Climate Solutions

Implementing multistrata agroforestry systems on which one or more layers of crops grow in the shade of taller trees. This systems mimic the structure of natural forests. Layered trees and crops achieve high rates of both carbon sequestration and food production. In tropical humid climates, efforts to protect and scale up multistrata agroforestry should be a high priority.

Agroforestry that integrates trees on cropland is primarily known as silvoarable agroforestry or, in some specific spatial arrangements, alley cropping. This system involves growing agricultural or horticultural crops simultaneously with a long-term tree crop on the same land area.

Set of practices that protects soils by minimizing plowing (no-till/reduced tillage) and maintaining continuous soil cover (by retaining crop residues or growing cover crops). This increases soil carbon sequestration and reduces nitrous oxide emissions. These techniques are commonly used in conservation agriculture, regenerative, and agro-ecological cropping systems.

Improving aquaculture through better feed efficiency and the decarbonization of on-farm energy use. Feed conversion ratios (FCRs) – the amount of feed it takes to produce a given amount of biomass can be improved by feed formulations that increase digestibility, genetic or breeding modifications to improve digestive efficiency in the cultured animal, species-specific feed formulations, and optimizing ration size and feeding frequency. At the same time, shifting generators used in animal aquaculture from diesel and petrol-based to systems that are fully or, at least, partly based on renewable energy resources such as photovoltaic and solar thermal panels or wind turbines. This will reduce greenhouse gas emissions from on-site energy use.

Reducing crop residue burning involves a multi-pronged approach that combines in-situ and ex-situ management techniques, supportive policies, and farmer education. In-situ management methods improve soil health by incorporating residues back into the land. Ex-situ approaches create alternative income streams and industrial raw materials from the residue

Cultivated meat (also called lab-grown or cultured meat) is a cellular agriculture product that, when used to replace meat from livestock, can reduce emissions. Cultivated meat is developed through bioengineering. Its production uses sample cells from an animal, in addition to a medium that supports cell growth in a bioreactor. Energy is required to produce the ingredients for the growth medium and to run the bioreactor (e.g., for temperature control, the mixing processes, aeration).

Implementing interventions for minimizing food loss from the stages of production, handling, storage and processing within the supply chain. For example, improving and/or investing in post-harvest and cold-storage infrastructure, optimizing harvesting and storage techniques, financing advanced agricultural equipment to limit food loss. By reducing food loss - the need for land and resources used to produce food is reduced as well as the greenhouse gases released in the process.

Implementing interventions for minimizing food wastage from the stages of distribution, retail, and consumption. For example by generating public awareness, and changing consumer behavior. By reducing food waste - the need for land and resources used to produce food is reduced as well as the greenhouse gases released in the process.

Holistic approach to managing fire that addresses the ecological, social, and economic dimensions of fire regimes. It moves beyond a sole focus on fire suppression to include prevention, preparedness, the beneficial use of fire as a land management tool, and post-fire recovery, with the goal of minimizing fire damage while maximizing its benefits

Irrigation water use efficiency involves reducing water use without compromising crop productivity by improving irrigation scheduling and/or equipment. Irrigation produces GHG emissions by altering biogeochemical cycling of carbon and nitrogen cycles in water and soils, and through energy use for pumping. Reducing the duration of soil saturation, the amount of groundwater extracted, and the total volume of water pumped can help reduce associated emissions.

Implementing liquid manure management strategies in cattle and pig production systems. For example, reducing storage time by spreading manure daily on land and installing tightly sealed, impermeable coverings on existing anaerobic lagoons. This makes it possible to capture the methane gas produced and utilize it as fuel.

Implementing fertilizer application practices that use right source, right rate, right time and right placement principles. More judicious use of fertilizers can curb emissions and reduce energy-intensive fertilizer production. The true solution to nutrient management, however, is the use of land management practices that eliminate most, if not all, need for synthetic nitrogen. This solution replaces overuse of nitrogen fertilizers—a frequent phenomenon in agriculture

Reforming and improving the management of wild-capture fisheries to reduce excess effort, overcapitalization and overfishing. This solution reduces the number of vessel-days and allows depleted fish stocks to rebuild to a level that allows fish population to regrow and be sustainably maintained over time. This in turn reduces fuel use, increases carbon sequestration in dead fish, and sustains catch in the long term.

Production of plant-based foods to provide alternatives to animal-based food, which is a significant source of greenhouse gas emissions.

Implementing low-methane rice production techniques, including mid-season drainage and alternate wetting and drying, more balanced application of nutrients, use of rice varieties (cultivars) that are less water-loving, and seeding rice without tilling the ground. This can reduce methane emissions and sequester carbon. This solution replaces conventional paddy rice production in mechanized (non-smallholder) regions.

Implementing silvopasture practices to integrate trees, pasture, and forage into a single system for raising livestock. Incorporating trees into agriculture increases carbon sequestration. Silvopasture also offer financial benefits for farmers and ranchers. The health and productivity of both animals and the land improve.

Balanced use, conservation, and enhancement of forest ecosystems to meet the social, economic, and environmental needs of present and future generations. The core objective of SFM is to ensure that the benefits derived from forests are sustainable while maintaining their vital functions and overall health. It includes actions such as implementing reduced-impact logging, extended harvest rotations and liana (woody vine) cutting in order to improve forest management in timber production areas, sequestering carbon in the process

Installing alternative building insulation materials such as cellulose, cork, wood fiber, plant fibers (kenaf, hemp, jute), sheep's wool, and recycled PET plastic in place of conventional ones. In particular, we highlight the impact of using cellulose instead of stone wool, glass wool (fiberglass), mineral, or plastic insulation (including expanded polystyrene (EPS), extruded polystyrene (XPS), polyurethane (PUR), and polyisocyanurate (PIR)) in new and retrofit buildings

Boosting the efficiency of appliances and equipment cuts GHG emissions by reducing the amount of electricity used to operate these devices. Appliance and equipment efficiency typically refers to larger devices in residential buildings that run on electricity, such as refrigerators, freezers, washing machines, dishwashers, dryers, and televisions. To drive higher efficiency for these devices, various countries have established regional energy efficiency standards, rating systems, and labeling programs.

Improving a building's envelope involves upgrading the physical barrier between the conditioned interior and the unconditioned exterior to optimize energy efficiency, enhance indoor comfort, and increase durability. Key strategies include enhanced insulation, air sealing, and high-performance windows and doors

Switching conventional pneumatic or electric control systems to automation systems in order to control heating, cooling, lighting, and appliances in commercial buildings. They cut greenhouse gas emissions by enhancing energy efficiency.

Implementing initiatives to shift from polluting fuels and technologies to clean cooking technologies in low-income communities. Clean cooking can reduce pollution from burning wood or coal in traditional stoves and protect human health. Many clean cooking technologies exist, with a wide range of impacts on emissions: highly efficient coal stoves, natural gasifier stoves, liquid petroleum gas (LPG) stoves, and solar-powered household stoves. This solution replaces traditional cookstoves that burn wood and/or charcoal inefficiently and without ventilation.

Installing cool roofs on existing buildings. Cool roofs reflect sunlight, reducing building energy use for heating and/or cooling.

Replacing stand-alone water- and space-heating systems with renewably powered district heating. District systems reduce greenhouse gas emissions by heating multiple buildings with hot water from a central plant.

Replacing conventional heating, ventilation, and air conditioning (HVAC) systems with high-efficiency heat pumps in both residential and commercial applications. Conventional heating and/or cooling systems include gas- and oil-fired furnaces, gas- and oil-fired boilers, low-efficiency air conditioners, electric resistance furnaces, and electric resistance unit heaters. Heat pumps extract heat from the air and transfer it—from indoors out for cooling, or from outdoors in for heating. With high-efficiency, they can dramatically lower building energy use.

Switching incandescent or fluorescent commercial and residential lighting to LEDs (light-emitting diodes). LEDs are the most energy-efficient bulbs available. Unlike older technologies, they transfer most of their energy use into light, rather than waste heat.

Replacing conventional for low-flow taps and showerheads. Cleaning, transporting, and heating water requires energy. More efficient fixtures and appliances like low-flow taps and showerheads can reduce home water use, thereby reducing emissions

Switching conventional fossil fuel-based water heating to solar water heaters for residential use or commercial buildings. Heating water for showers, laundry, and washing dishes accounts for a quarter of residential energy use worldwide. Solar water heating—exposing water to the sun to warm it—can reduce that fuel consumption.

Reducing the heat transferred through typical windows used in residential and nonresidential buildings by improving the thermal insulation capacity of the glass. Windows typically constitute a small portion of a building envelope but account for a substantial portion of the heat transferred (gained or lost) between the indoor space and the external environment. Using double-glazed rather than single-glazed windows cuts GHG emissions by reducing the energy required to heat or cool a building’s interior and improves the thermal comfort of its occupants.

Restoring the fertility and productivity of degraded, abandoned land. Restoring degraded lands to productivity can simultaneously improve food security, farmers’ livelihoods, ecosystem health, and carbon sequestration. Can include afforestation and reforestation but also addresses other aspects of ecosystem health. This solution replaces the conventional practice of abandoning degraded grassland.

Conversion to forest of land that historically has not contained forests. Afforestation is the direct human-induced conversion of land that has not been forested for a period of at least 50 years to forested land through planting, seeding and/or the human-induced promotion of natural seed sources. Effective governance is needed to limit trade-offs of some mitigation options such as large scale afforestation and bioenergy options due to risks from their deployment for food systems, biodiversity, other ecosystem functions and services, and livelihoods. This measure can take decades to deliver measurable results. For this reason and the potential trade-offs, it is considered a transitional solution.

Growing biomass crops on degraded land is a strategy to produce renewable energy feedstocks without competing with food production on fertile agricultural land. This approach offers the dual benefit of generating energy and aiding in the ecological restoration of the degraded areas

Protecting coastal wetlands from degradation by human activities. Unlike most terrestrial ecosystems, coastal wetlands—salt marsh, mangrove, and seagrass ecosystems—can sequester carbon for centuries without becoming saturated. Protecting them inhibits degradation and safeguards their carbon sinks. This solution focuses on legal mechanisms of coastal wetland protection, including the establishment of Protected Areas (PAs) and Marine Protected Areas (MPAs), which are managed with the primary goal of conserving nature.

Restoring coastal wetlands (including mangroves, seagrasses, and salt marshes) to prior conditions, whether naturally or through human intervention.

Protecting forestlands in boreal, subtropical, temperate and tropical regions. Long-term protection of tree-dominated ecosystems through establishment of protected areas (PAs), managed with the primary goal of conserving nature, and land tenure for Indigenous peoples. In their biomass and soil, forests are powerful carbon storehouses. Protection prevents emissions from deforestation, shields stored carbon, and enables ongoing carbon sequestration. This solution replaces unprotected forests.

Restoration of degraded boreal, subtropical, tropical and temperate forests. Forest restoration is the process of returning previously forested land to a forested state. As forests regrow, they remove carbon from the atmosphere and sequester it in biomass. This solution only includes reforestation of previously forested land with an element of direct human intervention, and therefore exclude entirely passive tree regrowth on abandoned land (i.e., unassisted natural regeneration).

Protecting grasslands, including rangeland, shrubland, and savanna. Grasslands hold large stocks of carbon, largely underground. Legal protection of grassland and savanna ecosystems through the establishment of protected areas (PAs), which are managed with the primary goal of conserving nature, and land tenure for Indigenous peoples. These protections reduce grassland degradation, which preserves carbon stored in soils and vegetation and enables continued carbon sequestration by healthy grasslands.

Restoration of grasslands and savannas that have been converted to other uses to prior conditions, whether naturally or through human intervention. Grassland and savanna restoration includes a spectrum of practices, such as returning ecologically appropriate grazing and fire regimes, reseeding with native species, and controlling invasive and woody plants.

Key component of a conservation approach known as "trophic rewilding," involves reintroducing native large herbivores to landscapes where they have been diminished or lost. This strategy aims to reinstate natural ecological processes and dynamics that are vital for maintaining healthy, resilient ecosystems

Implementing managed grazing practices to enhance net carbon sequestration and other aspects of soil and vegetation by strategically adjusting stocking rates, controlling intensity and timing of grazing, enclosing grasslands to encourage resting, and/or adopting other grazing practices. This solution replaces conventional grazing on grasslands, including both pastures and rangelands.

Protecting peatland ecosystems in boreal, temperate, subtropical and tropical regions through establishment of protected areas (PAs), which preserves stored carbon and ensures continued carbon sequestration by reducing degradation of the natural hydrology, soils, and/or vegetation. This solution focuses on non-coastal peatlands that have not yet been drained or otherwise severely degraded.

Reducing peatland degradation, safeguarding carbon sinks, and restoring currently degraded peatlands. Peatlands hold vast amounts of carbon. Forestry, farming, fire, and fuel extraction release carbon and reduce peatlands’ ability to store more. Rewetting can reduce emissions while supporting peatlands’ role as carbon sinks.

Cultivation of trees for timber or other biomass uses particularly in grazing lands and degraded croplands. Greenhouse gases are sequestered in soils, biomass, and timber. Tree plantation on degraded land also aims to reduce emissions from deforestation by providing an alternative source of timber

Seaweed ecosystem protection is the long-term protection from degradation of wild subtidal brown and red seaweed ecosystems. Establish Marine Protected Areas (MPAs): Designate specific MPAs to protect critical wild seaweed habitats and the genetic diversity they hold. Implement Regulations: Enact and enforce policies and legislation to regulate wild seaweed harvesting, ensuring sustainable practices that allow for regrowth and minimal environmental impact. Collaboration with Local Farmers: Engage local seaweed farmers and communities as stewards and protectors of wild stocks, leveraging their knowledge and proximity to conservation areas.

Seaweed (also called macroalgae) ecosystem restoration involves the reestablishment of wild red, brown, and green seaweed through interventions that recover degraded, damaged, or destroyed seaweed ecosystems. Healthy seaweed ecosystems remove CO₂ from the water column and convert it into biomass through photosynthesis, allowing additional CO₂ to be taken up in the ocean from the atmosphere. Some of this biomass carbon ends up sequestered, either on-site in sediment or off-site in the deep sea or at the seafloor. Advantages include the widespread human and environmental benefits associated with restored, healthy seaweed ecosystems. Disadvantages include its unclear effectiveness and climate impact, as well as its potentially high costs and difficulty of adoption at scale.

Producing biochar by slowly bake biomass in the absence of oxygen. Biochar can be used to produce energy, improve soils and store carbon. This solution provides an alternative to disposing of unused biomass through burning or decomposition.

Using technological solutions for capturing carbon dioxide (CO2) emissions from industrial facilities/sources, and safely storing it underground.

Deployment of CCS infrastructure (capture facilities, pipelines, and storage sites) for decarbonizing specific industrial processes that inherently produce CO2 such as cement and chemical production, and potentially steelmaking. Using technological solutions for capturing carbon dioxide (CO2) emissions from industrial facilities/sources, and using the captured CO2 to produce valuable products or safely storing it underground. For example, using captured CO2 to produce building materials like cement or concrete or converting CO2 into synthetic fuels or chemicals.

Bioenergy with carbon capture and storage, or BECCS, involves capturing and permanently storing CO2 from processes where biomass is converted into fuels or directly burned to generate energy. Because plants absorb CO2 as they grow, this is a way of removing CO2 from the atmosphere.

Renewable fuel produced through the natural breakdown of organic matter in an oxygen-free environment, a process called anaerobic digestion. Biogas is primarily composed of methane and carbon dioxide and transforms waste into valuable resources: energy and nutrient-rich bio-fertilizer.

Biomethane is a type of biogas, but it's the highly purified version; biogas is the raw gas from organic matter (mostly methane and CO2), while biomethane has had the CO2 and impurities removed, making it nearly identical to fossil natural gas and suitable for injection into pipelines or use as vehicle fuel.

Replacing conventional electricity-generating technologies such as coal, oil, and natural gas power plants with concentrated solar power (CSP) facilities/technologies. CSP uses sunlight as a heat source. Arrays of mirrors concentrate incoming rays onto a receiver to heat fluid, produce steam, and turn turbines.

Replacing the conventional practice of obtaining all electricity from a centralized grid with the use of decentralized energy storage systems. Standalone batteries (BESS) and electric vehicles store energy. They can enable 24/7 electricity supply even when the sun isn’t shining or the wind isn’t blowing. Distributed energy storage is an essential enabling technology for many solutions. Microgrids, net zero buildings, grid flexibility, and rooftop solar all depend on or are amplified by the use of dispersed storage systems, which facilitate uptake of renewable energy and avert the expansion of coal, oil, and gas electricity generation

Switching conventional electricity-generating technologies such as coal, oil, and natural gas to distributed solar photovoltaics (PV). These are systems that typically are sited on rooftops, but have less than 1 megawatt of capacity. Whether grid-connected or part of stand-alone systems, rooftop solar panels and other distributed solar photovoltaic systems offer hyper-local, clean electricity generation. Solution implemented by households and building owners

Connecting multiple buildings in a dense area to a single, highly efficient source of cooling. The increased energy efficiency and reduction in use of high global warming potential refrigerants can translate into substantial emissions reductions and lower operating expenses. District cooling systems that integrate cool thermal storage have the potential to significantly reduce electricity demand during peaks when demand for cooling can strain electricity grids.

Replacing conventional electricity-generating technologies such as coal, oil, and natural gas power plants for geothermal power systems. Steamy hot water from underground reservoirs is the fuel for geothermal power. It can be piped to the surface to drive turbines that produce electricity without pollution.

Implementing practices and technologies to increase grid flexibility. The grid is the dynamic web of electricity production, transmission, storage, distribution and consumption that was designed for constant, centralized power production, not for the variability of solar and wind power. For electricity supply to become predominantly or entirely renewable, the grid needs to become more flexible and adaptable than it is today.

Adaptations for hydropower technologies to convert the kinetic and potential energy of water into electricity. This solution replaces diesel generators and other conventional electricity-generating technologies. While low-carbon, large projects can disrupt ecosystems, fish migration, and require the displacement of people. Hence, large-scale hydropower can be considered a transitional solution, one that can help move us away from fossil fuels in the near term, but do not represent a long-term systemic climate solution.

Switching from conventional electricity-generating technologies such as coal, oil, and natural gas to micro wind turbines. These turbines can generate clean electricity in diverse locations, from urban centers to rural areas, without access to centralized grids.

Switching from conventional electricity-generating technologies such as coal, oil, and natural gas power plants to nuclear power plants. Nuclear power plants split atomic nuclei, releasing energy that is then used to generate electricity. GHG emissions are far lower than those of coal-fired plants. However, nuclear power is expensive and offers many reasons for concern, including waste management

Replacing conventional electricity-generating technologies such as coal, oil, and natural gas power plants for ocean power systems. Wave- and tidal-power systems harness natural ocean flows—among the most powerful and constant dynamics on Earth—to generate electricity.

Switching from conventional electricity-generating technologies such as coal, oil, and natural gas to offshore wind turbines. Winds over sea are more consistent than those over land. Offshore wind turbines tap into that power to generate utility-scale electricity without emissions.

Switching from conventional electricity-generating technologies such as coal, oil, and natural gas to onshore wind turbines. Onshore wind turbines generate electricity at a utility scale, comparable to power plants. They replace fossil fuels with emissions-free electricity.

Producing perennial biomass feedstocks for generating heat and electricity. Perennials are generally defined as plants that live three or more years. This solution replaces conventional electricity-generating technologies such as coal, oil, and natural gas power plants, and also bioenergy sources like forests, annual crops, or waste, which generally have higher climate impact. Perennial grasses have naturally high productivity, need fewer chemicals and water, and are not food crops. They also have the advantage of sequestering modest amounts of soil carbon while producing bioenergy. This solution can be considered as a "bridge" solution, one that can complement wind and solar power until energy storage grows and the grid becomes more flexible.

Designing and installing small hydropower systems for generating clean energy. Small hydropowers capture the energy of free-flowing water without using a dam. Run-of-the-river small hydropower does not divert and store large amounts of water. In-stream hydro generates electricity using underwater turbines anchored to the riverbed that spin from the flowing river current. This solution replaces diesel generators and other conventional electricity-generating technologies

Implementing large-scale energy storage to ensure electricity supply can match demand. It enables the shift to variable renewables and curbs emissions from polluting “peaker” plants. Energy can be stored in many forms, including: (1) gravitational potential energy (pumped hydroelectric energy storage); (2) chemical energy (batteries - BESS); (3) mechanical energy (flywheels or compressed air energy storage); (4) thermal energy storage (molten salt); and (5) hydrogen storage.

Switching conventional electricity-generating technologies such as coal, oil, and natural gas to utility-scale solar photovoltaics (PVs). The sun provides a virtually unlimited, clean, and free energy source. PVs take advantage of that resource, using large arrays of PV panels to capture that energy and transform it to electricity. They operate at a utility scale like conventional power plants, but have dramatically lower GHG emissions. Solution implemented by public and private utilities

Installing facilities to convert waste to energy through incineration, gasification, or pyrolysis. It is a trash management strategy that can also reduce greenhouse gas emissions by reducing methane generation from landfills and releasing energy that can substitute for that generated by fossil fuels. However, it also can contaminate air, water, and land with toxic pollutants. This can be considered a transitional solution, one that can help move us away from fossil fuels in the near term, but is not part of a clean energy future.

Replacement of hydrofluorocarbons (HFCs), which are highly potent greenhouse gases, by alternative refrigerants with lower global warming impact, including ammonia, carbon dioxide, propane, and isobutane.

Renewable, plant-based alternatives to conventional plastics that can reduce emissions by replacing fossil-based feedstocks with biogenic carbon feedstocks. These feedstocks are biomass materials that absorb atmospheric CO₂ during growth and serve as the carbon source for plastic production. The chemical and biological properties of bioplastics are well understood, commercially validated, and can reduce emissions when produced sustainably and managed properly at their end-of-life. Benefits include reducing fossil fuel reliance, alleviating plastic pollution, and, in targeted uses, supporting circularity. However, these are counterbalanced by their inconsistent emissions savings, high costs, and scalability constraints.

Managing coal mine methane (CMM) is the process of reducing methane emissions released from coal deposits and surrounding rock layers due to mining activities. CMM is naturally found in coal seams and released into the atmosphere when the coal seams are disturbed. Coal mines can continue to emit methane even after being closed or abandoned, which is known as abandoned mine methane (AMM). CMM and AMM can be captured and then utilized as a fuel source or destroyed before they reach the atmosphere

Improving district heating for industry involves using low-carbon alternatives, such as electric boilers, heat pumps, solar thermal, deep geothermal and waste heat from other industries, to provide heat to industries for their operations.

Carbon-free chemical produced using entirely renewable energy sources, such as solar and wind power. Solution for decarbonizing hard-to-abate sectors like agriculture (fertilizer production), global shipping, and heavy industry.

Green hydrogen reduces emissions when replacing fossil fuel–based hydrogen as a feedstock in the production of more complex molecules such as ammonia for fertilizers and methanol for the production of other commodity chemicals. Green hydrogen production in this solution uses on-site renewable electricity or off-site renewable electricity that directly supplies the facility. It replaces hydrogen produced from fossil fuels. This solution does not include the use of green hydrogen as a fuel or as a feedstock in the production of hydrogen-based fuels.

Switching conventional to cleaner cement production. Adoption of this solution consists of: 1) using alternative fuels. Alternative fuels that can be used to heat cement kilns in place of fossil fuels are typically biomass and waste-based fuels. Switching to alternative fuels decreases emissions by reducing the mining and combustion of fossil fuels and recovering energy from waste streams that would have otherwise released GHG during decomposition or incineration 2) reducing clinker intensity. Clinker intensity can be reduced by replacing portland cement with materials such as volcanic ash, certain clays, finely ground limestone, ground bottle glass, or industrial waste products. 3) improving process efficiency. Efficiency upgrades include a broad suite of technologies such as improved controls, electrically efficient equipment (e.g., mills, fans, and motors), thermally efficient and multistage kilns, and waste heat recovery.

Production of near-zero emission steel. This solution focuses on drastically reducing or eliminating carbon dioxide (CO2) emissions during steel manufacturing, primarily through the use of renewable energy and innovative technologies. This involves replacing traditional methods like blast furnaces, which rely on coal, with processes that utilize green hydrogen and electric arc furnaces (EAFs) powered by renewable electricity

Adopting approaches to reduce methane emissions from oil and gas (O&G) supply chains, including fixing leaks in components (eg pipes, valves, compressors), upgrading control equipment and pipeline materials, changing procedures, and destroying methane by burning methane as a fuel or in flares.

Reducing nondurable plastics by eliminating overpackaging, boosting reuse at the producer and consumer level, and offering new delivery models (deposit schemes, refill stations). This can achieve significant reductions in both GHG emissions and plastic waste.

Managing leakages of refrigerants from existing appliances and ensuring recovery, reclaiming/recycling, and destruction of refrigerants at end of life. Controlling leaks and disposal of these chemicals can avoid emissions in buildings and landfills.

Replacing less efficient aircrafts with more fuel-efficient aircrafts or retrofitting existing aircraft to improve fuel efficiency. Technologies and practices to reduce the amount of fuel needed include more fuel-efficient engines, new wingtip devices, and reducing airplanes’ weight.

Production of battery technologies for electric vehicles (EV/BEV). The energy for the motors comes from an onboard battery, which is normally charged using electricity from the grid.

Sharing car trips by adding more passengers in order to reduce individual or societal costs per traveler. Implementing or stimulating carpooling includes use of high occupancy-vehicle (HOV) and high occupancy-tolling (HOT) lanes, HOV priority parking, and shared taxis. Ride-hailing systems often are used as single user taxis, which doesn’t increase car occupancy; however the shared version of these services (UberPOOL, Lyft Shared Rides, etc.) can increase occupancy if well implemented. This solution replaces single-occupancy driving in the urban realm.

Switching fossil fuel-based motorized transport to electric bicycles. Battery-powered motors can boost the use of bicycles, reducing greenhouse gas emissions from cars. Also known as pedelecs or e-bikes, electric bicycles can be deployed as privately owned electric bicycles or as shared electric bicycles. The adoption of electric bicycles reduces emissions of CO₂ and methane from cars by displacing pkm traveled via car.

Switching fossil fuel-based motorized transport to electric bicycles. Battery-powered motors can boost the use of bicycles, reducing greenhouse gas emissions from cars. Also known as pedelecs or e-bikes, electric bicycles can be deployed as privately owned electric bicycles or as shared electric bicycles, which are available as part of bicycle sharing networks typically operated at the city level for short-term rental on a per-trip basis. The need for docking stations and rebalancing services (i.e., the use of larger vehicles to reposition bicycles to avoid one-way trips that create shortages in some places and surpluses in others) increases the carbon emissions of electric bicycles per pkm compared with private electric bicycles. By renting out electric bicycles one trip at a time, however, bicycle-share systems can make electric bicycles affordable to a larger percentage of the public, further increasing the number of pkm that can be shifted to electric bicycles.

Replacing conventional internal combustion engine (ICE) vehicles powered by gasoline or diesel with battery electric vehicles (EV/BEV), as well as building out the necessary infrastructure (especially charging stations) to support them.

Replacing conventional internal combustion engine (ICE) vehicles powered by gasoline or diesel with electric scooters and motorcycles, as well as building out the necessary infrastructure to support them. Increase travel by scooters and motorcycles that have an electric motor

Electrifying freight train tracks to reduce energy consumption. This solution replaces the use of diesel freight trains. Electrified tracks allow freight trains to stop burning dirty diesel. When powered by renewables, electric trains can provide nearly emissions-free transport

Adopting fuel efficiency measures and technologies to reduce truck emissions. Existing fleets can be retrofitted, while new trucks can be built to be more efficient or fully electric. Design and technology measures to increase a truck’s fuel efficiency include low-rolling-resistance tires, more efficient engines, devices to reduce idling and aerodynamic drag, and predictive cruise control. Replacing conventional diesel buses with Battery Electric Vehicles (BEV) and Fuel Cell Electric Vehicles (FCEV). When powered by renewables, buses can provide nearly emissions-free transport

Charging stations and supporting systems required to recharge EVs conveniently and reliably. Its development is critical for enabling widespread EV adoption and reducing transportation emissions

Improving fishing vessel efficiency reduces CO₂ emissions by using gear, vessel, or operational changes that lower fuel use in wild capture fisheries. Vessel upgrades include propulsion-related changes, such as installation of more efficient engines, and non-propulsion-related alterations, such as modified bows and hulls that reduce drag. Changing to low-fuel-use gear to catch fish, when and where possible, can also reduce CO2 emissions. Operational changes, such as speed reductions or route optimization, can likewise lead to more efficient fuel use.

Green hydrogen is a clean, emissions-free liquid fuel produced through electrolysis powered by renewable energy that can replace fossil fuels in some transportation sectors. Unlike hydrogen from fossil fuels (gray or blue hydrogen), green hydrogen generates no CO₂ emissions during production. For transportation, green hydrogen can be used in two main ways: (1) in fuel cell electric vehicles (FCEVs) to generate electricity onboard and power electric motors, or (2) combusted in specially designed hydrogen combustion engines or turbines. For aviation, liquid hydrogen may fuel aircraft engines directly, be used to produce synthetic jet fuels, or power fuel cell airplanes. For long-haul trucking, hydrogen can replace diesel by powering fuel cell trucks, which offer long range and fast refueling.

Construction of high-speed rail (HSR) track networks to shift intercity travel onto HSR. High-speed rail offers an alternative to trips made by car or airplane. It requires special, designated tracks, but can dramatically curtail emissions.

Replacing conventional internal combustion engine (ICE) vehicles with hybrid cars. A transitional technology, hybrid cars are non-plugin internal combustion engine fuel cars that run on or are supported by electric motors for at least part of the journey. The combination improves fuel economy—more miles on a gallon—and lowers emissions.

Infrastructure for production, storage, and distribution of green hydrogen, including refueling stations for trucks and specialized handling systems for liquid or compressed hydrogen at airports. Investment in green hydrogen infrastructure could unlock cross-sectoral benefits, supporting decarbonization of industry, power, and potentially heating.

Renewable fuels derived from sustainable organic materials (biomass) that are designed to significantly reduce greenhouse gas (GHG) emissions compared to traditional fossil fuels. First-Generation: Produced from food crops like corn, sugarcane, or soybean oil [1.2]. While widely available, they raise concerns about competition with food production and land use change Second-Generation (Advanced): Derived from non-food biomass and waste materials, mitigating the food-versus-fuel debate. These typically offer greater GHG reductions. Third-Generation: Produced from microalgae and macroalgae, which can grow rapidly and often in non-arable land or wastewater, holding promise for high yields per acre.

Increasing any form of travel that does not use a motor or engine. In practice, pedestrian travel and cycling account for most nonmotorized utilitarian passenger travel. Improve infrastructure such as sidewalks, footpaths, and bike lanes.

Adopting energy-efficient technologies and practices to reduce the use of ship fuel for international maritime shipping. Fuel-saving innovations include: flat extensions called ducktails at the rear that lower resistance and compressed air pumped through the bottom of the hull that “lubricates” passage through the water.

Enhancing and/or increasing the use of any form of passenger transportation that uses publicly available vehicles (e.g., buses, streetcars, subways, commuter trains, and ferries) operating along fixed routes. This requires building new public transit capacity. Second is improving the emissions performance of public transit networks through electrification and efficiency improvements. Electrified or low-emission transit modes achieve the greatest climate impact, especially in regions with clean electricity grids. However, even diesel-based public transit systems can outperform fossil fuel-powered cars on a per-pkm basis if they have high ridership and operate efficiently.

Design, construction, and maintenance of rail transport systems. This includes the infrastructure for rail tracks and track infrastructure within stations and terminals.

Replacing conventional aviation fuels with sustainable aviation fuels (SAF). SAF is a low-carbon alternative to conventional jet fuel that reduces life-cycle greenhouse gas emissions from fuel production particularly when using only non-petroleum feedstocks such as waste oils, agricultural residues, and municipal solid waste. It is usually produced using renewable electricity and captured CO₂. However, supply is a critical constraint as there is limited feedstock availability. There are also major ecological and social risks, including competition for land and feedstocks that could displace food production or degrade ecosystems, as well as unequal access to the benefits of SAF deployment. Scaling synthetic SAF (e-fuels) requires vast amounts of clean electricity, water, and CO₂ – raising concerns about resource use and trade-offs with other sectors. life-cycle emissions reductions vary widely depending on the feedstock and production pathway.

Replacing business trips with telepresence, using audiovisual technology (software-based, such as Zoom or Skype, or hardware-based, such as immersive rooms)

Increasing building deconstruction and recycling rates

Developing compost facilities to convert organic waste into soil carbon. Composting can range from backyard bins to industrial-scale operations. This solution focus on centralized (city- or regional-level) composting systems for the organic waste (OW) components of municipal solid waste (MSW).This solution replaces the disposal of biodegradable urban organic waste in landfills

Waste management approach that processes organic waste close to its source of generation, such as at homes, schools, community gardens, or neighborhood-level facilities. This contrasts with large, centralized systems that transport all waste to distant facilities

Landfill management is the process of reducing methane emissions from landfill gas (LFG). This solution focuses on biocovers. Biocovers have an organic layer that provides an environment for the bacteria to grow and a gas distribution layer to separate the landfill waste from the organic layer.

Landfill management is the process of reducing methane emissions from landfill gas (LFG). This solution focuses on capturing methane generated from municipal solid waste in landfills and burning the captured biogas to generate electricity or heat.

Developing new circular material flows and business models that transform waste and residual streams into valuable secondary raw materials. Activities include nutrient recovery from wastewater (e.g. phosphorus via Ash2Phos), cross-sector joint ventures that close material loops, and innovation testbeds that replace virgin resource extraction with circular alternatives. Directly addresses the UN-identified root cause of 50% of global climate emissions: unsustainable extraction and processing of virgin raw materials.

Transforming waste into valuable secondary raw materials, including chemicals, focusing on resource recovery, detoxification, and closing material loops. Examples include phosphorus recovery from sludge, and purifying waste solvents like acetone, ethanol, and glycol using advanced separation and distillation to create high-quality secondary raw materials

Recycling household and industrial glass materials to produce needed goods with fewer emissions. This reduces the amount of glass manufactured from virgin sources and reduces the environmental burden of landfilling

Bulk production of metals (not end-use) goods from recycled materials, replacing production from virgin materials extracted from nonrenewable ores. Production from recycled materials requires less energy and water than production from ore and so has a lower greenhouse gas footprint.

Producing recycled paper, replacing production of conventional or virgin paper produced from tree pulp. Recycling used paper involves processes such as sorting, shredding, hydropulping, and de-inking, whereas conventional paper production involves steps such as harvesting, debarking, chipping, and mechanical or chemical pulping. Both processes use energy and emit greenhouse gases, but recycling uses less energy and results in lower greenhouse gas emissions.

Production of plastic nondurable goods from recycled feedstocks. This replaces the conventional approach of producing plastic nondurable goods from virgin, petroleum-based plastics. Production from recycled feedstocks reduces waste in landfills and dumps, environmental pollution, and extraction of oil, and requires less energy than conventional plastics production.

Collection, processing, and repurposing of used or discarded textile materials into new products. Reducing waste by reusing fibres and fabrics from old garments, textiles, and industrial by-products

Treatment, neutralisation, and detoxification of hazardous and industrial waste streams to prevent environmental contamination and reduce greenhouse gas emissions. Activities include physical, chemical, and biological treatment of hazardous materials, contaminated soils, and industrial residues; safe disposal of toxic substances; and conversion of hazardous waste into inert or reusable materials. Reduces methane and toxic gas emissions from uncontrolled waste disposal and enables recovery of secondary materials from industrial waste streams.