Greenhouse gas (GHG)emissions from human activities intensify thegreenhouse effect. This contributes toclimate change.Carbon dioxide (CO₂), from burningfossil fuels such ascoal,oil, andnatural gas, is the main cause of climate change. Thelargest annual emissions are from China followed by the United States. The United States hashigher emissions per capita. The main producers fueling the emissions globally arelarge oil and gas companies. Emissions from human activities have increasedatmospheric carbon dioxide by about 50% over pre-industrial levels. The growing levels of emissions have varied, but have been consistent among allgreenhouse gases. Emissions in the 2010s averaged 56 billion tons a year, higher than any decade before.^[2] Total cumulative emissions from 1870 to 2022 were 703GtC (2575GtCO₂), of which 484±20GtC (1773±73GtCO₂) fromfossil fuels and industry, and 219±60GtC (802±220GtCO₂) fromland use change.Land-use change,such as deforestation, caused about 31% of cumulative emissions over 1870–2022,coal 32%, oil 24%, and gas 10%.^[3][4]

Carbon dioxide is the main greenhouse gas resulting from human activities. It accounts for more than half of warming.Methane (CH₄) emissions have almost the same short-term impact.^[5]Nitrous oxide (N₂O) andfluorinated gases (F-gases) play a lesser role in comparison. Emissions of carbon dioxide, methane and nitrous oxide in 2023 were all higher than ever before.^[6]

Electricity generation, heat andtransport are major emitters; overall energy is responsible for around 73% of emissions.^[7] A growing concern for electricity usage is the expansion of artificial intelligence (AI), which is projected to significantly increase global energy demand.^[8]Deforestation and other changes in land use also emit carbon dioxide andmethane. The largest source of anthropogenicmethane emissions isagriculture, closely followed bygas venting andfugitive emissions from thefossil-fuel industry. The largest agricultural methane source islivestock.Agricultural soils emitnitrous oxide partly due tofertilizers. Similarly,fluorinated gases fromrefrigerants play an outsized role in total human emissions.

The current CO₂-equivalent emission rates averaging 6.6 tonnes per person per year,^[9] are well over twice the estimated rate 2.3 tons^[10][11] required to stay within the 2030 Paris Agreement increase of 1.5 °C (2.7 °F) over pre-industrial levels.^[12] Annual per capita emissions in the industrialized countries are typically as much as ten times the average in developing countries.^[13]

Thecarbon footprint (orgreenhouse gas footprint) serves as an indicator to compare the amount of greenhouse gases emitted over the entirelife cycle from the production of a good or service along thesupply chain to its final consumption.^[14][15]Carbon accounting (or greenhouse gas accounting) is a framework of methods to measure and track how muchgreenhouse gas an organization emits.^[16] This accounting is used to help understand the various effects of emissions on positive and negative impacts they have on the climate including on human mortality.^[17]

The major anthropogenic (human origin) sources of greenhouse gases are carbon dioxide (CO₂), nitrous oxide (N
₂O), methane and three groups of fluorinated gases (sulfur hexafluoride (SF
₆),hydrofluorocarbons (HFCs) andperfluorocarbons (PFCs, sulphur hexafluoride (SF₆), and nitrogen trifluoride (NF₃)).^[26] Though thegreenhouse effect is heavily driven bywater vapor,^[27] human emissions of water vapor are not a significant contributor to warming.

AlthoughCFCs are greenhouse gases, they are regulated by theMontreal Protocol which was motivated by CFCs' contribution toozone depletion rather than by their contribution to global warming. Ozone depletion has only a minor role in greenhouse warming, though the two processes are sometimes confused in the media. In 2016, negotiators from over 170 nations meeting at the summit of theUnited Nations Environment Programme reached a legally binding accord to phase outhydrofluorocarbons (HFCs) in theKigali Amendment to theMontreal Protocol.^[28][29][30] The use of CFC-12 (except some essential uses) has been phased out due to itsozone depleting properties.^[31] The phasing-out of less activeHCFC-compounds will be completed in 2030.^[32]

Starting about 1750, industrial activity powered by fossil fuels began to significantly increase the concentration of carbon dioxide and other greenhouse gases. Emissions have grown rapidly since about 1950 with ongoing expansions in global population and economic activity following World War II. As of 2021, measured atmospheric concentrations of carbon dioxide were almost 50% higher than pre-industrial levels.^[33][34]

The main sources of greenhouse gases due to human activity (also calledcarbon sources) are:

• Burning fossil fuels: Burning oil, coal and gas is estimated to have emitted 37.4 billion tonnes of CO₂-eq in 2023.^[35] The largest single source is coal-fired power stations, with 20% of greenhouse gases (GHG) as of 2021.^[36]
• Land use change (mainly deforestation in the tropics) accounts for about a quarter of total anthropogenic GHG emissions.^[37]
• Livestockenteric fermentation andmanure management,^[38] paddyrice farming, land use andwetland changes, human-made lakes,^[39] pipeline losses, andcovered vented landfill emissions leading to higher methane atmospheric concentrations. Many of the newer style fully vented septic systems that enhance and target the fermentation process also are sources ofatmospheric methane.
• Use ofchlorofluorocarbons (CFCs) inrefrigeration systems, and use of CFCs andhalons infire suppression systems and manufacturing processes.
• Agricultural soils emit nitrous oxide (N₂O) partly due to application offertilizers.^[40]
• The largest source of anthropogenicmethane emissions isagriculture, closely followed bygas venting andfugitive emissions from thefossil-fuel industry.^[41][42] The largest agricultural methane source islivestock. Cattle (raised for both beef and milk, as well as for inedible outputs like manure and draft power) are the animal species responsible for the most emissions, representing about 65% of the livestock sector's emissions.^[43]

This section needs to beupdated. Please help update this article to reflect recent events or newly available information.(April 2024)

Global greenhouse gas emissions are about 50 Gt per year^[45] and for 2019 have been estimated at 57 Gt CO₂ eq including 5 Gt due to land use change.^[46] In 2019, approximately 34% [20 GtCO₂-eq] of total net anthropogenic GHG emissions came from the energy supply sector, 24% [14 GtCO₂-eq] from industry, 22% [13 GtCO₂-eq] from agriculture, forestry and other land use (AFOLU), 15% [8.7 GtCO₂-eq] from transport and 6% [3.3 GtCO₂-eq] from buildings.^[47]

The current CO₂-equivalent emission rates averaging 6.6 tonnes per person per year,^[9] are well over twice the estimated rate 2.3 tons^[10][11] required to stay within the 2030 Paris Agreement increase of 1.5 °C (2.7 °F) over pre-industrial levels.^[12]

While cities are sometimes considered to be disproportionate contributors to emissions, per-capita emissions tend to be lower for cities than the averages in their countries.^[48]

A 2017 survey of corporations responsible for global emissions found that100 companies were responsible for 71% of global direct and indirect emissions, and that state-owned companies were responsible for 59% of their emissions.^[49][50]

China is, by a significant margin, Asia's and the world's largest emitter; it emits nearly 10 billion tonnes each year, more than one-quarter of global emissions.^[51] Other countries with fast growing emissions areSouth Korea, Iran, and Australia (which apart from the oil rich Persian Gulf states, now has the highest per capita emission rate in the world). On the other hand, annual per capita emissions of the EU-15 and the US are gradually decreasing over time.^[52] Emissions in Russia and Ukraine have decreased fastest since 1990 due to economic restructuring in these countries.^[53]

2015 was the first year to see both total global economic growth and a reduction of carbon emissions.^[54]

Annual per capita emissions in the industrialized countries are typically as much as ten times the average in developing countries.^[13]: 144 Due to China's fast economic development, its annual per capita emissions are quickly approaching the levels of those in theAnnex I group of the Kyoto Protocol (i.e., the developed countries excluding the US).^[52]

Africa and South America are both fairly small emitters, accounting for 3-4% of global emissions each. Both have emissions almost equal to international aviation and shipping.^[51]

There are several ways of measuring greenhouse gas emissions. Some variables that have been reported include:^[56]

• Definition of measurement boundaries: Emissions can be attributed geographically, to the area where they were emitted (the territory principle) or by the activity principle to the territory that produced the emissions. These two principles result in different totals when measuring, for example, electricity importation from one country to another, or emissions at an international airport.
• Time horizon of different gases: The contribution of given greenhouse gas is reported as a CO₂ equivalent. The calculation to determine this takes into account how long that gas remains in the atmosphere. This is not always known accurately^{[clarification needed]} and calculations must be regularly updated to reflect new information.
• The measurement protocol itself: This may be via direct measurement or estimation. The four main methods are the emission factor-based method, mass balance method, predictiveemissions monitoring systems, andcontinuous emissions monitoring systems. These methods differ in accuracy, cost, and usability. Public information fromspace-based measurements of carbon dioxide byClimate Trace is expected to reveal individual large plants before the2021 United Nations Climate Change Conference.^[57]

These measures are sometimes used by countries to assert various policy/ethical positions on climate change.^[58]: 94The use of different measures leads to a lack of comparability, which is problematic when monitoring progress towards targets. There are arguments for the adoption of a common measurement tool, or at least the development of communication between different tools.^[56]

Emissions may be tracked over long time periods, known as historical or cumulative emissions measurements. Cumulative emissions provide some indicators of what is responsible for greenhouse gas atmospheric concentration build-up.^[59]: 199

The national accounts balance tracks emissions based on the difference between a country's exports and imports. For many richer nations, the balance is negative because more goods are imported than they are exported. This result is mostly due to the fact that it is cheaper to produce goods outside of developed countries, leading developed countries to become increasingly dependent on services and not goods. A positive account balance would mean that more production was occurring within a country, so more operational factories would increase carbon emission levels.^[61]

Emissions may also be measured across shorter time periods. Emissions changes may, for example, be measured against the base year of 1990. 1990 was used in theUnited Nations Framework Convention on Climate Change (UNFCCC) as the base year for emissions, and is also used in theKyoto Protocol (some gases are also measured from the year 1995).^{[13]: 146, 149} A country's emissions may also be reported as a proportion of global emissions for a particular year.

Another measurement is of per capita emissions. This divides a country's total annual emissions by its mid-year population.^[62]: 370 Per capita emissions may be based on historical or annual emissions.^{[58]: 106–107}

One way of attributing greenhouse gas emissions is to measure theembedded emissions (also referred to as "embodied emissions") of goods that are being consumed. Emissions are usually measured according to production, rather than consumption.^[63] For example, in the main internationaltreaty on climate change (theUNFCCC), countries report on emissions produced within their borders, e.g. the emissions produced from burning fossil fuels.^{[64]: 179 [65]: 1} Under a production-based accounting of emissions, embedded emissions on imported goods are attributed to the exporting, rather than the importing, country. Under a consumption-based accounting of emissions, embedded emissions on imported goods are attributed to the importing country, rather than the exporting, country.

A substantial proportion of CO₂ emissions is traded internationally. The net effect of trade was to export emissions from China and other emerging markets to consumers in the US, Japan, and Western Europe.^[65]: 4

Emission intensity is a ratio between greenhouse gas emissions and another metric, e.g., gross domestic product (GDP) or energy use. The terms "carbon intensity" and "emissions intensity" are also sometimes used.^[68] Emission intensities may be calculated usingmarket exchange rates (MER) orpurchasing power parity (PPP).^[58]: 96

Carbon accounting (or greenhouse gas accounting) is a framework of methods to measure and track how much greenhouse gas an organization emits.^[16]

Cumulative and annual CO₂ emissions

Cumulatively, the U.S. has emitted the greatest amount of CO₂, though China's emission trend is now steeper.^[44]

Annually, the U.S. emitted the most CO₂ until early in the 21st century, when China's annual emissions began to dominate.^[44]

[[file:Cumulative CO₂ emission by world region.png|0px|alt=]]

Cumulative CO₂ emission by world region

Cumulative per person emissions by world region in 3 time periods

Cumulative anthropogenic (i.e., human-emitted) emissions of CO₂ from fossil fuel use are a major cause ofglobal warming,^[77] and give some indication of which countries have contributed most to human-induced climate change. In particular, CO₂ stays in the atmosphere for at least 150 years and up to 1000 years,^[78] whilst methane disappears within a decade or so,^[79] and nitrous oxides last about 100 years.^[80] The graph gives some indication of which regions have contributed most to human-induced climate change.^{[81][82]: 15} When these numbers are calculated per capita cumulative emissions based on then-current population the situation is shown even more clearly. The ratio in per capita emissions between industrialized countries and developing countries was estimated at more than 10 to 1.

Non-OECD countries accounted for 42% of cumulative energy-related CO₂ emissions between 1890 and 2007.^{[64]: 179–80} Over this time period, the US accounted for 28% of emissions; the EU, 23%; Japan, 4%; other OECD countries 5%; Russia, 11%; China, 9%; India, 3%; and the rest of the world, 18%.^{[64]: 179–80}The European Commission adopted a set of legislative proposals targeting a reduction of the CO₂ emissions by 55% by 2030.

Overall, developed countries accounted for 83.8% of industrial CO₂ emissions over this time period, and 67.8% of total CO₂ emissions. Developing countries accounted for industrial CO₂ emissions of 16.2% over this time period, and 32.2% of total CO₂ emissions.

However, what becomes clear when we look at emissions across the world today is that the countries with the highest emissions over history are not always the biggest emitters today. For example, in 2017, the UK accounted for just 1% of global emissions.^[51]

In comparison, humans have emitted more greenhouse gases than theChicxulub meteorite impact event which caused theextinction of the dinosaurs.^[83]

Transport, together withelectricity generation, is the major source of greenhouse gas emissions in theEU. Greenhouse gas emissions from the transportation sector continue to rise, in contrast to power generation and nearly all other sectors. Since 1990, transportation emissions have increased by 30%. The transportation sector accounts for around 70% of these emissions. The majority of these emissions are caused by passengervehicles and vans. Road travel is the first major source of greenhouse gas emissions from transportation, followed by aircraft and maritime.^[84][85] Waterborne transportation is still the leastcarbon-intensive mode of transportation on average, and it is an essential link insustainablemultimodal freight supply chains.^[86]

Buildings, like industry, are directly responsible for around one-fifth of greenhouse gas emissions, primarily fromspace heating and hot water consumption. When combined with power consumption within buildings, this figure climbs to more than one-third.^[87][7][88]

Within the EU, theagricultural sector presently accounts for roughly 10% of total greenhouse gas emissions, with methane from livestock accounting for slightly more than half of 10%.^[89]

Estimates of total CO₂ emissions do includebiotic carbon emissions, mainly from deforestation.^[58]: 94 Including biotic emissions brings about the same controversy mentioned earlier regarding carbon sinks and land-use change.^{[58]: 93–94} The actual calculation of net emissions is very complex, and is affected by how carbon sinks are allocated between regions and the dynamics of theclimate system.

The sharp acceleration in CO₂ emissions since 2000 to more than a 3% increase per year (more than 2 ppm per year) from 1.1% per year during the 1990s is attributable to the lapse of formerly declining trends incarbon intensity of both developing and developed nations. China was responsible for most of global growth in emissions during this period. Localised plummeting emissions associated with the collapse of the Soviet Union have been followed by slow emissions growth in this region due to moreefficient energy use, made necessary by the increasing proportion of it that is exported.^[90] In comparison, methane has not increased appreciably, andN
₂O by 0.25% y⁻¹.

Using different base years for measuring emissions has an effect on estimates of national contributions to global warming.^{[82]: 17–18 [91]} This can be calculated by dividing a country's highest contribution to global warming starting from a particular base year, by that country's minimum contribution to global warming starting from a particular base year. Choosing between base years of 1750, 1900, 1950, and 1990 has a significant effect for most countries.^{[82]: 17–18}

TheGlobal Carbon Project continuously releases data about CO₂ emissions, budget and concentration.

Carbon dioxide (CO₂) is the dominant emitted greenhouse gas, while methane (CH₄) emissions almost have the same short-term impact.^[5] Nitrous oxide (N₂O) and fluorinated gases (F-gases) play a lesser role in comparison.

Greenhouse gas emissions are measured inCO₂ equivalents determined by theirglobal warming potential (GWP), which depends on their lifetime in the atmosphere. Estimations largely depend on the ability of oceans and land sinks to absorb these gases.Short-lived climate pollutants (SLCPs) including methane,hydrofluorocarbons (HFCs),tropospheric ozone andblack carbon persist in the atmosphere for a period ranging from days to 15 years; whereas carbon dioxide can remain in the atmosphere for millennia.^[95] Reducing SLCP emissions can cut the ongoing rate of global warming by almost half and reduce the projectedArctic warming by two-thirds.^[96]

Greenhouse gas emissions in 2019 were estimated at 57.4 GtCO₂e, while CO₂ emissions alone made up 42.5 Gt including land-use change (LUC).^[97]

While mitigation measures fordecarbonization are essential on the longer term, they could result in weak near-term warming because sources of carbon emissions often also co-emitair pollution. Hence, pairing measures that target carbon dioxide with measures targeting non-CO₂ pollutants – short-lived climate pollutants, which have faster effects on the climate, is essential for climate goals.^[98]

• Fossil fuel (use for energy generation, transport, heating and machinery in industrial plants):oil,gas andcoal (89%) are the major driver of anthropogenic global warming with annual emissions of 35.6 GtCO₂ in 2019.^[99]: 20
• Cement production (burning of fossil fuels) (4%) is estimated at 1.42 GtCO₂
• Land-use change (LUC) is the imbalance ofdeforestation andreforestation. Estimations are very uncertain at 4.5 GtCO₂.Wildfires alone cause annual emissions of about 7 GtCO₂^[100][101]
• Non-energy use of fuels, carbon losses in coke ovens, andflaring in crude oil production.^[99]

Methane has a high immediate impact with a 5-year global warming potential of up to 100.^[5] Given this, the current 389 Mt of methane emissions^[99]: 6 has about the same short-term global warming effect as CO₂ emissions, with a risk to trigger irreversible changes in climate and ecosystems. For methane, a reduction of about 30% below current emission levels would lead to a stabilization in its atmospheric concentration.

• Fossil fuels (32%) (emissions due to losses during production and transport) account for most of the methane emissions including coal mining (12% of methane total), gas distribution and leakages (11%) as well as gas venting in oil production (9%).^{[99]: 6 [99]: 12}
• Livestock (28%) with cattle (21%) as the dominant source, followed by buffalo (3%), sheep (2%), and goats (1.5%).^{[99]: 6, 23}
• Human waste and wastewater (21%): When biomass waste in landfills and organic substances in domestic andindustrial wastewater is decomposed by bacteria in anaerobic conditions, substantial amounts of methane are generated.^[99]: 12
• Rice cultivation (10%) on flooded rice fields is another agricultural source, whereanaerobic decomposition of organic material produces methane.^[99]: 12

N₂O has a high GWP and significant Ozone Depleting Potential. It is estimated that the global warming potential of N₂O over 100 years is 265 times greater than CO₂.^[102] For N₂O, a reduction of more than 50% would be required for a stabilization.

Most emissions (56%) of nitrous oxide comes from agriculture, especially meat production: cattle (droppings on pasture), fertilizers, animal manure.^[99]: 12Further contributions come from combustion of fossil fuels (18%) andbiofuels^[103] as well as industrial production ofadipic acid andnitric acid.

Fluorinated gases includehydrofluorocarbons (HFC), perfluorocarbons (PFC),sulfur hexafluoride (SF₆), andnitrogen trifluoride (NF₃). They are used by switchgear in the power sector, semiconductor manufacture, aluminum production and a largely unknown source of SF₆.^[99]: 38 Continued phase down of manufacture and use of HFCs under theKigali Amendment to the Montreal Protocol will help reduce HFC emissions and concurrently improve the energy efficiency of appliances that use HFCs like air conditioners, freezers and other refrigeration devices.

Hydrogen leakages contribute to indirect global warming.^[104]When hydrogen is oxidized in the atmosphere, the result is an increase in concentrations of greenhouse gases in both the troposphere and the stratosphere.^[105] Hydrogen can leak fromhydrogen production facilities as well as any infrastructure in which hydrogen is transported, stored, or consumed.^[106]

Black carbon is formed through the incomplete combustion of fossil fuels,biofuel, andbiomass. It is not a greenhouse gas but aclimate forcing agent. Black carbon can absorb sunlight and reducealbedo when deposited on snow and ice. Indirect heating can be caused by the interaction with clouds.^[107] Black carbon stays in the atmosphere for only several days to weeks.^[108] Emissions may be mitigated by upgrading coke ovens, installing particulate filters on diesel-based engines, reducingroutine flaring, and minimizing open burning of biomass.

Global greenhouse gas emissions can be attributed to differentsectors of the economy. This provides a picture of the varying contributions of different types of economic activity to climate change, and helps in understanding the changes required tomitigate climate change.

Greenhouse gas emissions can be divided into those that arise from the combustion of fuels to produce energy, and those generated by other processes. Around two thirds of greenhouse gas emissions arise from the combustion of fuels.^[109]

Energy may be produced at the point ofconsumption, or by a generator for consumption by others. Thus emissions arising from energy production may be categorized according to where they are emitted, or where the resulting energy is consumed. If emissions are attributed at the point of production, then electricity generators contribute about 25% of global greenhouse gas emissions.^[110] If these emissions are attributed to the final consumer then 24% of total emissions arise from manufacturing and construction, 17% from transportation, 11% from domestic consumers, and 7% from commercial consumers.^[111] Around 4% of emissions arise from the energy consumed by the energy and fuel industry itself.

The remaining third of emissions arise from processes other than energy production. 12% of total emissions arise from agriculture, 7% from land use change and forestry, 6% from industrial processes, and 3% from waste.^[109]

Coal-fired power stations are the single largest emitter, with over 20% of global greenhouse gas emissions in 2018.^[113] Although much less polluting than coal plants, naturalgas-fired power plants are also major emitters,^[114] taking electricity generation as a whole over 25% in 2018.^[115] Notably, just 5% of the world's power plants account for almost three-quarters of carbon emissions from electricity generation, based on an inventory of more than 29,000 fossil-fuel power plants across 221 countries.^[116] In the 2022 IPCC report, it is noted that providing modern energy services universally would only increase greenhouse gas emissions by a few percent at most. This slight increase means that the additional energy demand that comes from supporting decent living standards for all would be far lower than current average energy consumption.^[117]

In March 2024, theInternational Energy Agency (IEA) reported that in 2023, global CO₂ emissions from energy sources increased by 1.1%, rising by 410 million tonnes to a record 37.4 billion tonnes, primarily due to coal. Drought-related decreases in hydropower contributed to a 170 million tonne rise in emissions, which would have otherwise led to a decrease in the electricity sector's emissions.^[118] The implementation ofclean energy technologies likesolar,wind, nuclear,heat pumps, andelectric vehicles since 2019 has significantly tempered emissions growth, which would have been threefold without these technologies.^[118]

Deforestation is a major source of greenhouse gas emissions. A study shows annual carbon emissions (or carbon loss) from tropical deforestation have doubled during the last two decades and continue to increase. (0.97 ±0.16 PgC per year in 2001–2005 to 1.99 ±0.13 PgC per year in 2015–2019)^[130][129]

Land-use change, e.g., the clearing of forests for agricultural use, can affect the concentration of greenhouse gases in the atmosphere by altering how much carbon flows out of the atmosphere intocarbon sinks.^[131] Accounting for land-use change can be understood as an attempt to measure "net" emissions, i.e., gross emissions from all sources minus the removal of emissions from the atmosphere by carbon sinks.^{[58]: 92–93}

There are substantial uncertainties in the measurement of net carbon emissions.^[132] Additionally, there is controversy over how carbon sinks should be allocated between different regions and over time.^[58]: 93 For instance, concentrating on more recent changes in carbon sinks is likely to favour those regions that have deforested earlier, e.g., Europe.

In1997, human-caused Indonesian peat fires were estimated to have released between 13% and 40% of the average annual global carbon emissions caused by the burning offossil fuels.^{[133][134][135]}

Transportation accounts for 15% of emissions worldwide.^[136] Over a quarter of global transport CO₂ emissions are from road freight,^[137] so many countries are further restrictingtruck CO₂ emissions to help limit climate change.^[138]

Maritime transport accounts for 3.5% to 4% of all greenhouse gas emissions, primarily carbon dioxide.^[139][140] In 2022, the shipping industry's 3% of global greenhouse gas emissions made it "the sixth largest greenhouse gas emitter worldwide, ranking between Japan and Germany."^{[141][142][143]}

Jet airliners contribute to climate change by emitting carbon dioxide (CO₂), nitrogen oxides,contrails and particulates.In 2018, global commercial operations generated 2.4% of all CO₂ emissions.^[144]

In 2020, approximately 3.5% of the overall human impacts on climate are from the aviation sector. The impact of the sector on climate in the last 20 years had doubled, but the part of the contribution of the sector in comparison to other sectors did not change because other sectors grew as well.^[145]

Some representative figures for CO₂ average direct emissions (not accounting for high-altitude radiative effects) of airliners expressed as CO₂ and CO₂ equivalent per passenger kilometer:^[146]

• Domestic, short distance, less than 463 km (288 mi): 257 g/km CO₂ or 259 g/km (14.7 oz/mile) CO₂e
• Long-distance flights: 113 g/km CO₂ or 114 g/km (6.5 oz/mile) CO₂e

In 2018, manufacturing construction materials and maintaining buildings accounted for 39% of carbon dioxide emissions from energy and process-related emissions. Manufacture of glass, cement, and steel accounted for 11% of energy and process-related emissions.^[148] Because building construction is a significant investment, more than two-thirds of buildings in existence will still exist in 2050.Retrofitting existing buildings to become more efficient will be necessary to meet the targets of the Paris Agreement; it will be insufficient to only apply low-emission standards to new construction.^[149] Buildings that produce as much energy as they consume are calledzero-energy buildings, while buildings that produce more than they consume areenergy-plus.Low-energy buildings are designed to be highly efficient with low total energy consumption and carbon emissions—a popular type is thepassive house.^[148]

The construction industry has seen marked advances in building performance and energy efficiency over recent decades.^[150]Green building practices that avoid emissions or capture the carbon already present in the environment, allow for reduced footprint of the construction industry, for example, use ofhempcrete,cellulose fiber insulation, andlandscaping.^[151]

In 2019, the building sector was responsible for 12 GtCO₂-eq emissions. More than 95% of these emissions were carbon, and the remaining 5% were CH₄,N₂O, and halocarbon.^[152]

The largest contributor to building sector emissions (49% of total) is the production of electricity for use in buildings.^[153]

Of global building sector GHG emissions, 28% are produced during the manufacturing process of building materials such assteel,cement (a key component ofconcrete),^[154] and glass.^[153] The conventional process inherently related to the production of steel and cement results in large amounts of CO₂ emitted. For example, the production of steel in 2018 was responsible for 7 to 9% of the global CO₂ emissions.^[155]

The remaining 23% of global building sector GHG emissions are produced directly on site during building operations.^[153]

Embodied carbon emissions, or upfront carbon emissions (UCE), are the result of creating and maintaining the materials that form a building.^[156] As of 2018, "Embodied carbon is responsible 11% of global greenhouse gas emissions and 28% of global building sector emissions ... Embodied carbon will be responsible for almost half of total new construction emissions between now and 2050."^[157]

GHG emissions which are produced during the mining, processing, manufacturing, transportation and installation of building materials are referred to as theembodied carbon of a material.^[158] The embodied carbon of a construction project can be reduced by using low-carbon materials for building structures and finishes, reducing demolition, and reusing buildings and construction materials whenever possible.^[153]

As of 2020^[update]Secunda CTL is the world's largest single emitter, at 56.5 million tonnes CO₂ a year.^[159]

Flaring and venting ofnatural gas in oil wells is a significant source of greenhouse gas emissions. Its contribution to greenhouse gases has declined by three-quarters in absolute terms since a peak in the 1970s of approximately 110 million metric tons/year, and in 2004 accounted for about 1/2 of one percent of all anthropogenic carbon dioxide emissions.^[160]

TheWorld Bank estimates that 134 billion cubic meters of natural gas are flared or vented annually (2010 datum), an amount equivalent to the combined annual gas consumption ofGermany andFrance or enough to supply the entire world with gas for 16 days. This flaring is highly concentrated: 10 countries account for 70% of emissions, and twenty for 85%.^[161]

Steel and aluminum are key economic sectors where CO₂ is produced. According to a 2013 study, "in 2004, the steel industry along emits about 590M tons of CO₂, which accounts for 5.2% of the global anthropogenic GHG emissions. CO₂ emitted from steel production primarily comes from energy consumption of fossil fuel as well as the use oflimestone to purifyiron oxides."^[162]

More recent estimates suggest that global steel production emitted around 2,280 million tons of CO₂ in 2017, indicating the scale has increased significantly. A 2022 study found that across bulk material sectors—steel, aluminum, cement, and paper—total emissions reached approximately 8.4 billion tons of CO₂ equivalent.^[163]

Plastics are produced mainly from fossil fuels. It was estimated that between 3% and 4% of global GHG emissions are associated with plastics' life cycles.^[164] The EPA estimates^[165] as many as five mass units of carbon dioxide are emitted for each mass unit ofpolyethylene terephthalate (PET) produced—the type of plastic most commonly used for beverage bottles,^[166] the transportation produce greenhouse gases also.^[167]Plastic waste emits carbon dioxide when it degrades. In 2018 research claimed that some of the most common plastics in the environment release the greenhouse gases methane andethylene when exposed to sunlight in an amount that can affect the earth climate.^[168][169]

Due to the lightness of plastic versus glass or metal, plastic may reduce energy consumption. For example, packaging beverages in PET plastic rather than glass or metal is estimated to save 52% in transportation energy, if the glass or metal package issingle-use, of course.

In 2019 a new report "Plastic and Climate" was published. According to the report, the production and incineration of plastics will contribute in the equivalent of 850 million tonnes ofcarbon dioxide (CO₂) to the atmosphere in 2019. With the current trend, annual life cycle greenhouse gas emissions of plastics will grow to 1.34 billion tonnes by 2030. By 2050, the life cycle emissions of plastics could reach 56 billion tonnes, as much as 14 percent of the Earth's remainingcarbon budget.^[170] The report says that only solutions which involve areduction in consumption can solve the problem, while others like biodegradable plastic, ocean cleanup, using renewable energy in plastic industry can do little, and in some cases may even worsen it.^[171]

The global print and paper industry accounts for about 1% of global carbon dioxide emissions.^[172] Greenhouse gas emissions from thepulp and paper industry are generated from the combustion of fossil fuels required for raw material production and transportation, wastewater treatment facilities, purchased power, paper transportation, printed product transportation, disposal and recycling.

In 2020,data centers (excluding cryptocurrency mining) and data transmission each used about 1% of world electricity.^[173] Thedigital sector produces between 2% and 4% of global GHG emissions,^[174] a large part of which is fromchipmaking.^[175] However the sector reduces emissions from other sectors which have a larger global share, such as transport of people,^[176] and possibly buildings and industry.^[177]

Mining forproof-of-workcryptocurrencies requires enormous amounts of electricity and consequently comes with a largecarbon footprint.^[178] Proof-of-work blockchains such asBitcoin,Ethereum,Litecoin, andMonero were estimated to have added between 3 million and 15 million tonnes of carbon dioxide (CO₂) to the atmosphere in the period from 1 January 2016 to 30 June 2017.^[179] By the end of 2021, Bitcoin was estimated to produce 65.4 million tonnes of CO₂, as much asGreece,^[180] and consume between 91 and 177 terawatt-hours annually (0.3% to 0.6% of world electricity). Bitcoin is the least energy-efficient cryptocurrency, using 707.6 kilowatt-hours of electricity per transaction.^{[181][182][183]}

A study in 2015 investigated the global electricity usage that can be ascribed toCommunication Technology (CT) between 2010 and 2030. Electricity usage from CT was divided into four principle categories: (i) consumer devices, including personal computers, mobile phones, TVs and home entertainment systems; (ii) network infrastructure; (iii) data center computation and storage; and lastly (iv) production of the above categories. The study estimated for the worst-case scenario, that CT electricity usage could contribute up to 23% of the globally released greenhouse gas emissions in 2030.^[184]

The healthcare sector produces 4.4–4.6% of global greenhouse gas emissions.^[185]

Based on the 2013 life cycle emissions in the health care sector, it is estimated that the GHG emissions associated with US health care activities may cause an additional 123,000 to 381,000 DALYs annually.^[186]

According to UNEP, global tourism is a significant contributor to the increasing concentrations of greenhouse gases in the atmosphere, with air travel accounting for a substantial share of tourism's carbon footprint—up to 70% in some countries like Iceland.^[189][190]

Recent studies show that tourism produces around 1 kg of CO₂ per dollar spent—about 25% higher than the global economic average—highlighting its substantial carbon intensity.^[190]

Banks' financed emissions - the greenhouse gas emissions linked to the investment and lending activities offinancial institutions - represent around 75% of their carbon footprint.^[191] TheNetwork for Greening the Financial System estimates that climate disasters could dent global economic growth up to 3% in the next five years,^[192] and that the financial sector could play a key role in mitigating the risks of climate change.^[192]

TheNet-Zero Banking Alliance has created guidelines for climate target setting for banks,^[193] while the Partnership for Carbon Accounting Financials is developing a harmonized approach to assess and disclose the greenhouse gas emissions associated with financial institutions' loans and investments.^[194]

The responsibility for anthropogenic climate change differs substantially among individuals, e.g. between groups orcohorts.

This pie chart illustrates both total emissions for each income group, and emissionsper person within each income group. For example, the 10% with the highest incomes are responsible for half of carbon emissions, and its members emit an average of more than five times as muchper person as members of the lowest half of the income scale.^[198]

Though total CO₂ emissions (size of pie charts) differ substantially among high-emitting regions, the pattern of higher income classes emitting more than lower income classes is consistent across regions.^[199] The world's top 1% of emitters emit over 1000 times more than the bottom 1%.^[199]

Fueled by theconsumptive lifestyle ofwealthy people, the wealthiest 5% of the global population has been responsible for 37% of the absolute increase in greenhouse gas emissions worldwide. It can be seen that there is a strong relationship between income and per capita carbon dioxide emissions.^[51] Almost half of the increase in absolute global emissions has been caused by the richest 10% of the population.^[200] In the newest report from the IPCC 2022, it states that the lifestyle consumptions of the poor and middle class in emerging economies produce approximately 5–50 times less the amount that the high class in already developed high-income countries.^[201][202] Variations in regional, and national per capita emissions partly reflect different development stages, but they also vary widely at similar income levels. The 10% of households with the highest per capita emissions contribute a disproportionately large share of global household greenhouse gas emissions.^[202]

Studies find that the most affluent citizens of the world are responsible for mostenvironmental impacts, and robust action by them is necessary for prospects of moving towards safer environmental conditions.^[203][204]

According to a 2020 report byOxfam and theStockholm Environment Institute,^[205][206] the richest 1% of the global population have caused twice as much carbon emissions as the poorest 50% over the 25 years from 1990 to 2015.^{[207][208][209]} This was, respectively, during that period, 15% of cumulative emissions compared to 7%.^[210] The bottom half of the population is directly responsible for less than 20% of energy footprints and consume less than the top 5% in terms of trade-corrected energy. The largest disproportionality was identified to be in the domain of transport, where e.g. the top 10% consume 56% of vehicle fuel and conduct 70% of vehicle purchases.^[211] However, wealthy individuals are also oftenshareholders and typically have more influence^[212] and, especially in the case ofbillionaires, may also direct lobbying efforts, direct financial decisions, and/or control companies.

Based on a study in 32 developed countries, researchers found that "seniors in the United States and Australia have the highest per capita footprint, twice the Western average. The trend is mainly due to changes in expenditure patterns of seniors".^[213]

Governments have taken action to reduce greenhouse gas emissions tomitigate climate change. Countries and regions listed in Annex I of theUnited Nations Framework Convention on Climate Change (UNFCCC) (i.e., the OECD and former planned economies of the Soviet Union) are required to submit periodic assessments to the UNFCCC of actions they are taking to address climate change.^[214]: 3 Policies implemented by governments include for example national and regional targets to reduce emissions, promotingenergy efficiency, and support for anenergy transition.

In October 2023, the USEnergy Information Administration (EIA) released a series of projections out to 2050 based on current ascertainable policy interventions.^{[228][229][230]} Unlike many integratedsystems models in this field, emissions are allowed to float rather than be pinned tonet‑zero in 2050. A sensitivity analysis varied key parameters, primarily future GDP growth (2.6% pa as reference, variously 1.8% and 3.4%) and secondarilytechnological learning rates, futurecrude oil prices, and similarexogenous inputs. The model results are far from encouraging. In no case did aggregate energy-related carbon emissions ever dip below 2022 levels (see figure 3 plot). The IEO2023 exploration provides a benchmark and suggests that far stronger action is needed.

This section is an excerpt fromClimate change mitigation § Needed emissions cuts.[edit]

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The annual "Emissions Gap Report" byUNEP stated in 2022 that it was necessary to almost halve emissions. "To get on track for limiting global warming to 1.5°C, global annual GHG emissions must be reduced by 45 per cent compared with emissions projections under policies currently in place in just eight years, and they must continue to decline rapidly after 2030, to avoid exhausting the limited remaining atmosphericcarbon budget."^[231]: xvi The report commented that the world should focus on broad-based economy-wide transformations and not incremental change.^[231]: xvi

In 2022, the Intergovernmental Panel on Climate Change (IPCC) released itsSixth Assessment Report on climate change. It warned that greenhouse gas emissions must peak before 2025 at the latest and decline 43% by 2030 to have a good chance of limiting global warming to 1.5 °C (2.7 °F).^[232][233] Or in the words of Secretary-General of the United NationsAntónio Guterres: "Main emitters must drastically cut emissions starting this year".^[234]

A 2023 synthesis by leading climate scientists highlighted ten critical areas in climate science with significant policy implications. These include the near inevitability of temporarily exceeding the 1.5 °C warming limit, the urgent need for a rapid and managed fossil fuel phase-out, challenges in scaling carbon dioxide removal technologies, uncertainties regarding the future contribution of natural carbon sinks, and the interconnected crises of biodiversity loss and climate change. These insights underscore the necessity for immediate and comprehensive mitigation strategies to address the multifaceted challenges of climate change.^[235]

In 2023, China, the United States, India, EU, Russia, Japan, and Iran - the world's largest CO₂ emitters - together accounted for 69.7% of total global fossil CO₂ emissions.^[236]

This section is an excerpt fromList of countries by carbon dioxide emissions § Fossil carbon dioxide emissions by country.[edit]

List of countries by carbon emissions^[237]

Location	% of global total	Fossil emissions (1,000,000 tons per year)		% change from 2000
		2023	2000
World	100%	39,023.94	25,725.44	+52%
China	34.0%	13,259.64	3,666.95	+262%
United States	12.0%	4,682.04	5,928.97	−21%
India	7.6%	2,955.18	995.65	+197%
European Union	6.4%	2,512.07	3,563.26	−30%
Russia	5.3%	2,069.50	1,681.14	+23%
Japan	2.4%	944.76	1,248.81	−24%
Iran	2.0%	778.80	353.93	+120%
International Shipping	1.8%	706.32	503.29	+40%
Indonesia	1.7%	674.54	299.09	+126%
Saudi Arabia	1.6%	622.91	265.24	+135%
Germany	1.5%	582.95	871.74	−33%
Canada	1.5%	575.01	543.04	+6%
South Korea	1.5%	573.54	474.16	+21%
International Aviation	1.3%	491.63	355.32	+38%
Mexico	1.2%	487.09	396.71	+23%
Brazil	1.2%	479.50	349.40	+37%
Turkey	1.1%	438.32	227.05	+93%
South Africa	1.0%	397.37	347.30	+14%
Australia	1.0%	373.62	353.87	+6%
Vietnam	1.0%	372.95	56.52	+560%
Italy,San Marino andVatican City	0.8%	305.49	454.72	−33%
United Kingdom	0.8%	302.10	551.68	−45%
Poland	0.7%	286.91	313.02	−8%
Malaysia	0.7%	283.32	130.78	+117%
France andMonaco	0.7%	282.43	401.21	−30%
Taiwan	0.7%	279.85	238.02	+18%
Thailand	0.7%	274.16	174.82	+57%
Egypt	0.6%	249.33	127.91	+95%
Kazakhstan	0.6%	239.87	132.22	+81%
Spain andAndorra	0.6%	217.26	313.24	−31%
United Arab Emirates	0.5%	205.99	88.46	+133%
Pakistan	0.5%	200.51	111.87	+79%
Iraq	0.5%	192.91	88.81	+117%
Argentina	0.5%	183.78	136.76	+34%
Algeria	0.5%	180.36	87.94	+105%
Philippines	0.4%	161.29	74.25	+117%
Uzbekistan	0.4%	137.90	130.67	+6%
Ukraine	0.3%	136.20	360.02	−62%
Nigeria	0.3%	127.94	100.30	+28%
Qatar	0.3%	127.91	31.75	+303%
Bangladesh	0.3%	124.79	26.97	+363%
Netherlands	0.3%	122.87	176.91	−31%
Kuwait	0.3%	111.63	54.48	+105%
Colombia	0.3%	100.86	62.57	+61%
Oman	0.2%	93.09	26.32	+254%
Czech Republic	0.2%	90.51	132.31	−32%
Venezuela	0.2%	84.60	137.75	−39%
Belgium	0.2%	84.31	124.97	−33%
Chile	0.2%	84.00	53.85	+56%
Romania	0.2%	70.77	97.42	−27%
Morocco	0.2%	69.86	33.56	+108%
Turkmenistan	0.2%	65.99	39.34	+68%
North Korea	0.2%	64.27	73.81	−13%
Libya	0.2%	61.26	49.28	+24%
Israel andPalestine	0.2%	61.25	59.30	+3%
Austria	0.2%	58.82	66.69	−12%
Peru	0.1%	58.40	28.98	+102%
Singapore	0.1%	57.07	45.52	+25%
Serbia andMontenegro	0.1%	56.12	50.64	+11%
Belarus	0.1%	54.18	56.26	−4%
Greece	0.1%	51.67	96.05	−46%
Ecuador	0.1%	45.33	22.04	+106%
Norway	0.1%	44.07	41.77	+5%
Hungary	0.1%	43.83	59.48	−26%
Azerbaijan	0.1%	42.77	28.79	+49%
Bulgaria	0.1%	39.79	48.17	−17%
Bahrain	0.1%	37.43	17.77	+111%
Portugal	0.09%	36.17	64.41	−44%
New Zealand	0.09%	35.80	32.89	+9%
Sweden	0.09%	35.39	57.98	−39%
Slovakia	0.09%	34.86	41.68	−16%
Hong Kong	0.09%	34.67	41.90	−17%
Switzerland andLiechtenstein	0.09%	34.22	44.80	−24%
Myanmar	0.09%	33.37	10.04	+232%
Ireland	0.08%	32.48	43.82	−26%
Finland	0.08%	32.27	57.53	−44%
Tunisia	0.08%	31.50	21.13	+49%
Dominican Republic	0.08%	31.35	19.01	+65%
Angola	0.07%	28.23	16.51	+71%
Mongolia	0.07%	28.12	9.04	+211%
Trinidad and Tobago	0.07%	27.22	19.13	+42%
Denmark	0.07%	26.77	53.16	−50%
Laos	0.07%	26.02	0.93	+2,685
Syria	0.07%	25.59	45.90	−44%
Ghana	0.06%	24.16	6.09	+297%
Bolivia	0.06%	23.81	8.20	+190%
Jordan	0.06%	23.58	16.47	+43%
Cuba	0.06%	22.07	28.99	−24%
Bosnia and Herzegovina	0.06%	22.00	14.28	+54%
Kenya	0.06%	21.73	8.91	+144%
Guatemala	0.05%	21.35	9.69	+120%
Sudan andSouth Sudan	0.05%	21.27	6.00	+255%
Sri Lanka	0.05%	20.52	11.46	+79%
Tanzania	0.05%	19.37	3.11	+523%
Cambodia	0.05%	17.97	2.00	+798%
Nepal	0.05%	17.93	3.42	+424%
Croatia	0.04%	17.46	19.37	−10%
Lebanon	0.04%	17.33	15.31	+13%
Ethiopia	0.04%	16.71	3.88	+331%
Panama	0.04%	14.72	5.19	+184%
Ivory Coast	0.04%	14.41	6.97	+107%
Puerto Rico	0.04%	13.82	25.18	−45%
Lithuania	0.03%	13.11	11.66	+13%
Georgia	0.03%	12.86	5.21	+147%
Slovenia	0.03%	12.08	15.04	−20%
Senegal	0.03%	12.02	3.99	+201%
Zimbabwe	0.03%	11.74	14.60	−20%
Estonia	0.03%	11.44	17.38	−34%
Honduras	0.03%	10.95	5.00	+119%
Yemen	0.03%	10.90	15.74	−31%
Cameroon	0.03%	10.76	5.73	+88%
Kyrgyzstan	0.03%	10.46	4.80	+118%
Moldova	0.03%	9.93	6.89	+44%
Mozambique	0.02%	9.74	1.57	+520%
Brunei	0.02%	9.72	6.07	+60%
Tajikistan	0.02%	9.31	2.78	+234%
Uruguay	0.02%	8.82	5.57	+58%
North Macedonia	0.02%	8.76	9.04	−3%
Afghanistan	0.02%	8.71	1.02	+757%
Costa Rica	0.02%	8.57	5.12	+67%
El Salvador	0.02%	8.38	5.80	+45%
Paraguay	0.02%	8.25	3.64	+127%
Zambia	0.02%	8.06	1.95	+313%
Armenia	0.02%	7.73	3.57	+116%
Botswana	0.02%	7.42	4.10	+81%
Congo	0.02%	7.25	4.51	+61%
Uganda	0.02%	7.22	1.41	+411%
Cyprus	0.02%	7.18	7.13	+1%
Luxembourg	0.02%	7.01	8.80	−20%
Jamaica	0.02%	6.86	10.21	−33%
Mali	0.02%	6.66	0.80	+730%
Latvia	0.02%	6.55	7.23	−9%
Malawi	0.02%	6.45	3.10	+108%
Benin	0.02%	6.44	1.54	+317%
New Caledonia	0.02%	6.21	2.18	+185%
Burkina Faso	0.02%	6.00	0.88	+583%
Papua New Guinea	0.02%	5.95	2.95	+102%
Nicaragua	0.01%	5.73	3.77	+52%
Gabon	0.01%	4.93	6.60	−25%
Mauritania	0.01%	4.65	1.07	+336%
Albania	0.01%	4.59	3.23	+42%
Namibia	0.01%	4.36	1.95	+124%
Mauritius	0.01%	4.21	2.44	+73%
Madagascar	0.01%	4.10	1.69	+142%
Democratic Republic of the Congo	0.01%	3.80	1.88	+102%
Equatorial Guinea	0.01%	3.78	2.74	+38%
Guinea	0.01%	3.72	1.47	+153%
Haiti	0.009%	3.54	1.69	+109%
Guyana	0.008%	3.30	1.66	+99%
Iceland	0.008%	3.09	2.85	+8%
Macao	0.008%	3.01	1.48	+104%
Maldives	0.007%	2.88	0.64	+352%
Niger	0.007%	2.82	0.70	+302%
Suriname	0.007%	2.63	1.48	+78%
Chad	0.007%	2.57	0.24	+962%
Réunion	0.007%	2.57	2.05	+25%
Togo	0.006%	2.49	1.25	+99%
Curaçao	0.006%	2.43	5.67	−57%
Fiji	0.006%	2.21	1.46	+51%
Bhutan	0.005%	1.99	0.41	+388%
Malta	0.004%	1.68	2.13	−21%
Bahamas	0.004%	1.68	1.00	+69%
Rwanda	0.004%	1.65	0.68	+142%
Liberia	0.004%	1.64	0.40	+307%
Palau	0.004%	1.44	2.12	−32%
Eswatini	0.004%	1.39	1.10	+27%
French Polynesia	0.003%	1.26	0.72	+75%
Seychelles	0.003%	1.24	0.76	+63%
Guadeloupe	0.003%	1.17	0.62	+89%
Martinique	0.003%	1.09	0.67	+62%
Sierra Leone	0.003%	1.07	0.43	+147%
Cape Verde	0.003%	1.01	0.28	+256%
Lesotho	0.002%	0.88	0.35	+148%
Somalia	0.002%	0.87	0.63	+38%
Burundi	0.002%	0.84	0.29	+186%
Barbados	0.002%	0.80	0.59	+35%
Djibouti	0.002%	0.75	0.74	+1%
East Timor	0.002%	0.70	0.23	+208%
Gibraltar	0.002%	0.69	0.34	+102%
Eritrea	0.002%	0.67	0.67	no change%
Gambia	0.002%	0.61	0.27	+126%
Greenland	0.001%	0.58	0.00	+43,369
Aruba	0.001%	0.53	0.27	+97%
Samoa	0.001%	0.47	0.19	+149%
Solomon Islands	0.001%	0.42	0.24	+78%
French Guiana	0.001%	0.38	0.17	+119%
Central African Republic	0.001%	0.37	0.26	+43%
Cayman Islands	0.001%	0.36	0.13	+172%
Bermuda	0.001%	0.35	0.15	+133%
Guinea-Bissau	0.001%	0.35	0.20	+71%
Antigua and Barbuda	0.001%	0.32	0.14	+139%
Comoros	0.001%	0.32	0.09	+250%
Saint Lucia	0.001%	0.30	0.10	+207%
Vanuatu	0.001%	0.29	0.08	+238%
Belize	0.001%	0.28	0.14	+101%
Western Sahara	0.001%	0.26	0.26	+4%
Tonga	0.001%	0.22	0.10	+118%
São Tomé and Príncipe	0.001%	0.21	0.06	+288%
Grenada	0.0004%	0.14	0.06	+149%
Cook Islands	0.0004%	0.14	0.06	+133%
Saint Kitts and Nevis	0.0003%	0.12	0.05	+140%
Turks and Caicos Islands	0.0003%	0.10	0.02	+481%
Kiribati	0.0002%	0.10	0.03	+197%
Saint Vincent and the Grenadines	0.0002%	0.10	0.04	+131%
Dominica	0.0002%	0.08	0.06	+44%
British Virgin Islands	0.0002%	0.08	0.03	+172%
Saint Pierre and Miquelon	0.0001%	0.04	0.02	+129%
Anguilla	0.0001%	0.02	0.02	+48%
Falkland Islands	0.0000%	0.02	0.01	+170%
Saint Helena, Ascension and Tristan da Cunha	0.0000%	0.02	0.01	+58%
Faroe Islands	0.0000%	0.00	0.00	+20%

In 2020, carbon dioxide emissions fell by 6.4% or 2.3 billion tonnes globally.^[252] In April 2020,NO_x emissions fell by up to 30%.^[253] In China,lockdowns and other measures resulted in a 26% decrease in coal consumption, and a 50% reduction in nitrogen oxide emissions.^[254] Greenhouse gas emissions rebounded later in the pandemic as many countries began lifting restrictions, with the direct impact of pandemic policies having a negligible long-term impact on climate change.^[252][255]

• Arctic methane emissions – Release of methane in the Arctic
• Carbon offsets and credits – Carbon dioxide reduction scheme
• List of locations and entities by greenhouse gas emissions
• Low-carbon economy – Climate-friendly economy
• Net zero emissions – Rate of human-caused greenhouse gas emissionsPages displaying short descriptions of redirect targets
• World energy supply and consumption – Global production and usage of energy