Saturday, 19 December 2009

The Copenhagen Accord - a liberal emissions regime for the USA and China

The Copenhagen Accord will maintain the Kyoto divide

The prospects of achieving a consensus agreement in Copenhagen, with nearly two hundred nations having spanned two years arguing word by word over draft texts for a new climate change treaty, were never good. The diversity of perceptions of equity and self interested agendas make it remarkable that the UN process has got as far as it has.

The  proactive move by a group of countries led by the USA and China, whose  leaders agreed between themselves the text of a 'Copenhagen Accord' to be presented to other COP15 parties, led to cries of 'undemocratic' and 'outside the UN process'. These objections sound hollow in relation to the urgency of the need for nations to cooperate to address the threat of climate change, and the slowness of the UN process which has failed to place a draft negotiating text on the table at COP15 after two years of effort.

The worst features of the Copenhagen Accord* are that it contains few of the elements considered to be important for an effective climate deal. There are no quantified emissions reduction targets or timescales for peaking emissions, no reference to a legally binding agreement, and no detail on how targets or actions might be monitored or independently verified. Although finance from developed countries for climate change mitigation and adaptation in developing countries is set at 100 billion US dollars a year by 2020, there is vagueness about the sources of such finance.

The nations that devised the Accord (USA, China, India, Brazil and South Africa) are all outside Kyoto Annex 1. In other words they did not take on binding emissions reductions targets under the Kyoto protocol (in the case of the USA as a result of non ratification)

The Accord maintains the Kyoto divide prescribing that Annex1 countries should.... 'commit to implement individually or jointly the quantified economy-wide emissions targets for 2020 to be submitted ...... to the secretariat by 31 January 2010 for compilation', and that 'Non-Annex I Parties ......will implement mitigation actions...' The intention is that national commitments from both groups will be added as appendices to the Accord. 

Thus if the Accord is adopted as a legal agreement, since it incorporates the Kyoto structure  the USA  would need to clarify its status.

The EU and Japan have apparently endorsed the Accord but indicated that it falls far short of the type of agreement that they had hoped would be concluded. Some nations find the Accord unacceptable so the final COP15 session merely 'noted' the Accord.

Where the path from Copenhagen will lead now is uncertain and there must be doubts about whether the UNFCCC process can continue. 

The new grouping of USA, China, India plus Brazil and South Africa includes the worlds' two largest CO2 emitters. Under the Accord, when/if transformed into a legal treaty, the developing nations would undertake 'actions' not binding emissions targets and 'will undertake domestic measurement, reporting and verification' which will be reported under 'guidelines that will ensure that national sovereignty is respected'. The USA might need to ratify Kyoto but potentially could remain outside.

Figure 21.1   Percentage of world CO2 emissions - 'Copenhagen Accord' group of nations

Because the combined CO2 emissions of the 'Accord' group comprising USA, China, India, Brazil and South Africa were the source 49% of world emissions in 2008, (excluding land use and forestry emissions LULUCF) their performance in reducing their CO2 emissions under the liberal regime suggested by the wording of the Copenhagen Accord will be the major determinant of the worlds' CO2 emissions trajectory.

The potential effectiveness of the Copenhagen Accord as an instrument for mitigating climate change looks questionable because it does not contain strong constraints that would make the worlds largest CO2 emitters fully accountable. 

*All quotations in italics refer to Copenhagen Accord Draft decision -/CP.15 FCCC/CP/2009/L.7 18 December 2009   

Sunday, 6 December 2009

Cumulative CO2 emissions: the 1,000 Gt budget for limiting global warming to 2C

Almost one quarter of the fifty year CO2 budget for the 2C temperature threshold has been used between 2000 and 2008

The probability of exceeding temperature thresholds as global warming progresses can be related to cumulative CO2 emissions - the year on year sum of CO2 emissions over a defined period of time.

Underlying the negotiations at COP15 is the issue of how to share, between nations, a finite and limited budget of CO2 that can be emitted into the atmosphere over the next fifty years.

Meinshausen et al analysed the probability of exceeding a 2C temperature threshold over the period 2000-2050 in relation to cumulative CO2 emissions and concluded that 

'Limiting cumulative CO2 emissions over 2000–50 to 1,000 Gt CO2 yields a 25% probability of  warming exceeding 2C, and a limit of 1,440 Gt CO2 yields a 50% probability'

If the world is to stay within a 2C warming threshold the cumulative CO2 emissions budget to be shared between all nations over the next fifty years is just 1,000 Gt CO2 or an average of 20 Gt per year. World CO2 emissions in 2008 were 31.6 Gt.

If a 50% risk of exceeding 2C warming is considered acceptable then a budget of 1,440 Gt CO2 could be shared out over the next fifty years.

Emissions of CO2 from the countries with the largest emissions over the period 1990-2008 are shown in Figure 20.1. Cumulative CO2 emissions on a plot of CO2 emissions vs. years can be represented by the 'area under the curve'. For each country the total area up to its trend line, read from the base line, represents the cumulative emissions for the period 1990-2008 and the trend lines show how CO2 emissions have changed over time.

        Figure 20.1 CO2 Emissions: Cumulative emissions landscape 1990-2008  

At present the USA has the largest cumulative emissions area for the period 1990-2008 but China's emissions trend, with annual emissions starting to exceed those of the USA in 2008, means that in future China is likely to become the country with both the largest annual and  largest cumulative CO2 emissions.

Figure 20.2 Cumulative CO2 emissions 2000

Figure 20.2 shows contributions to cumulative CO2 emissions from countries with the largest emissions in the shorter period between 2000and 2008 and that world cumulative CO2 emissions for this eight year period were ~250 Gt.

Concerted efforts will be needed to limit warming to 2C

Using Meinshausen's criterion of 1,000 Gt CO2 emitted between 2000 and 2050 corresponding to a 25% probability of staying below 2C, we find that because ~250 Gt CO2 has already been emitted between 2000 and 2008, all countries of the world, during the next forty or so years, should budget to emit no more than ~750 Gt CO2

In relation to the planet's fifty year 1,000 Gt CO2 'budget', that almost 250 Gt has already been emitted in the first eight years is staggering.

On this analysis one quarter of the fifty-year CO2 budget has already been used up in the last eight years, so radical change is needed if the world is not to go beyond the 2C warming threshold.

An unprecedented agreement at the COP15 Copenhagen summit, which sets aside national self interest and leads to concerted efforts from the all the world's nations, will be needed to stay within a global 1,000 Gt CO2  'budget' and limit warming to 2C.


Greenhouse-gas emission targets for limiting global warming to 2°C
Meinshausen M et al.  Nature 458, 1158-1162 (30 April 2009)
BP Statistical Review of World Energy 2009

Note i) One giga tonne Gt = one thousand million tonnes
Note ii) The data used here, from the 2009 BP Statistical Review of World Energy, differ slightly from data used by Meinshausen who took world CO2 emissions for the period 2000-2006 to be 234 Gt CO2.