Rethinking resource use: waste reduction and circularity could cut 1.5 Gt of emissions a year by 2035 – the IEA’s COP31 report explained

The world generates around 2.6 billion tonnes of municipal solid waste every year – enough to bury New York City under ten metres of rubbish. Rethinking resource use is therefore not only a waste management issue but an energy and climate one: that is the core message of a new special report by the International Energy Agency (IEA), prepared at the request of the Türkiye COP31 Presidency and launched at the climate summit in Antalya in November 2026.

Across three areas – waste prevention and material efficiency; collection, sorting and recycling; and sustainable energy recovery from residual waste – the agency sees a combined potential of more than 1.5 gigatonnes of CO2-equivalent a year by 2035. Here is where that number comes from, what the IEA recommends to governments, and what it means when read from Hungary and the EU.

In short: Rethinking resource use could cut global greenhouse gas emissions by more than 1.5 Gt CO2-eq a year by 2035, according to the IEA – comparable to bringing the emissions of half the world’s car fleet to zero. The largest share comes from waste prevention and material efficiency (0.7 Gt), followed by sustainable energy recovery (at least 0.6 Gt) and recycling (at least 0.4 Gt). The figures are potentials derived from the agency’s net zero scenario, not forecasts.

How big is the problem? Waste in numbers

According to the report, more than 23 billion tonnes of waste are generated worldwide each year (excluding mining, electronic and medical waste), of which around 2.6 billion tonnes is municipal solid waste (MSW). UN and World Bank scenarios suggest that MSW generation could grow by 60–65% by 2050 if policy and practice do not change.

Collection itself is far from universal:

• around 83% of MSW is collected globally, but only about 30% in some developing economies;
• the World Bank estimates that roughly 30% of MSW is openly dumped or left uncollected;
• of the waste that is collected, on average 18% is recycled and a further 7% is composted or sent to anaerobic digestion.

On the climate side, the disposal, treatment and incineration of waste account for about 4% of global greenhouse gas emissions. The waste sector emitted around 1.9 Gt CO2-eq in 2025, roughly 85% of it methane. Waste is responsible for nearly a fifth of human-caused methane emissions – third behind agriculture (47%) and energy (36%), but with the strongest relative growth over the past 25 years.

Methane matters because it is short-lived but powerful: it stays in the atmosphere for about 12 years and causes roughly 30 times more warming than CO2 over a 100-year period, and about 80 times more over 20 years. The report argues that rapid cuts in waste methane – particularly before 2035 – are among the most effective ways to slow near-term warming.

More than half of waste sector emissions (56%) come from emerging market and developing economies excluding China, while advanced economies have some of the highest per capita figures.

Why this is bigger than the waste sector’s 4%

One of the IEA’s key points is that the waste sector inventory only shows the end of the story. A large share of the emissions linked to waste arises earlier – in raw material extraction, manufacturing and transport – and is booked under other sectors. Two examples from the report:

• food loss and waste, counted across the full value chain, account for 6–8% of global emissions;
• five energy-intensive material sectors – steel, cement, chemicals (including plastics), aluminium and paper – represent 65% of industrial energy consumption and 75% of industrial CO2 emissions, or just under 20% of global energy-related CO2.

There is also an accounting trap. Waste incineration with energy recovery is reported under the energy sector, not the waste sector (around 0.15 Gt CO2-eq in 2025). In the European Union, landfilled municipal waste fell from 112 Mt in 2000 to 48 Mt in 2024, while incineration with energy recovery grew from 36 Mt to 61 Mt. Part of the waste sector’s improving balance is therefore a reallocation rather than an absolute reduction – a point the report also makes about China’s rapid incineration build-out. For the state of European capacity, see our analysis of incineration overcapacity in Europe.

Rethinking resource use in three action areas

The report follows the logic of the waste hierarchy: prevent first, then keep materials in circulation, and only recover energy from what is left.

Waste prevention and material efficiency: around 0.7 Gt

This is the largest contribution. Material efficiency spans design, fabrication and use: lighter and more durable structures, fewer production losses, longer lifetimes, repair and shared use. The biggest material users are buildings and infrastructure (essentially all cement and about half of steel), vehicles, and packaging and consumer products, which together with textiles account for over 70% of plastics demand.

In the IEA’s Net Zero Emissions by 2050 Scenario (NZE), material efficiency reduces demand for key energy-intensive materials by around 6% on average in 2035 compared with a scenario based on stated policy settings:

• steel: from around 2,050 Mt to around 1,900 Mt;
• cement: from around 4,000 Mt to around 3,700 Mt;
• high-value chemicals (the main precursors to plastics): from around 550 Mt to around 510 Mt;
• paper: from around 470 Mt to around 460 Mt.

The clinker-to-cement ratio would fall from 0.71 to 0.65 over the same period. The saving is close to Indonesia’s total annual energy-related emissions. The IEA offers two illustrations: Quay Quarter Tower in Sydney, where more than 65% of the existing structure was retained, avoiding about 7,300 tonnes of embodied CO2, and the city-wide REUSABLE system in Aarhus, Denmark, where the same takeaway cups circulate among participating businesses.

The report identifies design as the strongest point of leverage, because this is where material inputs, lifetimes and repairability are largely decided. We have covered that question in our article on why the concept of planned obsolescence needs rethinking, and its packaging side in our piece on lightweight packaging.

Collection, sorting and recycling: at least 0.4 Gt

The differences between materials are striking. Globally, around 80% of end-of-life steel, about 65% of aluminium and roughly 55% of paper ends up in a new product. For plastics, only about 20% is collected for recycling, and after sorting and processing losses roughly 15% actually becomes new plastic (in the EU, the collection figure is just over 30%).

Plastics therefore hold the largest untapped potential: in the NZE Scenario, the share of demand met by recycling doubles from around 10% today to 20% in 2035. For metals the headroom is smaller, but the benefit per tonne is large: scrap-based steel uses about 12% of the energy of production from iron ore, and secondary aluminium about 5% of the energy of primary production. Scrap would rise from around 32% to 39% of metallic inputs in steelmaking, and secondary production from 36% to 44% of aluminium output.

The report is notably candid here: the climate benefit of plastics recycling depends heavily on the technology. Mechanical recycling needs far less energy than virgin polymer production, whereas chemical recycling is more energy-intensive, and recycling does not necessarily deliver much lower emissions than landfilling, because landfilled plastic hardly decomposes. Downcycling is also common. For more on these questions, see our coverage of the Carbon Flows report, of how chemically recycled plastic may be accounted for under the UK Plastic Packaging Tax, and of plastics flows in Germany.

The illustration is Seoul, where households must collect transparent PET bottles separately from other plastics, yielding higher-quality secondary material. How strongly the design of a collection system shapes results was shown in Hungary by the Corvinus–ELTE study on door-to-door selective collection.

Sustainable energy recovery: at least 0.6 Gt

The IEA stresses that energy recovery is for unavoidable, non-recyclable residues only and must not displace the higher levels of the hierarchy. Within this area, the lead role goes not to incineration but to biogases.

• Energy recovered from waste amounted to around 5 EJ in 2025, about 1% of global energy demand.
• Production of biogases (biogas and biomethane) stands at around 1.6 EJ today and could quadruple to nearly 6 EJ by 2035 – equivalent to all the liquefied natural gas exported via the Strait of Hormuz in 2025.
• Quadrupling would save around 0.5 Gt CO2-eq a year, with a double dividend: methane from landfills and manure management is avoided, and fossil fuels are displaced. Around 70% of this potential lies in emerging market and developing economies.
• At least a further 0.1 Gt comes from using organic solid waste in industry and power generation; in cement, the share of renewable wastes could triple from about 6% of thermal energy needs today to about 18%.

The example is Indore, India, where the city’s largest plant converts 550 tonnes of organic waste a day into biomethane that fuels more than 400 city buses.

On incineration, the report is nuanced. Plastics make up 12.5% of MSW by mass and, when burned, emit more CO2 per unit of energy than natural gas; the displacement benefit of incineration also declines as energy systems decarbonise. We looked at how those emissions might be handled in our article on waste-to-energy CCUS and the EU ETS.

Biogas is not automatically climate-friendly either. On average, biogas plants currently leak methane equivalent to 6% of their output, which can undercut or entirely eliminate the climate benefit. In Denmark, average losses were measured at 2.5% in 2021 and regulation is pushing them lower. The remedies are known: closed digestate storage, combustion of off-gases during upgrading, and leak detection and repair.

Six policy priorities for governments

1. Place value on resource efficiency across government policies: progress indicators, taxation, public procurement and permitting – and integrate waste reduction objectives into Nationally Determined Contributions.
2. Examine design regulations to prioritise circularity: extended producer responsibility (EPR), repairability and durability standards and whole-life carbon rules, starting with buildings, vehicles and packaging.
3. Allocate sufficient funds for collection, sorting and recycling, and establish robust waste governance: not only for investment but for ongoing operations, with clear lines of responsibility between national and local government.
4. Incentivise the use of organic waste as bioenergy: separate collection, tax credits, renewable energy quotas and streamlined permitting for facilities demonstrating low leakage.
5. Make resource efficiency part of core curricula and professional training: for designers, engineers, architects, construction site managers and waste sector executives.
6. Strengthen international collaboration, knowledge exchange and access to finance: particularly for emerging market and developing economies.

The report urges caution in several places. Landfill taxes and bans can lead to open dumping if viable alternative treatment is not yet in place, and long-term contracts for waste-to-energy should take into account that prevention and recycling will reduce waste volumes over time. Related reading: our analyses of circular skills and of the industry call for a harmonised EU EPR regulation.

What does this mean for Hungary?

The report is global; it contains no country-level recommendations and does not analyse Hungary by name. Several of its findings nevertheless apply directly.

Hungary is an IEA member and bound by the EU’s waste targets: by 2035, 65% of municipal waste must be recycled and no more than 10% may be landfilled. Today the bulk of the country’s residual waste still goes to landfill, so by the report’s logic the methane from landfilled organic waste is a tangible climate item here too. Separate collection and anaerobic treatment of organic waste, and capturing as much landfill gas as possible, are therefore not only waste management questions but energy security ones. How far Hungary is from the 2035 targets is shown in our article on the University of Pannonia’s network model of municipal solid waste management.

The second lesson is sequencing. According to the IEA, the maturity of a system determines the next steps: where collection and sorting are already in place, the priorities shift to design rules, less-recycled materials – above all plastics – and the use of organic waste. The third is finance: the report explicitly notes that paying for infrastructure is not enough, and ongoing operating costs must be covered as well.

A critical reading: what to treat with caution

The report builds on official data and the IEA’s own models, and its reasoning can be followed. A few limitations are worth keeping in mind – some of which the authors flag themselves.

• These are potentials, not forecasts. The 1.5 Gt figure comes from the IEA’s net zero scenario, which shows what climate goals would require, not what current policies are set to deliver.
• The parts and the headline do not match exactly. The three areas (0.7 + 0.4 + 0.6) add up to 1.7 Gt, yet the report speaks of “more than 1.5” Gt and does not explain the gap.
• Most of the savings would not appear in the waste sector. The benefits of material efficiency and recycling show up in industry; those of biogases partly in energy and agriculture.
• The data are uncertain. The report puts the uncertainty of waste sector emission estimates at 35–134% for methane and 10–490% for nitrous oxide, and there are inconsistencies within the document itself: waste’s share of methane is given as both “nearly 20%” and “nearly 18%”, and MSW generation as both 2.6 and 2.7 billion tonnes.
• The COP31 target halves growth; it does not reduce waste. On the World Bank’s high-ambition pathway, MSW still rises from around 2.7 billion tonnes in 2022 to 2.9 billion tonnes in 2035, instead of 3.2 billion tonnes under business as usual.
• It was written by an energy agency, through an energy lens. The focus is on the intersection of waste and the energy system; areas of prevention such as cutting food waste or scaling up reuse are only touched upon.

In the report’s favour, its peer reviewers included not only industry associations (aluminium, cement) but also a representative of Zero Waste Europe, and the text consistently puts prevention first.

Summary

What is new in the IEA report is not the individual solutions – most are proven technologies – but the fact that one of the world’s leading energy institutions treats waste as part of energy and climate policy. The order of priorities is clear: the biggest gains come from using less material and keeping it in use for longer; next come better collection and recycling, especially for plastics; and finally the use of residual organic waste as biogas, under strict methane leakage control. The numbers are upper-end estimates, and delivery depends on the regulatory and financing decisions governments are willing to take.

More coverage is available in our English news section.

Frequently asked questions: rethinking resource use in the IEA report

What does rethinking resource use mean in the IEA report?

It means designing products, buildings and infrastructure so that they need less material, last longer and can be repaired, reused and recycled. The IEA highlights three areas: waste prevention and material efficiency; collection, sorting and recycling; and sustainable energy recovery from the waste that remains. Together, these reduce waste, energy demand and greenhouse gas emissions.

How much could waste reduction and circularity cut emissions by 2035?

By more than 1.5 Gt CO2-eq a year, which the IEA compares to bringing the emissions of half the global car fleet to zero. Waste prevention and material efficiency could deliver around 0.7 Gt, collection, sorting and recycling at least 0.4 Gt, and sustainable energy recovery at least 0.6 Gt. These are potentials from the agency’s net zero scenario, not forecasts.

How much does waste contribute to global greenhouse gas emissions?

The disposal, treatment and incineration of waste account for about 4% of global greenhouse gas emissions and nearly a fifth of human-caused methane emissions. The waste sector emitted around 1.9 Gt CO2-eq in 2025, roughly 85% of it methane. The full footprint is larger, because emissions from producing materials are reported under other sectors.

What is the COP31 Presidency’s target for municipal solid waste?

The Türkiye COP31 Presidency aims to reduce the projected increase in global municipal solid waste generation by at least 50% by 2035. This matches the World Bank’s high-ambition scenario, in which waste grows from around 2.7 billion tonnes in 2022 to 2.9 billion tonnes, instead of 3.2 billion tonnes under business as usual. Waste would still grow, only more slowly.

Why do plastics have the greatest potential for increased recycling?

Because plastics are recycled far less than metals or paper. Globally, only about 20% of end-of-life plastics are collected for recycling and roughly 15% actually become new plastic, compared with around 80% for steel. According to the IEA, the share of plastics demand met by recycling could double by 2035, from about 10% to 20%.

What role can biogas play in recovering energy from waste?

According to the IEA, production of biogases could quadruple by 2035, from around 1.6 EJ today to nearly 6 EJ, saving roughly 0.5 Gt CO2-eq a year. The condition is tight control of methane leaks: biogas plants currently lose methane equivalent to 6% of their output on average, which can undercut or entirely eliminate the climate benefit.

🔗 Official sources and references: 👉

• International Energy Agency: Synergies Between Waste Reduction, Resource Efficiency and Energy Systems Decarbonisation – An input to COP31 (special report, November 2026; CC BY 4.0)
• International Energy Agency: Rethinking how the world uses resources can help cut waste, strengthen economies and lower emissions (press release, November 2026)
• International Energy Agency: Executive summary (executive summary of the report)

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