a safe climate or we have a global catastrophe. There are no middle-of-the-road compromises. We must head back towards zero. At 1 degree Celsius the genie is out of the bottle, at 2 degrees Celsius the bottle is broken.

WHAT HAS TO BE DONE: Presently there is political denial, an arrogance of power that leads governments to believe that they can negotiate with the climate and the laws of physics and chemistry, a land of tradeoffs, where climate is just another issue, the politics partisan, and where the biggest polluters are appeased, all embedded in a culture of compromise and failure.

We are treating climate in the business as usual mode rather than the emergency mode with which we respond to fires and natural disasters. We faced by an overwhelming, human-caused "natural" disaster — global warming — yet our government fails to recognise this emergency.

An emergency exists when:

• events threaten to overwhelm
• when the outcome is often, like an election, binary (you either win or lose big time)
• when delay in action comes at a great price, even tipping the system into a different state
• when the imperative is to apply large amounts of resources quickly

This precisely describes the climate threat today.

We need an emergency transition plan, a whole-of-society plan, a vast remaking of how we live that is zero-carbon and sustainable; a just transition, a vast restructuring of jobs and skills and industry and economy. The obstacles to such a plan are not primary economic or tecnological, but political and social.

We have the technologies or they are within grasp. We have the economic capacity: $50 billion has just been spent on two stimulus packages, but not with a climate focus.

We have a Future Fund. Should we use it wisely now to make sure we have a future?I am sure governments do not want to go down in history as having saved the banks but not the planet.

Ian Dunlop, formerly a senior oil, gas and coal industry executive and CEO of the Australian Institute of Company Directors, says:

Honesty about this challenge is essential, otherwise we will never develop realistic solutions. We face nothing less than a global emergency, which must be addressed with a global emergency response, akin to national mobilisations pre-WWII or the Marshall Plan… This is not extremist nonsense, but a call echoed by an increasing numbers of world leaders as the science becomes better understood… In the face of catastrophic risk, emission reduction targets should be based on the latest, considered, science, not on a political view of the art-of-the-possible.

WHAT GOVERNMENT MUST DO

1. Be honest about the science, rather than the present approach of downplaying the severity of the problem and celebrating dinky achievement wrapped in delusional, up-beat rhetoric. Remember, Australia's emissions are still rising and the extra volume of coal flowing through two new export facilities, approved by Labor, will increase global carbon pollution by more than Australia’s total greenhouse gas output .
2. Government must have a frank conversation with the Australian people about the problem and how we can solve it together. Contrast the approach of the Australian and US energy Secretaries. US energy secretary Stehen Chu recently told Californians "We're looking at a scenario where there's no more agriculture in California (and) I don't actually see how they can keep their cities going" either, saying the need was billions of dollars for alternative energy research and infrastructure. Then look at Australian energy minister Martin Ferguson's love affair with coal, and his opposition to feed-in tariffs because "it is too early to be picking winners", when the government's "clean coal" initiative is precisely about "picking winners".
3. Start planning and implementing a rapid transition to a post-carbon economy. This requires:
   * Serious funding for safe climate innovation and scaling up of technologies, the drivers of change.
   * A large-scale national, all-sector energy efficiency and plan: many of the actions that can be taken today actually save money in the long-term. And an efficiency programme reduces the amount of new generating capacity to be built.
   * Constructing a smart grid for demand management and a new high-efficiency national grid to effectively hook renewables into the system. Even Garnaut recognise the need for such grids as a public responsibility due to market failure.
4. Plan and implement the rapid phase-out of the coal industry. The coal industry is a toxic asset. Carbon capture and storage is a cargo cult that cannot deliver in the relevant time frame and may not deliver at all. As Guy Pearce notes in his Quarterly Essay "Quarry vision", McDonalds employs twice as many people as the coal industry. We can have a coal industry or we we can have a planet fit for succeeding generations, but we cannot have both.
5. Spend the annual $9 billion subsidy the fossil fuel industry receives to start constructing some of the big building blocks of the post-carbon economy; for example an all-scale gross feed-in tariff to drive the construction of renewable capacity. Spend on public transport infrastructure what we spend on road infrastructure. Since 1996 the Victorian government has allocated more than $9 billion on road network expansion, and less than $2 billion on public transport infrastructure. Letss swap the columns.
6. Provide transformative political leadership. An opportunity exists within the Labor caucus, if not yet in the Cabinet, to stand with the climate action movement, to link people power with a courageous moral stance by parliamentarians. Recently I asked a former senior federal minister what it would take for a group of Labor parliamentarians to publicly argue that the scientific imperatives should be put first and campaign for a rapid transition to a post-carbon economy. The answer was simple: "Some people, including in cabinet, are going to have put their their career second".

What's up with emisions reductions of 25-40% by 2020?

The “25-40/2020” scenario was published in the IPCC’s 2007 Fourth Assessment Report Working Group III report, in Box 13.7 on page 776, “The range of the difference between emissions in 1990 and emissions allowances in 2020/2050 for various GHG [greenhouse gas] concentrations for Annex I and non-Annex I [Kyoto] countries as a group”, where targets were given for stabilisation at 450, 550 and 650 ppm CO2e.The targets for 450 CO2e were:

Region: Annex 1 countries
2020: –25% to –40%
2050: –80% to –95%
Region: non-Annex 1 countries
2020: Substantial deviation from baseline in Latin America, Middle East, East Asia and Centrally-Planned Asia
2050: Substantial deviation from baseline in all regions

25-40/2020 subsequently became a focus of debate at the COP 13 (Conference of the Parties to the UNFCCC) meeting in Bali in December 2007, and then the principal advocacy target in 2008 in Australia for organisations such as the Climate Institute, the World Wildlife Fund, the Australian Conservation Foundation and the Climate Action Network Australia, and for a number of climate scientists who entered the public policy debate. Garnaut talked about a 450ppm target requiring Australian emissions to be reduced to 25% below 1990 by 2020 (noticeably dropping the upper range of 40% range, a sleight of hand he was not alone in undertaking). So how might we assess such an advocacy proposal?

The temperature increase: Analysis for the 2006 Stern report (p. 195) shows that, taking uncertainty about climate sensitivity into account, a 450ppm CO2e target has:
• A 26–78% probability of exceeding 2 degrees
Celsius (˚C) relative to pre-industrial
• A 4–50% probability of exceeding 3˚C
• A 0–34% probability of exceeding 4˚C
• A 0–21% probability of exceeding 5˚C

Using a risk-management approach, it cannot be said that this is even a 2˚C target. And 2˚C is far, far too high, given the now clear evidence that at less than 1˚C of warming we are already on the precipice of climate catastrophe, from the Arctic to the Great Barrier Reef, from the Himalayas to Siberia.

Climate sensitivity: The work of the IPCC generally assumes a climate sensitivity (CS: that is, how much temperatures would increase with a doubling of GHG levels) of 3˚C. Whilst “short-term” CS is well established at 3˚C ± 0.5˚C, there is now a very convincing case that long-term climate sensitivity (including “slow” carbon feedbacks such as ice-sheet albedo, loss of ocean carbon-sink efficiency, loss of permafrost and other soil carbon, carbon release from tropical rainforests drying/ wild-fire, and so on) is closer to 6˚C. There is strong evidence in climate history of the last million years to support this view. This is recognised in the IPCC 2007 synthesis report which notes that “emissions reductions... might be underestimated due to missing carbon cycle feedbacks” (page 67) and this may require the cumulative emissions budget for the 21st century (the total amount of GHGs than can be emitted for a stabilisation level) to be “about 27% less” than is assumed. But the 25-40/2020 target and other IPCC emission reduction scenarios do not include this consideration!

On carbon cycle feedbacks, there is already evidence that the strength of ocean, and especially some land, carbon sinks are weakening and becoming less efficient, and that this will persist into the future. Thus the predictions from climate-carbon- cycle models may be too conservative and CO2 in the atmosphere will probably increase more rapidly than the models suggest, which has implications for the development of policies that seek to stabilise atmospheric CO2 at a given level, including those of the IPCC (Cox & Jones).

The IPCC gives a CS range of 1.5–4.5˚C and warns that “policymakers may want to use the highest values of climate sensitivity... to guide decisions” (and virtually admits it is higher than the 3C the IPCC chooses to assume). This precautionary warning has apparently been ignored by those who advocated the 25-40/2020 target during 2008.

If long-term CS is 6˚C, then 450ppm would produce a temperature increase of 4.1˚C, enough to melt all ice sheets and produce a 70-metre sea-level rise, amongst many impacts that would end life on this planet for most people and most species.

After a careful reassessment of climate sensitivity and climate history data, James Hansen and his co-authors concluded in a 2008 research paper that the tipping point for the presence, or absence, of any substantial ice-sheets on Earth is around 450 ppm (plus or minus 100 ppm) of CO2. This means that the CO2 levels often associated with a 2˚C rise may just be the tipping point for the total loss of all ice sheets on the planet and a huge sea-level rise. Yet this is what the principal advocacy was by “our” side in 2008!

[For a more detailed discussion of climate sensitivity, see the discussion on pages 15-16 of the
Climate Safety report published in late 2008 in the UK]The impacts: 450ppm CO2e is roughly the current GHG level, and in 2008 Ramanathan and Feng found that if greenhouse gases were fixed at their 2005 levels (and assuming the IPCC CS of 3˚C), the inferred warming is 2.4˚C (range 1.4˚C to 4.3˚C) and that 2.4˚C would be sufficient to result in the loss of Arctic summer sea-ice, the Himalayan–Tibetan glaciers and the Greenland ice-sheet (based on Lenton et al). The loss of Greenland ice sheet produces about a 7-metre global sea-level rise. One conclusion is that advocacy of the 20-40/2020 target, for example by the ACF in its 2008 Special Places campaign, will result in the destruction of many of Australia’s “special places” ACF wants to protect; Kakadu, for example, will salinate with a sea-level rise of less than a metre.

The scenario is out of date. The scenarios in IPCC 2007 WGIII Box 13.7 were prepared in 2005 or earlier.
• The 450ppm scenario relies heavily of the work of Del Elzen and Meisnhausen, presented at a 2005 UK Met conference (and then published as chapters 28 and 31 in Avoiding dangerous climate change, Schellnhuber (ed.), CUP). Since then, emissions from non-Annex I nations have grown beyond all expectation, which means that emission reductions scenarios need to be re-visited.
• Thus in recent powerpoints, Meinshausen has crossed out the words “Substantial deviation from baseline in Latin America, Middle East, East Asia and Centrally-Planned Asia” and pasted over “–15% to –30% by 2020” for non-Annex 1 nations, a recognition that the 2007 propositions need re-working.
• In addition, the IPCC methodology (and emissions reduction scenarios generally) implies that climate change is a linear event, where predictable changes in emission levels will have predictable outcomes and impacts. But events such as the “big melt” in the Arctic summer of 2007 are non-linear and unpredicted events that can turn climate science knowledge on its head and demand that the whole question of what needs to be done and what are appropriate targets be urgently re-assessed in light of new data, including evidence that carbon cycle feedbacks are kicking in sooner than expected. The Arctic shows that tipping points for dangerous climate change and large sea-level rises have already been passed, a fact that the IPCC did not recognise in failing to include any emission scenarios for less than 2–2.4˚C in its 2007 report.
• It is noteworthy that IPCC author Bill Hare, in the climate chapter for the 2009 State of the World report, includes detailed modeling by the Potsdam Institute for Research on Global Warming Effects of a 1-degree stabilisation scenario (the first I have seen), and sketches the actions for a 300 ppm target. It will be interesting to see if Hare’s views, which in the past have been influential in groups such as CANA and Greenpeace, will be embraced.
• Potsdam Institute head Hans Joachim Schellnhuber says previous predictions about climate change and its catastrophic effects were too cautious and optimistic. “In nearly all areas, the developments are occurring more quickly than it has been assumed up until now,” Schellnhuber told the Saarbruecker Zeitung newspaper in an interview published on 29 December. “We are on our way to a destabilization of the world climate that has advanced much further than most people or their governments realize.”
A safe-climate target

James Hansen told scientists at an American Geophysical Union conference in December 2007 that: “We either begin to roll back not only the emissions [of CO2] but also the absolute amount in the atmosphere, or else we’re going to get big impacts ... We should set a target of CO2 that’s low enough to avoid the point of no return.” In order to achieve the return of the Arctic sea-ice, we have seen above that Hansen and his co-authors have identified the target as in the range 300–325ppm CO2, well below the current level. Given the key role the Arctic plays in the global climate system, a precautionary approach would therefore suggest a long-term target of 300ppm CO2e.

This would rule out a domino effect of sea-ice loss, albedo flip, a warmer Arctic, a disintegrating Greenland ice sheet, more melting permafrost, and further knock-on effects of massively increased greenhouse gas emissions, rising atmospheric concentrations and accelerated global warming.

Any proposal for a target higher than 300ppm would imply confidence that it is safe to leave the Arctic sea ice melted, and an assumption that this would not bring about the train of consequences just described. This is, implicitly, the view of all the major nations and organisations involved in setting climate policy. Accordingly, they must be challenged to provide a reasoned argument as to why leaving the Arctic Ocean free of ice in summer is safe. If they cannot, the only acceptable course of action is clear.

David Spratt
March 2009