Context

As the imperative to address climate change intensifies, understanding the effectiveness of policy interventions becomes paramount. In the context of addressing these urgent challenges and given the inadequacy of current policies to address this issue, this study examines the extent to which Nationally Determined Contributions (NDCs) and Long-Term Targets (LTTs) can contribute to achieving ambitious climate goals.

Methodology

Recognizing the critical need for effective climate action, we employ the advanced modelling tools PROMETHEUS and GCAM to assess the implications of different scenarios–Current Policies (CP), Nationally Determined Contributions (NDC), and combination of NDCs with Long-Term Targets (NDC_LTT)–on the future development of energy system and emission. This study, by employing these well-known models, seeks to provide an improved understanding of the impacts of NDCs on global emission trajectories and whether the integration of NDCs and LTTs can help close the gap towards Paris-compatible pathways. The following scenario assumptions are used:

• Current Policies (CP): The scenario is based on the current portfolio of actual emissions reduction policies as well as credible policy targets until 2030 in EU and non-EU countries. For the period post-2030 action, the CP scenario assumes that climate policy continues but is not strengthened. The CP scenario assumes that the rate of change of emission intensity of GDP over 2020–2030 remains the same after 2030.The applied policy targets until 2030 (for example, renewable energy mix targets, vehicle fuel standards) are maintained as minimum levels beyond 2030 to avoid backtracking of achieved policies.
• Nationally Determined Contributions (NDC): The scenario assumes the implementation of stated 2030 emission targets captured in NDCs submitted or announced by June 2022, capturing all mitigation ambition updates during and after COP26. These NDC targets are applied on top of current policies (CP) modelled in the previous scenario; in regions where current policies overachieve on the mitigation targets in NDCs, no additional emission constraints are applied. For the period after 2030, the same method based on constant carbon intensity of GDP reduction rates over 2020–2050 is applied as in the CP scenario.
• NDCs with Long-Term Targets (NDC_LTT): The scenario is based on the NDC assumptions until 2030 but, for regions that formulated an LTT, such as net-zero commitments or other targets for 2050 or later (either in law, policy documents, or only announced), emission constraints are applied that linearly decline from 2030 NDC emission levels towards the LTT. For regions without LTTs, post-2030 emissions follow an identical path as in the NDC scenario.

Sectoral focus

The study analyzes various sectors including buildings, transportation, electricity generation, and industry to provide insights into the limitations of existing policies and the potential of enhanced commitments to drive transformative changes in a global scale. The effectiveness of these policies varies across different sectors, highlighting the challenges that need to be addressed for achieving the required emission reduction targets in the medium- and long-term.

The results of the NDC-constrained scenarios (NDC and NDC_LTT) are identical until 2030, but their differences increase substantially in the following period (2030–2050) in both energy supply and demand sectors (including transport, industry, and buildings). Key findings indicate significant shifts in energy consumption, fuel mix, technology adoption, and emission trajectories, particularly under the synergistic action represented by the NDC_LTT scenario.

You can explore below the resulting global emissions from GCAM and PROMETHEUS models and for the following scenarios: 

• Current Policies (CP): The scenario is based on the current portfolio of actual emissions reduction policies as well as credible policy targets until 2030 in EU and non-EU countries.
• Nationally Determined Contributions (NDC): The scenario assumes the implementation of stated 2030 emission targets captured in NDCs submitted or announced by June 2022, capturing all mitigation ambition updates during and after COP26.
• NDCs with Long-Term Targets (NDC_LTT): The scenario is based on the NDC assumptions until 2030 but, for regions that formulated an LTT, such as net-zero commitments or other targets for 2050 or later (either in law, policy documents, or only announced), emission constraints are applied that linearly decline from 2030 NDC emission levels towards the LTT.

Focusing on the industry sector, the NDC-constrained scenarios would lead to a 3–7% reduction in industry-related emissions compared to CP scenario in 2030, with even larger emission reductions achieved in the NDC_LTT scenario by 2050 (reductions larger than 25% from CP levels in both models) due to the increased adoption of cleaner technologies and fuels (e.g., renewable electricity, green hydrogen), the imposition of carbon pricing that penalizes fossil fuel use (so as to meet the NDC and LTT targets), and the accelerated energy efficiency improvements in all industrial sub-sectors.

You can explore below the resulting global emissions from GCAM and PROMETHEUS models.

Global CO2 emissions from buildings sector will experience a 12% reduction in the GCAM model in 2030 (in the NDC constrained scenarios relative to CP) and a more substantial 17% in PROMETHEUS due to the more holistic representation of several energy efficiency options such as building retrofits to improve thermal insulation and uptake of electric heat pumps. The projected emission reductions accelerate in the period after 2030, especially in the NDC_LTT scenario, with models showing a 31–39% reduction compared to CP levels in 2050. This indicates a growing emphasis on energy efficiency to reduce energy requirements, especially for space and water heating purposes, and an accelerated transition toward electrification of end-uses and cleaner energy solutions for residential and commercial buildings.

You can explore below the resulting global emissions from GCAM and PROMETHEUS models.

In the transportation sector, the models show that the NDC constrained scenarios will lead to CO2 emissions reduction in 2030 (relative to CP levels), but the magnitude ranges from 2% in the GCAM model to 10% in PROMETHEUS. This is due to the higher potential both for efficiency improvements (e.g., uptake of more efficient cars, trucks, and planes) and for an accelerated uptake of electric vehicles. The variance in these results arises from the different assumptions about the pace of technological advancements, policy support for electric vehicles, and consumer preferences in the two models.

This variance increases even more in the long-term, as the NDC_LTT scenario is projected to lead to a mere 8% reduction in global transport CO2 emissions in GCAM (compared to CP levels), while the reduction is substantially higher in the PROMETHEUS model (67% below CP levels), largely driven by the restructuring of the transport sector through the uptake of electric vehicles as well as other clean energy options in specific transport segments (e.g., advanced biofuels, hydrogen, e-fuels). In contrast, GCAM, due to its structure, follows a more conservative estimate of emission reduction in the transport sector, including the representation of technological advancements, fuel transitions, and policy effectiveness, and assumes that most of the mitigation effort will be driven by the energy supply sector.

You can explore below the resulting global emissions from GCAM and PROMETHEUS models.

The increased renewable energy uptake in 2030 (in the NDC and NTC_LTT scenarios compared to CP) combined with the phase out of carbon-intensive technologies (in particular coal and gas-fired power plants) would lead to a 13% and 20% reduction in CO2emissions from electricity generation according to GCAM and PROMETHEUS, respectively. The adoption of high carbon pricing that penalizes the use of fossil fuels is the major driver for emissions reductions achieved in energy supply. Looking ahead to 2050, the widespread adoption of low- and zero-carbon technologies—driven by a fast ramp-up of solar PV and wind power with smaller contributions by biomass, hydro, and nuclear—combined with the closure of high emission power plants would lead to reduction in CO2 electricity-related emissions that range from 37–51% in the NDC scenario.

The combination of NDCs and LTTs, though, would further accelerate decarbonization efforts and lead to a transformative shift in electricity generation, with electricity-related CO2emissions reaching reductions of 90–94% by 2050 due to widespread uptake of renewable energy technologies, the deployment of advanced carbon capture and storage (CCS) technologies—including Biomass combined with CCS (BECCS) leading to net negative emissions–and comprehensive policy frameworks that create a conductive environment for sustainable energy practices, especially in the form of high carbon pricing.

You can explore below the resulting global emissions from GCAM and PROMETHEUS models.