Contraction & Convergence (C&C)

"C&C has the virtue of simplicity. Equal per capita emissions is a natural focal point.
Contestable computations based on economic variables do not need to enter the allocation
formula." Professor Ross Garnaut

C&C the UK Climate Act, CO2
& future global carbon constraint

Carbon budgeting consistent with 'Paris Agreement' is now increasingly widely supported.
The UK Government faces a Judicial Review of their under-ambition against the Climate Act and the Paris Agreement - in a nutshell like this,.

All Country CREDIT DEBIT introduction


Contraction & Convergence - A short history of the non-ideological 'C&C' concept of 'Equity = Survival'

In 2017, we are approaching the 'event horizon' of irreversibility with climate change.
Ater 29 years of GCI's seminal, sustained & successful international effort establishing the non-ideological Contraction and Convergence (C&C) concept, this record includes the following: -

As Chairman of the Climate Change Committee Adair Turner had written to the Minister (Ed Milliband) saying: -

"We believe that it is difficult to imagine a global deal which allows the developed countries
to have emissions per capita in 2050 which are significantly above a sustainable global average."

He subsequently confirmed at a hearing of the Energy and Climate Change committee that: -

" . . . if for reasons of urgency the overall contraction rate had to be accelerated,
the convergence rate rate would have to be accelerated relative to that . . .

In 2009, GCI submitted evidence to the first 'Carbon Budget Enquiry' of the UK House of Commons Environmental Audit Committee (EAC) setting out why the UK Climate Act was based on, 'the right principle but applied at the wrong rates': -

  • with contraction to zero emissions by 2100 for a less than 50% chance of limiting temperature rise to 2° C, while omitting to allow for feedback effects,
    the UK Met Office modelling of the source:sink function was unrealistically 'optimistic' and seriously misleading by end-loading the risks;

  • with convergence to equal per capita emissions entitlements prescribed globally by 2050, by when 80% of the remaining carbon budget had been used up,
    the model was presented in a prescriptive and inequitable way, especially in the light of the UK's high share in the history of CO2 emissions from fossil fuel burning.

However, through the Copenhagen Climate Change Committee, the UK Government insisted on advocating this prescription at COP-15 in 2009, and it was met with strong refusal from Developing Countries. It was clear the UK Government did not politically grasp the full reality of sharing a limited and shrinking global carbon budget.

At that time, the UKMO agreed with GCI's definition of 'Sink-Efficiency'. However, they subsequently pushed back strongly against criticsm of their carbon contraction:concentration scenario in the UK Climate Act
('2016 3% Low'). This was the source of what would become (and still is) a wider and substantial disagreement.

To replace the SRES emissions scenarios, in 2010, the UKMO gathered the 'new' feedback-free 'Representative Concentration Pathways' (RCP) scenarios to 'lead' preparations for IPCC AR5. The lowest carbon budget was in the RCP 2.6 scenario, similar to the UKCA. The highest (RCP 8.5) equalled levels at the Permian Extinction!

For reasons unexplained to this day, the RCP scenarios for 1.5° C were removed at this time. Though UKMO deny all knowledge of this, these scenarios finally re-surfaced in IPCC AR5, but only in 2016 (meaning even if they weren't used during IPCC AR5 preparations, they must have existed and been calculated before 2010).

GCI started work on the Carbon Budget Accounting Tool (CBAT). Primarily to project a precautionary approach to risk management, the heuristic modelling of feedback-emissions/effects in the CBAT animation was also to countervail the UKMO's climate feedback-free projections of the predominantly fossil fuel driven RCP methodology.

In 2013, the first version of CBAT was presented in evidence to the second EAC Enquiry in 2013. This demonstrated why the dangers obscured by the feedback-free RCP methodology were an issue of grave concern.
The UKMO denied these omissions, despite admitting these omissions on their own website in 2010 (see here pp 12 & 13).

As the original RCP spreadsheets show, the UKMO's feedback-free climate model behind the UK Climate Act, was monotonically iterated into all the RCP scenarios, from smallest to the largest. GCI rebutted the inadequate arguments made by the UKMO to the EAC in the House of Commons Enquiry, seeking to obfuscate this.

Comparison was made between the obfuscating 'Keeping Control' curves from the UKMO and CBAT's potential 'Loss of Control' curves. With CBAT, GCI offered a more transparent and inclusive methodology to cognitively map this intractably difficult area of uncertainty & 'risk-calculation'. GCI's submission to EAC was headlined thus: -.

“As the planet warms, a steady rate of feedback acceleration in the years ahead makes it possible to contemplate a scenario where positive feedback is driving the system as a whole from a point after which ‘human-budget-emission-control’ becomes irrelevant. To continue, after twenty years, to ignore this anywhere, let-alone in ‘climate-science-policy modelling’ community is another form of ‘climate-denial’. Doing this unintentionally provides assistance to ‘climate-deniers’ against whom James Hansen has already and rightly levelled the charge of crimes against humanity for willing dangerous rates of climate-change upon the future. For UNFCCC-compliance, the struggle is now between control & a loss of control. To deal with this we need a new approach that will be precautionary, prevention-based and strategically goal-focused. It will distinguish between ‘budget-emissions’ which we can control and ‘feedback emissions’ and effects which we can’t. The approach will quantify as best we can, the runaway potential of rates of change that result from ‘Rapidly Inter Acting Feedback Effects’ [RIAFE] and the dangers of doing too little too late.”

Considering the huge rising risks and costs involved in getting this wrong, CBAT embedded a basis for precautionary policy-making & risk-averse decision-taking based on exploring the rates of rising risks of what we do know, but also those we don't or where we don't know with meaningful accuracy, future inter-active change rates of the: -

  • carbon contraction of human budget emissions (this is a 'sociological' strategy/policy matter; if it ever was, it is no longer a 'sceptical climate-science' matter)
  • weakening of the sink-function showing the 'constancy' of the airborne-fraction of emissions starts changing
  • further rise of heat-trapping carbon concentrations and water vapour in the global atmosphere
  • further consequential rise of global temperature and consequently
  • sea level rise
  • ocean warming and acidfication
  • ice and permafrost melt with increases in negative albedo causing
  • secondary (non-budget) emission releases from non-fossil sources
  • increasing stress on biological and ecological buffer systems
  • showing the value of 'climate sensitivity' (dT = λ*dF) is not 'constant' but is inexorably revealed as the temperature-response to temperature-rise itself.

. . . . the net result of which will be the interactive compounding effect on overal warming from the above 'knowns', plus what inevitably are further 'unknowns'.
The structure of the user-choice arrays in CBAT is

Together, the potential of these feedback dynamics represent an existential threat. So it is vital to remember there is an unpayable cost for any underestimates of the rates of change projected in the 'scientific community's conservative models', resulting in 'too little emissions control too late' from the policy community.

For whatever reason, simply ignoring the full potential spread of rapid interactive feedback dynamics, so falsely implying that we 'know' all this when we so obviously don't, is at the very least profoundly irresponsible.

To justify the amount of public money that has been invested in UKMO & their climate models, we need something more precautionary-policy-relevant & useful than 'complacently voyeuristic' come-what-may 100-year weather forecasts that under-estimate the risks & realities of the rates of global temperature rise and increasingly catastrophic climate-damages we face.

The justification for doing this is already apparent in that rates of change are already accelerating faster than rates predicted by the climate models.
The context in which this acceleration is occuring is embedded within the user-interactive CBAT cognitive mapping dynamic.

UKMO's subsequent response was to assert that CBAT had 'an error' in it & requested the coding to 'prove this'.
The coding was provided but since then, the UKMO have been unable to prove anything and have remained unwilling or unable to say what in fact 'the error' actually is.

In 2014 the final version of the CBAT 'user-chooser' animation was published online. It was very well received by many experts.

Former Government's chief scientist Sir David King called it "a beautiful piece of work" & used it to persuade John Schellnhuber (Director of Potsdam Climate Impacts) et al to abandon the RCP 2.6 scenario of 288 Gt C under-pinning the UKCA & adopt the carbon weight/rate equivalent of the Carbon Budgets as published in NATURE instead. of Equity

CBAT - the Carbon Budget Accounting Tool.

Here are the four 'domains' of CBAT where domains 2, 3 & 4 automatically pick up the user-selected carbon-budget emissions in domain one.
On opening, the default setting is the contraction rate of global emissions - the global 'carbon-budget' - in the UK Climate Act.
It is 'cognitive-mapping', so the CBAT-user
can increase or decrease this 'carbon-budget' and separately, the potential for the consequential change rates arising: -

  • 'Domain One' - 'Contraction & Concentrations', with response arrays of 'climate feedbacks' & 'climate-effects' (temperature, sea level rise and ocean acidifcation)
  • 'Domain Two' - 'Contraction and Convergence' where regional shares converge on the international per capita average arising
  • 'Domain Three' - 'Contraction and Conversion' exploring the rate at which fossil fuel consumption needs to be replaced with renewable sources
  • 'Domain Four' - 'Climate Damages and Growth' exploring the rate of the climate-damage curves arising from different rates of carbon contraction

A description of CBAT by Plan-B was published thereafter; a technical note is here.

In 2015 GCI created web pages based on CBAT methodology and the INDCs.
These led on the image below which, with 'the three budgets for compliance with 1.5° to 2.0° C - as in the 'Paris Climate Agreement' - became very widely used.

This global carbon budgeting also became the basis of a legal strategy in 2015.
This is being used in the UK Courts this year (2017), for Judicial Review of the UKCA initiated by Plan B
, which action David King supports.

From the above and from what follows, it is clear there is a growing consensus that the 'path-integral' of the global carbon contraction budget needs to be

  • three times lighter by carbon weight and
  • three times faster by contraction-rate

than the global carbon budget in the UK Climate Act.

In 2016, telling his audience at the IEA in January that, 'we face a looming climate catastrophe', Sir David King (former UK Government Chief Scientist & climate negotiator) presented this analysis of future carbon budgets in relation to the INDCs under the Paris Agreement, elaborating on what it will take to avoid that catastrophe.

In 2017, on this basis the UK Government has been asked to explain what they intend to do about the inadequacy of their climate response (illustrated here) against the temperature goals now in the Paris Agreement to which the UK is a signatory. As responses received from HMG have been inadequate, Judicial Review now seems certain.

Stephen Hawking, tells the BBC - "We are close to the tipping point where global warming becomes irreversible."

John Schellnhuber et al abandon the RCP 2.6 scenario of 288 Gt C under-pinning the UKCA (from UKMO) and adopt the carbon weight/rate equivalent of the Carbon Budgets as published in NATURE, while retaining the unrealistically delayed feedback schedule of 'tipping points'.

UKMO unexpectedly declares these carbon budgets as scientifically sound for the new target of 1.5° - comparing the 'shrinking carbon budgets' now look like this: -

In June 2017 the European Parliament voted to make the Paris Agreement legally binding.

In a now 30 year effort on the climate-science/policy interface, both diagnosing the problem & cognitively mapping the solution with C&C, this sequence of developments adds to the vindication of GCI's whole approach. Many parties have made statements to that effect and many eminent individuals have agreed with the approach

By so profoundly under-estimating the risks we face (see IPCC 1-4) in conjuction with the extent of misdirection wrapped in the monotinic absurdity of the feedback-free RCP scenarios that dominated IPCC AR5 (2015), this is now plain for all to see.

  • In 2010, doubling the upper ppmv CO2 concentration limit from 1000 ppmv to 2000 ppmv (RCP 8.5) for the IPCC AR5; (why and for whom was this done?).
  • In 2010, the removal of RCP scenarios for 1.5° C for IPCC AR5 by the UKMO et al is still completely unexplained; (why and for whom was this done?).
  • Now, already in just 2017, we are seeing the abandonment of even the lowest limit 450 ppmv (RCP 2.6)
  • This is in favour of smaller carbon budgets to try & return to 350 ppmv for an upper temperature limit of 1.5°C, as per the Paris Agreement.
  • All this is being done recognizing the climate emergency we are in (already called in 1996 by GCI at COP-2 - see page 26).

In the light of this, a letter from Bindmans to the Secretry of State posing a Judicial Review challenging the UK Government's under-performance on climate change has been sent (26 09 2017).

This is a deliberate initiative in the common interest, to avoid the 'looming climate catastrophe' that lies ahead if we don't organize, make & complete an international programme of GHG emissions control that is adequate to that purpose.

All these are now not 'scientific' but 'political' questions needing political answers and as necessary judicial decisions, if we are to have any chance of success in this effort.
Moreover, in the light of the inequitable history of CO2 emissions, it is clearly futile for the perpetrators of climate change to try and further ignore this All Country CREDIT DEBIT historical account.

In the case of the UK this is clearly set out as follows: -

A detailed comparison of the UK Government's future Carbon Budget with the UK Carbon Budget from Plan B is here

A comparison with the UNEP GAP Report is here

A more extended comparison of the IPCC's SRES to RCP story is here