Responses to the 'Carbon Budget Accounting Tool' (CBAT)

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Ernst von Weizsacker
Chairman of the Club of Rome: -

"Fine tool for a gruesome reality-forecast."

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Julian Salt
Insurance Consultant: -

"For negotiators to make the next steps more effective, they have to not only grapple with the rising tide of man-made emissions, but also the far more important issue of feedback emissions (both natural and induced).

This CBAT model created by Aubrey Meyer encapsulates this issue in his usual style of beautiful imagery that at a glance will show any negotiator the seriousness of the problem at hand.

CBAT will at a stroke negate all present emissions targets as futile and force them to reconsider the whole issue from a global perspective. As past efforts have shown, if this approach is not taken another 10-20 years will be wasted in more UNFCCC meetings.

I commend this model to any agency that cares to listen and act on his findings."

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David Wasdell
Chairman of the Apollo Gaia Group: -

"We recognise that GCI has made a unique breakthrough in creating a user-interactive, non-directive dashboard with potential to simulate such an inclusive range of the system dynamics of the natural/human interaction! Separating the contribution to CO2 concentrations driven by anthropogenic emissions from the contribution coming from the feedback system is brilliant at a conceptual level." 

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Bill McGuire
Professor of Geophysical & Climate Hazards, University College London [UCL]
Director UCL's Aon Benfield UCL Hazard Centre [1997 2010]: -

"The failure of IPCC5 and the [UKMO's] UK Climate Act to address the critical issue of carbon feedbacks, particularly in relation to methane release as a consequence of permafrost thawing, is both disappointing and dangerous.

By effectively setting the likely consequences of such feedback effects at zero, future temperature projections are minimised, so pandering to those who wish to play down the level of warming we can expect and reducing the perceived impact of climate change down the line.

By separating out the effects of human-induced and feedback-related emissions, the GCI's brilliant CBAT visualisation tool sidesteps the wishful thinking and provides a sharp dose of reality.

I urge all who wish to view a true picture of how climate change will transform our world as the century progresses to use it and promote it."

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Professor Michael Mainelli
Gresham College, Long Finance & London Accord: -

"This truly is a most wonderful device. 
Chiara and I will promote it via Long Finance’s London Accord.

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Jelle Hielkema
Ex UN FAO Remote Sensing & author the 'Rainbow' Website

Coming from Music, the purest expression of Nature, Aubrey Meyer has put his energies for the last 24 years into formulating, giving shape to and also getting very substantial support for, a solution to the challenge presented by the global climate changes which we are all now facing and which so seriously threaten our future.

This solution is called 'Contraction and Convergence (C&C).

No-one has framed and communicated the response strategy for negotiating and achieving compliance with the objective of the UNFCCC [if we can still achieve it], more perfectly than Aubrey Meyer with the C&C concept and comapign and support for this is already extensive and diverse.

Here C&C has been developed into the rigorous 'Carbon Budget Analysis Tool' (CBAT). Having done-the-maths, this peerless and quite beautiful heuristic device is user-interactive in a user-friendly way.

The CBAT's user's two main controls are: -

[1] a vertical slider for the 'carbon-weight' of emissions budgets and atmospheric concentrations, [the fundamental challenge facing UNFCCC negotiators] and

[2] a horizontal slider for inter-regional convergence rates for emissions budgets across time [the challenge arising for the negotiators - how to share that budget].

Together with various other controls for a range of different budgets, feedback types, levels of climate-sensitivity and consequential values for temperature, sea-level rise and ocean acidity, it brings a high degree of strategic clarity to the policy debate that has been completely lacking so far. So I wholeheartedly recommend its use to the concerned public and the policy community.

Domain One - Contraction and Concentrations – quantitatively analyses the relationship between possible future greenhouse gas emissions scenarios and how these might accumulate in future atmospheric concentrations paths, especially in the light of potential runaway feedback effects.

Domain Two - 'Contraction and Convergence - captures any of the Carbon Contraction Budgets chosen in Domain One and gives users the choice of setting any start-date and any end-date for any 'convergence window' inside any of those contraction rates.

CBAT is default programmed with three carbon-budgets HI LOW & MEDIUM [MEDIUM is equivalent to the UK Climate Act]. However any carbon-budgets can be programmed into CBAT and it will simply analyse and display whatever carbon budgets it is presented with.

This is appropriate as CBAT is primarily a 'policy-model' rather than a climate-model.

Another compelling feature of the version of CBAT already online and working, will soon be tabulated numerical values of the choices made combing Domains One and Two. These users will be able to summon at will.

Having been aware of the development of CBAT since late 2011, I am really looking forward to the addition of the two remaining Domains - Contraction and Conversion and Damages and Growth - thus bringing to completion this unique and ingenious conceptual tool.


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Jeffrey Newman
Rabbi Finchley Reform Synagogue: -

"Aubrey is an incomparable thinker."

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Dr Mayer Hillman
Senionr Fellow Emeritus Policy Studies Institute

The complementary roles of the Global Commons Institute’s
Contraction & Convergence framework & Carbon Accounting Budget Tool

The time for equivocation should be long over. International agreement has to be speedily reached on the weight of the global carbon budget remaining if we are not to breach the ceiling of no more than a 2 degree C rise in the global temperature – now generally considered to be the level above which the rise cannot be reversed. The longer the delay in attempting to avoid this situation, the greater is the likelihood that that will not be possible.

Determination of that budget should obviously precede, not follow, discussion of such current issues as:

  • whether democratic governments around the world are right in seeing one of their main functions as, within reason, treating public demand as a given to be met as efficiently, cost-effectively and in the least environmentally-damaging way as is now possible;

  • justification of the use of nuclear power instead of fossil fuels in electricity generation;

  • the extraction of gas by ‘fracking’ to ease the transition from coal to total dependence on renewable sources of energy;

  • the extent to which individuals can be encouraged to reach decisions that take account of their adverse consequences, such as travelling long distances or having a large family.

The need for consensus on the budget is rendered all the more urgent given the more than four-fold difference in the calculated weight and rates of carbon budgets put forward by the climate scientists considered to be among the most eminent in their field – for instance, the central budget of the UK 2008 Climate Act, [395 Gt C], that in last autumn’s Inter-governmental Panel on Climate Change (IPCC) report [250 GtC] and that of James Hansen [170 GtC] where the ceiling is no more than a rise of 1.5 degrees C. Yet, remarkably, the UK Government rejects the call for it to revise its dates and targets for the reduction in emissions set down in its Act.

Concern should be growing internationally about the lack of agreement on the budget. There can be little doubt that, at such a critical time in our history, scientifically-based rather than politically-based decisions affecting the future must be taken. This is especially true as the scale of the societal changes needed is so challenging, and certainly as further delay in responding to this can only result in reducing the time available for reason to prevail and effective action to be taken.

Equally remarkably, is the fact that international Governments represented at the last two UN Conference of the Parties (COP) meetings appear to be content with the proposition that the next major step to be taken in negotiations aimed at reaching decisions to avoid ecological catastrophe is an undertaking that, at the Paris COP in 2015, each country will come to the table with a figure on the contribution in terms of carbon reductions that is prepared to make!

In the late 1980s, Aubrey Meyer, at the time an accomplished violinist and composer, was attracted to writing an opera based on the life and murder of Chico Mendes, a Brazilian who devoted what proved to be his last years to trying to protect the tropical rainforests from destruction by developers. In exploring themes for the opera, he was inevitably drawn to the role of rainforests in changing the climate and to understanding related ecological issues.

In 1990, Meyer co-founded the Global Commons Institute (GCI) and, since then, has been the prime source of the Institute’s activities and campaigning. He has seen its role as providing a rational response to the challenge laid down in the objective and principles of the United Nations Framework Convention on Climate Change (UNFCC).

To that end, he has worked on the development of the concept of Contraction and Convergence (C&C) based on the principle of ‘Equity and Survival’, repeatedly arguing that the measure of any strategy aimed at limiting the damage of climate change must ab initio have a numerate framework and that, in its absence, the way forward cannot be adequately devised. The C&C concept is explained in one of the Schumacher Briefings [Green Books, 1998].

Recognition of Meyer as one of the most influential persons in this crucial area of international and national policy is reflected in the impressive number of awards he has received.

Most recently, Meyer has turned his attention to taking the concept of C&C to a stage allowing for evaluation of any strategy with a stated global carbon budget and of revealing its outcomes. He has logically given it the title of a Carbon Budget Accounting Tool (CBAT).

CBAT's primary components are the concentration of carbon dioxide and methane in the atmosphere, the temperature, the sea-level rise, ocean acidity, and crucially the regional, national and per capita shares of the budget in any year up to the year at which the ceiling will be reached.

Four domains are covered in the model:

  • Contraction and Concentrations;

  • Contraction and Convergence;

  • Contraction and Conversion; and

  • Damages and growth.

Anyone applying the tool will recognise it is a quantum leap in developing guidance for a UNFCCC-compliant international climate agreement. It is extremely user-friendly as it enables climate scientists and policy makers to make carbon-budget choices and come face-to-face with the consequences of these choices. As far as I am aware, no one else has proposed an equivalent tool, let alone one that can be seen to be preferable to CBAT. Once a carbon budget is set, the application of this model will point the way to focusing the strategic debate on how the sharing of the budget is to be negotiated internationally. It allows implementation of transition measures to evolve, subject to the limit for compliance with the objective of the UNFCCC.

This then leaves two options open to those seriously concerned about the world’s predicament in relation to the rate of progress in climate change negotiations and the current failure to act decisively on it. Either CBAT is accepted and applied as soon as possible, or it is rejected.

If we are to avoid further procrastination, as seems unlikely, the latter option logically points to an obligation on those objecting to it to provide a justification for doing so, together with a proposal in favour of what they consider to be a better alternative. This can then be comparably evaluated. Failure to adopt either option can only be interpreted as an indication of acceptance of the policies being pursued at present as the best in the circumstances.  

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Tim Smit
CEO The EDEN Project

“For most of us the world is an inconceivably big place and the word global, while swank and important sounding conveys little or nothing in terms of emotional charge.

Inertia and mute impotence are sometimes the only honest response you can make, because what can an individual do in the face of such figures with so many numbers you go dizzy looking at them let alone understanding them.

The great gift of this web-site and the tireless work of Aubrey Meyer is that you get a sense that out of the haze a roadmap is presenting itself and it speaks to the most powerful instinct we have – our need for meaning and its close cousin-optimism.

Here is evidence that we are engaged in a great game called our future and the odds, while stacked against us, can still be won. To look at the future and know it is still ours to make is a powerful incentive indeed.

It is now simply a question of whether the name we gave ourselves…Homo sapiens was accurate or a monumental act of vanity…now that is a challenge worth rising to…congratulations.”

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Laurie Barlow
AIA San Marino, California United States of America L Barlow & Company: -

"CBAT is truly excellent! Just an incredible tool.

It's showing the interconnectedness of the three factors (temperature, acidity, and sea level) with a graphic user interface, which nobody else has done. I don't think too many people "do the math" correctly, it requires an iteration of calculations and an examination of the different scenarios to understand the impact of 450 PPMV as a "runaway" scenario, and how many Gt C's per year have to be reduced in order to avoid it. This escapes the political posturing and goes directly to the analysis of the problem in such a way that people can understand the consequences and visually see what could happen in the future.

Static charts can't show these relationships, especially with the segregated feedback scenario that reflects the planetary feedback relationships being added to human emissions and shows the acceleration of the impact of carbon on the biosphere. Depressingly, even with carbon emissions at zero, we don't get back to the planet we had in 1960 (316 PPMV), let alone the levels before the industrial revolution (260–280 PPMV).

Question to the world: How do we pull that slider down to the lowest position [-40], equal to the concentrations level falling to equal the starting position in 2010 or effectively a CAF-0% reference by 2110 [negative feedback]? I should think that would be a worthy challenge to the human race, one of the finest systems gaming opportunities out there. This simulation is the start of a new, comprehensive way of looking at this problem, making the Apollo program look like child's play. Which it was. And here we are at 400 ppmv half a century later."

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Walter Vergara
Chief - Climate Change and Sustainability Division (INE/CCS)
Inter-American Development Bank

"Good initiative."

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Donald A. Brown
Scholar In Residence,
Sustainability Ethics and Law, Widener University School of Law, Pennsylvania, USA:

"I believe the new CBAT model should be of great value both to international climate negotiators, governments and NGOs engaged in international climate negotiations.

It allows those interested in developing a global solution to visualize the otherwise complex interactions of international carbon budgets, atmospheric greenhouse gas concentrations, and emissions reductions commitments.

Although I am personally familiar with the relationships between the variables represented in the CBAT, I found having the ability to change inputs to the model through the use of the CBAT made me understand at a deeper level the policy choices facing the international community.

A clear understanding of how national emissions reductions commitments affect global climate change impacts requires an understanding of: -

  1. complex relationships between atmospheric ghg concentrations, likely global temperature changes in response to ghg atmospheric concentrations,

  2. rates of ghg emissions reductions over time and all of this requires making assumptions about how much CO2 from emissions will remain in the atmosphere,

  3. how sensitive the global climate change is to atmospheric ghg concentrations, and

  4. when the international community begins to get on a serious emissions reduction pathway guided by equity considerations.

The problem in understanding these variables is a challenge that no static graph can capture.  

The CBAT model should therefore be very useful for all who hope to understand future climate change policy options and the scale of the global challenge facing the world.

I have been engaged in climate change policy options since the 1992 Earth Summit at which the United Nations Framework Convention was opened for signature and have attended most of the Conference of Parties under the UNFCCC since then.

Yet even though I have significant experience and knowledge about future climate change policy challenges, the CBAT model helped me visualize the significance of certain policy options facing the world.

I also fully support efforts to make contraction and convergence (C&C) the central framework for allocating national greenhouse gas emissions in the years ahead. C&C is also flexible enough to deal with several equity issues raised by others."

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Dave Hampton
The Carbon Coach

  1. First impressions are immensely positive. It's fresh, clear and good looking and conjures up memories of those exhibits i used to love at the science museum as a child where you could twiddle a couple of knobs and influence what you saw.

  2. I like the clinical delivery of the three vital stats - the (devastatingly all important) numbers - without any panic fuss or judgement: sea level, ocean acidity, and of course mean temp rise.

  3. I guess C-BAT is mainly for relative experts butI like the way it integrates everything. You can imagine a Facilities Manager using a tool like this (a BMS - building management system) to optimise the long term comfort conditions for their occupants over time

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Dr Paul Read
Research Fellow Monash Sustainability Institute, Monash University, Australia

"I can see an awful of hard work went into developing CBAT.

I'm thoroughly impressed because the mission of Aubrey Meyer and colleagues is to translate some very complex science in such a way that the public can understand it and embrace a solution in the form of C&C - a tall order when scientists like myself worry so much about the statistical and theoretical restraints to such an extent that the big message is often lost in terms of socio-economic impact and equity.

The broad trends and impacts of climate change remain and scientific discourse needs a great deal of work to bring the message to the people who now have the power to vote on the future of their own children.

The CBAT, as it continues to evolve given the self-evident dedication of its authors, should become a critical tool that fills the gap between the realities of climate science and the realities of human impact as the science continues to unfold and provides much more accuracy and simplicity in support of the broader message.

A beautiful promise to Aubrey's daughter so many years ago is still kept."

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Paul G. Harris
Chair Professor of Global & Environmental Studies,
Hong Kong Institute of Education: -

"GCI’s new Carbon Budget Analysis Tool is an innovative way to help citizens, government officials and non-governmental actors get their heads around the growing impacts of our lifestyle choices for the future.

The tool illustrates how changes in how we live – whether we pollute the atmosphere more in the future or finally overcome our addictions to pollute less – can have marked consequences in future decades.

A vital message that comes from the tool is that acting now will be far easier than acting later – and that doing nothing will be catastrophic indeed."

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Professor Helmut Helmut Burkhardt
Science for Peace & Ryerson University Toronto, Canada

"CBAT is an excellent tool to visualize effects of human and natural actions."

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Dr Philip Hanlon
'AFTERnow' programme, Glasgow University: -

"If the 'medium is the message' then the primary message is that (i) there is cause (carbon released through human activity) and an effect (temperature, sea level etc.) and (ii) we have choices to make - we can influence the 'causes' which will determine the 'effects'.

I like the way that the timeframe for the unfolding of consequences is made clear by the model - the very wide spread of possible PPMV by 2100, for example, is powerfully illustrated.

I have become accustomed to the shape of your contraction curve - it is becoming 'iconic' and it has a strong visual presence in the bottom half of the graphic - this is a good thing. The more the shape of that curve gets into our collective minds the better.

I could imagine the model being used by those who are familiar with the underlying concepts. The model has the potential to make it clear that choices today have far reaching effects into the, not too distant, future.

I agree with your comments that we are in a phase where defeatism and indifference are in the air. This is, I think, not surprising. You will, I am sure, be used to the five stages of reaction that patients typically experience when they receive 'bad news' about a diagnosis.

Climate change is bad news about a collective diagnosis of our civilization. The first three stages involve denial, anger and 'bargaining' - this is what we have seen over the last decade or more.

The next stage is depression/fatalism - this is what we are currently experiencing. However, the final stage is acceptance and even transcendence. This is what your model can help us move towards."

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Henry Nicholls
Author of the Way of the Panda

"This is a great tool, one that shows clearly that the decisions we make now will have profound consequences."

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Several independent C&C and CBAT-related web-logs have been published so far: -

Ethics and Climate

Long Finance - London Accord

YALE 360

Greensward CIVITAS

GAIA Economics


Climate Consent

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There is no precedent for the rate at which we have driven up CO2 concentrations since burnning fossil carbon since ~1800. People generally realize that as the planet warms, *more* rather than *less* of these non-human feedback-emissions will occur, that this is a *problem* and that measuring the rates of all this is a challenge to meet if we are really facing the problem in search of a solution in terms of UNFCCC-compliance.

This whole discussion is a little moot without some quantification of weights, rates and dates of carbon release. And, as many have said, as in IPCC AR5, simply
leaving all these feedbacks out of the climate-model is not a solution

A way of helping at least to meet [if not to master] this challenge is perhaps exploring this carbon-weight/rate/date issue using 'CBAT' [Carbon Budget Accounting Tool] - the 'HELP' button gives information [mouse wander & click features].

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Some Support for the Classic C&C Concept over the years.