Limiting Temperature Overshoot
The Art
The Science
United Nations Environment Programme (2026). Limiting Overshoot: Navigating exceedance of 1.5°C and pathways towards return. Nairobi. https://doi.org/10.59117/20.500.11822/49857 , Figure ES1
Figure ES 1: Temperature overshoot: actions and challenges (See next page)
Description: This is an illustrative depiction of temperature overshoot and the actions and challenges associated
with limiting its magnitude, duration and consequences. The visual features in the top panel are indicative and do not represent precise warming magnitudes, rates or probabilities. The black dashed line represents an overshoot pathway adapted from an SSP2-4.5 pathway based on IPCC (2021), while the light grey dashed line represents a high-overshoot pathway adapted from Reisinger et al. (2025). The horizontal line marks the 1.5°C global warming level, relative to 1850–1900. The light grey trajectories in the background are illustrative and are informed by visual interpolation across an ensemble of SSP scenarios and tipping-point peaks, depicting a world that may become increasingly challenging depending on the actions we take. The red dots are an illustrative representation of actions in mitigation and adaptation to limit overshoot. …
The art is based on the graph in the bottom panel depicting adaptation strategies.
Excerpts from Executive Summary*
“…While the international community has made progress on climate change, global action to cut greenhouse gas emissions has not been fast enough to avoid global warming crossing 1.5°C above pre-industrial levels in the next few years.
This means surpassing the multi-decadal global warming level of 1.5°C, the central long-term temperature goal
of the Paris Agreement, as affirmed by the International Court of Justice and backed by a UN General Assembly resolution. Even an optimistic scenario of current government pledges (full implementation of all national climate plans plus meeting additional net-zero targets) puts expected peak temperature rise at 1.8°C. …
Risks and impacts include faster sea-level rise, a higher likelihood of collapse of ecosystems such as coral reefs, more extreme heat and wildfires, and profound changes to the cryosphere (ice sheets, sea ice, glaciers, permafrost and snow). For example, glaciers could lose more than a quarter of their mass by 2100, which could raise sea levels by 9 to 12.5` cm (for warming up to/less than +3°C) and permanently alter water availability in many places. There is also a higher risk of irreversible tipping points to global systems such
as the West Antarctic and Greenland ice sheets, the Atlantic Meridional Overturning Circulation (AMOC) and the Amazon rainforest — which would reshape the world forever. …
… With unprecedented action it is possible to minimize and adapt to the impacts of exceedance and return to 1.5°C — which would keep options open to protect the poor and vulnerable, minimize harm to infrastructure and livelihoods, and support people and nature.
To do so, the world must get onto an ‘overshoot, peak and decline’ pathway that holds temperature rise to the lowest level possible, then brings it down by the end of the century, all while taking adaptation actions that reduce vulnerability to the current or expected impacts of climate change.
This is by no means an acceptable or preferred pathway; it is simply the best remaining option.
The global response needs to encompass three interconnected phases: immediate response, coping and containment, and long-term resilience.
· Immediate response phase (as temperatures approach, then exceed, 1.5°C): Slow warming quickly through deep emissions cuts, including to methane and other short-lived climate pollutants. Adopt urgent adaptation measures that protect the most-vulnerable people and ecosystems.
· Coping and containment phase (as temperatures peak): Advance deep and sustained decarbonization that achieves at least net-zero emissions. Develop societal resilience, while managing severe impacts and risks.
· Long-term resilience phase (as temperatures decline and stabilize): Deliver sustained net-
negative carbon dioxide (CO2) emissions. Enhance sustainability and resilience. Ensure lasting adaptation where irreversible limits have been reached. “
* United Nations Environment Programme (2026). Limiting Overshoot: Navigating exceedance of 1.5°C and pathways towards return. Nairobi. https://doi.org/10.59117/20.500.11822/49857
