In exchange for political support, the Brazilian government is signalling landholders to increase deforestation, putting the country’s contribution to the Paris Agreement at risk¹. The President of Brazil has signed provisionary acts and decrees lowering environmental licensing requirements, suspending the ratification of indigenous lands, reducing the size of protected areas and facilitating land grabbers to obtain the deeds of illegally deforested areas². This could undermine the success of Brazil’s CO₂ emission reductions through control of deforestation in the previous decade. Integrated assessment models are tools to assess progress in fulfilling global efforts to curb climate change^3,4. Using integrated assessment models developed for Brazil, we explore 2 °C-compliant CO₂ emission scenarios estimating the effort needed in other sectors of the economy to compensate for the weakening of environmental governance, potentially resulting in higher deforestation emissions. We found that the risk of reversals of recent trends in deforestation governance could impose a burden on other sectors that would need to deploy not yet mature technologies to compensate for higher emissions from land-use change. The abandonment of deforestation control policies and the political support for predatory agricultural practices make it impossible to meet targets consistent with Brazil’s contribution to a 2 °C world.

Decarbonization of energy-using sectors is essential for tackling climate change. We use an ensemble of global integrated assessment models to assess CO₂ emissions reduction potentials in buildings and transport, accounting for system interactions. We focus on three intervention strategies with distinct emphases: reducing or changing activity, improving technological efficiency and electrifying energy end use. We find that these strategies can reduce emissions by 51–85% in buildings and 37–91% in transport by 2050 relative to a current policies scenario (ranges indicate model variability). Electrification has the largest potential for direct emissions reductions in both sectors. Interactions between the policies and measures that comprise the three strategies have a modest overall effect on mitigation potentials. However, combining different strategies is strongly beneficial from an energy system perspective as lower electricity demand reduces the need for costly supply-side investments and infrastructure.

Despite faster-than-expected progress in clean energy technology deployment, global annual CO₂ emissions have increased from 2020 to 2023. The feasibility of limiting warming to 1.5 °C is therefore questioned. Here we present a model intercomparison study that accounts for emissions trends until 2023 and compares cost-effective scenarios to alternative scenarios with institutional, geophysical and technological feasibility constraints and enablers informed by previous literature. Our results show that the most ambitious mitigation trajectories with updated climate information still manage to limit peak warming to below 1.6 °C (‘low overshoot’) with around 50% likelihood. However, feasibility constraints, especially in the institutional dimension, decrease this maximum likelihood considerably to 5–45%. Accelerated energy demand transformation can reduce costs for staying below 2 °C but have only a limited impact on further increasing the likelihood of limiting warming to 1.6 °C. Our study helps to establish a new benchmark of mitigation scenarios that goes beyond the dominant cost-effective scenario design.