In the first of a series of posts, I focus on objectives and some issues regarding technology.
Anyone who takes seriously the task of analysing climate change policy is liable to be daunted by what they find. The literature is vast, embracing many disciplines – climate science, technology, economics, behavioural science, international relations – and many sources – governments, inter-governmental bodies, academics, think tanks, campaign groups, industry bodies. Just to understand the elements of current policy is a challenge, as my previous post – and the many sources I had to refer to to put it together – shows. Then there is what might be termed the problem of numbers. On the one hand one cannot get very far in policy analysis without considering numbers – to assess the importance of issues, to distinguish the possible from the unrealistic, and to compare the costs of different approaches. On the other hand the literature abounds in numbers that for one reason or another are not useful, ranging from the poorly defined, the excessively detailed and the out of date to the incorrect and the just plain silly (a favourite from the last category: “recycling just one banana skin generates enough energy to charge your smartphone twice” (1)).
The complexity of the issues surrounding climate change policy perhaps invites the taking of short cuts. In terms of the classification of thinkers into hedgehogs – those who view the world through one big idea – and foxes – those influenced by a variety of ideas (2) -, it seems that many of those who offer opinions on climate change policy have what may be called hedgehog tendencies. The prisms through which different groups view climate change policy are varied: environmentalism; criticism of profit-seeking corporations; faith in free markets to deliver innovative solutions; inequality (both between and within countries); general distrust of experts; and (at a more technical level) lively appreciation of the merits of a uniform carbon price. Each of these prisms brings something useful to the policy debate, but is too narrowly focused to offer anything like a sensible overall policy package. Climate change policy analysis – perhaps even more than most policy areas – needs foxes as well as hedgehogs.
I start with objectives. The objective of net zero by 2050 is the centrepiece of current UK policy. In recommending this objective, the Climate Change Committee referred to the Paris Agreement aims of limiting the increase in global average temperature to well below 2°C and pursuing efforts to limit it to 1.5°C. It also noted the Agreement’s emphasis on equity and expectation that developed countries should take the lead. Against that background the Committee considered that “an appropriate UK contribution … should go beyond what is required for the world overall” and recommended a path leading to net zero by 2050 as “towards the high end of the estimated range of necessary reductions for a limit of 1.5°C” (3).
The Committee also argued that “setting and pursuing [the net zero target] will confirm the UK as a leader among the developed countries on climate action” (4). It noted that several other climate leaders had set or were considering net zero targets by 2050 or earlier, and warned that for the UK to adopt a weaker or later target would undermine these moves towards a broader international consensus. This is a most important point. The UK’s territorial emissions are only about 1% of the global total, so any influence it can exert, via its policy towards the 1%, on other countries’ policies towards the remaining 99%, represents a significant outcome of UK policy. As it happens, a large number of countries have now committed, either in law or as government policy, to a target of net zero by 2050 or earlier, including Australia, France, Germany, Japan, South Korea, Spain and the US (5).
A possible criticism of the net zero target is that it is not grounded in economic analysis seeking to find the optimal balance between the harm done by climate change, including in the very long term, and the costs of mitigation. A number of economists have developed Integrated Assessment Models which, in principle, can be used to determine mitigation paths which maximise welfare over time. Such paths are typically characterised in terms not of carbon budgets progressing towards a net zero target at a certain date, but of a gradually increasing social cost of carbon. For example, one version of the DICE model developed by Nordhaus and others implied a social cost of carbon to maximise welfare of $43 in 2020 rising to $105 in 2050 and $295 in 2100 (6). In my view these models do not provide a suitable basis for setting climate policy. One problem is that they depend on numerous assumptions, some based on less than conclusive evidence, and some involving contentious ethical judgments. Perhaps the most contentious issue is what discount rate, if any, should be used in comparing costs of mitigation with the harm they are expected to avoid in the distant future. Nordhaus (2018) states that “the debate on discounting … is just as unsettled as it was when first raised three decades ago” (7). A matter on which economists are far from agreed is not an adequate basis from which to try to build a national and international consensus on climate policy.
I readily accept that 2050 may not be the optimal date for the net zero target. If it were possible to specify a suitable model and resolve all necessary issues regarding assumptions, the optimal date might well be found to be a few years either earlier or later. But the nature of the climate change problem is that it requires global action. To achieve a consensus around an easily understood objective which may only approximate to optimality would be a fairly good outcome. To lose the opportunity for such a consensus by focusing on the possible sub-optimality of the 2050 date would not.
However, acceptance of the net zero target should not be taken to imply that any methods of reducing emissions are acceptable. Net zero is not an ultimate objective but a means to the end of limiting climate change. Climate is influenced not only by the quantity of greenhouse gases in the atmosphere but also by the reflectivity (albedo) of the earth’s surface. The widespread view that planting trees helps to mitigate climate change is an oversimplification: in some circumstances, especially at high latitudes, the effect of trees in sequestering carbon can be outweighed by their effect in absorbing more sunlight than lighter surface covers such as grass or snow (8). Although the Climate Change Committee’s recommendations on the Sixth Carbon Budget include increasing the rate of afforestation to 50,000 hectares (about 190 square miles) per year by 2035 (9), I could not find any mention of reflectivity in the Committee’s very detailed supporting methodology document (10). Hence my first proposal:
Proposal 1: Emissions-reducing projects involving large-scale changes in land use such as afforestation should be adopted only if careful assessment of their total effects, including their effects on reflectivity, clearly demonstrates a mitigating effect on climate change.
Subject to that caveat, I support the UK’s maintenance of the net zero by 2050 target. But I am not persuaded by all the points made by the Climate Change Committee in recommending that objective. In arguing that the the UK should go beyond what is required for the world overall, the Climate Change Committee noted that the UK has “a significant carbon footprint attached to imported products” (11) (ie consumption emissions, which are not included within the UK’s net zero target and carbon budgets). While that is a correct statement, the unstated suggestion is that the UK’s consumption emissions are a relatively minor issue which is adequately addressed by adopting a challenging net zero target. It is hard to measure consumption emissions with great accuracy, given the the impracticability of determining the emissions from production of many different goods from many countries (and this may become even harder in future as some production processes in some countries become decarbonized). However, it is estimated that 43% of the emissions associated with UK consumption are embedded in imports (12). Reducing its consumption emissions is potentially therefore a very significant way in which the UK can contribute to mitigation of global climate change, requiring an objective of its own. Hence:
Proposal 2: The UK should adopt an objective of substantially reducing the emissions embodied in its imports
Whether such an objective is best expressed as a quantified target is debatable, given the difficulty of accurate measurement.
The Climate Change Committee presented as a merit of the net zero target that it applies to all greenhouse gases, aggregated using the GWP100 metric (13). This is another oversimplification. The GWP100 metric weights different gases according to the contributions which 1 tonne of a gas would make to global warming over 100 years (14). Thus it provides a good measure of the long-term warming effect of a cocktail of gases. However, policy also needs to consider the short-term effect of greenhouse gases, which can be crucial in determining whether and when warming will reach 1.5°C or 2°C, and in that context GWP100 is a poor measure because it gives insufficient weighting to the warming effect of short-lived greenhouse gases, primarily methane. Sun et al (2021) state:
“… current net zero targets do not inherently call for early action on short-lived GHG’s, which a growing body of research shows is a key strategy to slow down global warming in the near-term. Emissions of short-lived GHG’s account for nearly a third of today’s gross warming, and … emissions reductions in these GHG’s can quickly lead to slowing down the global-mean rate of warming” (15)
In conjunction with substantial global reductions in carbon emissions, early reductions in methane emissions can reduce by about 0.2°C the peak of global warming, which could make the difference between success and failure in meeting the Paris objective of keeping the increase in global mean temperatures below 2°C (16). Hydrofluorocarbons – a large group of mostly short-lived greenhouse gases (17) widely used in refrigeration and air-conditioning – can also contribute to this effect. Hence:
Proposal 3: The UK should supplement its net zero target with specific legally binding targets for reductions in short-lived greenhouse gas emissions including methane and hydrofluorocarbons
Although the UK has regulations in place regarding fluorinated gases including hydrofluorocarbons, these do not include a specific focus on short-lived hydrofluorocarbons (guidance relies on the flawed GWP100 metric (18)). So far as methane is concerned, the UK (along with over 100 countries) has signed the Global Methane Pledge aiming to cut global methane emissions by 30% by 2030 (19), but has not yet adopted a legally binding target for reductions in its own emissions.
In arguing that the net zero objective is achievable, the Committee stated that its scenarios for reaching the target are based on “known” (or “existing”) technologies (20). This again is an oversimplification. I am struck by the contrast with Bill Gates’ book (reviewed in this post), which lists numerous technologies needed to achieve net zero (21). Admittedly Gates was addressing the problem of getting the whole world to net zero. But the main reason for the difference is surely the vagueness of claiming that a technology is “known”? A widely used framework for assessing the status of a technology is the 9-point Technology Readiness Level scale (22), where Level 1 is “basic principles observed” and Level 9 is “actual system proven in operational environment”. Technological innovation is often a gradual process, and the suggestion that technologies are either known or unknown is not helpful. Research, development and innovation have a crucial part to play in getting the UK to net zero.
Sensible policy on technology for climate change mitigation requires an appropriate balance in several respects: between the roles of the government and the private sector; between technologies already at an advanced state of readiness and those which are more speculative; and between making new things possible, reducing the cost of what can already be done, and facilitating and promoting uptake of proven technologies. There is a risk however that policy may be distorted by over-ambitious aspirations to make the UK a global leader in climate-related technologies. In the introduction to his Ten Point Plan for a Green Industrial Revolution (2020), the Prime Minister wrote:
“We will turn the UK into the world’s number one centre for green technology and finance, laying the foundation for decades of economic growth by delivering net zero emissions in a way that creates jobs” (23).
The UK has indeed been a global leader in some aspects of climate change mitigation: for example in being one of the first countries to adopt a legally binding target for emissions reductions. As a developed country with one of the world’s largest seven economies, and with a relatively long history of industrial emissions, it has a responsibility to act as a leader. In respect of technology, it can reasonably aspire to technological leadership in fields where it has or can develop a comparative advantage, because of either its natural resources and geography or its stock of physical and human capital. Offshore wind energy is perhaps such a field.
It would, however, be a mistake for the UK to attempt to become a technological leader in every climate-related field. The likely outcome would be that resources for innovation would be spread too thinly to be effective, with the UK’s efforts in many fields dwarfed by those elsewhere. Furthermore, an obsession with leadership may result in opportunities to learn from other countries being missed. Hence:
Proposal 4: The UK government should accept that, for some technologies needed for climate change mitigation, its main focus should be on encouraging and facilitating the application and adaptation to the UK’s circumstances of what has been learned through innovation and experience in other countries. It is neither necessary nor advantageous for the UK to try to achieve global leadership across the full range of climate-related technologies.
My final proposal in this post concerns the assessment of progress towards net zero. The progressively reducing carbon budgets are important because mitigation of climate change depends not only on the level of emissions at 2050 and beyond but also on the pathway of emissions between now and 2050 (24). These budgets also serve as a measure of progress towards net zero, but only in a very imperfect way. Currently, the UK is towards the end of the third budget period, for which the budget, likely to be achieved, is equivalent to a reduction in emissions of about 34% relative to 1990. That indicates progress in a sense. But it is misleading to assess progress towards net zero without regard to the degree of readiness of the technologies that will be needed to complete the transition. Have the technologies needed to secure the remaining 66% reduction been demonstrated to work, in the particular circumstances in which they need to operate in the UK, at reasonable cost? And if not what are the innovations that are needed?
I cannot find answers to these questions in the Climate Change Committee’s latest progress report to Parliament. In fact, although the report runs to more than 200 pages, it contains very little about technology. For example, a lengthy chapter entitled “Underlying progress on key enablers of the path to Net Zero” is divided into sections headed, respectively, “Governance and delivery”; “People and public engagement”, “Just Transition – who pays and who gains?”, “Just Transition – workers and skills”, and “Other key drivers of progress” (25). Within the latter, there is a short subsection (26) on innovation and infrastructure. Hence:
Proposal 5: The annual progress reports to Parliament by the Climate Change Committee should focus in more detail on the extent of the UK’s technological readiness to achieve the net zero target by 2050.
Cement production is an example of a sector in which the UK (and indeed the world) appears to lack the technology needed for net zero, in the sense that the reasonable cost requirement has not yet been met. One way to express the cost issue is what Gates calls the green premium – the percentage by which the cost of producing a good using the cheapest available zero-carbon technology exceeds the cost of conventional production (27). For cement, he quotes (for the US) a range for the green premium of 75% to 140% (28). The equivalent range for the UK will probably be slightly different, but in any case that’s a large extra cost, given that cement is an essential input to concrete which is used in very large quantities in buildings and infrastructure.
The Climate Change Committee uses the more conventional concept of abatement cost – the cost per tonne of CO2 of reducing emissions to zero. I could not find in its publications an abatement cost for cement production, but for the whole of the manufacturing and construction sectors, of which cement production is an important part, it indicates a cost of c £100 per tonne (29). Gates’ figures however are equivalent to £150 to £280 per tonne (30). These are not necessarily inconsistent with the Committee’s figure since the abatement cost may be much lower for other parts of the manufacturing and construction sectors. But it does highlight the need for more detailed information on technologies and costs to give credibility to the Committee’s claims about the feasibility and costs of attaining net zero.
Notes and References
- Seen in a leaflet about food waste recycling distributed in the Merton area of south west London. The connection with climate change is that the processing of the food waste to produce fertiliser and gas which is used to generate electricity results in much less CO2 equivalent emissions than would taking the waste to landfill.
- Wikipedia – The Hedgehog and the Fox https://en.wikipedia.org/wiki/The_Hedgehog_and_the_Fox
- Climate Change Committee (2019) Net Zero – The UK’s contribution to stopping global warming p 19
- Climate Change Committee, as (3) above p 21
- Energy & Climate Intelligence Unit – Net Zero Scorecard https://eciu.net/netzerotracker
- Nordhaus W D (2018) Climate change: The Ultimate Challenge for Economics Nobel Prize Lecture https://www.nobelprize.org/uploads/2018/10/nordhaus-lecture.pdf p 454
- Nordhaus, as (6) above p 455
- Popkin G (2019) How much can forests fight climate change? Nature 15 January 2019 https://www.nature.com/articles/d41586-019-00122-z p 281
- Climate Change Committee (2020) The Sixth Carbon Budget https://www.theccc.org.uk/wp-content/uploads/2020/12/The-Sixth-Carbon-Budget-The-UKs-path-to-Net-Zero.pdf p 170
- Climate Change Committee (2020) The Sixth Carbon Budget Methodology Report https://www.theccc.org.uk/wp-content/uploads/2020/12/The-Sixth-Carbon-Budget-Methodology-Report.pdf pp 223-6
- Climate Change Committee, as (3) above p 19
- DEFRA UK’s Carbon Footprint 1997-2018 https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/979588/Defra_UK_carbon_footprint_accessible_rev2_final.pdf p 3
- Climate Change Committee, as (3) above pp 16-17
- NIWA What are ‘Global Warming Potentials’ and ‘CO2 Equivalent Emissions’? https://niwa.co.nz/atmosphere/faq/what-are-global-warming-potentials-and-co2-equivalent-emissions
- Sun T et al (2021) Path to net zero is critical to climate outcome Nature Article No. 22173 (2021) https://www.nature.com/articles/s41598-021-01639-y p 2
- Sun T et al, as (15) above. See Chart A p 4
- IPCC (2013) Climate Change 2013: The Physical Science Basis Ch 8 Anthropogenic and Natural Radiative Forcing https://www.ipcc.ch/site/assets/uploads/2018/02/WG1AR5_Chapter08_FINAL.pdf Table 8.A.1 pp 731ff
- EU Regulation No. 517/2014 specifies GWP100 in Article 2 Definition 6 https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX%3A32014R0517&qid=1608306002561. Since Brexit the equivalent rules apply in the UK via Regulation SI 2021/543 https://www.legislation.gov.uk/uksi/2021/543/contents/made
- BBC (2/11’2021) COP26: US and EU announce global pledge to slash methane https://www.bbc.co.uk/news/world-59137828
- Climate Change Committee, as (3) above pp 21 & 26
- Gates B (2021) How to Avoid a Climate Disaster Allen Lane p 200
- Science Direct – Technology Readiness Level https://www.sciencedirect.com/topics/engineering/technology-readiness-level
- H M Government (2020) The Ten Point Plan for a Green Industrial Revolution https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/936567/10_POINT_PLAN_BOOKLET.pdf p 3
- Sun T et al, as (15) above p 1
- Climate Change Committee (2021) Progress in Reducing Emissions: 2021 Report to Parliament https://www.theccc.org.uk/wp-content/uploads/2021/06/Progress-in-reducing-emissions-2021-Report-to-Parliament.pdf pp 96-105
- Climate Change Committee, as (24) above p 104
- Gates B, as (21) above p 59
- Gates B, as (21) above p 107
- Climate Change Committee, as (9) above Read from Fig 5.6 p 261
- To convert Gates’ figures to abatement costs per tonne of CO2 we need the following data: UK cement production in 2019 was 9.1 M tonnes (31) and generated 4.4 M tonnes CO2 emissions (32), implying that emissions from producing 1 tonne of cement were c 0.5 tonnes. The cost of producing 1 tonne of cement was c £100 (33), so with the green premium would have been in the range £75 to £140 per tonne of cement, or £150 to £280 per tonne CO2.
- Statista – Cement production in Great Britain from 2001 to 2019 https://www.statista.com/statistics/472849/annual-cement-production-great-britain/#:~:text=In%202019%2C%20plants%20in%20Great,million%20metric%20tons%20of%20cement.
- DBEIS – 2019 UK greenhouse gas emissions: final figures – data tables (Excel) https://www.gov.uk/government/statistics/final-uk-greenhouse-gas-emissions-national-statistics-1990-to-2019 Table 1.2 row 78 col AF
- Construction Enquirer https://www.constructionenquirer.com/2021/11/01/industry-to-be-hit-with-16-cement-price-hike/