2024年3月,中国的二氧化碳(CO2)排放量下降了3%。这标志着自2022年12月放宽防疫措施、重启经济活动以来,中国碳排放量连续14个月的增长告一段落。
Carbon Brief基于官方数字和商业数据进行的新分析显示,中国CO2排放量在2023年或已达峰。
2024年3月CO2排放量下降的驱动因素包括光电和风电的快速增长,这满足了电力需求增长的90%,以及建筑活动的减少。
石油需求增长也陷入停滞,表明疫情后的经济反弹可能已临近尾声。
如果中国能维持去年创纪录的清洁能源建设水平,该国有望在2023年实现碳达峰。
然而,整个行业和政府对清洁能源的增长前景看法不一。如果中国尚未实现碳达峰,如何弥合分歧将是决定碳达峰何时到来的关键因素。
该分析的其他关键发现包括:
- 尽管电力需求强劲增长,但光电和风电的增长推动化石燃料发电量份额从前一年的67.4%下降至2024年3月的63.6%。
- 由于中国房地产建设活动的持续萎缩,2024年3月钢铁产量下降了8%,水泥产量下降了22%。
- 电动汽车现在约占中国道路上汽车总量的十分之一,将汽油需求增长拉低了约3.5个百分点。
- 去年创纪录的太阳能新增发电装机中,约45%是规模较小的分布式光伏,导致看似出现了“数据缺失”问题。
为什么三月排放量出现下降?
根据中国国家统计局发布的初步能源消费数据,2024年第一季度中国的碳排放量总体显著增加。

今年1月和2月的碳排放量仍较2023年的低基数大幅增长,彼时中国经济仍因刚结束不久的清零防疫措施而受到抑制。
因此,与2023年同期相比,2024年第一季度的CO2排放量同比增长了3.8%,煤炭消费量增长了3%,石油消费量增长了4%,天然气消费量增长了11%。
转折点出现在今年3月份。由于该月份的煤炭消费量降低了1%,石油消费保持平稳,而水泥产量则下降了22%,导致3月CO2排放量同比下降了3%。尽管天然气消费量增长了14%,但由于其在中国能源结构中占比较小,从而影响有限。
如下图所示,自2022年12月放宽疫情限制措施后,中国的碳排放量从2023年2月开始回升。
因此,2023年1月至2月的同比比较仍然受到去年疫情导致的低基数影响,这使得3月的数据成为能够清楚地反映碳排放趋势的首个月度数据。

近年来,中国碳排放量增长的主要推动力来自电力部门(见下文)。
反之,3月碳排放趋势转为下降,主要原因也是电力部门的排放量增长的大幅放缓。由于光电和风电的强劲增长,电力部门3月的碳排放量仅同比增长了1%。
如下图所示,尽管电力部门的排放量企稳,但建筑业对钢铁和水泥的需求持续下降,这才是3月份碳排放量减少的最主要原因。
钢铁产量下降了8%,因此炼钢厂的主要燃料炼焦煤的产量也随之降低。水泥产量同比骤降了22%。
由于政府对房地产行业高杠杆的打击和对金融风险的管控,以及建筑行业过去的繁荣导致了产能过剩,房地产行业投资已连续第三年收缩,这使得上述排放趋势可能会继续维持。

尽管建筑业需求出现收缩,但中国对钢铁和其他能源密集型金属的需求并未出现预期的大幅下降。
这背后的原因是制造业的快速增长和对该行业的投资,而在设施建设和工业机械生产中都需使用金属制品。
但是,随着全球各种商品和大宗货物的市场逐渐饱和,这种制造业的增长不太可能持续下去。当局的经济政策现在强调“新质生产力”,这是推动经济增长摆脱对传统重工业的依赖的最新尝试。“新质生产力”指高端的制造和研发,这些领域的能源密集程度大多比中国的传统工业部门更低。
从2024年3月其他行业的情况来看,运输用油的需求在经历了几个月的强劲增长之后,变得与去年同期相比近乎持平。这表明疫情后的需求反弹可能正在逐渐消失。
航空燃料(+35%)和汽油(+7%)产量仍在增长,说明客运需求出现增长。但柴油产量增长停滞(+1%),原油加工量也仅增加了1%。
电动汽车的增长正显著削减石油需求量。根据过去十年的累计销售数据估计,电动汽车在道路上所有车辆中的占比从去年的7.0%增加到10.5%。这表明,电动汽车的普及使汽油需求增长降低了3.5个百分点。
天然气需求出现大幅反弹,同比增长14%。此前天然气价格高企导致需求下降。天然气消费的增长主要来自工业和家庭部门。
随着燃气电厂利用率有所恢复,电力部门的天然气消费量增长了8%,但这仅占总体增长很小的一部分。
天然气在中国能源结构中的占比曾连续增长了二十多年,在2021至2023年间有所下降,现在开始恢复增长。
近期推动碳排放量增长的一个因素仍在继续:化工行业的煤炭消费量增长了14%,延续了2022和2023年两位数的增长趋势。
尽管目前还没有足够的数据来估算4月份的CO2排放量,但当月的工业数据表明,3月排放下降的趋势仍在继续。
由于光伏发电满足了大部分的电力需求增长,火力发电量——主要来自煤电——缓慢增长了1.3%。钢铁、水泥和焦炭产量分别下降了8%、9%和7%,反映出建筑需求的持续减少。炼油量下降了3%。
国内煤炭开采量下降了3%,而进口量增加了11%,这意味着总供应量减少了5%。
天然气需求进一步强劲增长,进口量增长了15%,国内产量增加了3%。在能源密集型行业中,化工和有色金属行业的产量继续保持较快增长。
光电和风电满足需求增长
企稳的电力部门排放量值得关注,因为电力需求继续以7.4%高速增长,而受长期干旱的影响,水电利用率低于长期平均水平。
过去几年,工业用电推动电力需求迅速增长。3月,工业需求增长放缓,但服务业的反弹维持了整体需求的增长。
近一半的用电需求增长来自工业,其中有色金属、化工、机械和电子等行业是最主要的需求增长的领域。服务业贡献了需求增长的三分之一,主要源自批发和零售贸易,另有六分之一来自家庭用电。
在2022年历史性的热浪引发一波空调购买潮的推动下,家庭用电需求在过去几年也出现了激增,尤其是在以前没有空调的低收入家庭。
尽管电力需求快速增长,但由于分布式光伏电站的大规模部署,规模以上工业发电量增速放缓至3%。
(与大型集中式太阳能发电场相比,分布式光伏电站指的是装机规模较小的发电系统,通常安装在家庭和企业的屋顶上。)
总体而言,由于2023年光电和风电装机的创纪录增长,光电和风电发电量占比已达到22%,并在3月实现了近90%的同比增长。非化石燃料发电量占比从去年的32.6%上升至36.2%。

分布式光伏对发电的贡献越来越大,但这在一定程度上被中国月度电力数据的报告方式所掩盖。国家统计局只发布大型光伏和风力发电站的月度发电量。它还系统性地上修了前几年的数据,这表明其没有实时捕捉新进入市场的企业的发电量。
由于去年创纪录的光伏新增装机容量中有45%是分布式发电,对小型光伏装机的排除对这些数字的影响比以往大得多。
这在中国和海外引起很多困惑,特别是报告的用电量数据远大于发电量数据,这显然是不可能的,彭博社甚至称其为“数据缺失问题”。
然而,用电量和规模以上工业发电量之间不断扩大的差距表明,分布式光伏在满足用电需求方面的贡献越来越大。
与月报数据不同,中国的年度统计公报中没有“缺失”的数据,因为年度统计包括所有电厂,无论其规模。例如,2023年的年度统计公报显示,光伏发电量是月度统计的两倍,风电发电量则多出了10%。
事实上,如果按照月度数据中的装机容量和利用小时数来计算发电量,得到的数据与年度报告数据非常接近。这清楚地表明,尽管统计局的月度数据中没有纳入分布式光伏的发电量,但其的确为满足电力需求做出重大贡献。
清洁能源热潮继续
去年光电和风电新增发电装机容量约300吉瓦(GW),这推动了3月份碳排放量的下降。这种热潮在2024年前三个月加速,与去年相比增长了40%。
太阳能发电新增装机容量46吉瓦,同比增长36%;风电新增装机容量16吉瓦,同比增长50%。
通常来说,第一季度的新增装机容量增速一般较低,而且由于报告滞后,相当多的新增装机在年底才被报告。
强劲的同比增长表明,对新项目能否成功并网的担忧并未影响新增装机容量增加的步伐。即便今年剩下时间里增速会有所放缓,但迄今为止的数据表明,去年创纪录的增速可能会在2024年持续。
今年1月至3月,太阳能电池板产量在去年的高基数上又增长了20%,表明中国和海外的需求强劲。
电动汽车产量增长了29%,汽车总产量恢复了下降趋势,这使得电动汽车占比持续快速攀升,在第一季度达到了31%,而去年同期为26%。
由于光电和风电项目的经济效益显著,对新增装机的主要限制来自并网。因担心无法消纳新增发电量,去年多个省级电网运营商已开始限制新增光电和风电项目。
这凸显了中国电网运营上的短板,因为风电和光电占中国总发电量的份额仍然有限,仅为15%。相比之下,两者在欧盟电力系统中的占比为27%,德国、西班牙和希腊达到40%。
中国已开始采取行动解决该问题。国家发改委已开始放宽光电和风电并网的要求。这将增加风光项目投资者的不确定性,但提高了电网运营商的消纳能力,从而支持发电装机和发电量的增长。
国家发改委还发布了一项推动储能发展的政策,承诺到2027年,电力系统将能够支撑新增风光装机容量,同时将因电网问题而浪费的发电量比例保持在较低水平。
虽然光电和风电已开始满足大部分或全部用电需求的增长,但煤电投资仍在继续。第一季度,火电装机的新增速度同比略有放缓,但各省2024年的“重点项目清单”中包括超过200吉瓦的火电项目,其主要是燃煤电厂。
未来仍充满变数
中国3月份碳排放量的下降可能标志着自2020年以来碳排放的强劲增长出现了转折点。正如 Carbon Brief 去年秋天发布的一篇分析所述,目前清洁能源的增长率有可能使该国提前实现碳达峰。
因此,清洁能源增长是否会持续,是影响中国未来排放路径的关键问题。但是,外界对于未来风电和光电的发展速度仍存在很大分歧。
中国光伏行业协会在其“保守”情景中预测,2024年至2030年间年均新增装机容量为225吉瓦,比2023年的217吉瓦略有增加。在“乐观”情景下,这一数字将加速至每年280吉瓦。根据该协会预测,中国的太阳能总装机容量将从目前的660吉瓦,到2030年增加到2200至2600吉瓦。
据风电行业数据,要实现2060年碳中和目标,中国需要在2021年至2025年间每年新增超过50吉瓦的风电装机。从2026年起,每年新增装机超过60吉瓦。这是一个相对适中的轨迹,因为2023年风电新增装机容量已经达到76吉瓦。
另一方面,国家能源局局长章建华在最近一篇文章中写道,清洁能源的新增装机容量应保持在每年100吉瓦以上,但这不到2023年实际水平的一半。这意味着他认为最近的加速增长是反常的,可能难以持续。
与之类似,在国家能源局2024年的工作计划中,从总发电装机容量和非化石能源发电容量占比,可以推算出非化石能源新增装机的目标在170吉瓦左右。(尽管2023年工作计划的目标是160吉瓦,但实际新增接近300吉瓦。)
下图展现了对于光电和风电发展的不同愿景。深蓝色线代表了章建华的预期,即年新增装机容量将回落到2020年至2022年水平;浅蓝色和红色线是可再生能源行业预测的增长趋势,其大致保持在2023年的水平,或稳步增长。

到2030年,光伏行业协会和国家能源局就光电和风电的装机目标差距为1400至1800吉瓦。如果新增的清洁能源发电量在2030年能够取代煤电,那么碳排放量将比当前水平下降10至15%。到2035年,随着风电和光电进一步发展,碳排放量将比当前水平下降20至25%。
章建华在文章中指出了一些挑战,以解释为何他认为清洁能源新增发电容量水平较低,包括储能价格机制尚未健全,能源转型政策合力亟待加强,以及集中连片新能源发展用地、用海空间不足等。
尽管如此,减缓光电、风电和相关储能的新增装机速度将给中国经济泼上一盆冷水,因为这些清洁能源行业已成为经济增长的一个关键来源。
此外,最近对这些行业生产能力的大量投资,只有在清洁能源设备需求持续增长的情况下才能得到利用和回报。
政府雄心的减弱也反映在今年设定的较为保守的官方目标上。根据环保部最近设定的目标,2024年碳强度(每单位GDP的排放量)的目标降幅为3.9%。
尽管这一目标超过过去三年碳强度年均仅下降1.5%的水平,但考虑到GDP增速目标是“约5%”,该碳强度目标实际将允许碳排放量增长逾1%。
在2021年至2023年碳排放量快速增加之后,中国已经严重偏离了2025年和2030年的碳强度目标,而2024年的年度目标未能缩小这一差距。
3.9%正是实现“十四五”规划中碳排放强度下降18%的目标所需的年均下降幅度。因此,该目标避免了落后幅度进一步扩大,但对弥补迄今为止的进展滞后毫无作用。
国家发改委还设定了一个相对保守的目标,即到2024年将“化石能源强度”降低2.5%,这将允许碳排放量增加2%以上。
章建华还认为,在2026至2030年期间,清洁能源应满足70%的能源消费增长,这一目标也与清洁能源新增装机容量放缓的趋势一致。
这意味着,能源消费增长的30%仍将通过增加化石燃料的使用来满足,因此CO2排放量也将继续增加。
持续增长的碳排放量意味着中国将面临无法实现2030年的碳强度承诺的风险,而这是中国在《巴黎协定》下提交的国际气候承诺的一部分。因为假设GDP年均增长5%或更低,根据这一承诺,从2023年到2030年,能源部门的CO2排放量没有增加的空间。
因此,中国能否实现其气候承诺,取决于清洁能源增长是否会继续显著超过中央政府制定的目标,亦或是这些目标在未来是否会提高。
数据来源
本分析数据来源于中国国家统计局、国家能源局、中国电力企业联合会、中国海关官方发布的数据以及行业数据提供商WIND资讯。
电力行业煤炭消费量是根据煤炭发电量和燃煤电厂每月平均发热量来估算的,以避免官方煤炭消费量影响近期数据的问题。煤炭发电量根据火力发电总量和燃煤、燃气、生物质电厂报告容量和利用小时数计算,以得到综合火力发电数据。
当数据来自多个来源时,本文交叉引用不同来源并尽可能使用官方来源,调整总消费数控,以匹配国家统计局报告的消费增长和能源结构变化。
2024年第一季度的数据进行了调整,以匹配国家统计局初步官方数据中报告的整个季度的同比增长率。但无论有没有这种调整,三月份排放量下降的结论都成立。
二氧化碳排放量估算基于国家统计局默认的 2018 年燃料热值和中国最新国家温室气体排放清单中的排放因素。水泥二氧化碳排放基于截至 2023 年的年度估算。
对于石油消耗量,表观消耗量是根据炼油厂吞吐量计算,减去石油产品的净出口量。
The post 分析:月度碳排放量下降或表明中国已在2023年碳达峰 appeared first on Carbon Brief.
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Pawa in Palau
This week our powerful Pacific team is in Palau for the Pacific Islands Forum Leaders Meeting. This is a major moment in our campaigns for Pacific climate justice and to stop deep sea mining. So what’s it all about, what can we expect over the coming days, and why is this year’s meeting in particular so important? Read on to find out!
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What is the Pacific Islands Forum (PIF)?
The Pacific Islands Forum, or ‘PIF’, is our region’s most important political organisation. It is where countries of the Pacific — including Australia and New Zealand — come together to collaborate on shared challenges and to set collective goals.
The PIF Leaders Meeting is an annual weeklong event that includes a dedicated meeting of the Pacific’s small island developing states (PSIDS), many special side events organised by Pacific civil society, the leaders’ meeting itself, and more. At the end of the week, leaders issue a Forum Communiqué, capturing what they have agreed on, their shared priorities and the actions they will take together.
This year’s meeting is being held in the beautiful northern Pacific nation of Palau, the same place our Pacific team gathered back in January to plan for the year.

What’s at stake this year?
Climate change has dominated the PIF for decades. Pacific leaders have been crystal clear it is their number one priority, and the annual gathering is the moment they can exert maximum pressure on Australia over its fossil fuel record.
The voyage to COP31
This year’s meeting comes less than three months before COP31, where Australia will take on the role of President of Negotiations — a role it has committed to undertaking in partnership with the Pacific — and less than a month before the ‘Pacific Pre-COP’, to be held in Fiji and Tuvalu.
Following a fraught round of mid-year negotiations in Bonn, PIF leaders will need to set out a clear vision and priorities for COP31. These include accelerating a just global transition away from fossil fuels, defending science as the foundation of international climate cooperation, and increasing the availability and accessibility of finance for renewable energy and climate adaptation.

Accountability for Australian fossil fuel exports
Since the last PIF Leaders Meeting, Australia has signed the Belém Declaration on the Transition Away from Fossil Fuels. The declaration reaffirmed the legally binding commitment to help limit global warming to 1.5°C and recognised that this is incompatible with new fossil fuel production. Yet, Australia has continued to approve new coal and gas projects, including at least five since the last PIF Leaders Meeting.

What is Greenpeace doing?
We’re going big this year, taking six members of our team to Palau to support Pacific leaders to hold the line, hold Australia accountable, and show the world what’s at stake. We’ll lobby leaders, hold press conferences, share our messages with the world, and support our incredible local partners in Palau.

How can you get involved?
PIF is the first in a drumbeat of major moments where we’ll be carrying the voices of the Pacific to the world. Come October we’ll be voyaging to Fiji on our ship Oceania for the Pacific Pre-COP, and in November we’ll be off to Antalya for the world’s climate negotiations (COP31).
Learn more about the Pacific way to a fossil fuel free future by checking out our report and exhibition.
Follow our journey, and check back here for more ways to join the movement for climate justice. Together we have the pawa!
Climate Change
From firefighting to future-proofing: Preventing wildfires must be the priority
Gill Einhorn is head of the Forest Future Alliance and Natalie Çilem is community lead of the Global Wildfire Leadership Network.
Wildfires have devastated communities across the world this summer, claiming lives, displacing thousands of people and leaving billions in economic damage in their wake. In Europe alone, wildfires have already caused an estimated €19 billion in losses this year.
They are an economic, financial and public health challenge that is growing faster than many governments and markets are prepared for – and exposing the real costs of poor land management.
A system built for recovery, not resilience
Far more money is currently spent responding to the disastrous effects of wildfires than preventing them in the first place. The United Nations Environment Programme estimates that more than half of wildfire-related spending goes towards response, while planning receives only around 0.2 percent. This problem is not limited to wildfires; over 95 percent of disaster aid between 2005 and 2017 was allocated to response, and less than 4 percent was directed towards prevention or preparedness.
Forests are critical, but without investment in how land is managed and protected, their value is neither stable nor guaranteed. Protecting forests requires investing not only in conservation, but in the conditions that keep forests standing.
Each dollar invested in wildfire-resistant construction could save around $210 in avoided future economic losses, according to a report by the World Economic Forum and Forest Future Alliance. Despite this evidence that prevention can significantly reduce future costs, wildfire resilience remains chronically underfunded.
This spending discrepancy is creating significant challenges for insurers, asset owners and financial institutions. Global insured losses from natural catastrophes reached $107 billion in 2025, with wildfires, floods and storms accounting for 92 percent of claims.
In this context, insurers are reassessing where and how they are willing to underwrite risk. Around 56 percent of global wildfire losses between 2000 and 2023 were uninsured. In some high-risk areas, insurers are scaling back coverage altogether, leaving homeowners, businesses and governments to shoulder a growing share of the costs – making it increasingly difficult to break even.
Proven solutions are already paying off
In many regions, wildfires are driven not by natural causes but by the deliberate clearing of land for agriculture. Degraded landscapes are becoming drier, more flammable and increasingly vulnerable to catastrophic loss, creating a vicious cycle of deforestation, economic damage and rising emissions.
The answer is not simply stronger firefighting capacity. Governments, investors and businesses must work together to shift capital upstream into prevention, resilience and long-term landscape stewardship of healthy forests. That means planting appropriately, investing in heat-resistant species, exploring approaches that minimise fire footprints through active management, and exploring the AI and technology solutions that are burgeoning.


Solutions to this already exist and are proven to have an impact. Following devastating wildfires year-on-year, Portugal shifted its approach to wildfire management, increasing prevention spending within its national rural fire management system from around 20 percent in 2017 to approximately 60 percent in 2022. While many countries remain locked in a reactive cycle of disaster response, public policy can shift investment upstream and make resilience a priority before fires occur.
Indigenous communities have long used proactive land stewardship to reduce wildfire risk while supporting healthy and productive landscapes. For example, the Cheslatta Carrier Nation in British Columbia traditionally managed fuels through cultural fire practices but now implements mechanised fuel removal methods under commercial agreements. By combining Indigenous stewardship with sustainable forest management, Cheslatta is generating community benefits while also boosting wildfire prevention.
Resilience can also be strengthened through finance and technology. FireSat, a partnership led by Earth Fire Alliance with Google.org, the Gordon and Betty Moore Foundation and Muon, is a satellite constellation designed for rapid wildfire detection. Scanning every 20 minutes, it can detect fires 400 times smaller than current systems and track them through smoke and darkness in almost real time. In California alone, FireSat could prevent up to 350,000 acres from burning each year. It has recently received significant new investments allowing it to expand towards a constellation of more than 50 satellites that will monitor every point on Earth every 20 minutes or less.
In Brazil’s Pantanal, the Embrace the Forest initiative uses AI-powered detection towers across 2.5 million hectares to support earlier intervention and faster response. During the severe 2024 fire season, the initiative contributed to a 40 percent reduction in burned area compared to 2020.


These examples illustrate what is possible when resilience is treated as an investment priority rather than a recovery cost. But we must ensure funding for these measures is scaled before disaster strikes. Initiatives like the Global Wildfire Leadership Network (GWLN) are key, bringing together corporate decision-makers, investors, insurers, governments and Indigenous leaders to direct investment towards prevention and align finance, technology and stewardship to protect nature, safeguard communities and strengthen future economic stability. With a goal of doing more together than the sum of our parts, the network focuses on Forest Future Alliance GWLN Solutions Labs – where partners sign up with the intent to collaborate.
Rewarding prevention
Financial incentives must be created that reward prevention. This can be done by scaling public-private partnerships, supporting long-term landscape stewardship, investing in community capacity including Indigenous wisdom and technology. Ultimately, our terrestrial natural reserves are critical infrastructure that support resilient economies and thriving communities.
One in three people are dependent on forest services, goods and economic opportunities for survival, so it’s in all our interests to protect what we have. Forests support cooling, water and food security – and are a very cost-effective way of removing carbon dioxide from the atmosphere, where done appropriately.
UN chief warns climate crisis “in overdrive” as El Niño threatens to fuel the fire
No sector can solve this challenge alone. The benefits of wildfire resilience are shared across communities, governments, insurers, investors, utilities and businesses. A single intervention can protect homes and livelihoods, reduce insurance claims, secure water supplies and lower future public costs. Because the benefits are shared, the solutions must be too. Coalitions of actors can take proven approaches further than any one individual or organisation could alone.
As wildfires continue to burn at an unprecedented scale, the opportunity now is to roll out solutions, shift investment upstream and build a future where resilience, rather than recovery, becomes the foundation of thriving economies.
The post From firefighting to future-proofing: Preventing wildfires must be the priority appeared first on Climate Home News.
From firefighting to future-proofing: Preventing wildfires must be the priority
Climate Change
Guest post: Why tough methane cuts are crucial for keeping warming ‘well-below’ 2C
Methane is a powerful greenhouse gas and the second-largest contributor to global warming after carbon dioxide (CO2).
Methane traps heat in the atmosphere more efficiently than CO2, but has a significantly shorter lifespan, fading after just a few decades.
Therefore, reducing emissions of methane – a gas primarily produced by agriculture, fossil fuels and waste management – is a powerful option for limiting global warming in the near-term.
Yet climate strategies and models often only focus on CO2, or combine all greenhouse gases into one metric known as “CO2 equivalent”.
The latter approach makes reducing methane emissions dependent on modelling choices and assumptions about the “equivalence” of methane and CO2.
It hides the opportunities and challenges linked to methane’s high warming and short lifetime.
In a new study, published in Communications Earth & Environment, we offer a different perspective that “decouples” CO2 and methane reduction and takes global warming limits as a starting point for determining the required level of methane cuts.
We show that, even under the most ambitious existing national net-zero targets, an absence of methane reduction leads to peak warming that exceeds 1.85C above pre-industrial levels.
The study highlights that, to limit peak warming to well-below 2C, net-zero CO2 targets must be complemented by stringent methane emissions cuts.
CO2 equivalent
How much methane corresponds to one tonne of CO2?
The question is as difficult to answer as: ‘how much spaghetti equals a chicken?’ You could compare the two meals according to their calories, protein content or cost. Each metric can be convenient, but is only valid for that specific comparison – no amount of spaghetti is the same as a chicken.
The same is true for the conversion of emissions of methane and other gases to CO2-equivalent emissions. It can be convenient, as it allows different gases to be compared or combined into a single number. This is why the metric is used in climate targets or evaluating the effectiveness of different mitigation options.
But, because methane and CO2 have different atmospheric lifetimes and warming properties, any conversion is only valid for a chosen time horizon and a chosen baseline.
Depending on the assumptions baked into calculations, methane mitigation can either appear as an immediate priority or framed as almost unnecessary.
There are a number of metrics that scientists use to convert greenhouse gases – whether methane, hydrofluorocarbons or nitrous oxide – into CO2-equivalent emissions:
- “GWP20” measures how much heat a greenhouse gas traps in the atmosphere over a 20-year period, relative to CO2. It emphasises urgent methane mitigation but has been criticised for its implicit discounting of future damages.
- “GWP100” looks at a 100-year timeline. It gives more weight to long-term warming and is used in “integrated assessment models” (IAMs) used by scientists, national emission reporting to the UN and by the GHG Protocol used by companies.
- “GWP*” considers the rate of emissions, rather than warming over a fixed time horizon. Under GWP*, very limited methane reductions bring CO2-equivalent emissions to zero, meaning remaining methane emissions can be designated as causing “no additional warming”. (This interpretation remains controversial as it assumes the continuation of historical levels of warming.)
IAMs are the tools used to generate future emissions scenarios. Because they combine CO2 and methane emissions, the impact of methane emission cuts alone is difficult to isolate in existing emission scenarios.
IAM-generated scenarios also assume mitigation decisions driven by costs. Combinations of CO2 and methane emission pathways that are not purely cost-effective are, therefore, not represented, even though climate policy is messy and emission pathways are rarely cost-effective in the real world.
Only a few countries – including Japan, Mexico and South Korea – specify methane mitigation targets.
A different approach
In our study, we separate CO2 and methane emissions and treat them as independent.
Instead of choosing a conversion method, we suggest that states and organisations set a limit on peak global warming first, then, based on their existing net-zero targets, determine the minimum compatible methane reduction target.
Companies and countries around the world have set net-zero targets focused on CO2, as well as those that include all greenhouse gases. As a result, our research looks at the necessary methane reductions for both types of goal. We consider scenarios where companies or countries deliver linear – in other words, steady – emissions reductions to reach net-zero.
Using a simple climate model, we systematically combined methane and CO2 (or greenhouse gas) mitigation pathways starting in 2025 and calculated peak warming.
The figure below shows how peak warming depends on both the year of reaching net-zero CO2 and the level of methane cuts.
The blue arrows in the figure show that to limit warming to 1.7C under a 2050 net-zero CO2 scenario, methane emissions would need to fall by at least 69% by 2050, relative to 2020.
Our research also finds that, if an organisation or country’s 2050 net zero-target covers all greenhouse gases, its methane emissions would need to fall by 63% instead.
However, under current policies, methane emissions are expected to increase by around 20% by 2050, relative to 2020. We find that this pathway would result in peak warming above 2C by 2050 – even if global CO2 emissions were to reach net-zero by that date (see purple bar on the right-hand side of the figure above).
The figure also shows how, if methane emissions remained at 2020 levels and net-zero CO2 was delivered by 2040 or later, warming would exceed 1.85C. This level of warming is above what has been argued as consistent with the Paris Agreement’s “well-below” 2C limit.
Conversely, cutting methane emissions by around one-third – in line with the Global Methane Pledge target for 2030 – could reduce peak warming by 0.15C, of which 0.05C could be delivered by interventions that come at no net cost. These are shown by the orange and red bars, respectively, on the figure above.
The table below highlights the minimum compatible methane cuts for three different peak warming levels and net-zero CO2 or greenhouse-gas emission targets.
| Peak warming | Year of net-zero CO2 emissions | Year of net-zero greenhouse-gas emissions | ||||
| 2050 | 2060 | 2100 | 2050 | 2060 | 2100 | |
| 1.7C | -69% | – | – | -63% | – | – |
| 1.8C | -32% | -56% | – | -11% | -47% | – |
| 2C | +8% | -8% | -83% | >50% | +33% | -78% |
Minimum methane emission reductions between 2020 and the year of net-zero emissions, consistent with peak warming of 1.7C, 1.8C, and 2.0C at 50% likelihood, assuming linear emission trajectories. For some net-zero targets and peak warming levels, there are no compatible methane mitigation targets (indicated by “–”).
Remaining carbon budget
The global carbon budget refers to the amount of cumulative CO2 emissions allowable while still meeting a particular global warming threshold.
The 2021 climate science report from the Intergovernmental Panel on Climate Change (IPCC) and a 2023 Nature study estimated that, by 2025, the remaining carbon budget for holding warming to 2C would be around 1,000-1,150bn tonnes of CO2 (GtCO2).
We find that these estimates are founded on the assumption of methane reductions of 27-35% by 2050, relative to a 2020 baseline. (A 2024 Communications Earth & Environment study reached similar conclusions.)
Under the GWP* metric, where methane emissions are only cut to maintain “no additional warming”, the remaining carbon budget would be constrained. The best estimate of a 2C budget shrinks by around 30% to approximately 750GtCO2.
Finally, if methane emissions are not cut at all in the future, our findings suggest that the remaining carbon budget for 1.7C of global warming has, in effect, already been exhausted.
Our analysis shows how peak warming depends on both CO2 and methane reduction – and how methane-specific targets can help refine existing net-zero targets.
Crucially, we show that complementing net-zero CO2 targets with stringent methane cuts is necessary to limit peak warming to well-below 2C.
Weber, K. et al. (2026) Limiting warming by CO2 and methane mitigation in an expanded scenario space, Communications Earth & Environment, doi:10.1038/s43247-026-03832-1
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The post Guest post: Why tough methane cuts are crucial for keeping warming ‘well-below’ 2C appeared first on Carbon Brief.
Guest post: Why tough methane cuts are crucial for keeping warming ‘well-below’ 2C
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