Ten Years After the Paris Agreement, the World Is Missing Its 1.5°C Promise as COP31 Nears

Introduction

Ten years ago, in a conference hall in Paris, nearly 200 countries agreed on something the world had never managed before: a single, near-universal plan to hold global warming in check. The Paris Agreement, adopted on 12 December 2015, promised to keep the rise in global temperatures well below 2 degrees Celsius above pre-industrial levels, and to pursue efforts to limit it to 1.5 degrees. It was hailed at the time as a turning point, the moment the world finally agreed on the destination, even if the route was left to each country to draw for itself.

The anniversary arrives this week. The agreement entered into force on 4 November 2016, so its tenth year of operation has just begun, and Al Jazeera marked the moment on 5 November 2026 with a review asking a simple question: has the world kept its climate promises? The assessments published around the anniversary give an answer that is uncomfortable, but not entirely bleak.

On the evidence now available, the world has not kept the central promise. The 1.5-degree goal, the number that defined the Paris deal, is slipping out of reach. National climate plans, taken together, point to emissions in 2035 only about 12 per cent below 2019 levels, according to a study published in Nature Climate Change in May 2026, far short of the cuts the science says are needed. Global emissions were still rising in 2024. And the United States, the world’s second-largest emitter, formally left the agreement in January 2026.

Yet the same evidence shows the agreement did change the direction of travel. Before Paris, the world was on course for warming of around 4 degrees by the end of the century; today the trajectory implied by current policies and pledges is closer to 2.1 to 2.8 degrees, according to researchers at the Institute for Sustainable Development and International Relations. That is still a dangerous overshoot of the Paris goals, but it is a measure of what a decade of coordinated pressure achieved, and of how much remains undone as negotiators prepare to gather in Antalya, Türkiye, for COP31 on 9 November. This is the full assessment of the Paris Agreement 10 years 1.5C promises November 2026.

1. What Paris promised ten years ago

The Paris Agreement was adopted at the COP21 climate conference in December 2015 after two weeks of negotiation, and it was deliberately designed differently from everything that had come before it. The Kyoto Protocol, the earlier climate treaty, had imposed binding targets on a small group of developed countries and left the rest of the world outside its obligations. Paris took the opposite approach: almost every country in the world would take part, each setting its own plan, with the plans reviewed and strengthened over time. That universality was the deal’s great strength, and, as the decade since has shown, also its great vulnerability.

The agreement’s structure rested on a bargain. Developed countries accepted that they should lead, including by providing finance to help developing countries cut emissions and adapt to the warming already under way. Developing countries accepted that they too would act, submitting national climate plans known as Nationally Determined Contributions, or NDCs, and updating them every five years. A transparency framework would let the world see who was doing what, and a global stocktake, the first of which concluded in 2023, would measure collective progress against the temperature goals.

The deal was never a guarantee. It was a framework for ambition, built on the hope that peer pressure, falling clean-energy costs and the visible costs of climate damage would push each round of national plans further than the last. Ten years on, that hope has been tested in full, and the record is now clear enough to judge.

1.1 The 1.5°C and well-below-2°C goals

The temperature goals were the heart of the agreement. Countries agreed to hold the increase in the global average temperature to well below 2 degrees Celsius above pre-industrial levels, and to pursue efforts to limit the increase to 1.5 degrees. The 1.5-degree figure was not a scientific afterthought. It was fought for by small island states and the least developed countries, whose negotiators argued that the difference between 1.5 and 2 degrees was the difference between survival and disappearance for their nations.

The science has since sharpened the distinction. At 1.5 degrees of warming, coral reefs are badly damaged but some survive; at 2 degrees, almost all are lost. Heatwaves that were once rare become regular at 1.5 degrees and far more punishing at 2. Sea-level rise, Arctic ice loss and the risk of crossing thresholds in the climate system all grow steeply across that half-degree gap. That is why the 1.5-degree goal became the defining number of the Paris era, the yardstick against which every national plan and every annual report is now measured.

1.2 The five-year ratchet and national plans

The mechanism meant to deliver the goals was the ratchet. Every five years, each country would submit a new Nationally Determined Contribution, and each new plan was expected to be more ambitious than the last. The first round of plans was submitted before Paris itself. The second round was due in 2020. The third round, the one that would carry the world towards 2030 and 2035, was due in September 2025, just before the COP30 conference in Belém, Brazil.

Alongside the plans, the agreement created a transparency system under which countries report their emissions and their progress, and a global stocktake every five years to take the collective temperature. Article 9.1 of the agreement obliges developed nations to provide financial resources to help developing countries with mitigation and adaptation. The design was elegant on paper: a cycle of pledges, scrutiny and rising ambition. Whether the cycle would actually turn fast enough was always the open question, and the third round of plans has now given the world its clearest answer.

2. The verdict at ten years: the 1.5°C line is slipping away

The clearest finding of the tenth-anniversary assessments is that the 1.5-degree goal, as originally framed, is no longer within reach on current policies. That does not mean the Paris Agreement has failed in every respect, but it does mean the world has to reckon with a fact its negotiators hoped to avoid: the temperature limit that defined the deal is being crossed, at least for a time, and the task is shifting from preventing that crossing to limiting how far beyond it the world goes and how long it stays there.

The evidence for that shift has accumulated through 2025 and 2026. The year 2024 was the first calendar year in which the global average temperature exceeded 1.5 degrees above pre-industrial levels. The United Nations noted in September 2026 that exceeding the 1.5-degree target is now unavoidable. And the national plans submitted ahead of COP30, when added together, still fall far short of the emissions cuts the science requires. None of this was inevitable in 2015. All of it is now documented.

2.1 2024 and the first year above 1.5°C

The year 2024 was the first calendar year in which the average global temperature rose more than 1.5 degrees above the pre-industrial baseline. It was a symbolic moment, and scientists were careful to explain what it did and did not mean. The Paris goal is defined in terms of the long-term average, measured over decades, not a single year, so one hot year does not by itself constitute a breach of the agreement. But the direction of travel was unmistakable, and researchers warned that the milestone had arrived earlier than many had expected.

A study published in Nature Climate Change in 2025 found that twelve consecutive months at or above 1.5 degrees signalled an earlier-than-expected breach of the Paris threshold. The heat of 2024 was driven in part by a strong El Niño, but the underlying trend was the steady accumulation of greenhouse gases in the atmosphere. Each year of rising emissions makes the long-term crossing more certain, and the question is no longer whether the world will pass 1.5 degrees for a sustained period, but when, and by how much.

2.2 The UN’s overshoot warning

In September 2026, the United Nations formally noted that exceeding the 1.5-degree global warming target is unavoidable, and that the world has entered an era of overshoot. The language matters. Overshoot does not mean abandoning the goal. It means accepting that temperatures will rise past 1.5 degrees for a period, and that the task now is to bring them back down, by cutting emissions deeply and, in time, removing carbon dioxide from the atmosphere.

That shift changes the politics of climate action. The goal of limiting warming, minimising the peak temperature and shortening the duration of overshoot remains, in the words of one anniversary assessment, and is expressed in the same terms by the researchers who have spent the decade measuring the gap. But the conversation is moving from prevention to management: how high the peak goes, how long the overshoot lasts, and how much damage is done while temperatures are above the line. For the countries most exposed to heat, sea-level rise and crop failure, that is a bitter change of subject.

3. The numbers behind the gap

The anniversary assessments are unusually rich in numbers, and the numbers tell a consistent story. Whatever the precise measure, the world is cutting emissions far more slowly than the Paris goals require, and the gap between what national plans promise and what the science demands has narrowed only slightly in a decade. The figures below are the ones that recur across the studies published for the tenth anniversary, and they are worth setting out plainly, because they are the facts against which the next decade will be judged.

The starting point is the scale of the problem. Global greenhouse gas emissions reached 57.7 gigatonnes in 2024, according to the United Nations Environment Programme’s Emissions Gap Report 2025, a rise of 2.3 per cent on 2023. Emissions are not falling. They are still rising, and each year of increase consumes more of the remaining carbon budget, the total amount of carbon dioxide the world can still emit while keeping warming to a given level.

3.1 What current plans deliver by 2035

A study published in Nature Climate Change in May 2026, led by a team from the Potsdam Institute for Climate Impact Research, examined the national climate plans submitted by 113 parties to the Paris Agreement by November 2025. Its finding was that if all of those plans are implemented in full, global greenhouse gas emissions in 2035 would be around 12 per cent below the 2019 level. The authors stressed that this was a positive signal: the plans do bend the curve downwards. But they were equally clear that it is a long way short of what is needed.

A separate analysis by the World Resources Institute of the plans submitted by the time COP30 ended in Belém reached a similar conclusion from a different angle. The 122 countries that had submitted new or updated plans by the end of that conference were, together, delivering only around 11 per cent of the emissions cuts needed to stay at 1.5 degrees. The two studies measure slightly different things, but they point the same way: the plans on the table deliver roughly a tenth of what the goal requires.

3.2 What the science says is needed

The gap becomes stark when the plans are set against the science. According to the Intergovernmental Panel on Climate Change, a pathway compatible with 1.5 degrees implies a 43 per cent fall in emissions by 2030 compared with 2019. The UN Environment Programme’s 2025 report, titled Off Target, put the requirement in terms of 2035: aligning with 1.5 degrees requires a 55 per cent cut in emissions below 2019 levels by 2035, while meeting the 2-degree threshold still requires a 35 per cent reduction over the same period. Current national policies deliver neither outcome.

The same report projected that, based solely on current adopted policies, warming of 2.8 degrees by 2100 is now the central expectation. And the carbon budget is nearly spent. Researchers estimated in 2018 that the world had about 580 billion tonnes of carbon dioxide it could still emit and stay below 1.5 degrees with a 50 per cent chance. By early 2026, only around 170 billion tonnes of that budget remained, meaning that at the current rate of about 42 billion tonnes a year, roughly four years are left before it is gone entirely.

4. Two gaps: ambition and implementation

Researchers who have followed the Paris process for a decade draw a distinction between two different shortfalls, and the distinction matters, because each gap needs a different remedy. The first is the ambition gap: the difference between what countries have promised in their national plans and what the temperature goals require. The second is the implementation gap: the difference between what countries have promised and what their policies actually deliver. The world is failing on both counts, but not in the same way, and not for the same reasons.

The ambition gap is a matter of arithmetic. Add up every NDC, assume every one is delivered in full, and the total still falls far short of the Paris goals. The implementation gap is a matter of politics and capacity. Many countries have submitted plans that look strong on paper but have not yet passed the laws, built the infrastructure or found the money to make them real. Closing the first gap requires bolder pledges. Closing the second requires delivery, and delivery is where the Paris framework has the least power to compel.

4.1 The ambition gap in the pledges

The ambition gap is visible in the collective arithmetic of the national plans. A perspective published in Frontiers in Public Health for the tenth anniversary concluded that the NDCs from all countries combined will not be sufficient to meet even the least ambitious Paris target, a 66 per cent chance of staying below 2 degrees by the end of this century. In other words, even if every plan is honoured, the world is still more likely than not to overshoot the weaker of the two Paris goals.

The third round of plans also exposed a problem of participation. The submissions were due in September 2025, ahead of COP30, but fewer than a third of all Paris Agreement parties met that deadline. Late submissions from major emitters further weakened the collective picture, and some major fossil fuel producers, including Saudi Arabia and Iran, submitted no plans at all by the end of the Belém conference. A framework that depends on every country filing a plan cannot work when a large share of them do not file on time, or at all.

4.2 The implementation gap in delivery

The implementation gap is harder to measure, but it is visible wherever plans meet reality. The Potsdam study measured only what is written down in national plans, not what actually happens, and its authors warned that the gap between planned and delivered emissions is measurable in several countries that have submitted ambitious plans but lack the regulatory capacity to carry them out. A plan is not a policy, and a policy is not a power station, a railway or a retrofitted building.

The global emissions figures tell the same story. If implementation were keeping pace with ambition, emissions would be falling. Instead they rose by 2.3 per cent in 2024, to 57.7 gigatonnes. Some of that rise reflects economic growth and energy demand, and some of it reflects the slow pace of replacing fossil fuels in heavy industry, aviation and shipping. But the overall pattern is clear: the world is pledging more than it is delivering, and the difference between the two is itself one of the largest sources of emissions the planet faces.

5. The biggest shock: the United States walks out

No single event of the past decade did more to shake the Paris framework than the departure of the United States. The US is the world’s second-largest emitter of greenhouse gases, accounting for about 11 per cent of global emissions in 2024 according to the US Energy Information Administration, behind only China. Its withdrawal removed the world’s largest economy and one of its largest historical emitters from the agreement, and it did so at the very moment the framework needed its strongest members to lead the next round of pledges.

The departure also carried a political message. The United States had been central to the negotiation of the Paris deal in 2015, and its exit signalled that the consensus behind the agreement was fraying. Other countries have not followed it out of the door, and the framework has held together without Washington. But the absence of the United States has weakened the agreement’s finance, its diplomacy and its credibility, and it has given cover to governments that would prefer to slow down rather than speed up.

5.1 The January 2026 withdrawal

President Trump signed the order to withdraw the United States from the Paris Agreement on his first day back in office in January 2025. The withdrawal took formal effect on 27 January 2026, a year later, under the agreement’s own rules. In January 2026 the Trump administration also announced the withdrawal of the United States from the UN Framework Convention on Climate Change itself, the parent treaty under which the Paris Agreement sits.

With the American departure, the United States joined Iran, Libya and Yemen as the only nations absent from the accord. The symbolism was not lost on negotiators. The country that had hosted the talks that produced the modern climate regime, and that had pushed hardest for the Paris deal in 2015, was now outside both the agreement and its parent convention, while the rest of the world carried on without it.

5.2 What the exit means for the rest of the world

The practical effects of the American withdrawal are still being measured, but the early estimates are sobering. One study published in 2024 found that the absence of the United States reduces global achieved emission reductions by more than 38 per cent, a measure of how much the world’s climate effort depends on the largest economies acting together. The withdrawal also removed American climate finance from the system at a time when developing countries were already warning that the money promised to them was arriving too slowly and in too small a quantity.

There is a counter-argument, and it is worth recording. Some analysts argue that the Paris framework proved resilient precisely because it survived the American exit, and that other countries, including China and the European Union, stepped forward to fill part of the diplomatic gap. That resilience is real, and it is one of the more hopeful findings of the anniversary. But resilience is not the same as success, and a framework that can survive the loss of its second-largest emitter is not the same as a framework that can meet its goals without it.

6. What Paris did change

It would be wrong to read the tenth anniversary as a story of unbroken failure. The Paris Agreement did change the world, and the change is measurable. The question is whether it changed the world enough, and fast enough, and the honest answer is that it changed the direction of travel without yet changing the speed. That distinction is the key to understanding both what the agreement achieved and why its goals are slipping away.

Before Paris, the world was on a path towards warming of around 4 degrees by the end of the century, according to the assessments published at the time. Today, the trajectory implied by current policies and pledges is between 2.1 and 2.8 degrees. That is still far above the Paris goals, and it would bring severe consequences, but it represents a reduction of more than a degree in the expected warming of the century. In the history of international agreements, that is a substantial achievement. It is also, by the agreement’s own standard, not enough.

6.1 A lower trajectory than the world feared

The clearest evidence that Paris bent the curve comes from the Potsdam study. Its authors calculated that without the Paris Agreement, global emissions by 2035 could be 20 to 48 per cent higher than in 2019. Against that counterfactual, the 12 per cent reduction implied by current national plans looks very different: not a success, but a decisive break with the path the world was on before 2015. The agreement, in other words, did not solve the climate problem, but it did stop the problem from getting worse as fast as it otherwise would have.

The Institute for Sustainable Development and International Relations reached a similar conclusion in its anniversary assessment. The temperature rise trajectory by the end of the century, it found, has been reduced from around 4 degrees to between 2.1 and 2.8 degrees. That is the measure of a decade of national plans, clean-energy investment, falling technology costs and the political pressure the Paris framework created. It is also a reminder of how far the world was from safety in 2015, and how far it still has to travel.

6.2 Clean energy, finance and the parts that moved

The parts of the climate transition that moved fastest were the ones where economics and policy pointed in the same direction. Solar and wind power expanded far faster than most forecasts in 2015 had imagined, and their costs fell steeply. Electric vehicles moved from a niche to a substantial share of new car sales in the largest markets. Governments that had never produced a climate plan before now produce one every five years, and the transparency framework means their progress, or lack of it, is visible to the world.

Other parts moved slowly, and the anniversary assessments are frank about them. Climate finance for adaptation, the money that helps poorer countries cope with the warming already under way, still falls far short of what is needed, a shortfall the United Nations itself warned about in a separate report covered in these pages. Carbon dioxide removal, which the IPCC’s Sixth Assessment Report describes as unavoidable for reaching net zero, remains small: in 1.5-degree-consistent pathways, the median amount of carbon dioxide captured and stored by 2100 is around 665 gigatonnes, yet realistic deployment by 2050 could offset only about 7 to 9 gigatonnes of carbon dioxide equivalent a year. The technology exists, but not yet at the scale the goals require.

7. COP31 in Antalya: the next test

The tenth anniversary does not arrive in a vacuum. It arrives four days before the next round of climate negotiations, COP31, opens in Antalya, Türkiye, on Monday 9 November 2026. The timing is deliberate in one sense and accidental in another: the anniversary gives the Antalya conference a natural theme, and a natural question. Ten years after Paris, can the world turn its promises into action? The conference’s own organisers have framed it in exactly those terms, describing Antalya as the place where dialogue becomes global action.

The conference runs from 9 to 20 November at the Antalya Expo Center in Soğucaksu, and it brings together the 31st session of the Conference of the Parties, the eighth session of the parties to the Paris Agreement, and the subsidiary bodies that do the detailed negotiating work. A World Leaders’ Summit convenes heads of state and government on 11 and 12 November. The agenda is, by design, about implementation rather than new headline targets: the question is no longer what the world should promise, but how it will deliver what it has already promised.

7.1 What is on the table in Türkiye

COP31 is intended to shift the emphasis from negotiating new commitments towards implementing existing ones, according to the House of Commons Library briefing on the conference, and its five priorities reflect that focus. They are accelerating electrification, turning climate commitments into bankable projects, mobilising public and private finance, strengthening climate adaptation, and protecting the oceans. Each of those priorities is, in effect, a response to one of the gaps identified in the anniversary assessments: the ambition gap, the implementation gap and the finance gap.

The structure of the fortnight reflects the same priorities. Monday 9 November is Food, Agriculture and Health Day. Tuesday 10 November is Energy and Transport Day. Wednesday 11 November is Zero Waste and the first day of the leaders’ summit. The second week includes Science, Industry and Technology Day on Monday 16 November and Human and Social Development Day on Wednesday 18 November. The conference venue is closed on Sunday 15 November, and the final text is due by Friday 20 November.

7.2 The shared Türkiye–Australia presidency

This conference differs from other years in its leadership. Türkiye holds the presidency, with its Minister of Environment, Urbanisation and Climate Change, Murat Kurum, nominated as COP31 President, while Australia leads the negotiation process, with Chris Bowen as President of Negotiations. The dual-leadership structure, agreed under a partnership between the two countries, is unusual, and it was designed to bridge the interests of a host country that is itself a major emerging economy and a negotiating chair with a strong record on climate ambition.

The run-up to the conference has already reflected that partnership. Official pre-COP meetings and leaders’ events were held in Fiji and Tuvalu from 5 to 8 October, bringing Pacific island leadership and priorities into the preparations. Australia submitted its own 2035 Nationally Determined Contribution in September 2025, committing to reduce emissions by 62 to 70 per cent below 2005 levels. Whether the partnership can produce a conference outcome that matches the scale of the anniversary’s findings is the question the next fortnight will answer.

8. What remains unconfirmed and what to watch next

Much about the next phase of the Paris era is still unconfirmed, and the anniversary assessments are careful to say so. The world knows the scale of the gap. It does not yet know whether the political will exists to close it, whether the finance will arrive, or whether the next round of national plans will be bolder than the last. The answers to those questions will come, in part, from Antalya, and in part from the months that follow, as countries decide whether the tenth anniversary was a moment of reckoning or just another milestone.

There are also questions the assessments cannot yet answer. How high will the peak temperature go, and how long will the overshoot last? How much carbon dioxide removal can realistically be deployed, and at what cost? Will the countries that missed the September 2025 deadline submit stronger plans, or will the next round repeat the pattern of the last? And will the legal pressure now building on governments, including a case filed by ten Australians before the UN Human Rights Committee in June 2026 arguing that continued fossil fuel export approvals breach Australia’s duty to protect them from climate harm, change the politics of the next round? None of these is settled, and all of them will shape what Paris means in its second decade.

8.1 The questions COP31 must answer

The first test in Antalya is finance. Developing countries have been clear that they cannot deliver their plans without money, and the anniversary assessments show that adaptation finance in particular is far short of what is needed. The second test is implementation: whether the conference produces concrete mechanisms, rather than declarations, for turning commitments into bankable projects and for holding countries to the plans they have filed. The third test is ambition: whether any country uses the anniversary moment to strengthen its own plan, and whether the collective outcome acknowledges, in plain terms, that the 1.5-degree goal is now an overshoot to be managed rather than a limit to be kept.

None of these tests has a certain outcome. The conference’s focus on implementation is welcome, but implementation is the hardest part of climate policy, and it is where the Paris framework has the least leverage. The leaders’ summit on 11 and 12 November will be the first indication of whether heads of government intend to treat the anniversary as a moment for decisions, or as a backdrop for speeches.

8.2 What to watch next

The immediate dates are clear. COP31 opens in Antalya on Monday 9 November, the World Leaders’ Summit runs on 11 and 12 November, and the conference is due to conclude on Friday 20 November. Watch for any new or strengthened national climate plans submitted during the conference, for the finance package that emerges, and for the language of the final text on the 1.5-degree goal and on overshoot. Watch, too, for what happens after Antalya: whether the countries that missed the September 2025 deadline file stronger plans, whether the United States’ absence shapes the outcome, and whether the conversation in the months that follow is about preventing a breach that has already happened or managing one that is under way.

Ten years after Paris, the agreement’s promise is not dead, but it is no longer the promise that was made in 2015. The world did not keep the 1.5-degree limit, and it is now deciding how much overshoot it will accept and how quickly it will return. That is a harder, less inspiring task than the one the negotiators set themselves a decade ago. It is also the task that will define the next ten years, and the fortnight in Antalya is where it begins.

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