This week, the international court of justice (ICJ) opened two weeks of hearings on states’ climate-related legal obligations – and the consequences, if “significant harm” is caused.
It is taking place against a backdrop of rapidly escalating climate impacts. Emissions continue to rise, rather than falling rapidly, as needed to avoid dangerous levels of global warming.
It is the ICJ’s largest ever case, with more than 100 countries and international organisations making interventions, deploying a wide variety of legal arguments.
Ralph Regenvanu, climate envoy for Vanuatu, which led the campaign for the ICJ hearings, said in his opening address: “[T]his may well be the most consequential case in the history of humanity.”
Below, Carbon Brief interviews leading international law scholar Prof Philippe Sands – who drafted the pleadings for Mauritius, but is speaking here in a personal capacity – to find out more about the legal issues at stake and the wider significance of the ICJ case.
On the significance of the case: “It’s the first time the ICJ has been called upon to address legal issues relating to climate change.”
On climate obligations under the UN: “Will the court open the door to the situation that the 1992 [UN climate] convention … [is] not the be all and end all?”
On the responsibility of states: “The question at the beating heart of this case, really, is the consequences of emissions over time.”
On historical emissions: “The big issue is, are you liable for the continuing consequences of your past emissions?”
On applying international law: “When drafting the climate treaty regime, [did] states…exclude the application of general international law?”
On expectations for the case: “What I’m interested in, really, is an advisory opinion that is capable of having hard, practical application.”
On the state of the science: “A procedure in which the judges hear privately from any person…is unusual. It’s unorthodox.”
On the significance of the submissions: “The oral phase is very important, because it basically concentrates the issues down to the most significant and narrow set of issues.”
Carbon Brief: Would you be able to start by just situating this case in its wider legal context and explaining why it could be so consequential?
Philippe Sands: Well, it’s the first time the international court of justice has been called upon to address legal issues relating to climate change. The ICJ is the principal judicial organ of the United Nations and, although the advisory opinion that it hands down will not be binding on states, it is binding on all UN bodies. The determinations that the court makes will have consequences that go very far and that will have a particular authority, in legal and political terms. Of course, everything turns on what the court actually says.
CB: Would you be able to summarise the key legal arguments that are being fought over in this case?
PS: No! I mean, there’s just a huge number of issues that are coming up. But, essentially, the court has been asked two questions by the UN General Assembly – the first time, I believe, that a request from the General Assembly has been consensual, with no objections. The two questions are, firstly, what are the obligations for states under international law to protect the climate system? And, secondly, what are the legal consequences under these obligations, where, by their acts and emissions, [states] cause significant harm to the climate system? So, there are two distinct questions – and about 100 states and international organisations of various kinds have made submissions on the vast range of issues that are raised by these two questions. The questions are very, very broad and that signals to me that the court’s response may be quite general. But, for me, the crucial issues are, firstly, what the court says about the state of the science: is it established, or is there any room for doubt? Secondly, what are the obligations of states having regard to the clarity of the science? Thirdly, are there legal obligations on states in relation to the climate system that exist and arise outside of the treaty regime – the 1992 [UN Framework] convention [on climate change], the Kyoto Protocol, the Paris Agreement and so on and so forth. And, related to that, fourthly – this is the most intense, legally interesting aspect – what are the responsibilities of states for historic emissions under general international law? And, in particular, are the biggest contributors liable under international law to make good any damages that may arise from their historic actions? But, I mean, there’s just such a vast array of questions that are addressed, it’s impossible to summarise briefly.
Activists demanding that rich countries pay up for climate finance protest at COP29 in Baku, Azerbaijan on November 22, 2024. (Photo: Sean Gallup/Getty Images)
Critics of the “COP of false solutions” said that instead of much-needed funding, developing nations got “a global Ponzi scheme that the private equity vultures and public relations people will now exploit.”
It was early Sunday by the time the United Nations climate summit wrapped up in Baku, Azerbaijan after running into overtime to finalize deals on carbon markets and funding for developing countries that were sharply condemned by campaigners worldwide.
“COP29 was a dumpster fire. Except it’s not trash that’s burning—it’s our planet,” declared Nikki Reisch of the Center for International Environmental Law. “And developed countries are holding both the matches and the firehose.”
Recalling last year’s conference in the United Arab Emirates, Oil Change International global policy senior strategist Shady Khalil highlighted that “the world made a deal at COP28 to end the fossil fuel era. Now, at COP29, countries seem to have been struck with collective amnesia.”
“With each new iteration of the texts, oil and gas producers managed to dilute the urgent commitment to phase out fossil fuels,” Khalil said. “But let’s be clear: Rich countries’ failure to lead on fossil fuel phaseout and to put the trillions they have hoarded on the table has done more to imperil the energy transition than any obstructionist tactics from oil and gas producers.”
This year’s conference began November 11 and was due to conclude on Friday, but parties to the Paris agreement were still negotiating the carbon market rules, which were finalized late Saturday, and the new collective quantified goal (NCQG) on climate finance.
“The carbon markets in Article 6 of the Paris agreement were pushed through COP29 in a take-it-or leave-it outcome,” said Tamra Gilbertson of Indigenous Environmental Network, decrying “a new dangerous era in climate change negotiations.”
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As Climate Home Newsreported, they establish two types of markets: “The first—known as Article 6.2—regulates bilateral carbon trading between countries, while Article 6.4 creates a global crediting mechanism for countries to sell emissions reductions.”
The outlet pointed to expert warnings that “the rules for bilateral trades under 6.2 could open the door for the sale of junk carbon credits—one of the weaknesses of the previous crediting mechanism set up by the U.N. known as the Clean Development Mechanism (CDM).”
Jonathan Crook of Carbon Market Watch said in a statement that “the package does not shine enough light on an already opaque system where countries won’t be required to provide information about their deals well ahead of actual trades.”
“Even worse, the last opportunity to strengthen the critically weak review process was largely missed,” he continued. “Countries remain free to trade carbon credits that are of low quality, or even fail to comply with Article 6.2 rules, without any real oversight.”
As for Article 6.4, “much lies in the hands of the supervisory body” that’s set to resume work in early 2025, said Crook’s colleague, Federica Dossi. “To show that it is ready to learn from past mistakes, it will have to take tough decisions next year and ensure that Article 6.4 credits will be markedly better than the units that old CDM projects will generate.”
“If they are not, they will have to compete in a low-trust, low-integrity market where prices are likely to be at rock bottom and interest will be low,” Dossi added. “Such a system would be a distraction, and a waste of 10 years worth of carbon market negotiations.”
Some campaigners suggested that no matter what lies ahead, the embrace of carbon markets represents a failure. Kirtana Chandrasekaran at Friends of the Earth International said that “the supposed ‘COP of climate finance’ has turned into the ‘COP of false solutions.’ The U.N. has given its stamp of approval to fraudulent and failed carbon markets.”
“We have seen the impacts of these schemes: land grabs, Indigenous peoples’ and human rights violations,” Chandrasekaran noted. “The now-operationalized U.N. global carbon market may well be worse than existing voluntary ones and will continue to provide a get out of jail free card to Big Polluters whilst devastating communities and ecosystems.”
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Chandrasekaran’s colleague Seán McLoughlin at Friends of the Earth Ireland was similarly critical of the conference’s finance deal, asserting that “Baku is a big F U to climate justice, to the poorest communities who are on the frontlines of climate breakdown.”
“COP29 has failed those who have done least to cause climate change and who are most vulnerable to climate breakdown because the process is still in thrall to fossil fuel bullies and rich countries more committed to shirking their historical responsibility than safeguarding our common future,” he said. “Now it’s back to citizens to demand our governments do the right thing. We must keep demanding the trillions, not billions owed in climate debt and a comprehensive, swift, and equitable fossil fuel phaseout. The struggle for climate justice is not over.”
Campaigners and developing nations fought for $1.3 trillion in annual climate finance from those most responsible for the planetary crisis. Instead, the NCQG document only directs developed countries to provide the Global South with $300 billion per year by 2035, with a goal of reaching the higher figure by also seeking funds from private sources.
The deal almost didn’t happen at all. As The Guardiandetailed Saturday: “Developed countries including the U.K., the U.S., and E.U. members were pushed into raising their offer from an original $250 billion a year tabled on Friday, to $300 billion. Poor countries argued for more, and in the early evening two groups representing some of the world’s poorest countries walked out of one key meeting, threatening to collapse the negotiations.”
While Simon Stiell, executive secretary of U.N. Climate Change, celebrated the NCQG as “an insurance policy for humanity, amid worsening climate impacts hitting every country,” Chiara Martinelli, director at Climate Action Network Europe, put it in the context of the $100 billion target set in 2009, which wealthy governments didn’t meet.
“Rich countries own the responsibility for the failed outcome at COP29,” Martinelli said. “The talk of tripling from the $100 billion goal might sound impressive, but in reality, it falls far short, barely increasing from the previous commitment when adjusted for inflation and considering the bulk of this money will come in the form of unsustainable loans. This is not solidarity. It’s smoke and mirrors that betray the needs of those on the frontlines of the climate crisis.”
Also stressing that “it’s not even real ‘money,’ by and large,” but rather “a motley mix of loans and privatized investment,” Oxfam International’s climate change policy lead, Nafkote Dabi, called the agreement “a global Ponzi scheme that the private equity vultures and public relations people will now exploit.”
“The terrible verdict from the Baku climate talks shows that rich countries view the Global South as ultimately expendable, like pawns on a chessboard,” Dabi charged. “The $300 billion so-called ‘deal’ that poorer countries have been bullied into accepting is unserious and dangerous—a soulless triumph for the rich, but a genuine disaster for our planet and communities who are being flooded, starved, and displaced today by climate breakdown.”
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Rachel Cleetus from the Union of Concerned Scientists, who is in Baku, took aim at not only rich governments, but also the host, saying that “the Azerbaijani COP29 Presidency’s ineptitude in brokering an agreement at this consequential climate finance COP will go down in ignominy.”
Cleetus’ group is based in the United States, which is preparing for a January transfer of power from Democratic President Joe Biden to Republican President-elect Donald Trump, who notably ditched the Paris agreement during his first term.
“The United States—the world’s largest historical contributor of heat-trapping emissions—is going to see a monumental shift in its global diplomacy posture as the incoming anti-science Trump administration will likely exit the Paris agreement and take a wrecking ball to domestic climate and clean energy policies,” Cleetus warned. “While some politically and economically popular clean energy policies may prove durable and action from forward-looking states and businesses will be significant, there’s no doubt that a lack of robust federal leadership will leave U.S. climate action hobbled for a time.”
“Other nations—including E.U. countries and China—will need to do what they can to fill the void,” she stressed. “Between now and COP30 in Brazil next year, nations have a lot of ground to make up to have any hope of limiting runaway climate change.”
Ben Goloff of the U.S.-based Center for Biological Diversity called out the departing Biden administration, arguing that it “should be going out with at least a signal of its moral climate commitment, not copping out ahead of the Trump 2.0 disaster.”
Experienced climbers scale a rock face near the historic Dumbarton castle in Glasgow, releasing a banner that reads “Climate on a Cliff Edge.” One activist, dressed as a globe, symbolically looms near the edge, while another plays the bagpipes on the shores below. | Photo courtesy of Extinction Rebellion and Mark RichardsOrcas comment on killer apes destroying the planet by continuing to burn fossil fuels.
Activists demonstrate against industrial agriculture and agribusiness lobbyists on day eight at the UNFCCC COP29 Climate Conference on November 19, 2024 in Baku, Azerbaijan. (Photo by Sean Gallup/Getty Images)
“By the end of the UN climate talks, we must see at least a trillion dollars in public finance on the table,” said one campaigner.
As the clock winds down at the UN climate summit taking place in Baku, Azerbaijan, green groups are sounding the alarm Thursday following the release of a draft climate finance deal that they say falls short of what’s needed to support climate-vulnerable countries and adequately address the planetary crisis.
“The clock is ticking. COP29 is now down to the wire,” said UN Secretary-General António Guterres on Thursday, just a day before the two-week conference is set to conclude.
Finance has been a major focus of this year’s summit. Under the 20125 Paris Agreement, countries are supposed to come up with a “new collective quantified goal”—or NCQG in COP jargon—that will govern how much money from rich countries will be transferred to developing countries in order to help the latter cut their emissions and adapt to climate change.
No equivalent climate finance arrangement has been agreed to before, though countries at the summit broadly agree that richer countries, who are responsible for much of historic CO2 emissions, should help poorer and more climate-vulnerable nations deal with natural disasters and their transition to green energy.
The draft text that dropped early Thursday, however, was received poorly.
Oxfam International’s climate justice lead, Safa’ Al Jayoussi, said “COP29 must do more than simply repeat the same threadbare promises. Rich countries have spent decades now stalling and blocking genuine progress on climate finance. This has left the Global South suffering the most catastrophic consequences of a climate crisis they did not create. The draft text scandalously misses the crucial element of declaring a clear public commitment to a new climate finance goal.”
Instead of specifying how much annually should be funneled towards developing countries via climate finance, the NCQG draft text displayed “X” in place of any actual figures or monetary commitments.
Oscar Soria, a director at the Common Initiative think tank, told the Guardian: “The negotiating placeholder ‘X’ for climate finance is a testament of the ineptitude from rich nations and emerging economies that are failing to find a workable solution for everyone.”
“By the end of the UN climate talks, we must see at least a trillion dollars in public finance on the table,” added Andreas Sieber, 350.org associate director of policy and campaigns. Economists told the summit attendees last week that developing countries need at least $1 trillion annually by 2030 to deal with climate change.
A specific and shared concern from campaigners was the draft text’s inclusion of carbon market schemes as a way “to scale up” climate finance. While the draft promotes “high-integrity voluntary carbon markets” and other “instruments that mobilize new sources of climate finance and private finance” as part of the equation, critics have long warned that these market-based approaches are nothing but false solutions designed to benefit corporate investors, wealthier nations, and the fossil fuel industry itself.
“Labelling carbon credits as climate finance—which they are unreservedly not—should be axed from the text or risk creating a dangerous escape route for polluters. The same goes for explicitly allowing investments in fossil fuel infrastructure. This is fundamentally incompatible with the goals of the Paris Agreement,” said Laurie van der Burg, Oil Change International’s global public finance manager, in response to the draft text.
While Article 6 of the Paris Agreement allows for the international transfer of carbon credits, groups warned the changes in the COP29 draft would dramatically strengthen the foothold of such schemes.
“Shockingly, COP29 is set to agree to carbon markets that are even worse than the voluntary carbon markets,” said Kirtana Chandrasekaran, a climate campaigner with Friends of the Earth International. “We know these markets have failed. They are riddled with fraud and they do not reduce emissions or provide finance. Communities everywhere and, in fact, the planet itself is on the line.”
Without addressing these concerns, advocates of a meaningful deal at the conference say COP29 is headed for failure.
As 350.org‘s Sieber argued, paying the “historic debt that rich countries owe will enable all nations to take action on climate at home and meet the collective goal agreed last year at COP28—to triple renewable energy, and transition away from fossil fuels. Right now, we only see cowardice and a void in leadership, ignoring the undeniable science that we can’t keep polluting our planet with dirty oil, gas and coal.”
“The time to course correct is now—the European Union and other rich countries must stop playing poker with the planet and humankind’s future at stake,” Sieber added. “It’s time to put their cards on the table and commit real, transformative funding—no more excuses, no more delays, it’s time.”
Experienced climbers scale a rock face near the historic Dumbarton castle in Glasgow, releasing a banner that reads “Climate on a Cliff Edge.” One activist, dressed as a globe, symbolically looms near the edge, while another plays the bagpipes on the shores below. | Photo courtesy of Extinction Rebellion and Mark RichardsOrcas comment on killer apes destroying the planet by continuing to burn fossil fuels. Second version, corrected text.
A protester holds a sign with a Shell logo during a demonstration on March 11, 2023 in The Hague, Netherlands. (Photo: Michel Porro/Getty Images)
“This setback will only help us grow stronger,” said the Dutch climate group that originally brought the case. “Large polluters are powerful. But united, we as people have the power to change them.”
Climate campaigners didn’t sugarcoat their reactions to a Dutch court decision on Tuesday that overturned a landmark 2021 ruling ordering the oil behemoth Shell to cut its planet-warming emissions nearly in half by the end of this decade.
“We are shocked by today’s judgment,” said Donald Pols, director of Milieudefensie, the Netherlands-based environmental group that originally filed suit against Shell in 2018.
“It is a setback for us, for the climate movement, and for millions of people around the world who worry about their future,” Pols said of Tuesday’s ruling by the Hague Court of Appeal. “But if there’s one thing to know about us, it’s that we don’t give up. This setback will only help us grow stronger. Large polluters are powerful. But united, we as people have the power to change them.”
The original 2021 ruling, as CNBC noted, marked “the first time in history that a company was found to have been legally obliged to align its policies with the Paris Agreement” and “sparked a wave of lawsuits against other fossil fuel companies.”
Despite acknowledging that Shell has “an obligation toward citizens to reduce CO2 emissions,” the appeals court on Tuesday scrapped a legal mandate compelling the company to slash its emissions by 45% by 2030 compared with 2019 levels, saying it was “unable to establish that the social standard of care entails an obligation for Shell to reduce its CO2 emissions by 45%, or some other percentage.”
“It is primarily up to the government to ensure the protection of human rights,” the court added.
Laurie van der Burg of Oil Change Internationalsaid in response that “while we mourn today’s setback, the ruling establishes a responsibility for Big Oil and Gas to act that future litigation can build on.”
“The court ruled protection against climate change is a human right, and corporations have a responsibility to reduce their emissions,” she added. “As far as we know, this is the first case where a court has acknowledged that new investments in oil and gas are incompatible with international climate goals.”
“Today’s ruling underscores the importance of world leaders now negotiating at the U.N. Climate Summit in Baku taking responsibility.”
Shell, which is responsible for just over 2% of global CO2 emissions, said in a statement that it was “pleased” with the court’s ruling and claimed to be “making good progress in our strategy to deliver more value with less emissions.”
But research by the human rights organization Global Witness has found that Shell has consistently overstated the scale of its investments in green energy—including by characterizing fossil fuels as “renewable.”
“Even as Shell claims to be reducing its oil production, it is planning to grow its gas business by more than 20% over the next few years, leading to significant additional emissions,” Global Witness wrote in a complaint to the U.S. Securities and Exchange Commission last year.
Andy Palmen, the director of Greenpeace Netherlands, said Tuesday that while campaigners working toward a just phaseout of fossil fuel emissions are “disappointed that Shell is being allowed to continue polluting,” they “will not give up the fight.”
“This only motivates us more to take action against major polluters,” said Palmen. “It really gives hope that the court finds that Shell must respect human rights and has a duty to reduce its CO2 emissions.”
“Today’s ruling underscores the importance of world leaders now negotiating at the U.N. Climate Summit in Baku taking responsibility,” Palmen added, referring to the COP29 gathering that kicked off on Monday in Azerbaijan’s capital city. “The summit in Dubai last year marked the end of coal, oil, and gas, now governments must come up with concrete plans to move away from fossil fuels.”
The Dutch appeals court’s ruling came in the wake of new research showing that oil and gas production surged to an all-time high in 2023—the hottest year on record.
“The oil and gas industry is not transitioning,” the environmental group Urgewald and dozens of other NGOs found. “In fact, 95% of the upstream companies on [the Global Oil and Gas Exit List] are still exploring or developing new oil and gas resources. This includes the oil and gas producers TotalEnergies, Shell, BP, Eni, Equinor, OXY, OMV, and Ecopetrol, which all claim to be targeting net zero emissions by 2050.”
Nils Bartsch, head of oil and gas research at Urgewald, said Tuesday that the 2023 oil and gas production record is “deeply concerning.”
“If we do not end fossil fuel expansion and move towards a managed decline of oil and gas production,” said Bartsch, “the 1.5°C goal will be out of reach.”
This year is now virtually certain to beat 2023 as the hottest year on record, Carbon Brief analysis shows.
It will also be the first full year to surpass 1.5C above pre-industrial levels across the majority of observational records.
In this latest “state of the climate” quarterly update, Carbon Brief finds:
The year 2024 has seen record warm temperatures for seven of the nine months of the year where data is so far available.
The world, as a whole, has warmed approximately 1C since 1970 – and 1.2C to 1.4C since the mid-1800s.
A strong El Niño event contributed to exceptionally high global temperatures early in the year, but record or near-record temperatures persisted despite the fading of El Niño in recent months.
Record global temperatures have been seen across many regions of the planet over the first nine months of the year.
Global temperatures are closely aligned with the projections from climate models.
Global sea ice extent is currently at record lows and Antarctic sea ice has spent much of the year at near-record lows – second only to those seen in 2023.
The figure below shows Carbon Brief’s estimate of where 2024 temperatures will end up in each of the groups, based on the year to date and expected El Niño-Southern Oscillation (ENSO) conditions in the tropical Pacific for the remainder of the year.
The dots reflect the best estimate, while the whiskers show the two sigma (95%) confidence interval of the projections. The prior record year (2023 in all groups) is shown by the coloured square. https://interactive.carbonbrief.org/state-of-the-climate/24-Q3/projections.htmlCarbon Brief’s project of 2024 annual global average surface temperatures for each group, along with 95% confidence intervals and prior record (2023) values. 1.5C above pre-industrial (1850-1900) levels is shown by a dashed line. The average projection represents a composite of all five records following the WMO approach. Chart by Carbon Brief.
In all cases, the projected global average temperature for 2024 is virtually certain to exceed the prior record set in 2023.
Three of the five groups (Hadley, Berkeley and Copernicus/ECMWF) are very likely to show annual temperatures exceeding 1.5C above pre-industrial levels (defined here as the 1850-1900 period), while the NASA record has a roughly 40% chance of exceeding 1.5C. Only NOAA’s record is unlikely to show global temperatures above 1.5C this year.
These differences in warming since pre-industrial across different datasets primarily result from choice of ocean records used, as well as differences in approaches to filling in gaps between observations in the early part of the records (e.g. pre-1900s). It reflects the uncertainty in the degree of warming since the mid-1800s, with projected 2024 temperatures ranging from 1.44C (NOAA) to 1.61C (Berkeley Earth).
The figure also provides a composite average of the five different datasets, following the approach used in the sixth assessment report (AR6) from the Intergovernmental Panel on Climate Change (IPCC) and by the WMO. Carbon Brief’s analysis finds that 2024 will be the first year above 1.5C in the composite average.
This provides a way to determine the first year where we can reasonably say that the world has passed that warming level – even though 2023 exceeded 1.5C in the Berkeley Earth dataset and 2024 will not exceed 1.5C in the NOAA dataset.
(It is important to note that exceeding 1.5C in a single year is not equivalent to breaching the Paris Agreement limit. The goal is generally considered to refer to long-term warming – typically over two or three decades – rather than annual temperatures that include the short-term influence of natural fluctuations in the climate, such as El Niño.)
The figure below shows the annual temperatures from each of these groups between 1970 and present, with the year-to-date 2024 temperatures for each record shown as individual points. https://interactive.carbonbrief.org/state-of-the-climate/24-Q3/records_2024_to_date.htmlAnnual global average surface temperatures from NASA GISTEMP, NOAA GlobalTemp, Hadley/UEA HadCRUT5, Berkeley Earth and Copernicus/ECMWF (lines), along with 2024 temperatures to date (January-September, coloured shapes). Each series is aligned by using a 1981-2010 baseline, with warming since pre-industrial based on the IPCC AR6 estimate of warming between pre-industrial and the 1981-2010 period. Chart by Carbon Brief.
There is strong agreement between the different temperature records, with all of them showing approximately 1C warming between 1970 and present. Global temperatures have been around 1.3 above pre-industrial levels in recent years (with a range of 1.2C to 1.4C across the different temperature datasets, reflecting that the differences between them are larger in the 1800s and early 1900s).
As the chart below shows, 2024 (purple line) started out remarkably warm as a result of a strong El Niño event that built in 2023 (red) and peaked near the beginning of the year.
However, global temperatures have remained quite elevated despite the fading of El Niño conditions, setting records through June and remaining quite close to 2023’s exceptional highs in recent months.
Overall, 2024 has set or tied all-time records for seven of the 10 months available to-date in the ERA5 record. (This record uses weather model-based reanalysis to combine lots of different data sources over time.)https://interactive.carbonbrief.org/state-of-the-climate/24-Q3/monthly_global_temperature_anomalies_Q3_2024.htmlTemperatures for each month from 1940 to 2024 from Copernicus/ECMWF ERA5. Anomalies plotted with respect to a 1850-1900 baseline. Chart by Carbon Brief.
While human emissions of CO2 and other greenhouse gases are responsible for effectively all of the Earth’s long-term warming, temperatures in any given year are strongly influenced by short-term variations in the Earth’s climate that are typically associated with El Niño and La Niña events.
These fluctuations in temperature between the ocean and atmosphere in the tropical Pacific help make some individual years warmer and some cooler.
The figure below shows a range of different ENSO forecast models produced by different scientific groups. The values shown are sea surface temperature variations in the tropical Pacific – the El Niño 3.4 region – for three-month periods.
El Niño Southern Oscillation (ENSO) forecast models for overlapping three-month periods in the Niño3.4 region (July, August, September – JAS – and so on) for the remainder of 2024 and then into the spring and summer of 2025. Credit: CPC/IRI ENSO forecast.
Most models expect neutral conditions in the tropical Pacific, with only a few crossing the -0.5C Niño 3.4 sea surface temperature (SST) anomaly that represents the development of a formal La Niña event.
This should result in relatively cooler temperatures in 2025, though it is possible that the year ends up warmer than anticipated given the continuation of high temperatures in recent months – despite the absence of El Niño conditions.
Large areas of record warmth
While global average temperatures are an important indicator of changes to the broader climate system over time as a result of human activities, these impacts will differ as some regions experience more rapid warming or extreme heat events than is reflected in the global average.
The figure below shows the parts of the world that saw record warm or cold temperatures over the first three quarters of 2024 (January through to September) in the Berkeley Earth dataset compared to all prior years since global temperature record began in 1850.
Map of year-to-date (January-September) regions that set new records (warmest through to fifth warmest). Note that no regions set cold records for the year-to-date in 2024. Credit: Berkeley Earth
Notably, no area on Earth saw record cold (or even the second, third, fourth or fifth coldest temperatures on record). Nearly all of Central America and large parts of South America saw their warmest year to date on record, as did much of eastern Europe, Africa, China, south-east Asia, and Korea.
The figure below shows the temperature anomaly over the first nine months of the year compared to the 1951-80 baseline period used by Berkeley Earth. Warming was particularly pronounced over land regions, with many areas already showing warming of 1.5C or 2C above that baseline.
Map of year-to-date (January-September) global surface temperatures. Anomalies are shown relative to the 1951-80 period following the convention used by Berkeley Earth. Credit: Berkeley Earth
Temperatures are tracking climate model projections
Climate models provide physics-based estimates of future warming given different assumptions about future emissions, greenhouse gas concentrations and other climate-influencing factors.
The figure below shows the range of individual models forecasts featured in AR6 – known collectively as the CMIP6 models – between 1970 and 2030, with grey shading and the average projection across all the models shown in black. Individual observational temperature records are represented by coloured lines.https://interactive.carbonbrief.org/state-of-the-climate/24-Q3/model_obs_comps_Q3_2024.htmlTwelve-month average global average surface temperatures from CMIP6 models and observations between 1970 and 2024. Models use SSP2-4.5 forcings after 2015.Anomalies plotted with respect to a 1981-2010 baseline. Chart by Carbon Brief.
While global temperatures were running below the pace of warming projected by climate models for much of the period between 2008 and 2022, the past two years have been closer to the model average.
However, the CMIP6 models may be biassed a bit too warm, with a subset of “hot” models pushing up the average. The IPCC used an approach that weighted models based on how well they reproduced historical temperatures, rather than simply averaging all the models together.
Excluding these hotter models from the analysis results in observations over recent years much closer to the multi-model average and near the centre of the uncertainty range across all models. It also reveals that the past two years – 2023 and 2024 – have been near the upper end of the model range.https://interactive.carbonbrief.org/state-of-the-climate/24-Q3/model%20_obs_comps_filtered_Q3_2024.htmlTwelve-month average global average surface temperatures from CMIP5 models and observations between 1970 and 2024. Models use SSP2-4.5 forcings after 2015. Anomalies plotted with respect to a 1981-2010 baseline. Chart by Carbon Brief.
Record low global sea ice extent
Highly accurate observations of Arctic and Antarctic sea ice have been available since polar-observing satellites became available in the late 1970s.
Arctic sea ice extent during the first three-quarters of 2024 has been below or at the low end of the historical 1979-2010 range, but has not seen any record daily lows.
Antarctic sea ice, on the other hand, set new all-time low records for a few days in July and September, and has generally been the second lowest on record (after 2023) from June onwards.
The figure below shows both Arctic (red) and Antarctic (blue) sea ice extent in 2024, the historical range in the record between 1979 and 2010 (shaded areas) and the record lows (dotted black line).
Unlike global temperature records (which only report monthly averages), sea ice data is collected and updated on a daily basis, allowing sea ice extent to be viewed through to the present day.https://interactive.carbonbrief.org/state-of-the-climate/24-Q3/sea_ice.htmlArctic and Antarctic daily sea ice extent from the US National Snow and Ice Data Center. The bold lines show daily 2024 values, the shaded area indicates the two standard deviation range in historical values between 1979 and 2010. The dotted black lines show the record lows for each pole. Chart by Carbon Brief.
Global sea ice extent is estimated by combining both Arctic and Antarctic sea ice extent. The figure below shows global sea ice extent in each year, with 2024 shown in red. Currently global sea ice extent is at record-low levels, below the prior record for this date set in 2023.
Methodological note
A statistical multivariate regression model was used to estimate the range of likely 2024 annual temperatures for each group that provides a temperature record. This model used the average temperature over the first six months of the year, the average ENSO 3.4 region value during the first nine months of the year and the average predicted ENSO 3.4 value during the last three months of the year to estimate the annual temperatures.
The model was trained on the relationship between these variables and annual temperatures over the period of 1950-2023. The model then uses this fit to predict both the most likely 2024 annual value for each group, as well as the 95% confidence interval. The predicted ENSO 3.4 region values for the last three months of 2024 are taken from the IRI plume forecast.
The percent likelihood of different year ranks for 2024 is estimated by using the output of the regression model, assuming a normal distribution of results. This allows Carbon Brief to estimate what percent of possible 2024 annual values fall above and below the temperatures of prior years for each group, as well as the likelihood of the year exceeding 1.5C in each record.
