On May 22, Prime Minister Élisabeth Borne announced that the National Low Carbon Strategy (SNBC), the roadmap setting the country’s emissions trajectories by 2050, was being revised. The current roadmap – the SNBC-2 for insiders – does indeed expire in December 2023.
SNBC-3 must now align with our European commitments: in December 2020, the European Union (EU) raised its greenhouse gas emissions reduction target to 55% between 1990 and 2030, compared to 40 % previously. Quite a stairway to climb in just seven years.
The 55% target applies to all greenhouse gases, including international transport. It concerns emissions net of CO2 absorptions by changes in land use, measured by national inventories. It must be achieved without using international carbon credits. The constraint therefore relates to gross emissions, which must be reduced, and to the absorption capacity of atmospheric carbon, which must be increased.
Let’s start by looking at raw emissions. Since 1990, these emissions have fallen by a quarter. The entire reduction was achieved between 2005 and 2022. From one year to the next, these emissions are subject to fluctuations that can be significant. Over the period 2005-2022, they follow a trend, statistically robust and independent of political alternations: an annual decline of 1.8%, or 8.5 megatonnes (Mt) of CO2 equivalent per year.
The extension of this trend would lead to emissions of 340 Mt of CO2 equivalent in 2030. However, the ecological planning unit attached to the Prime Minister estimates that it would be necessary to aim for 270 Mt to be in phase with the European objective of – 55 %. Closing the gap in seven years therefore requires not doubling, as is often asserted, but tripling the pace of effort: from an annual decline of 1.8% to 5% or even 8.5 Mt to 17.5 Mt per year.
The vast majority of emissions from industry and the energy sector are directly regulated by the European CO2 quota trading system. For this category of emissions, the constraint is shared at European level and there are no specific national obligations.
For other emissions, mainly located in the sectors of transport, agriculture, buildings and waste, the passage from the European objective to the national objectives is carried out via a so-called “effort sharing” regulation. As part of this sharing, France must reduce emissions from these sectors by 47.5% by 2030, relative to 2005. One of the biggest tasks of the SNBC consists in distributing this reduction objective by sector and by economic agent.
One way of prioritizing the actions to be taken would be to use the criterion of the cost of the ton of CO2 avoided: if it costs 20 euros to reduce emissions through action A and 100 euros through action B, we reduce with the same initial bet five times more emissions by retaining share A rather than share B. It would be a shame to deprive yourself of it.
Under the authority of economist Patrick Criqui, significant work has been done to identify these costs by sector of activity. This toolbox seems relatively little used in the trade-offs proposed by the Matignon ecological planning unit. Reduction potentials are estimated using technical and economic methods adapted to the specific characteristics of each sector.
Representing, on its own, a third of national emissions, the transport sector clearly crystallizes the puzzle of the reassessment of the SNBC. In 2022, transport emissions were 5% higher than their 1990 level, compared to a drop of one third in all other sectors. The SNBC-3 project, prepared at Matignon, aims for a 30% drop between 2022 and 2030. How to achieve this?
To aim for a 30% reduction by 2030, it is therefore necessary to act simultaneously on demand by activating levers that have a faster impact on emissions: reducing unnecessary travel, expanding the practice of carpooling, promoting public transport and soft mobility, limiting the speed of road and motorway travel.
These so-called “sobriety” levers refer to the uses that citizens make of existing infrastructures. These uses are impacted by prices and household budget constraints, but not only. In 2022, the government subsidized energy prices with the famous tariff shield. The effects were quite different on household electricity and gas consumption, for which the sobriety messages were heard, and on fuels, the consumption of which increased markedly in the absence of such messages.
This division between actions on demand and on supply is important for the evaluation of the economic impacts of the climate roadmap. In their report submitted to the Prime Minister on the issue, economists Jean Pisani-Ferry and Selma Mahfouz assume that 15% of emission reductions are obtained through sobriety. Other scenarios, such as the one developed by the négaWatt association, rely on 33%.
This assumption is crucial for the calculation of the investments required to implement the SNBC. Part of the emission reductions resulting from sobriety in fact require little or no additional investment. But sobriety cannot be decreed. It implies citizen support, which is difficult to obtain when the social context is degraded.
This point is essential: what reduces CO₂ emissions is not to invest in decarbonized sources, it is to divest from fossil sources by withdrawing or reconverting the capital linked to the production or use of carbon. ‘fossil fuels. Productive capacity is therefore not increased by low-carbon investment and disinvestment must be financed by ensuring industrial and professional retraining.
To aim for climate neutrality, it is not enough to make the energy transition by freeing oneself from dependence on fossil fuels. A second systemic transformation is needed concerning activities working on “living carbon”: agriculture, forestry, organic waste management. We are very ill-prepared for it.
In the SNBC-3 project, the expected reduction in agricultural emissions, the second emitting sector after transport, is much more modest than those targeted in the other sectors. It results more from incremental developments than from the start of a systemic transition leading to a shift towards agricultural models based on the diversity of living things to produce in a resilient and intensive way per hectare. However, it is indeed a change of system that agriculture needs to reduce its specific emissions and contribute to the protection of the national carbon sink by protecting its living soils to store CO2.
The recent European regulation assigns France the objective of absorbing 34 Mt of atmospheric CO2 in 2030, while only 17 Mt were absorbed in 2022. This will be the main puzzle of the next SNBC: how to multiply by two the absorptive capacity of the national carbon sink when we have reduced it by three over the last fifteen years?
Christian de Perthuis is Professor of Economics, Founder of the Climate Economics Chair, Paris-Dauphine-PSL University.