The UNEP\u2019s new report \u2018Limiting Overshoot\u2019 <\/a>outlines a pathway called \u201covershoot, peak and decline\u201d to minimise and adapt to the impacts of an exceedance and an eventual return to 1.5\u00b0C. But even in the best case scenario where governments fully implement and exceed their current and future climate action plans, the UNEP states that our temperature rise will still hit 1.8\u00b0C before declining. <\/p>\n\n The UNEP stresses there are \u201cno good outcomes if we remain above 1.5\u00b0C\u201d and that we must focus on making the overshoot as small and short as possible. This will be determined by decisions taken today \u2013 rapid climate action across all sectors is \u201cboth necessary and feasible\u201d to hold warming as close to 1.5\u00b0C by 2100. <\/p>\n\n What does an overshoot of 1.5\u00b0C actually mean?<\/strong><\/p>\n\n In 2015, at the UN climate conference COP21 in Paris, close to 200 governments committed to efforts aimed at limiting global warming to 1.5\u00b0C and well within 2\u00b0C by 2100.<\/p>\n\n While the average global temperatures rose above target for the first time in 2024<\/a> \u2013 hitting 1.6\u00b0C above the pre-industrial period \u2013 this did not signify a long-term breach of the 1.5\u00b0C limit. One year is only a single indicator and what matters is the long-term trend \u2013 measured as a temperature increase over decades<\/a>, not individual months or years. <\/p>\n\n The term \u2018overshoot\u2019, however, is increasingly being used to describe future temperature trends <\/a>that temporarily exceed 1.5\u00b0C and are followed by future declines. Overshoot, peak and decline pathways are part of the new set of global emissions scenarios<\/a> which will provide the basis for upcoming climate research reports from the Intergovernmental Panel on Climate Change (IPCC), the UN\u2019s climate science panel.<\/p>\n\n What does the UNEP report say about avoiding a 1.5\u00b0C overshoot?<\/strong> <\/p>\n\n The UNEP said global action to cut greenhouse gas emissions had been too slow to stop temperatures rising more than 1.5\u00b0C in \u201cthe next few years\u201d<\/a>. <\/p>\n\n In terms of the planetary carbon budget, only about 130 Gt of additional CO2<\/sub> can be emitted from 2026 onwards to have even a 50% chance of limiting global warming to 1.5\u00b0C. To stay within this budget, CO2<\/sub> emissions would need to decline steadily from 2025 levels to zero in just over six years, leaving us with a huge emissions gap between current levels and what is needed. <\/p>\n\n So, after decades of \u201cinsufficient action\u201d, the UNEP outlined three challenges to limiting temperature overshoot:<\/p>\n\n The UNEP called for a global response that includes the three interconnected phases. An immediate response for slowing temperature rise, involving deep emission cuts and urgent measures to protect vulnerable populations. Secondly, a coping and containment phase focusing to boost climate resilience needs, followed by a third phase that focuses on building long-term resilience with net-negative emissions.<\/p>\n\n What\u2019s required, it added, was multilateral cooperation, climate finance and effective implementation of government policies to accelerate the transition away from fossil fuels and to expand renewable energies, cut methane pollution and protect land, forest and oceans.<\/p>\n\n What are the consequences of a 1.5\u00b0C overshoot? Cryosphere impacts such as Arctic sea ice and habitat loss, glacial loss, permafrost thaw and degradation will be on the frontline and these impacts will affect ecosystems and downstream communities dependent on seasonal melt water.<\/p>\n\n Loss of biodiversity in marine and terrestrial fronts from land use change and ocean acidification will trickle down to human health, food and water security as cities and infrastructure come under \u201cincreasing strain\u201d from extreme events and other impacts.<\/p>\n\n The UNEP also warned that some Small Island Developing States (SIDS) and low-lying coastal cities could become partially or completely submerged due to sea level rise. This could put continuity of their statehood itself in question.<\/p>\n\n All of these, among others, will mean that societies have to adjust constantly, raising issues of justice, power, and political legitimacy.<\/p>\n\n![\"With](\"https:\/\/www.greenpeace.org\/static\/planet4-international-stateless\/2026\/09\/d9340be7-gp1swd3y.jpg\" "\\"Aerial")
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The UNEP said that by delaying action we might lose the chance to return to 1.5\u00b0C and \u201cface an unprecedented, damaged world\u201d. The impacts of a 1.5\u00b0C overshoot would be wide and varied, affecting ecosystems, human systems and economic systems.
The repeated heatwaves and wildfires among the so-called natural disasters in 2026<\/a> are also the types of impacts we\u2019ve been warned about. A potential world of 1.5\u00b0C overshoot will see these types of disasters become more likely and potentially more severe in years to come.<\/p>\n\n![\"The](\"https:\/\/www.greenpeace.org\/static\/planet4-international-stateless\/2026\/09\/f3f7c821-gp0su2cjj.jpg\" "\\"Blomstrandbreen")
![\"During](\"https:\/\/www.greenpeace.org\/static\/planet4-international-stateless\/2026\/02\/4b2a9e3d-gp0su4ubo.jpg\" "\\"\"Respect")
![\"A](\"https:\/\/www.greenpeace.org\/static\/planet4-international-stateless\/2026\/09\/fba0217b-gp0su9sgq.jpg\" "\\"Wildfires")