Delayed action on climate change has put the Earth on course for a calamitous 2.3 to 2.5°C of average warming, but countries can still move swiftly to halt global warming before mid-century and bring emissions below 1.5°C by 2100, according to two separate reports released on the eve of this year’s United Nations climate summit, COP30, now taking place in Belém, Brazil.

The latest edition of the UN Environment Programme (UNEP)’s annual Emissions Gap Report finds that countries’ emission reduction promises, embodied in their latest Nationally Determined Contributions (NDCs) under the Paris climate agreement, “have barely moved the needle” on global warming, making it inevitable that average warming will at least temporarily exceed the Paris threshold of 1.5°C.

Climate Analytics agrees that warming will overshoot the 1.5°C target. But its most ambitious future scenario, titled Highest Possible Ambition, “shows how transformative climate action, scaling up renewables and electrifying the global economy, can slow and then halt global warming before 2050, and limit peak warming to around 1.7ºC,” the Berlin-based think tank states. “Temperatures could then be brought back down well below 1.5ºC by 2100, driven by a rapid fossil fuel phaseout, strong reductions in methane emissions, and scaling up carbon removal technologies.”

Warming Will Be Tough to Reverse

After a decade of measurable but far too slow emission reductions since the 2015 UN climate conference in Paris, UNEP says the accumulating level of warming “will be difficult to reverse—requiring faster and bigger additional reductions in greenhouse gas emissions to minimize overshoot, reduce damages to lives and economies, and avoid over-reliance on uncertain carbon dioxide removal methods.” And yet, on top of a “huge implementation gap” that has seen governments fall short of even their 2030 emission reduction targets, only 60 countries responsible for 63% of global emissions have even bothered to submit targets for 2035.

Those plans would reduce emissions by only 10%, one-sixth of what’s actually needed by the middle of the next decade, the Guardian reports.

Existing government policies, excluding measures in the new NDCs, would lead to a world of 2.8° average warming—and once again, even that extreme outcome depends on countries keeping their past promises.

The projection in this year’s Emissions Gap Report, the 16th in the continuing series, “was about 0.3°C lower than last year’s assessment,” the Financial Times writes. “But around a third of this improvement would be negated by the U.S.’ withdrawal from the Paris agreement and voiding the climate plans laid out by the Biden administration, and another third was down to changes to UN data processes. Just 0.1°C was gained through improved climate policies.”

UNEP reports that:

• Global greenhouse gas emissions increased 2.3% in 2024, compared to 1.6% between 2022 and 2023 and just 0.6% through the 2010s, bringing the annual growth in countries’ climate pollution to a pace last seen in the first decade of this century.

• Although fossil fuels played a “key role” in driving total emissions, deforestation and land use changes were the main culprits in last year’s increase.

• G20 countries accounted for 77% of the world’s emissions, up 0.7% from 2023. Of the world’s six largest emitters, the European Union was the only one that saw its climate pollution decline.

• Countries’ NDCs “have become incrementally more robust” over the last decade. But progress has been uneven, investment signals in the documents are still “limited”, and most of the gains in countries’ emission reduction targets “occurred prior to the new NDCs, which have done little to increase ambition and coverage.”

“Countries are making progress and laying out clear stepping stones towards net zero emissions. We also know that change is not linear, and some countries have a history of overdelivering,” said UN climate secretary Simon Stielll. But “we have a serious need for more speed and for helping countries take stronger climate actions. That acceleration must start now.”

‘Alarming, Enraging, Heartbreaking’

While it’s “still possible—just” to get emission reductions back on track, “nations have had three attempts to deliver promises made under the agreement, and each time they have landed off target,” said UNEP Executive Director Inger Andersen. “While national climate plans have delivered some progress, it is nowhere near fast enough, which is why we still need unprecedented emissions cuts in an increasingly tight window, with an increasingly challenging geopolitical backdrop.”

“This report’s findings, confirming that a crucial science-based benchmark for limiting dangerous climate change is about to be breached, are alarming, enraging, and heartbreaking,” said Rachel Cleetus, senior policy director, climate and energy program at the U.S. Union of Concerned Scientists. “Years of grossly insufficient action from richer nations and continued climate deception and obstruction by fossil fuel interests are directly responsible for bringing us here.”

But “world leaders still have the power to act decisively to sharply rein in heat-trapping emissions,” Cleetus added, and “any other choice would be an unconscionable dereliction of their responsibility to humanity.”

“This year’s Emissions Gap Report makes it abundantly clear that it isn’t the Paris agreement that’s failing—it’s a handful of powerful countries in the G20 that are failing to do what they’ve promised to do on climate change,” said Catherine Abreu, Ottawa-based director of the International Climate Policy Hub. “Some of these are the same countries creating geopolitical chaos, fuelling conflict, and working to derail the unstoppable train of the rising global green economy. These countries can’t hold the rest of the world back, but they can slow it down, and the UNEP report tells us how desperately little time we have left.”

Highest Possible Ambition

For the title of its most ambitious scenario for future emission reductions, Climate Analytics chose Highest Possible Ambition (HPA), the language the International Court of Justice used in its recent landmark advisory opinion to describe countries’ legal duty to deliver the fastest, deepest possible emission cuts through their NDCs.

“Failure of a state to take appropriate action to protect the climate system… may constitute an internationally wrongful act,” ICJ President Yūji Iwasawa said during the hearing. He called the climate crisis “an existential problem of planetary proportions that imperils all forms of life and the very health of our planet.”

Climate Analytics says the 1.5°C scenarios last published by the Intergovernmental Panel on Climate Change (IPCC) “are becoming increasingly outdated” due to governments’ tepid response to the crisis. But over that same five-year span, “renewable energy and other zero-carbon technologies have decreased substantially in cost and are far more cost-competitive than anticipated and can be scaled up faster.”

If countries can deliver on the Highest Possible Ambition scenario:

•.Global warming can be halted in the next 15 to 20 years.

• Global average temperature rise peaks at about 1.7°C before falling to about 1.2° by the end of this century.

• The period of “overshoot”, when the temperature increase exceeds 1.5°C, runs at least a decade longer and 0.1°C higher than the IPCC scenario “due to the political failure to cut emissions over the last five years,” Climate Analytics writes. That’s still a “highly dangerous” outcome, the report stresses, since every additional 1/10° warming increases the likelihood of “tipping points” in the Earth’s systems that could make it impossible to avert runaway climate change.

• The scenario shows the world hitting net zero carbon dioxide by 2045 and net zero greenhouse gas emissions in the 2060s—both about a decade earlier than the latest IPCC projection.

On the actual results, the Climate Analytics scenario is just as demanding as the IPCC’s, calling for a 49% emission reduction between 2025 and 2035 versus the UN’s 41% between 2020 and 2030. That target is based on a more up to date, and therefore more accurate assessment of the low cost of renewable energy and electrification, and the fast pace at which the energy transition can unfold.

“The rapid scale up of renewables and storage, combined with widescale electrification of the energy system, enables the HPA to overtake AR6 scenarios before 2040 to compensate (as much as is possible) for the extra cumulative emissions from 2020–2025,” the report says.

Renewables, Fossil Phaseout, Methane, and Not Just Any Carbon Removal

That conclusion rests on four “key levers at the heart of the transformation of our energy and land-use systems”:

• The HPA shows renewable electricity—principally solar, wind, and battery storage, with much less reliance on bioenergy than in the IPCC scenarios—delivering more than two-thirds of the world’s energy by 2050. “Renewable electrification is the mainstay of the energy transition, as it significantly outperforms all other options on cost, scalability, and energy efficiency. The HPA scenario sees global electricity generation nearly quadruple by 2050, with wind and solar supplying over 90% of electricity demand. Renewables capacity grows significantly, with a 3.5-fold increase by 2030—just ahead of the global tripling goal agreed at COP28.”

• The end of the fossil fuel era occurs much faster, with clean electricity fully replacing coal in the 2040s, gas in the 2050s, and oil in the 2060s. “Production and consumption of all fossil fuels peak immediately and fall rapidly,” with carbon capture and storage (CCS) playing a “negligible role,” the report states.

“Advanced economies take the lead in phasing out fossil fuels, achieving a fossil-free economy by mid-century,” Climate Analytics says. “The pace of phaseout substantially exceeds the levels seen in [IPCC] pathways, as it is the most important action needed to halt warming. The result is a fossil-free global economy by 2070 and a healthier, fairer ,and safer future for all.”

• Carbon dioxide removal (CDR) commercializes and quickly scales up in the 2030s, reaching five billion tonnes of carbon dioxide or equivalent in 2050—but the analysis doesn’t settle for just any old removals.

“The HPA scenario avoids large-scale nature-based CDR, given the risks of overreliance on natural sinks in a warming world,” the authors say. And “CDR needs to happen alongside the fossil fuel phaseout; it is not a substitute for it.”

• The scenario sees global methane emissions falling 20% from 2020 levels by 2030 and 32% by 2035, particularly in fossil fuel production. In the early days of the COP30 summit, Canada was one of several countries that signed on to a commitment to “drastically” cut fossil-related methane emissions by up to 75% by 2030, sufficient to shave 0.1% off average global warming by 2050.

The “very heavy cost reduction” for renewable energy, battery storage, electric vehicles, and electrification of transport and industrial processes is “the redeeming feature of the present situation,” Climate Analytics CEO Bill Hare told media in the days leading up to the report release. “That cost reduction is now making these technologies cheaper than fossil fuel technologies in most if not all markets, and that’s going to be essential for action to accelerate beyond the political circumstances we see at present.”

Hare cited Africa as a continent where renewables are scaling up fast enough to combat energy poverty at scale. And while there’s much to be concerned about in today’s global politics, Senior Expert Neil Grant said sub-Saharan Africa, Ethiopia, and Vietnam are seeing “a changing politics of countries realizing the benefits of the electrification revolution.”

China is “marching towards being the first electrostate, and I think countries are realizing that tackling climate change is not only a moral imperative, but actually does have very significant strategic and economic benefits,” he said.

But “the delay of the last five years doesn’t come for free,” Grant warned. “Critical to limiting the extent of overshoot and the duration of overshoot is getting to net zero. Warming will stop when we get to net zero carbon dioxide emissions, and warming will start to decline as we get to and sustain net zero greenhouse gas emissions.”