Evaluating long-term low emission development strategies and implications for the remaining global carbon budget

The imperative to halt global warming extends beyond human boundaries, intertwining with the urgent need to achieve net-zero emissions. To this end, the Paris Agreement (PA) states that all Parties should strive to formulate their Long-Term Low Greenhouse Gas Emission Development Strategies (LT-LEDS). This article comprehensively reviews the LT-LEDS submitted to the United Nations Framework Convention on Climate Change (UNFCCC) by 53 Parties (representing 75% of global emissions) as of September 23rd, 2022. First, it conducts an analysis of the quality and completeness of the LT-LEDS. The findings of this analysis highlight the need for improvement in the reported information, particularly to improve the clarity of the information presented and the monitoring of progress towards the objective of each LT-LEDS. Furthermore, the study confirms the noticeable absence of reference to the principles of equity, and common but differentiated responsibilities and respective capabilities in the light of different national circumstances. Yet these principles should frame climate action within the PA. Second, this article estimates the carbon budget to be utilized by the Parties that have integrated net-zero emission (NZE) targets within their LT-LEDS. The analysis reveals that this group of Parties (i.e. those reporting on LT-LEDS and those with NZE targets), currently encompasses 37% of the global population and is responsible for 62% of global emissions. If these NZE targets are met, the group is projected to consume a total of 431 GtCO2. This value notably exceeds the threshold of 400 GtCO2, exceeding the remaining global carbon budget estimated by the IPCC to be compatible with a 67% likelihood to achieve a temperature increase objective of 1.5°C.To achieve the objectives of the PA, it is necessary for all countries to develop and implement their LT-LEDS, and for the 53 countries that have already submitted them to enhance the quality and comprehensiveness of the reported information and to improve the monitoring of progress towards NZE targets.To achieve the long-term objective of limiting the global temperature increase to 1.5°C, more countries need to actively engage in formulating and implementing NZE commitments. It is also imperative to increase the level of ambition in the existing NZE commitments, particularly those formulated by developed countries.All LT-LEDS, encompassing both present submissions and those anticipated in the future, should be formulated in the light of equity considerations, and meticulously assess the share of the global carbon budget that will be allocated to the LT-LEDS’ net-zero CO2 commitments.The analysis of net-zero CO2 commitments reveals that the existing NZE targets set by developed nations entail a carbon budget consumption significantly exceeding their equitable share, while those formulated by less developed countries remain notably below their due allocation. This divergence could potentially limit the capacity of the latter group to foster their development, compounded by the challenges of addressing climate change impacts.Examination of the current NZE commitments underscores that the current trajectory of emission reductions lacks a comprehensive framework to instigate the transformative changes required to achieve the ambitious mitigation objectives of the Paris Agreement. Consequently, there is an imperative for more detailed and comprehensive long-term visions at the national level, which will serve as guidance for short-term policy decisions and effectively prioritize the fundamental structural shifts needed.