联合国发布报告警告升温突破1.5度已不可避免 维持现状本世纪或升温2.8度UN Warns 1.5C Limit Unavoidably Lost as World Faces 2.8C Warming Trajectory

联合国环境规划署在报告中改变了以往仅衡量减排承诺与1.5度差距的分析方法，转而聚焦于升温“超调”情景。该机构指出，数十年间化石燃料减排力度的不足，使得气温越过1.5度门槛在接下来的几年内成为既成事实。联合国环境规划署执行主任英格·安德森向记者表示，控温窗口已经关闭，目前的任务是通过尽可能缩短超调时间与幅度，找到一条最快让全球平均气温回落的路径。

The United Nations Environment Programme shifted its assessment framework in the new report, moving away from merely measuring the distance between pledges and the 1.5-degree Celsius target to evaluating emissions overshoot scenarios. UNEP noted that decades of insufficient cuts to fossil fuel pollution mean global temperatures will unavoidably slip past the threshold within the next few years. Inger Andersen, executive director of the UN Environment Programme, told reporters that the initial window has closed, framing the remaining objective as finding a way back as quickly as possible by keeping the overshoot period and peak temperature strictly limited.

报告警告，气温即使是暂时突破1.5度，也将显著增加触发不可逆临界点的概率，涵盖珊瑚礁退化、冰盖长期融化、永久冻土融化释放碳、海洋环流改变以及亚马逊雨林退化为草地等连锁反应。极端气候事件已在当前显现：过去一个夏季，欧洲记录了超过3.2万起与高温相关的过量死亡，而在尼泊尔和西藏地区，冰川坍塌引发的山洪导致近1500人遇难。宾夕法尼亚大学气候学家迈克尔·曼指出，超过1.5度后每增加零点几度的升温，在破坏程度、经济损失与生命代价上都会带来巨大冲击。

Exceeding 1.5 degrees Celsius, even temporarily, significantly heightens the danger of crossing irreversible tipping points, the report found. These risks include the permanent loss of coral reefs, long-term ice sheet retreat, permafrost carbon release, ocean circulation shifts, and the Amazon rainforest converting into grassland. Severe climate impacts are already unfolding: over the recent summer, Europe recorded more than 32,000 excess heat-related deaths, while glacier collapse fueled flash floods in Nepal and Tibet that killed nearly 1,500 people. University of Pennsylvania climate scientist Michael Mann observed that every additional fraction of a degree beyond 1.5 degrees Celsius imposes immense damage, mounting costs, and escalating human tolls.

联合国环境规划署在报告中列出多种排放情景，揭示各国既有行动与承诺目标之间存在显著断层。目前共有167个国家向联合国提交了气候行动方案，涵盖全球83%的温室气体排放量。然而测算显示，即使这些国家完全兑现各自的减排承诺，到2030年全球排放量仅能减少5%至8%，到2035年仅能降低11%至15%，所对应的全球升温峰值依然在2.6摄氏度左右，难以避免灾难性的极端天气。

The UN Environment Programme outlines contrasting emissions trajectories in the report, highlighting a substantial disconnect between current governmental actions and stated climate ambitions. To date, 167 nations have submitted climate action plans to the United Nations, accounting for 83% of global greenhouse gas emissions. However, modeling shows that even if every government fully meets its updated reduction pledges, global planet-warming emissions would decline by only 5% to 8% by 2030 and 11% to 15% by 2035 relative to 2025 levels, leaving peak warming hovering around 2.6 degrees Celsius.

如果各国仅维持现有政策而不追加行动，全球气温峰值预计将达到2.8摄氏度。报告指出，这一测算数值较往年有所上升，部分原因在于美国退出《巴黎协定》并撤回其减排承诺。即便在最理想假设下，即各国落实既有减排方案且所有设定净零目标的国家均如期实现，本世纪升温峰值仍将达到2.1摄氏度。气候分析机构首席执行官比尔·黑尔就此指出，各国政府必须尽快出台削减化石燃料使用的具体政策。

Without additional measures beyond existing policies, global temperatures are projected to climb to an average peak of 2.8 degrees Celsius above pre-industrial levels. The assessment notes that this figure increased compared to last year's forecast, driven partly by the United States abandoning the Paris Agreement and canceling its national emissions commitments. Even under an optimistic scenario where existing pledges are met and all countries with net-zero targets fulfill them, peak warming still reaches 2.1 degrees Celsius, prompting Climate Analytics Chief Executive Bill Hare to stress that governments must urgently enact policies curtailing fossil fuel consumption.

初步估算显示，在印度、中国与美国等主要排放国中，美国在2025年的碳排放增幅远超其他所有国家，与俄罗斯并列为二十国集团中人均排放最高的国家。这一增长受到电力需求攀升的直接拉动，其中大型人工智能数据中心扩张推高了用电负荷。同时，该国燃煤发电出现反弹，美国政府要求境内的燃煤电厂延长运营时间，不再按原计划关停。

Preliminary estimates show that while emissions rose in 2025 across several major emitters including China, Indonesia, and the United States, the increase in the U.S. far exceeded that of all other countries, leaving it tied with Russia for the highest per capita emissions in the G20. The surge was driven by rising electricity demand, partly linked to massive expansions in artificial intelligence data centers, alongside a resurgence of coal-fired power as the Trump administration ordered domestic coal plants to remain operational past planned retirement dates.

在政策层面，特朗普政府二度就任后撤销了车辆燃油效率标准，取消对风能和太阳能项目的税收抵免，并扩大石油与天然气开采。美国环境保护局更逆转既有立场，宣称温室气体不对人类健康与福祉构成威胁。此外，美方正寻求完全脱离联合国所有的气候工作，并在该报告的官方声明中表明不认可其分析或结论，同时宣布不会出席下个月在土耳其举行的第31届联合国气候大会。

Federal policy shifted toward supporting fossil fuel production by rolling back vehicle fuel-efficiency standards, lifting oil and gas restrictions, and terminating tax credits for solar and wind energy projects. The U.S. Environmental Protection Agency formally reversed its stance, stating that planet-warming greenhouse gases do not pose a threat to human health and welfare. Moving to detach the country from all United Nations climate initiatives, the administration stated in the report that it does not endorse or agree with the analysis or conclusions, and confirmed it will skip the upcoming COP31 negotiations in Turkey.

即将在土耳其举行的第31届联合国气候变化大会将围绕加速清洁能源投资与应对气候变化资金机制展开磋商。联合国环境规划署在报告中指出，为将全球气温峰值控制在1.7至1.8摄氏度之间，并在2100年前使平均升温回落至1.5摄氏度或以下，全球减排力度必须远超目前土耳其谈判桌上的任何方案。相较于2025年基准，该最低超调路径要求全球温室气体排放量在2030年减少18%，到2035年削减45%，并在2040年达到69%的减排幅度。

As global negotiators prepare to convene in Turkey next month for the COP31 climate summit to address clean energy investment acceleration and climate funding mechanisms, the UN Environment Programme report outlines what it would take to achieve the lowest possible overshoot pathway. To restrict peak warming to between 1.7 and 1.8 degrees Celsius and bring global average temperatures back down to 1.5 degrees Celsius or lower by 2100, emissions cuts must far surpass any proposals currently under negotiation for the upcoming talks. Relative to 2025 levels, this pathway mandates cutting global greenhouse gas emissions by 18% by 2030, 45% by 2035, and 69% by 2040.

实现该路径不仅需要在2035年前将全球可再生电力容量增至三倍，还必须在2040年前彻底淘汰煤炭。此外，该情景高度依赖大规模碳清除技术来吸收大气中的温室气体。报告特别强调，这类碳清除技术截至目前尚未在如此巨大的应用规模上得到实际验证。联合国秘书长安东尼奥·古特雷斯表示，超调并不意味着投降，各方仍有机会尽可能缩短升温周期，但所有国家尤其是主要排放国必须采取更有力的行动。

Reaching that trajectory requires tripling global renewable electricity capacity by 2035 and executing a full phaseout of coal power by 2040, alongside sweeping reductions in other fossil fuels. The scenario also depends heavily on deploying carbon removal technologies at scale to draw down atmospheric heat-trapping pollution. The report emphasizes that such carbon removal solutions have not yet been proven to function at the massive scale required. UN Secretary-General Antonio Guterres stated that overshoot is not surrender and that the temperature breach can be kept as brief as possible, stressing that all nations, particularly major emitters, must do far more.