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火山喷发对科学家及其气候模型构成了根本性挑战。

众所周知,剧烈的火山喷发会导致地表气温突然下降,多次喷发则会在几十年乃至几个世纪的时间尺度上影响气候变率。

当火山喷发将二氧化硫注入平流层时,会形成气溶胶,从而阻挡阳光到达地球表面。

与人类对气候变化的影响不同,后者发生缓慢且可以在各种社会经济情景下被纳入气候模型进行考量。火山喷发具有突发性,这给气候预测带来了挑战。

目前科学家尚无法预测火山喷发的发生时间、地点以及二氧化硫的排放量。

那么,在进行未来气候预测时,如何考虑火山喷发对气候的影响呢?

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在我们最近发表于《通讯-地球与环境》(Communications Earth & Environment)的研究中,我们表明火山喷发对全球气温预测的不确定性产生了重大影响。

我们的研究结果发现,如果将偶发的火山喷发纳入气候预测,突破《巴黎协定》所设定的1.5C升温上限的时间会略有延迟,但与此同时,未来几十年也将出现更多快速升温和降温的时期。

气候预测中的火山强迫

气候科学家将火山喷发对气候的影响——主要是通过释放出二氧化硫气体进入大气——称为“火山强迫”(volcanic forcing)。

当前的气候模型在进行未来预测时采用一个恒定的火山强迫值,该值是根据1850年至今的历史平均强迫值计算得出的。

国际耦合模式比较计划(CMIP)也是如此,这项全球模型工作为政府间气候变化专门委员会(IPCC)发布的重要评估报告提供基础数据。

然而,这种方法存在显著局限。

首先,历史平均强迫值无法表示火山爆发的偶发性。

大规模火山喷发呈零星分布——有时好多事件集中发生在某几个十年内,有时两个事件之间则可能相隔上百年。

此外,与数千年尺度的记录相比,从1850年至今的参考时期中,发生过的大规模喷发事件 ——指排放超过3太克(Tg)二氧化硫的喷发事件——相对较少。

最后,早期国际耦合模式比较计划气候模型中所使用的火山强迫重建数据并未包含排放量少于3太克二氧化硫的中小规模喷发。

这是因为这些喷发在1980年卫星时代开始之前大多未被探测到。然而,这些体量较小但发生频率更高的喷发事件,在长期火山强迫中贡献了30%至50%。

采取新方法

传统上,气候科学家认为气候预测中主要存在三种不确定性来源:内部变率、模型不确定性和情景不确定性。

其中,“内部”变率是指气候系统内部自然产生的波动,如厄尔尼诺现象;模型不确定性是指不同气候模型之间结果的差异;情景不确定性则涉及未来几十年全球可能的发展路径。

我们的研究结果表明,火山喷发应被明确视为气候预测中第四个重要的不确定性来源。

为了探究在考虑火山强迫不确定性的情况下,气候预测会发生怎样的变化,我们的研究采用了一种概率方法,这一方法建立在Bethke等人于2017年提出的研究基础之上。

为此,我们构建了“随机强迫情景”,其本质是1000种延续至本世纪末的火山活动可能时间线预测。

这些情景基于冰芯中记录的过去1.15万年火山活动历史,以及卫星观测和地质证据。每个情景都呈现了不同的喷发强度、地点、时间和频率的组合。

(在数学中,“随机”系统是指结果包含随机性或不确定性的系统,因此不可预测;这与“确定性”系统相对,后者的结果可以通过初始条件和一套规则或方程完全预测。)

随后,我们利用2015至2100年期间的随机火上强迫和历史平均火山强迫模拟气候预测,研究共享社会经济路径(SSPs)中三种不同排放情景下的升温变化:低排放情景(SSP1-1.9)、与现行气候政策相符的中等排放情景(SSP2-4.5)、非常高排放情景(SSP5-8.5)。

在这一步中,我们使用了一种称为FaIR的简化气候模型,也称“模拟器”。

通过模拟1000种不同的火山未来情况,我们发现在21世纪未来时期火山喷发所引起的气候不确定性,可能超过同期气候系统本身的内部变率。

我们还发现,到2030年代,火山喷发可能占全球气温预测总不确定性的三分之一以上。

下图中能看到这些结果。图中展示了不同来源对总不确定性的影响。火山为橙色、内部变率为深蓝色、气候模型响应为黄色,未来人类排放情景为绿色。

Chart: Annual mean contribution of uncertainties

对1.5C临界值的意义

我们的模拟结果表明,在气候预测中纳入可能的火山活动时间线后,短期内突破《巴黎协定》设定的1.5C升温上限的概率略有下降。

根据不同的排放情景,相较于使用恒定火山强迫的预测,模拟发现超过1.5C升温上限的概率下降了4%至10%。

尽管这一结果听起来似乎令人鼓舞,但未来的火山活动并不能在长期缓和由人类引起的全球变暖。

1815年坦博拉火山的喷发事件就是一个强有力的例证。这次喷发使全球气温平均下降了约0.8C,带来了“无夏之年”,导致欧洲、北美和中国大范围的作物歉收和饥荒。

火山喷发带来的降温效应是短暂的,通常只持续几年,其并不会改变由人类排放所导致的长期变暖趋势。

我们的研究发现,即使考虑多种可能的未来火山活动,在除了最低排放路径以外的所有情景中,全球变暖仍将在几十年内超过1.5C。

即便21世纪火山活动频繁,其对全球变暖的抵消作用也仅占很小一部分——这意味着减排对于实现长期气候目标仍然至关重要。

下方图表展示了在三种排放情景下,使用随机火山强迫(实线)与恒定火山强迫(虚线)时超过1.5C的概率(上图),以及两种强迫方式之间的概率差异(下图)。

Charts: Probability of exceeding 1.5C

十年尺度的气温变率

我们的研究提供的另一个重要发现是:一旦将火山强迫的变率纳入考虑,将更有可能出现极端温暖和寒冷的十年期。

在中等排放情景下,我们发现出现负向十年期趋势——即全球表面温度在某个十年内平均下降——的概率增加了10%到18%。

与此同时,出现极端温暖十年期的概率也随之增加,这反映出火山强迫的变率会同时提高变暖和变冷极端事件发生的可能性。

这一结果凸显了火山喷发如何在十年时间尺度上对全球气温趋势带来显著的波动。

迈向更完善的气候预测

了解火山对气候的影响,对于全面评估农业、基础设施和能源系统在未来所面临的风险至关重要。

使用全面的地球系统模型运行数千种火山情景并不切实际,因为这需要极高的计算资源。但与此同时,当前的方法也存在上文提到的显著局限。

不过,在未来的气候模型工作中,仍有折中方案可行。

即将开展的下一阶段气候建模实验——即CMIP7情景模式比较计划——可以采用更具代表性的“平均”火山强迫基线,这一基线纳入了历史记录中常被遗漏的小型喷发事件的影响。这一偏差现已在用于下一代气候模型模拟的历史火山强迫数据集中得到纠正。

此外,建模团队还应额外运行包含高频和低频未来火山活动的情景,以全面捕捉火山不确定性对气候预测的影响范围。

虽然人类导致的温室气体排放仍是气候变化的主导因素,但若能妥善考虑火山活动的不确定性,将有助于我们获得更全面的未来气候图景及其对社会的潜在影响。

The post 嘉宾来稿:探究火山喷发如何影响气候预测 appeared first on Carbon Brief.

嘉宾来稿:探究火山喷发如何影响气候预测

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Cropped 25 February 2026: Food inflation strikes | El Niño looms | Biodiversity talks stagnate

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We handpick and explain the most important stories at the intersection of climate, land, food and nature over the past fortnight.

This is an online version of Carbon Brief’s fortnightly Cropped email newsletter.
Subscribe for free here.

Key developments

Food inflation on the rise

DELUGE STRIKES FOOD: Extreme rainfall and flooding across the Mediterranean and north Africa has “battered the winter growing regions that feed Europe…threatening food price rises”, reported the Financial Times. Western France has “endured more than 36 days of continuous rain”, while farmers’ associations in Spain’s Andalusia estimate that “20% of all production has been lost”, it added. Policy expert David Barmes told the paper that the “latest storms were part of a wider pattern of climate shocks feeding into food price inflation”.

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NO BEEF: The UK’s beef farmers, meanwhile, “face a double blow” from climate change as “relentless rain forces them to keep cows indoors”, while last summer’s drought hit hay supplies, said another Financial Times article. At the same time, indoor growers in south England described a 60% increase in electricity standing charges as a “ticking timebomb” that could “force them to raise their prices or stop production, which will further fuel food price inflation”, wrote the Guardian.

TINDERBOX’ AND TARIFFS: A study, covered by the Guardian, warned that major extreme weather and other “shocks” could “spark social unrest and even food riots in the UK”. Experts cited “chronic” vulnerabilities, including climate change, low incomes, poor farming policy and “fragile” supply chains that have made the UK’s food system a “tinderbox”. A New York Times explainer noted that while trade could once guard against food supply shocks, barriers such as tariffs and export controls – which are being “increasingly” used by politicians – “can shut off that safety valve”.

El Niño looms

NEW ENSO INDEX: Researchers have developed a new index for calculating El Niño, the large-scale climate pattern that influences global weather and causes “billions in damages by bringing floods to some regions and drought to others”, reported CNN. It added that climate change is making it more difficult for scientists to observe El Niño patterns by warming up the entire ocean. The outlet said that with the new metric, “scientists can now see it earlier and our long-range weather forecasts will be improved for it.”

WARMING WARNING: Meanwhile, the US Climate Prediction Center announced that there is a 60% chance of the current La Niña conditions shifting towards a neutral state over the next few months, with an El Niño likely to follow in late spring, according to Reuters. The Vibes, a Malaysian news outlet, quoted a climate scientist saying: “If the El Niño does materialise, it could possibly push 2026 or 2027 as the warmest year on record, replacing 2024.”

CROP IMPACTS: Reuters noted that neutral conditions lead to “more stable weather and potentially better crop yields”. However, the newswire added, an El Niño state would mean “worsening drought conditions and issues for the next growing season” to Australia. El Niño also “typically brings a poor south-west monsoon to India, including droughts”, reported the Hindu’s Business Line. A 2024 guest post for Carbon Brief explained that El Niño is linked to crop failure in south-eastern Africa and south-east Asia.

News and views

  • DAM-AG-ES: Several South Korean farmers filed a lawsuit against the country’s state-owned utility company, “seek[ing] financial compensation for climate-related agricultural damages”, reported United Press International. Meanwhile, a national climate change assessment for the Philippines found that the country “lost up to $219bn in agricultural damages from typhoons, floods and droughts” over 2000-10, according to Eco-Business.
  • SCORCHED GRASS: South Africa’s Western Cape province is experiencing “one of the worst droughts in living memory”, which is “scorching grass and killing livestock”, said Reuters. The newswire wrote: “In 2015, a drought almost dried up the taps in the city; farmers say this one has been even more brutal than a decade ago.”
  • NOUVELLE VEG: New guidelines published under France’s national food, nutrition and climate strategy “urged” citizens to “limit” their meat consumption, reported Euronews. The delayed strategy comes a month after the US government “upended decades of recommendations by touting consumption of red meat and full-fat dairy”, it noted. 
  • COURTING DISASTER: India’s top green court accepted the findings of a committee that “found no flaws” in greenlighting the Great Nicobar project that “will lead to the felling of a million trees” and translocating corals, reported Mongabay. The court found “no good ground to interfere”, despite “threats to a globally unique biodiversity hotspot” and Indigenous tribes at risk of displacement by the project, wrote Frontline.
  • FISH FALLING: A new study found that fish biomass is “falling by 7.2% from as little as 0.1C of warming per decade”, noted the Guardian. While experts also pointed to the role of overfishing in marine life loss, marine ecologist and study lead author Dr Shahar Chaikin told the outlet: “Our research proves exactly what that biological cost [of warming] looks like underwater.” 
  • TOO HOT FOR COFFEE: According to new analysis by Climate Central, countries where coffee beans are grown “are becoming too hot to cultivate them”, reported the Guardian. The world’s top five coffee-growing countries faced “57 additional days of coffee-harming heat” annually because of climate change, it added.

Spotlight

Nature talks inch forward

This week, Carbon Brief covers the latest round of negotiations under the UN Convention on Biological Diversity (CBD), which occurred in Rome over 16-19 February.

The penultimate set of biodiversity negotiations before October’s Conference of the Parties ended in Rome last week, leaving plenty of unfinished business.

The CBD’s subsidiary body on implementation (SBI) met in the Italian capital for four days to discuss a range of issues, including biodiversity finance and reviewing progress towards the nature targets agreed under the Kunming-Montreal Global Biodiversity Framework (GBF).

However, many of the major sticking points – particularly around finance – will have to wait until later this summer, leaving some observers worried about the capacity for delegates to get through a packed agenda at COP17.

The SBI, along with the subsidiary body on scientific, technical and technological advice (SBSTTA) will both meet in Nairobi, Kenya, later this summer for a final round of talks before COP17 kicks off in Yerevan, Armenia, on 19 October.

Money talks

Finance for nature has long been a sticking point at negotiations under the CBD.

Discussions on a new fund for biodiversity derailed biodiversity talks in Cali, Colombia, in autumn 2024, requiring resumed talks a few months later.

Despite this, finance was barely on the agenda at the SBI meetings in Rome. Delegates discussed three studies on the relationship between debt sustainability and implementation of nature plans, but the more substantive talks are set to take place at the next SBI meeting in Nairobi.

Several parties “highlighted concerns with the imbalance of work” on finance between these SBI talks and the next ones, reported Earth Negotiations Bulletin (ENB).

Lim Li Ching, senior researcher at Third World Network, noted that tensions around finance permeated every aspect of the talks. She told Carbon Brief:

“If you’re talking about the gender plan of action – if there’s little or no financial resources provided to actually put it into practice and implement it, then it’s [just] paper, right? Same with the reporting requirements and obligations.”

Monitoring and reporting

Closely linked to the issue of finance is the obligations of parties to report on their progress towards the goals and targets of the GBF.

Parties do so through the submission of national reports.

Several parties at the talks pointed to a lack of timely funding for driving delays in their reporting, according to ENB.

A note released by the CBD Secretariat in December said that no parties had submitted their national reports yet; by the time of the SBI meetings, only the EU had. It further noted that just 58 parties had submitted their national biodiversity plans, which were initially meant to be published by COP16, in October 2024.

Linda Krueger, director of biodiversity and infrastructure policy at the environmental not-for-profit Nature Conservancy, told Carbon Brief that despite the sparse submissions, parties are “very focused on the national report preparation”. She added:

“Everybody wants to be able to show that we’re on the path and that there still is a pathway to getting to 2030 that’s positive and largely in the right direction.”

Watch, read, listen

NET LOSS: Nigeria’s marine life is being “threatened” by “ghost gear” – nets and other fishing equipment discarded in the ocean – said Dialogue Earth.

COMEBACK CAUSALITY: A Vox long-read looked at whether Costa Rica’s “payments for ecosystem services” programme helped the country turn a corner on deforestation.

HOMEGROWN GOALS: A Straits Times podcast discussed whether import-dependent Singapore can afford to shelve its goal to produce 30% of its food locally by 2030.

‘RUSTING’ RIVERS: The Financial Times took a closer look at a “strange new force blighting the [Arctic] landscape”: rivers turning rust-orange due to global warming.

New science

  • Lakes in the Congo Basin’s peatlands are releasing carbon that is thousands of years old | Nature Geoscience
  • Natural non-forest ecosystems – such as grasslands and marshlands – were converted for agriculture at four times the rate of land with tree cover between 2005 and 2020 | Proceedings of the National Academy of Sciences
  • Around one-quarter of global tree-cover loss over 2001-22 was driven by cropland expansion, pastures and forest plantations for commodity production | Nature Food

In the diary

Cropped is researched and written by Dr Giuliana Viglione, Aruna Chandrasekhar, Daisy Dunne, Orla Dwyer and Yanine Quiroz.
Please send tips and feedback to cropped@carbonbrief.org

The post Cropped 25 February 2026: Food inflation strikes | El Niño looms | Biodiversity talks stagnate appeared first on Carbon Brief.

Cropped 25 February 2026: Food inflation strikes | El Niño looms | Biodiversity talks stagnate

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Dangerous heat for Tour de France riders only a ‘question of time’

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Rising temperatures across France since the mid-1970s is putting Tour de France competitors at “high risk”, according to new research.

The study, published in Scientific Reports, uses 50 years of climate data to calculate the potential heat stress that athletes have been exposed to across a dozen different locations during the world-famous cycling race.

The researchers find that both the severity and frequency of high-heat-stress events have increased across France over recent decades.

But, despite record-setting heatwaves in France, the heat-stress threshold for safe competition has rarely been breached in any particular city on the day the Tour passed through.

(This threshold was set out by cycling’s international governing body in 2024.)

However, the researchers add it is “only a question of time” until this occurs as average temperatures in France continue to rise.

The lead author of the study tells Carbon Brief that, while the race organisers have been fortunate to avoid major heat stress on race days so far, it will be “harder and harder to be lucky” as extreme heat becomes more common.

‘Iconic’

The Tour de France is one of the world’s most storied cycling races and the oldest of Europe’s three major multi-week cycling competitions, or Grand Tours.

Riders cover around 3,500 kilometres (km) of distance and gain up to nearly 55km of altitude over 21 stages, with only two or three rest days throughout the gruelling race.

The researchers selected the Tour de France because it is the “iconic bike race. It is the bike race of bike races,” says Dr Ivana Cvijanovic, a climate scientist at the French National Research Institute for Sustainable Development, who led the new work.

Heat has become a growing problem for the competition in recent years.

In 2022, Alexis Vuillermoz, a French competitor, collapsed at the finish line of the Tour’s ninth stage, leaving in an ambulance and subsequently pulling out of the race entirely.

Two years later, British cyclist Sir Mark Cavendish vomited on his bike during the first stage of the race after struggling with the 36C heat.

The Tour also makes a good case study because it is almost entirely held during the month of July and, while the route itself changes, there are many cities and stages that are repeated from year to year, Cvijanovic adds.

‘Have to be lucky’

The study focuses on the 50-year span between 1974 and 2023.

The researchers select six locations across the country that have commonly hosted the Tour, from the mountain pass of Col du Tourmalet, in the French Pyrenees, to the city of Paris – where the race finishes, along the Champs-Élysées.

These sites represent a broad range of climatic zones: Alpe d’ Huez, Bourdeaux, Col du Tourmalet, Nîmes, Paris and Toulouse.

For each location, they use meteorological reanalysis data from ERA5 and radiant temperature data from ERA5-HEAT to calculate the “wet-bulb globe temperature” (WBGT) for multiple times of day across the month of July each year.

WBGT is a heat-stress index that takes into account temperature, humidity, wind speed and direct sunlight.

Although there is “no exact scientific consensus” on the best heat-stress index to use, WBGT is “one of the rare indicators that has been originally developed based on the actual human response to heat”, Cvijanovic explains.

It is also the one that the International Cycling Union (UCI) – the world governing body for sport cycling – uses to assess risk. A WBGT of 28C or higher is classified as “high risk” by the group.

WBGT is the “gold standard” for assessing heat stress, says Dr Jessica Murfree, director of the ACCESS Research Laboratory and assistant professor at the University of North Carolina at Chapel Hill.

Murfree, who was not involved in the new study, adds that the researchers are “doing the right things by conducting their science in alignment with the business practices that are already happening”.

The researchers find that across the 50-year time period, WBGT has been increasing across the entire country – albeit, at different rates. In the north-west of the country, WBGT has increased at an average rate of 0.1C per decade, while in the southern and eastern parts of the country, it has increased by more than 0.5C per decade.

The maps below show the maximum July WBGT for each decade of the analysis (rows) and for hourly increments of the late afternoon (columns). Lower temperatures are shown in lighter greens and yellows, while higher temperatures are shown in darker reds and purples.

Six Tour de France locations analysed in the study are shown as triangles on the maps (clockwise from top): Paris, Alpe d’ Huez, Nîmes, Toulouse, Col du Tourmalet and Bordeaux.

The maps show that the maximum WBGT temperature in the afternoon has surpassed 28C over almost the entire country in the last decade. The notable exceptions to this are the mountainous regions of the Alps and the Pyrenees.

Maximum WBGT across France for the month of July from 1974-2023. Rows show the values for each decade and columns show the hourly values for 3:00pm, 4:00pm, 5:00pm and 6:00pm. Lower temperatures are shown in lighter greens and yellows, while higher temperatures are shown in darker reds and purples. Triangles indicate the six Tour de France locations analysed in the study. Source: Cvijanovic et al. (2026)

The researchers also find that most of the country has crossed the 28C WBGT threshold – which they describe as “dangerous heat levels” – on at least one July day over the past decade. However, by looking at the WBGT on the day the Tour passed through any of these six locations, they find that the threshold has rarely been breached during the race itself.

For example, the research notes that, since 1974, Paris has seen a WBGT of 28C five times at 3pm in July – but that these events have “so far” not coincided with the cycling race.

The study states that it is “fortunate” that the Tour has so far avoided the worst of the heat-stress.

Cvijanovic says the organisers and competitors have been “lucky” to date. She adds:

“It has worked really well for them so far. But as the frequency of these [extreme heat] events is increasing, it will be harder and harder to be lucky.”

Dr Madeleine Orr, an assistant professor of sport ecology at the University of Toronto who was not involved in the study, tells Carbon Brief that the paper was “really well done”, noting that its “methods are good [and its] approach was sound”. She adds:

“[The Tour has] had athletes complain about [the heat]. They’ve had athletes collapse – and still those aren’t the worst conditions. I think that that says a lot about what we consider safe. They’ve still been lucky to not see what unsafe looks like, despite [the heat] having already had impacts.”

Heat safety protocols

In 2024, the UCI set out its first-ever high temperature protocol – a set of guidelines for race organisers to assess athletes’ risk of heat stress.

The assessment places the potential risk into one of five categories based on the WBGT, ranging from very low to high risk.

The protocol then sets out suggested actions to take in the event of extreme heat, ranging from having athletes complete their warm-ups using ice vests and cold towels to increasing the number of support vehicles providing water and ice.

If the WBGT climbs above the 28C mark, the protocol suggests that organisers modify the start time of the stage, adapt the course to remove particularly hazardous sections – or even cancel the race entirely.

However, Orr notes that many other parts of the race, such as spectator comfort and equipment functioning, may have lower temperatures thresholds that are not accounted for in the protocol, but should also be considered.

Murfree points out that the study’s findings – and the heat protocol itself – are “really focused on adaptation, rather than mitigation”. While this is “to be expected”, she tells Carbon Brief:

“Moving to earlier start times or adjusting the route specifically to avoid these locations that score higher in heat stress doesn’t stop the heat stress. These aren’t climate preventative measures. That, I think, would be a much more difficult conversation to have in the research because of the Tour de France’s intimate relationship with fossil-fuel companies.”

The post Dangerous heat for Tour de France riders only a ‘question of time’ appeared first on Carbon Brief.

Dangerous heat for Tour de France riders only a ‘question of time’

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DeBriefed 20 February 2026: EU’s ‘3C’ warning | Endangerment repeal’s impact on US emissions | ‘Tree invasion’ fuelled South America’s fires

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Welcome to Carbon Brief’s DeBriefed. 
An essential guide to the week’s key developments relating to climate change.

This week

Preparing for 3C

NEW ALERT: The EU’s climate advisory board urged countries to prepare for 3C of global warming, reported the Guardian. The outlet quoted Maarten van Aalst, a member of the advisory board, saying that adapting to this future is a “daunting task, but, at the same time, quite a doable task”. The board recommended the creation of “climate risk assessments and investments in protective measures”.

‘INSUFFICIENT’ ACTION: EFE Verde added that the advisory board said that the EU’s adaptation efforts were so far “insufficient, fragmented and reactive” and “belated”. Climate impacts are expected to weaken the bloc’s productivity, put pressure on public budgets and increase security risks, it added.

UNDERWATER: Meanwhile, France faced “unprecedented” flooding this week, reported Le Monde. The flooding has inundated houses, streets and fields and forced the evacuation of around 2,000 people, according to the outlet. The Guardian quoted Monique Barbut, minister for the ecological transition, saying: “People who follow climate issues have been warning us for a long time that events like this will happen more often…In fact, tomorrow has arrived.”

IEA ‘erases’ climate

MISSING PRIORITY: The US has “succeeded” in removing climate change from the main priorities of the International Energy Agency (IEA) during a “tense ministerial meeting” in Paris, reported Politico. It noted that climate change is not listed among the agency’s priorities in the “chair’s summary” released at the end of the two-day summit.

US INTERVENTION: Bloomberg said the meeting marked the first time in nine years the IEA failed to release a communique setting out a unified position on issues – opting instead for the chair’s summary. This came after US energy secretary Chris Wright gave the organisation a one-year deadline to “scrap its support of goals to reduce energy emissions to net-zero” – or risk losing the US as a member, according to Reuters.

Around the world

  • ISLAND OBJECTION: The US is pressuring Vanuatu to withdraw a draft resolution supporting an International Court of Justice ruling on climate change, according to Al Jazeera.
  • GREENLAND HEAT: The Associated Press reported that Greenland’s capital Nuuk had its hottest January since records began 109 years ago.
  • CHINA PRIORITIES: China’s Energy Administration set out its five energy priorities for 2026-2030, including developing a renewable energy plan, said International Energy Net.
  • AMAZON REPRIEVE: Deforestation in the Brazilian Amazon has continued to fall into early 2026, extending a downward trend, according to the latest satellite data covered by Mongabay.
  • GEZANI DESTRUCTION: Reuters reported the aftermath of the Gezani cyclone, which ripped through Madagascar last week, leaving 59 dead and more than 16,000 displaced people.

20cm

The average rise in global sea levels since 1901, according to a Carbon Brief guest post on the challenges in projecting future rises.


Latest climate research

  • Wildfire smoke poses negative impacts on organisms and ecosystems, such as health impacts on air-breathing animals, changes in forests’ carbon storage and coral mortality | Global Ecology and Conservation
  • As climate change warms Antarctica throughout the century, the Weddell Sea could see the growth of species such as krill and fish and remain habitable for Emperor penguins | Nature Climate Change
  • About 97% of South American lakes have recorded “significant warming” over the past four decades and are expected to experience rising temperatures and more frequent heatwaves | Climatic Change

(For more, see Carbon Brief’s in-depth daily summaries of the top climate news stories on Monday, Tuesday, Wednesday, Thursday and Friday.)

Captured

US emissions, MtCO2e, under a “current policy” scenario in which the EPA removes key federal climate regulations

Repealing the US’s landmark “endangerment finding”, along with actions that rely on that finding, will slow the pace of US emissions cuts, according to Rhodium Group visualised by Carbon Brief. US president Donald Trump last week formally repealed the scientific finding that underpins federal regulations on greenhouse gas emissions, although the move is likely to face legal challenges. Data from the Rhodium Group, an independent research firm, shows that US emissions will drop more slowly without climate regulations. However, even with climate regulations, emissions are expected to drop much slower under Trump than under the previous Joe Biden administration, according to the analysis.

Spotlight

How a ‘tree invasion’ helped to fuel South America’s fires

This week, Carbon Brief explores how the “invasion” of non-native tree species helped to fan the flames of forest fires in Argentina and Chile earlier this year.

Since early January, Chile and Argentina have faced large-scale and deadly wildfires, including in Patagonia, which spans both countries.

These fires have been described as “some of the most significant and damaging in the region”, according to a World Weather Attribution (WWA) analysis covered by Carbon Brief.

In both countries, the fires destroyed vast areas of native forests and grasslands, displacing thousands of people. In Chile, the fires resulted in 23 deaths.

Firefighters spray water on homes in Vina del Mar, Chile.
Firefighters spray water on homes in Vina del Mar, Chile. Credit: Esteban Felix / Alamy Stock Photo

Multiple drivers contributed to the spread of the fires, including extended periods of high temperatures, low rainfall and abundant dry vegetation.

The WWA analysis concluded that human-caused climate change made these weather conditions at least three times more likely.

According to the researchers, another contributing factor was the invasion of non-native trees in the regions where the fires occurred.

The risk of non-native forests

In Argentina, the wildfires began on 6 January and persisted until the first week of February. They hit the city of Puerto Patriada and the Los Alerces and Lago Puelo national parks, in the Chubut province, as well as nearby regions.

In these areas, more than 45,000 hectares of native forests – such as Patagonian alerce tree, myrtle, coigüe and ñire – along with scrubland and grasslands, were consumed by the flames, according to the WWA study.

In Chile, forest fires occurred from 17 to 19 January in the Biobío, Ñuble and Araucanía regions.

The fires destroyed more than 40,000 hectares of forest and more than 20,000 hectares of non-native forest plantations, including eucalyptus and Monterey pine.

Dr Javier Grosfeld, a researcher at Argentina’s National Scientific and Technical Research Council (CONICET) in northern Patagonia, told Carbon Brief that these species, introduced to Patagonia for production purposes in the late 20th century, grow quickly and are highly flammable.

Because of this, their presence played a role in helping the fires to spread more quickly and grow larger.

However, that is no reason to “demonise” them, he stressed.

Forest management

For Grosfeld, the problem in northern Patagonia, Argentina, is a significant deficit in the management of forests and forest plantations.

This management should include pruning branches from their base and controlling the spread of non-native species, he added.

A similar situation is happening in Chile, where management of pine and eucalyptus plantations is not regulated. This means there are no “firebreaks” – gaps in vegetation – in place to prevent fire spread, Dr Gabriela Azócar, a researcher at the University of Chile’s Centre for Climate and Resilience Research (CR2), told Carbon Brief.

She noted that, although Mapuche Indigenous communities in central-south Chile are knowledgeable about native species and manage their forests, their insight and participation are not recognised in the country’s fire management and prevention policies.

Grosfeld stated:

“We are seeing the transformation of the Patagonian landscape from forest to scrubland in recent years. There is a lack of preventive forestry measures, as well as prevention and evacuation plans.”

Watch, read, listen

FUTURE FURNACE: A Guardian video explored the “unbearable experience of walking in a heatwave in the future”.

THE FUN SIDE: A Channel 4 News video covered a new wave of climate comedians who are using digital platforms such as TikTok to entertain and raise awareness.

ICE SECRETS: The BBC’s Climate Question podcast explored how scientists study ice cores to understand what the climate was like in ancient times and how to use them to inform climate projections.

Coming up

Pick of the jobs

DeBriefed is edited by Daisy Dunne. Please send any tips or feedback to debriefed@carbonbrief.org.

This is an online version of Carbon Brief’s weekly DeBriefed email newsletter. Subscribe for free here.

The post DeBriefed 20 February 2026: EU’s ‘3C’ warning | Endangerment repeal’s impact on US emissions | ‘Tree invasion’ fuelled South America’s fires appeared first on Carbon Brief.

DeBriefed 20 February 2026: EU’s ‘3C’ warning | Endangerment repeal’s impact on US emissions | ‘Tree invasion’ fuelled South America’s fires

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