The United Nations Environment Programme (UNEP) yesterday published a new report, Limiting Overshoot: Navigating exceedance of 1.5°C and pathways towards return (the Report), examining the implications of exceeding the Paris Agreement’s 1.5°C temperature goal. The Report notes that global warming is now projected to reach at least 1.8°C and argues that climate policy must increasingly address not only whether 1.5°C is exceeded, but by how much and for how long. UNEP indicated that limiting the overshoot and peak, while pursuing pathways capable of bringing temperatures back down, will be critical to reducing climate risks and preserving future options for adaptation. This bulletin briefly summarizes the following key findings and pathways to respond to the global temperature overshoot set out in the Report: Overshoot is a pathway, not a moment. UNEP describes an “overshoot, peak and decline” pathway as the best remaining option to return global temperatures to or below 1.5°C by the end of the century. The pathway depends on minimizing peak warming through rapid and sustained greenhouse gas (GHG) reductions, reaching net-zero, and ultimately achieving net-negative emissions. The Report notes that lower peak warming and a shorter period above 1.5°C would reduce climate risks and impacts and improve the prospects of bringing temperatures back down. Going above 1.5°C must not mean abandoning the goal. UNEP states that global temperature rise is likely to cross 1.5°C within the next few years and that there are “no good outcomes” from remaining above that level. Risks intensify with every fraction of a degree and include more severe extreme weather, damage to food and water systems, ecosystem loss, and the possibility of crossing difficult or irreversible tipping points. Adaptation and mitigation must happen hand-in-hand. The Report emphasizes that mitigation and adaptation are interconnected and must advance together. Weak mitigation will increase climate impacts and adaptation needs,…
