The need for national deep decarbonization pathways for effective climate policy

TLDR

Global temperature limits of 2 °C require halving emissions by 2050 and full decarbonization by 2100, and the Paris Agreement obliges each nation to design reductions that fit the global carbon budget while engaging diverse stakeholders with differing decarbonization visions. The DDPP and its deep decarbonization pathways aim to give governments, businesses, civil society and researchers a shared, transparent framework to compare and debate concrete decarbonization scenarios, thereby building consensus for short‑term policies that align with long‑term climate goals. The project builds on energy, climate and economics literature to construct country‑scale, sector‑by‑sector pathways that backcast from 2050 endpoints, using a dashboard of emissions drivers to guide policy relevance and long‑term alignment. Applying this method to 16 country teams covering 74 % of global emissions, the study demonstrates that countries can meet the 2 °C target while sustaining development through efficiency gains and decarbonization of energy carriers such as electricity, hydrogen, biofuels and synthetic gas, and it identifies key enabling conditions for the transition.

Abstract

Constraining global average temperatures to 2 °C above pre-industrial levels will probably require global energy system emissions to be halved by 2050 and complete decarbonization by 2100. In the nationally orientated climate policy framework codified under the Paris Agreement, each nation must decide the scale and method of their emissions reduction contribution while remaining consistent with the global carbon budget. This policy process will require engagement amongst a wide range of stakeholders who have very different visions for the physical implementation of deep decarbonization. The Deep Decarbonization Pathways Project (DDPP) has developed a methodology, building on the energy, climate and economics literature, to structure these debates based on the following principles: country-scale analysis to capture specific physical, economic and political circumstances to maximize policy relevance, a long-term perspective to harmonize short-term decisions with the long-term objective and detailed sectoral analysis with transparent representation of emissions drivers through a common accounting framework or 'dashboard'. These principles are operationalized in the creation of deep decarbonization pathways (DDPs), which involve technically detailed, sector-by-sector maps of each country's decarbonization transition, backcasting feasible pathways from 2050 end points. This article shows how the sixteen DDPP country teams, covering 74% of global energy system emissions, used this method to collectively restrain emissions to a level consistent with the 2 °C target while maintaining development aspirations and reflecting national circumstances, mainly through efficiency, decarbonization of energy carriers (e.g. electricity, hydrogen, biofuels and synthetic gas) and switching to these carriers. The cross-cutting analysis of country scenarios reveals important enabling conditions for the transformation, pertaining to technology research and development, investment, trade and global and national policies.Policy relevanceIn the nation-focused global climate policy framework codified in the Paris Agreement, the purpose of the DDPP and DDPs is to provide a common method by which global and national governments, business, civil society and researchers in each country can communicate, compare and debate differing concrete visions for deep decarbonization in order to underpin the necessary societal and political consensus to design and implement short-term policy packages that are consistent with long-term global decarbonization.