{"id":172202,"date":"2026-01-14T07:23:00","date_gmt":"2026-01-14T06:23:00","guid":{"rendered":"https:\/\/renewable-carbon.eu\/news\/?p=172202"},"modified":"2026-01-08T11:40:24","modified_gmt":"2026-01-08T10:40:24","slug":"overshoot-returning-to-1-5c-requires-net-negative-emissions-targets","status":"publish","type":"post","link":"https:\/\/renewable-carbon.eu\/news\/overshoot-returning-to-1-5c-requires-net-negative-emissions-targets\/","title":{"rendered":"Overshoot: Returning to 1.5\u00b0C Requires Net-negative Emissions Targets\u00a0"},"content":{"rendered":"\n\n\n

Global warming is set to rise above 1.5\u00b0C by the early 2030s. Returning to 1.5\u00b0C before the end of the 21st century would not prevent all harms resulting from a period of excess temperatures, but it would reduce risks when compared to permanent warm\u00ading above 1.5\u00b0C. Limiting the magnitude and duration of this period of \u201covershoot\u201d to\u00a0manage climate risks requires enhanced near-term mitigation efforts to ensure that warming peaks well below 2\u00b0C, followed by sustained net-negative carbon dioxide (CO2<\/sub>) and potentially net-negative greenhouse gas (GHG) emissions globally. This pres\u00adents new challenges to international climate policy in efforts \u201cto keep 1.5\u00b0C alive\u201d. For frontrunners such as the European Union (EU), this will require reframing \u201cnet-zero\u201d as a transitional stage towards net-negative GHG emissions rather than an endpoint, and developing policy instruments that are able to deliver this.<\/strong><\/p>\n\n\n\n

In 2015, the United Nations Framework Con\u00advention on Climate Change (UNFCCC) created a long-term temperature goal with the adoption of its Paris Agreement, namely \u201cholding the increase in the global average temperature to well below 2\u00b0C above pre-industrial levels and pursuing efforts to limit the temperature increase to 1.5\u00b0C\u201d.<\/p>\n\n\n\n

Ten years later, global emissions of CO2<\/sub> and other GHGs are at their highest levels ever. It has now become virtually impossible to avoid exceeding 1.5\u00b0C, even when considering that global temperature goals do not refer to individual years, but 20-year running averages. Reaching and then exceed\u00ading 1.5\u00b0C is expected to happen by the early 2030s, regardless of the emissions reductions that may be achieved in the coming years. This was already indicated in the Synthesis Report<\/em> of the Sixth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) in 2023, and recently confirmed in the Emissions Gap Report<\/em> issued by the United Nations Environment Pro\u00adgramme (UNEP).<\/p>\n\n\n\n

This growing realisation \u2013 catalysed by a marked shift in UN officials\u2019 communica\u00adtions in late 2025 \u2013 confronts Parties to the UNFCCC with a choice either to aim for stabilising warming between 1.5\u00b0C and well below 2\u00b0C, or to try to achieve a reversal of global warming back to 1.5\u00b0C, after a period of overshoot<\/a> that may last multiple decades (see Figure 1<\/a>).<\/p>\n\n\n

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Figure 1 \u00a9 SWP<\/figcaption><\/figure><\/div>\n\n\n

Temporary overshoot as a concept<\/h3>\n\n\n\n

The physical climate system puts clear con\u00adstraints on human activities that are consist\u00adent with a peak and decline in the global average temperature. Global warming will be halted only when global net CO2<\/sub> emis\u00adsions from human activities reach zero, with peak warming determined largely by cumu\u00adlative net CO2<\/sub> emissions up to that point. A subsequent decline in global warming, which is needed to return to 1.5\u00b0C, relies on sustained net-negative CO2<\/sub> emissions from human activities, with total removals out\u00adweighing residual emissions of all long-lived GHGs. Reducing emissions of short-lived climate forcers, in particular methane (CH4<\/sub>), would also help limit peak warming. Further reductions beyond 2050 could con\u00adtribute to the subsequent decline in tem\u00adperature. In this sense, achieving net-zero GHG emissions globally, often dubbed \u201ccli\u00admate neutrality\u201d in climate policy circles, implies net-negative CO2<\/sub> emissions, leading to a slight decline in the global temperature.<\/p>\n\n\n\n

\u201cMagnitude\u201d and \u201cduration\u201d of an overshoot thus depend on the emissions profile both up to and after exceeding 1.5\u00b0C. The faster the world reaches net-zero CO2<\/sub> emis\u00adsions and the lower the rate of CH4<\/sub> emis\u00adsions, the less the exceedance of 1.5\u00b0C. The deeper the level of subsequent net-negative CO2<\/sub> emissions, the faster the return to 1.5\u00b0C (Figure 1<\/a>).<\/p>\n\n\n\n

Current scientific understanding suggests that net-negative CO2<\/sub> emissions would re\u00adduce global warming at roughly the same rate as ongoing emissions increase it. In quantitative terms, reducing the global aver\u00adage temperature by just 0.1\u00b0C would require about 220 gigatonnes (Gt) of net-negative CO2<\/sub> emissions. Gross amounts of carbon dioxide removal (CDR) will need to be even greater, given that it is impossible to reduce CO2<\/sub> emissions fully to zero (hence the net<\/em> in net-zero). For comparison: 220 Gt amount to five years of current annual emissions, and 100 years of current annual CDR levels (which are almost entirely in the form of con\u00adventional afforestation and reforestation). Novel methods, for example, bioenergy combined with carbon capture and storage (BECCS) and the direct capture of CO2<\/sub> from the ambient air and subsequent storage (DACCS), are both only in the early stages of development.<\/p>\n\n\n\n

Risks and impacts<\/h3>\n\n\n\n

Exceeding 1.5\u00b0C will result in greater im\u00adpacts on humans and ecosystems than if global warming had remained below that level, and it presents greater climate risks, including from extreme weather, ecosystem degradation, and socio-economic disruptions. Limiting overshoot \u2013 that is, limiting by how much and how long the world ex\u00adceeds 1.5\u00b0C in the first place \u2013 remains the critical step in addressing these threats.<\/p>\n\n\n\n

It is much less clear at this point how much a subsequent decline in temperature would reverse different climate risks. In prin\u00adciple, reducing global warming will help limit all physical climate changes \u2013 either because they are reversed (e.g. the frequency and intensity of heatwaves), or because the changes will not be as significant as they would have been had the global average temperature remained elevated above 1.5\u00b0C (e.g. sea level rise). However, the risk from climate change arises not merely from phy\u00adsical changes in climate, but from the inter\u00adaction of such changes with the exposure and vulnerability of human society and eco\u00adsystems. Regions that experience extreme climate events during the overshoot phase could face long-term social and economic consequences, since climate-related impacts such as malnutrition, poverty, and infrastruc\u00adture damage \u2013 along with weakened insti\u00adtutions and strained financial capacity \u2013 are likely to persist well beyond peak warming.<\/p>\n\n\n\n

For many ecosystems, a period of excess temperatures could disrupt species com\u00adpo\u00adsi\u00adtion and food webs that may be irrevers\u00adible or take many human generations to recover. However, species extinction will be irreversible, even if restoring a former eco\u00adsystem state were possible.<\/p>\n\n\n\n

A world that returns to global warming of 1.5\u00b0C will be a significantly altered and more damaged world than if this level of warming had never been exceeded.<\/p>\n\n\n\n

Political significance of overshoot<\/h3>\n\n\n\n

By now, relying on some form of overshoot trajectory has become the only way to \u201ckeep 1.5\u00b0C alive\u201d. We do not know yet whether the UNFCCC will explicitly adopt this vision in future decisions. So far, there has been no serious discussion about climate system impacts, political responsibilities, and future policy responses resulting from exceeding \u2013 and potential returning to \u2013 1.5\u00b0C. This is even though the term \u201covershoot\u201d can be found in many UNFCCC documents \u2013 it is used to refer to the nomenclature of IPCC-assessed mitigation pathways for achieving 1.5\u00b0C by 2100 but does not deal with its sub\u00adstance yet.<\/p>\n\n\n\n

Taking overshoot seriously would catalyse two paradigm shifts in global climate policy. Initially, the more obvious one seems to be the conceptual introduction of a phase of managed temperature decline, enabled by aiming for net-negative CO2<\/sub> emis\u00adsions globally, potentially to be fol\u00adlowed by net-negative GHG emissions. This would immediately raise the question of who is in charge to lead the way into net-negative territory. Under the UNFCCC\u2019s core principle of Common But Differentiated Respon\u00adsibilities<\/em> (CBDR), the answer can only be that developed countries will have to continue to be the frontrunners by adopting and pur\u00adsuing national net-negative targets, which entails stringent emissions reductions while rapidly upscaling CDR. If 1.5\u00b0C is to remain the core temperature goal, then net-zero can no longer be seen as an end point but only as a transition point in climate policy.<\/p>\n\n\n\n

However, the more pressing and maybe more disruptive shift will come with the inevitable, yet contentious introduction of a new interim \u2013 and perhaps only implicit \u2013 temperature target: peak warming. Although there has not been any discussion so far, the global climate debate is likely to focus on the 1.7\u20131.8\u00b0C range. Everything below 1.7\u00b0C does not seem feasible any\u00admore. Everything above 1.8\u00b0C would be too high a level to achieve a return to 1.5\u00b0C in this cen\u00adtury and also increase the potential for warming to exceed even 2\u00b0C, once scientific uncertainties are taken into account.<\/p>\n\n\n\n

Least-developed countries can be expected to call for enhanced financial flows to cover additional damages linked to the exceedance of 1.5\u00b0C, even if only thought to be tem\u00adporary. Since countries such as China, India, and Saudi Arabia seem to favour \u201cwell below 2\u00b0C\u201d as the focal point for global cli\u00admate policy, the UNFCCC may never be able to reach consensus on an exact peak warm\u00ading target. But even with ambiguity con\u00adcerning the intended peak level, reaching net-zero CO2<\/sub> emissions would remain the global focal point for climate action as a pre\u00adrequisite for halting further warming.<\/p>\n\n\n\n

Challenges for EU climate policy<\/h3>\n\n\n\n

If the EU really wants \u201cto keep 1.5\u00b0C alive\u201d, it will need to adopt and elevate the con\u00adcept of a temperature overshoot target and proactively deal with its consequences for long-term emissions targets, both in multi\u00adlateral fora and within Europe. Failing to do so will inevitably lead to the impression that \u201c1.5\u00b0C overshoot\u201d is nothing more than an interesting thought experiment, and that sta\u00adbilising global warming well above 1.5\u00b0C is by now the best the world can still hope for.<\/p>\n\n\n\n

At the global level \u2013 whether it is the UNFCCC, the G20, or the G7 \u2013 the over\u00adshoot concept can only gain political cred\u00adibility if developed countries underscore it by first committing to reaching and sustain\u00ading net-negative emissions. The requirement for frontrunners to enter net-negative terri\u00adtory holds, even if global ambition remains limited to net-zero GHG emissions, given the uneven distribution of responsibilities and capacities. This will inevitably trigger a renewed debate about global burden-shar\u00ading (including the role of emerging econo\u00admies such as China) and international col\u00adlective efforts to drastically upscale CDR in the medium- to long-term while managing risks from adverse side-effects.<\/p>\n\n\n\n

Within the EU, this would first and fore\u00admost entail setting a quantified net-negative GHG emissions target for 2060, as already implicitly foreseen in the European Climate Law, but currently only applied by a single member state (Denmark, with -110 % by 2050). This will refuel burden-sharing con\u00adflicts within the EU, where economically less advanced member states may demand that countries such as Germany, France, and Denmark take the lead and commit to deep levels of net-negative emissions, while Central and Eastern European countries \u2013 and those with high shares of hard-to-abate residual emissions \u2013 may follow only later. The same applies to economic sectors, where mitigation pathway modelling indicates that the European power sector will deliver net-negative emissions early on while agri\u00adculture stays net-positive (see SWP Research Paper 8\/2020<\/a>). Furthermore, the EU will be forced to develop viable macroeconomic and policy frameworks that advance beyond the standard \u201cpolluter pays\u201d principles and simple win-win narratives. Going deeply net-negative will turn carbon pricing from a source of income into a significant financial burden; so far, no convincing vision has been presented that illustrates how entering net-negative territory will give frontrunners a competitive advantage in the long run.<\/p>\n\n\n\n

The EU has been a pioneering force in international climate policy for more than three decades now, even within developed-country groupings such as the G7. Reaching net-negative emissions will be the next frontier that multiplies many current policy challenges. Making serious plans to enter this territory will provide a crucial example for the rest of the world.<\/p>\n\n\n\n

<\/div>\n\n\n\n

About the authors<\/h3>\n\n\n\n

Dr Oliver Geden is Senior Fellow in the EU \/ Europe Research Division and Head of the Research Cluster Climate Policy and Politics at SWP. Dr Andy Reisinger is honorary associate professor at the Institute for Climate, Energy and Disaster Services, Australian National University.<\/em><\/p>\n\n\n\n

<\/div>\n\n\n\n

This work is licensed under CC BY 4.0<\/a>\"\"<\/p>\n\n\n\n

This Comment reflects the authors\u2019 views.<\/p>\n\n\n\n

SWP Comments are subject to internal peer review, fact-checking and copy-editing. For further information on our quality control pro\u00adcedures, please visit the SWP website: https:\/\/www.swp-berlin.org\/en\/about-swp\/ quality-management-for-swp-publications\/<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

Global warming is set to rise above 1.5\u00b0C by the early 2030s. Returning to 1.5\u00b0C before the end of the 21st century would not prevent all harms resulting from a period of excess temperatures, but it would reduce risks when compared to permanent warm\u00ading above 1.5\u00b0C. Limiting the magnitude and duration of this period of […]<\/p>\n","protected":false},"author":59,"featured_media":172221,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_seopress_robots_primary_cat":"none","nova_meta_subtitle":"For frontrunners such as the European Union (EU), this will require reframing \u201cnet-zero\u201d as a transitional stage towards net-negative GHG emissions, and developing policy instruments that are able to deliver this","footnotes":""},"categories":[5572,5571,17143],"tags":[16380,10744,12330,10416,13087,15311,22310,27418,14441,10453,10743],"supplier":[17197,5585,7846],"class_list":["post-172202","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-bio-based","category-co2-based","category-recycling","tag-biobased","tag-carboncapture","tag-ccu","tag-circulareconomy","tag-climate","tag-emissions","tag-netzero","tag-overshoot","tag-policy","tag-recycling","tag-useco2","supplier-australian-national-university-anu","supplier-european-union","supplier-swp-berlin"],"_links":{"self":[{"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/posts\/172202","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/users\/59"}],"replies":[{"embeddable":true,"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/comments?post=172202"}],"version-history":[{"count":0,"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/posts\/172202\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/media\/172221"}],"wp:attachment":[{"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/media?parent=172202"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/categories?post=172202"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/tags?post=172202"},{"taxonomy":"supplier","embeddable":true,"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/supplier?post=172202"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}