Don’t shoot the messenger: why disliking a conclusion is not a good basis for disregarding it.

“… for a reasonable probability of avoiding the 2°C characterisation of dangerous climate change, the wealthier (Annex 1) nations need, temporarily, to adopt a de-growth strategy.”

Kevin Anderson & Alice Bows-Larkin

Climate Change negotiations; Warsaw 2013

This article summarises the reasoning behind the contentious conclusion arising from Alice Bows-Larkin and my research – that continuing with economic growth over the coming two decades is incompatible with meeting our international obligations on climate change. The piece was catalysed by a twitter dialogue between Nikolai Astrup (a Norwegian MP), Glen Peters (a researcher at Cicero), Paul Price and me, and followed the Tyndall Centre/Cicero event (slides available from the Tyndall site) at the Warsaw climate change negotiations (COP19, Nov. 2013).

At the end of Alice’s and my presentations at COP19, Nikolai Astrup stood up to disagree strongly with our conclusion that “for a reasonable probability of avoiding the 2°C characterisation of dangerous climate change the wealthier (Annex 1) nations need, temporarily, to adopt a de-growth strategy.” Central to our conclusion is the express and clear assumption that the near-term development of poorer (non-Annex 1) nations should not be stifled by an overly constrained carbon budget. This widely accepted position, allied with the maths around 2°C carbon budgets, has grave repercussions for the scale of the response required to address climate change. Put simply, for the wealthier nations, “the necessary levels of 2°C mitigation and short-to-medium term economic growth are incompatible”.

Nikolai Astrup has since and on several occasions asserted that our conclusion is wrong, but, despite several requests, has not provided any analytical evidence to support his position. Moreover, Glen Peters, whilst agreeing with our “maths”, argues that it is our ‘opinions’ that have brought us to the conclusion about de-growth. In as much as our ‘opinions’ are informed by analysis he is correct; certainly our conclusions emerge from a very clear and consecutive set of assumptions accompanied by the maths (with which he agrees). If Nikolai Astrup also broadly accepts the maths, then for them both (and perhaps others) to maintain their objections to our conclusion they must disagree, at a significant level, with our assumptions.

To understand whether their positions stem from dislike of the conclusion or critique of the assumptions, our headline assumptions are outlined below in a sequential and simplified format. Based on these, Nikolai and Glen can outline which assumptions: [1] they consider are unreasonable, [2] they have an alternative for, and [3] how this would change the conclusion we have drawn. The assumptions listed are distilled from two journal articles, Beyond Dangerous Climate Change and the earlier Reframing the climate change challenge; with the principal arguments also outlined in Romm misunderstands … and EU & UK decarbonisation – why so little science.

To reiterate, our headline assumptions all take at face value the international community’s commitment to address the causes of climate change – a commitment reaffirmed by national leaders on many occasions and most succinctly captured in the language of the Copenhagen Accord: “To hold the increase in global temperature below 2 degrees Celsius, and take action to meet this objective consistent with science and on the basis of equity” [emphasis added].

Reductions in emissions greater than 3-4% p.a. are incompatible with a growing economy (or so we’re repeatedly advised). From Stern and the UK’s Committee on Climate Change through to virtually every 2°C emission scenario developed by ‘Integrated Assessment Modellers’, reductions in absolute emissions greater than 3% to 4% year on year are judged incompatible with a growing economy. It is worth noting that if reductions of 4% each year are to occur in an economy growing at 2% each year, then the carbon intensity of the economy must continually improve at around 6% year on year. Despite considerable engagement with those developing energy-emission scenarios and lengthy literature searches, we have found no examples of economists suggesting that prolonged emission-reductions above 3 to 4% p.a. are economically sustainable. Almost to the contrary, Stern’s observation that annual reductions of greater than 1% have “been associated only with economic recession or upheaval” (Stern 2006: pp. 204) is a more typical refrain. The 2°C obligation relates to a twenty-first century carbon budget. The science underpinning climate change makes clear that the best correlation with temperature in 2100 is the total cumulative emissions of greenhouse gases emitted throughout that century (the carbon budget). In other words the global average temperature rise by 2100 depends on the total amount of carbon dioxide emitted between 2000 and 2100. The concept of the global carbon budget is now well established and the quantities of carbon dioxide emitted for different probabilities of 2°C are adequately defined. We choose a ~50% (as an upper-end) chance of exceeding 2°C. The probability of exceeding the 2°C threshold between acceptable and dangerous climate change has substantial implications for the size of the carbon budget. The language of the Copenhagen Accord can reasonably be translated as a low to very low chance of exceeding 2°C (around 1-10%). By contrast, for example, UK climate legislation is premised on a global budget with a ~65% chance of exceeding the 2°C commitment, which affords a carbon budget about twice that for a 10% chance. Given high and growing emissions between 2000 and 2013, the implication of the different budgets for the necessary mitigation rates is profound. For our analysis we used a range of probabilities – with the analysis underpinning our ‘contentious’ conclusion based on around a 50% chance of exceeding 2°C. Non-Annex 1 nations peak emissions by 2025. Our conclusion about de-growth relates specifically to the wealthier (Annex 1) nations, with their carbon budget determined by what remains when ambitious and very challenging assumptions are made about the poorer (non-Annex 1) nations. The details of these are outlined in our 2011 paper, with discussion on the important role of deforestation in the 2008 predecessor. However, by far the most significant factor relates to our explicit assumption that non-Annex 1 nations reach a peak in their emissions by 2025 and thereafter mitigate at an unprecedented 7% p.a. We acknowledge these are both extremely ambitious assumptions, but judge it to be the least inappropriate compromise between [1] practicality, [2] remaining within a 50:50 2°C carbon budget and [3] being cognisant of the Copenhagen Accord’s explicit reference to develop responses to 2°C “on the basis of equity”. The Annex 1 carbon budget depends on the global & non-Annex 1 budgets. Having both established an appropriate 2°C global carbon budget and developed a stringent emission pathway for the non-Annex 1 nations, the Annex 1 carbon budget is simply the subtraction of the non-Annex 1 budget from the global budget. Annex 1 nations need 8 to 10% p.a. emission reductions. Our original analysis was premised on recorded emissions up to 2009/10, since when global emissions have continued to increase whilst Annex 1 emissions have only slightly reduced (and actually increased on a consumption basis). Consequently the reduction rates we estimated in our 2011 paper will be still more challenging today (2013). Based on the above assumptions the rates of immediate emission reductions necessary for the Annex 1 nations to remain within their fair contribution to the 2°C carbon budget are between 8% and 10% p.a. (see Anderson & Bows 2011, with summary numbers in Table 1). Q.E.D. Annex 1 mitigation rates for 2°C are incompatible with economic growth. The dominant economic assertion is that rates of emission reduction beyond 3-4% p.a. are incompatible with economic growth. Yet the maths for a 50:50 chance of 2°C, allied with the above assumptions, demonstrate how, even with radical reductions in the projected carbon budgets of poorer nations, wealthier Annex 1 nations still need to deliver immediate reductions of at least 8 to 10% p.a. If Stern et al are even ‘half right’, economic growth is therefore incompatible with the Annex 1 nations making their fair contribution to a 50% chance of avoiding the 2°C characterisation of dangerous climate change.

To summarise, if:

1. reductions in emissions greater than 3-4% p.a. are incompatible with a growing economy,

2. the 2°C obligation relates to a twenty-first century carbon budget,

3. a 50% chance of exceeding 2°C is adjudged an acceptable risk of failure,

4. and Non-Annex 1 nations peak emissions by 2025 & subsequently reduce at ~7% p.a.,

5. then the wealthier nations’ carbon budget is the global 2°C budget minus the poorer nations’ budget,

6. and consequently wealthier nations must reduce emissions at 8 to 10% p.a.,

7. Q.E.D. Annex 1 mitigation rates for 2°C are incompatible with economic growth

In ongoing research related to our analysis, Alice and I have frequently enquired as to whether our assumptions are reasonable, with, to date, only nuanced adjustments suggested. Certainly some colleagues and commentators are explicit in their rejection of 2°C as the appropriate starting position; with arguments made both that 2°C is too stringent or that it should be tightened further, perhaps to 1.5°C. However, this is not what either Nikolai or Glen suggest; it is the conclusions in relation to 2°C that they openly reject (or question). However, given that they accept the maths and that the assumptions have, thus far, proved robust, I think it very likely Nikolai Astrup and Glen Peters don’t so much disagree with our conclusion, but rather that they simply dislike it.

If this is the case, I consider it inappropriate and misleading to muddle disliking a conclusion with reasoned criticism of it. This judgement extends well beyond Nikolai and Glen, to the many others who have rejected our conclusion without offering any substantive critique as to why.

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NB: Whilst the view that mitigation rates in excess of 3 to 4% p.a. cannot be reconciled with a growing economy is an explicit claim (or implicit outcome) of many climate-oriented economists, there is slim evidence to support the view either way; in essence it is little more than an assertion. When it comes to the ubiquitous nature of climate change mitigation, impacts and adaptation, we are without any appropriate historical analogues. In that regard mitigation rates well above the economists’ 3 to 4% p.a. range may yet prove compatible with some form of economic prosperity. Early work certainly suggests that this is an hypothesis worth exploring and to that end it is the focus of the Tyndall Centre’s forthcoming “radical emission reduction conference” at the Royal Society in London on 10th & 11th December 2013.

There is a risk that this final NB could be viewed as a self-defeating argument. However unless Nikolai, Glen and others are prepared to support a position that absolute and immediate mitigation rates of around 10% p.a. (i.e. improvements in the carbon intensity of GDP of ~12% year on year starting now) are possible, the NB offers no solace and a cogent base to assertions that our conclusions are wrong is still necessary.