August 22, 2024

expert reaction to analysis of 1,500 climate policies

Scientists comment on a Science analysis of 1500 climate policies. 

Dr Ajay Gambhir, Visiting Senior Research Fellow at the Grantham Institute – Climate Change and the Environment, Imperial College London, said:

“For decades, the climate policy community has been espousing carbon pricing, regulations, technology support and measures to shift behaviours as the appropriate policy mix to tackle rising emissions.

“But how much of each, when and where has remained elusive.

“Using innovative techniques based on machine learning, this paper is a hugely important first step towards getting a much more detailed view on that.

“Its findings, worrying though they are in terms of how little policy interventions have in total moved the needle, nevertheless set the stage for a critical research agenda on policy combinations to finally get the world on a path to net zero as quickly as possible.”

Prof Michael Grubb, Professor of International Energy and Climate Change, University College London (UCL), said:

“This is the most sophisticated study to date. But by focusing only on 69 statistically-identifiable large trend breaks, they miss the impact of thousands of smaller efforts globally, and the cumulative and often self-reinforcing impact of many smaller measures.  This likely explains their low numbers of global emission reductions to date, compared to the estimates of the IPCC Sixth Assessment, drawn from a wider range of literature and approaches.  However it is an important step forward in analysis of ‘what works’ and their conclusion that big impacts require combinations of policies makes absolute sense.”

Dr Robin Lamboll, Research Fellow at the Centre for Environmental Policy, Grantham Institute – Climate Change and Environment, Imperial College London, said: 

“This study provides a groundbreaking tool, investigating which climate policies have had immediate impacts reducing CO2 emissions.  

“However, it’s important not to over-interpret the headline result that only a few policies can be tied to emissions reductions; many policies are aimed at clean air or small sectors of the economy that this study wouldn’t be suited to detect.  

“The study only looks for policies making sudden reductions, whereas most climate policies work on the efficiency of new things or the long-term trajectory of emissions, taking many years to build up greener infrastructure or ways of living.  

“This paper shows that making quick emissions reductions is hard and works best with joined-up thinking. It also reminds us that change is typically slow.  

“This means we need to move faster to introduce well-thought-out legislation now so that we can see the results in years to come.” 

Prof Paul Ekins, Professor of Resources and Environmental Policy at the UCL Institute for Sustainable Resources, said:

“Time was when it was an accepted policy maxim that a policy problem required one, and only one, policy to be directed at it, with more being redundant at best and inefficient at worst. And for climate policy that one policy was usually recommended, especially by economists, to be carbon pricing. Thankfully, it is now recognised that for climate change, with policy having to influence the behaviours of numerous firms in different economic sectors, and human activities as different as transport and home heating, a mix of policies is much more likely to be effective. This paper adds empirical weight to this recognition. At the same time it acknowledges the importance of carbon pricing as an element of that policy mix, especially in respect of high-carbon processes and activities that have available and comparably priced low-carbon alternatives. As to the policy mixes that seem to work best, there are few surprises. At the same time there is enough difference between countries to emphasise the importance of country context. While the successful policies in one country may guide a policy maker in another, nothing can replace detailed policy design that is specific and sensitive to each country’s special social and political conditions.”

Dr Peter Barbrook-Johnson, Lecturer at the Environmental Change Institute, University of Oxford, said:

“This is an impressive study with a methodical approach to assessing climate policy impacts.

“Assessing policy impacts is very difficult at the best of times, let alone in the context of climate change and the energy transition, where there are so many economic, energy, technology, and international dimensions affecting things. This difficulty, and the many contextual factors, likely explains why so few policies appear to have large direct impacts on emissions.

“These results should be taken with that difficulty in mind – any individual specific findings are likely to be tricky to rely on. However, there are some important broad trends that policy makers should take note of.

“It is now overwhelmingly clear that policy mixes, in which policies aimed at carbon prices are combined with investment, mandates, standards and planning rules, are likely to be more effective than individual policies or pricing alone. Coordination of policy between different ministries, and between countries is also vital.

“Successful climate policy happens at the sector-level, not across the whole economy at once. Ministries responsible for specific economic and industrial sectors need to be empowered by finance and treasury ministries to support serious well-funded policy.

“We must develop policy fit for where we are at now. In sectors where progress towards net zero is in early stages, we need investment and nurturing of new technologies, not harsh penalisation of carbon technologies, nor price signals that just push us towards slightly more efficient carbon tech. In sectors where the transition is further along, we can start to rely on carbon pricing and outright bans more, to accelerate the adoption of renewables and low carbon tech.”

Lindsay Hooper, CEO of the Cambridge Institute for Sustainability Leadership, said:

“We need to learn from the past to have any hope of solving the problems of the future.  The climate catastrophe is too urgent a problem to not be deploying the best available solutions that have the highest potential for effective action.  This important study should be required reading for anyone involved in the policy development process, bringing rigour and insight into what has and hasn’t worked on climate policy. Our own work has spoken clearly about the value of coherent policy packages that pay attention to prices and to context.”

Prof Peter Bannister, Chair of the Sustainability and Net Zero Policy Centre at the Institution of Engineering and Technology (IET) said:

“The research into the effectiveness of climate policies is very interesting. It’s clear that the road to Net Zero will require the implementation of policies that have a varying impact in isolation but collectively can drive significant change. This is why we advocate for our government to adopt a whole system approach to decarbonising the UK economy that is supported by skills. Our research has found that 67% of UK employers have a sustainability strategy, however, 76% of those say that they need additional skills to implement that strategy.  

“This research has been conducted across 41 countries, all of which have bespoke social and political needs as well as unique geographic hurdles that will only become more apparent as the effects of climate change intensify. What may work in one nation may not work in another, and having a broad package of solutions is helpful to navigate those specific challenges faced by each country. Governments will of course want to take the most efficient and effective route to decarbonisation, and the utilisation of this new machine learning analysis can help supercharge that decision making process. This is another example of where technology can be deployed to help solve the climate emergency. Technologies can be extremely energy intensive, but they can also be used to further sustainability goals. Models like this can be valuable in understanding the environmental net gain of the core policy principles on which technological advancements are built on.”

Dr Stuart Jenkins, Researcher at Oxford University, said:

“This is unfortunately not all that surprising — for all the talk we have had since the Paris Agreement how much has the emissions curve actually deviated since 2015? The single largest change in emissions year-on-year came as a result of the COVID pandemic. Achieving a high-ambition climate outcome requires a near-COVID-level reduction in global emissions every year between now and 2050. 

“Part of the challenge is that many policies focus on the wrong thing, bluntly controlling emissions via carbon pricing or demand-side incentives. But defining climate policy in terms of emissions controls is like managing your bank account by setting rules for the net money flow alone. Whilst the net money flow is useful knowledge, if we want to understand our finances we need to track the two levers which actually control it: income and expenditure. Likewise, we need to start thinking about setting climate policies which track the important levers separately: reductions in gross CO2 production, and increases in CO2 capture and permanent storage. With these we have a much better chance of controlling the net emissions flow.”

Bob Ward, Policy and Communications Director at the Grantham Research Institute on Climate Change and the Environment at the London School of Economics and Political Science, said:

“This study is interesting but its methodology has some serious limitations. There are very effective policies and legislation that cannot be directly linked to marked increases in emissions reductions. For instance, the U.K. results appears to highlight the introduction of the Carbon Price Floor in 2013 which led to a sharp reduction in the use of coal for electricity generation. However the results overlook the importance of the 2008 Climate Change Act, even though it created the crucial system of five-year carbon budgets and 2050 emissions target. This study has exaggerated the extent of ineffective policies because its methodology has overlooked many important policies that have driven long-term emissions reductions, but without creating a sharp break in emissions trends.”

‘Climate policies that achieved major emission reductions: Global evidence from two decades’ by Annika Stechemesser et al. was published in Science at 7pm UK time Thursday 22 August 2024.

DOI: doi/10.1126/science.adl6547

Declared interests

Stuart Jenkins: No declared interests

Robin Lamboll: no interests to declare

For all other experts, no reply to our request for DOIs was received.