Overshooting 1.5°C is fast becoming inevitable. Minimising the magnitude and duration of overshoot is essential. Multiple lines of evidence indicate that, due to insufficient mitigation of greenhouse gases (GHGs), no pathway remains that avoids exceeding 1.5°C global warming for at least some decades, except for truly radical transformations. Minimising the magnitude and duration of the overshoot period is critical for reducing loss and damage and the risk of irreversible changes.

A rapid and managed fossil fuel phase-out is required to stay within the Paris Agreement target range. The fast-shrinking carbon budget means that governments and the private sector must stop enabling new fossil fuel projects, accelerate the early retirement of existing infrastructure, and rapidly increase the pace of renewable energy deployment. High-income countries must lead the transition and provide support for low-income countries. All countries should pursue an equitable and just transition, minimising socio-economic impacts on the most vulnerable segments of the population.

Robust policies are critical to attain the scale needed for effective carbon dioxide removal (CDR). While not a replacement for rapid and deep emissions reductions, CDR will be necessary to deal with hard-to-eliminate emissions and eventually to reduce the global temperature. Current CDR is predominantly forest-based, but rapid acceleration and deployment at scale of other CDR methods with permanent CO2 removal is required, supported by stronger governance and better monitoring.

Over-reliance on natural carbon sinks is a risky strategy: their future contribution is uncertain. Until now, land and ocean carbon sinks have grown in tandem with increasing CO2 emissions, but research is revealing uncertainty over how they will respond to additional climate change. Carbon sinks may well absorb less carbon in the future than has been presumed from existing assessments. Therefore, emission reduction efforts have immediate priority, with nature-based solutions serving to increase carbon sinks in a complementary role to offset hard-to-abate emissions.

Joint governance is necessary to address the interlinked climate and biodiversity emergencies. The international conventions on climate change and biodiversity (United Nations Framework Convention on Climate Change and the Convention on Biological Diversity, respectively) must find better alignment. Ensuring that the allocation of climate finance has nature-positive safeguards, and strengthening concrete cross-convention collaboration, are examples of key actions in the right direction.

Compound events amplify climate risks and increase their uncertainty. “Compound events” refer to a combination of multiple drivers and/or hazards (simultaneously or sequentially), and their impacts can be greater than the sum of individual events. Identifying and preparing for specific compound events is crucial for robust risk management and providing support in emergency situations.

Mountain glacier loss is accelerating. Deglaciation in response to climate change is even quicker in high mountain areas, including the Hindu Kush Himalayas and polar regions. This threatens populations downstream with water shortages in the longer term (including approximately 2 billion for the Himalayas), and exposes mountain dwellers to increased hazards, such as flash flooding.

Human immobility in areas exposed to climate risks is increasing. People facing climate risks may be unable or unwilling to relocate, and existing institutional frameworks do not account for immobility and are insufficient to anticipate or support the needs of these populations.

New tools to operationalise justice enable more effective climate adaptation. Monitoring the distinct dimensions of justice and incorporating them as part of strategic climate adaptation planning and evaluation can build resilience to climate change and decrease the risk of maladaptation.

Reforming food systems can contribute to just climate action. Food systems have a key role to play in climate action, with viable mitigation options spanning from production to consumption. However, interventions should be designed with and for equity and justice as linked outcomes, and implementation of mitigation measures should be done inclusively with diverse stakeholders across multiple scales.