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74-460: The United States Climate Change Technology Program or CCTP is a multi-agency planning and coordination entity. Its purpose is to accelerate the development and deployment of technologies that can reduce, avoid, or capture and store greenhouse gas emissions . CCTP was established administratively in 2002, authorized by the Energy Policy Act of 2005 , and appropriated funds in 2007. Currently,

148-570: A decade or so, and nitrous oxides last about 100 years. The graph gives some indication of which regions have contributed most to human-induced climate change. 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 CO 2 emissions between 1890 and 2007. Over this time period,

222-430: A function of frequency (or wavelength). The area between the curve for longwave radiation emitted by Earth's surface and the curve for outgoing longwave radiation indicates the size of the greenhouse effect. Different substances are responsible for reducing the radiation energy reaching space at different frequencies; for some frequencies, multiple substances play a role. Carbon dioxide is understood to be responsible for

296-442: A good or service along the supply chain to its final consumption. Carbon accounting (or greenhouse gas accounting) is a framework of methods to measure and track how much greenhouse gas an organization emits. The greenhouse effect occurs when greenhouse gases in a planet's atmosphere insulate the planet from losing heat to space, raising its surface temperature. Surface heating can happen from an internal heat source as in

370-517: 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. 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. The national accounts balance tracks emissions based on

444-479: A lesser role in comparison. Emissions of carbon dioxide, methane and nitrous oxide in 2023 were all higher than ever before. Electricity generation , heat and transport are major emitters; overall energy is responsible for around 73% of emissions. Deforestation and other changes in land use also emit carbon dioxide and methane . The largest source of anthropogenic methane emissions is agriculture , closely followed by gas venting and fugitive emissions from

518-856: A particular base year. Choosing between base years of 1750, 1900, 1950, and 1990 has a significant effect for most countries. Within the G8 group of countries, it is most significant for the UK, France and Germany. These countries have a long history of CO 2 emissions (see the section on Cumulative and historical emissions ). The Global Carbon Project continuously releases data about CO 2 emissions, budget and concentration. and industry (excluding cement carbonation) Gt C change Gt C Gt C Gt CO 2 (projection) Distribution of global greenhouse gas emissions based on type of greenhouse gas, without land-use change, using 100 year global warming potential (data from 2020). Total: 49.8 GtCO 2 e Carbon dioxide (CO 2 )

592-505: A result, the Sun emits shortwave radiation as sunlight while the Earth and its atmosphere emit longwave radiation . Sunlight includes ultraviolet , visible light , and near-infrared radiation. Sunlight is reflected and absorbed by the Earth and its atmosphere. The atmosphere and clouds reflect about 23% and absorb 23%. The surface reflects 7% and absorbs 48%. Overall, Earth reflects about 30% of

666-475: A significant contributor to warming. Although CFCs are greenhouse gases, they are regulated by the Montreal Protocol which was motivated by CFCs' contribution to ozone 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

740-457: 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. Other countries with fast growing emissions are South 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

814-434: A state of radiative equilibrium , in which the power of outgoing radiation equals the power of absorbed incoming radiation. Earth's energy imbalance is the amount by which the power of incoming sunlight absorbed by Earth's surface or atmosphere exceeds the power of outgoing longwave radiation emitted to space. Energy imbalance is the fundamental measurement that drives surface temperature. A UN presentation says "The EEI

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888-501: A temperature above absolute zero emit thermal radiation . The wavelengths of thermal radiation emitted by the Sun and Earth differ because their surface temperatures are different. The Sun has a surface temperature of 5,500 °C (9,900 °F), so it emits most of its energy as shortwave radiation in near-infrared and visible wavelengths (as sunlight). In contrast, Earth's surface has a much lower temperature, so it emits longwave radiation at mid- and far- infrared wavelengths. A gas

962-513: Is a greenhouse gas if it absorbs longwave radiation . Earth's atmosphere absorbs only 23% of incoming shortwave radiation, but absorbs 90% of the longwave radiation emitted by the surface, thus accumulating energy and warming the Earth's surface. The existence of the greenhouse effect, while not named as such, was proposed as early as 1824 by Joseph Fourier . The argument and the evidence were further strengthened by Claude Pouillet in 1827 and 1838. In 1856 Eunice Newton Foote demonstrated that

1036-450: Is a framework of methods to measure and track how much greenhouse gas an organization emits. Cumulative anthropogenic (i.e., human-emitted) emissions of CO 2 from fossil fuel use are a major cause of global warming , and give some indication of which countries have contributed most to human-induced climate change. In particular, CO 2 stays in the atmosphere for at least 150 years and up to 1000 years, whilst methane disappears within

1110-478: Is an associated effective emission temperature (or brightness temperature ). A given wavelength of radiation may also be said to have an effective emission altitude , which is a weighted average of the altitudes within the radiating layer. The effective emission temperature and altitude vary by wavelength (or frequency). This phenomenon may be seen by examining plots of radiation emitted to space. Earth's surface radiates longwave radiation with wavelengths in

1184-496: Is attributable mainly to increased atmospheric carbon dioxide levels. CO 2 is produced by fossil fuel burning and other activities such as cement production and tropical deforestation . Measurements of CO 2 from the Mauna Loa Observatory show that concentrations have increased from about 313 parts per million (ppm) in 1960, passing the 400 ppm milestone in 2013. The current observed amount of CO 2 exceeds

1258-440: Is because their molecules are symmetrical and so do not have a dipole moment.) Such gases make up more than 99% of the dry atmosphere. Greenhouse gases absorb and emit longwave radiation within specific ranges of wavelengths (organized as spectral lines or bands ). When greenhouse gases absorb radiation, they distribute the acquired energy to the surrounding air as thermal energy (i.e., kinetic energy of gas molecules). Energy

1332-465: Is because when these molecules vibrate , those vibrations modify the molecular dipole moment , or asymmetry in the distribution of electrical charge. See Infrared spectroscopy .) Gases with only one atom (such as argon, Ar) or with two identical atoms (such as nitrogen, N 2 , and oxygen, O 2 ) are not infrared active. They are transparent to longwave radiation, and, for practical purposes, do not absorb or emit longwave radiation. (This

1406-435: Is essential to the greenhouse effect. If the lapse rate was zero (so that the atmospheric temperature did not vary with altitude and was the same as the surface temperature) then there would be no greenhouse effect (i.e., its value would be zero). Greenhouse gases make the atmosphere near Earth's surface mostly opaque to longwave radiation. The atmosphere only becomes transparent to longwave radiation at higher altitudes, where

1480-421: Is exported. In comparison, methane has not increased appreciably, and N 2 O by 0.25% y . Using different base years for measuring emissions has an effect on estimates of national contributions to global warming. 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

1554-451: Is the dominant emitted greenhouse gas, while methane ( CH 4 ) emissions almost have the same short-term impact. Nitrous oxide (N 2 O) and fluorinated gases (F-gases) play a lesser role in comparison. Greenhouse gas emissions are measured in CO 2 equivalents determined by their global warming potential (GWP), which depends on their lifetime in the atmosphere. Estimations largely depend on

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1628-563: Is the first major source of greenhouse gas emissions from transportation, followed by aircraft and maritime. Waterborne transportation is still the least carbon-intensive mode of transportation on average, and it is an essential link in sustainable multimodal freight supply chains . Buildings, like industry, are directly responsible for around one-fifth of greenhouse gas emissions, primarily from space heating and hot water consumption. When combined with power consumption within buildings, this figure climbs to more than one-third. Within

1702-424: Is the most critical number defining the prospects for continued global warming and climate change." One study argues, "The absolute value of EEI represents the most fundamental metric defining the status of global climate change." Earth's energy imbalance (EEI) was about 0.7 W/m as of around 2015, indicating that Earth as a whole is accumulating thermal energy and is in a process of becoming warmer. Over 90% of

1776-476: Is the rate of energy flow per unit area. Energy flux is expressed in units of W/m , which is the number of joules of energy that pass through a square meter each second. Most fluxes quoted in high-level discussions of climate are global values, which means they are the total flow of energy over the entire globe, divided by the surface area of the Earth, 5.1 × 10  m (5.1 × 10  km ; 2.0 × 10  sq mi). The fluxes of radiation arriving at and leaving

1850-404: Is transferred from greenhouse gas molecules to other molecules via molecular collisions . Contrary to what is sometimes said, greenhouse gases do not "re-emit" photons after they are absorbed. Because each molecule experiences billions of collisions per second, any energy a greenhouse gas molecule receives by absorbing a photon will be redistributed to other molecules before there is a chance for

1924-665: Is very complex, and is affected by how carbon sinks are allocated between regions and the dynamics of the climate system . The graphic shows the logarithm of 1850–2019 fossil fuel CO 2 emissions; natural log on left, actual value of Gigatons per year on right. Although emissions increased during the 170-year period by about 3% per year overall, intervals of distinctly different growth rates (broken at 1913, 1945, and 1973) can be detected. The regression lines suggest that emissions can rapidly shift from one growth regime to another and then persist for long periods of time. The most recent drop in emissions growth – by almost 3 percentage points –

1998-468: The Department of Energy is designated as the lead agency. The following is a list of participating agencies. Greenhouse gas emissions Carbon dioxide (CO 2 ) is the main greenhouse gas resulting from human activities. It accounts for more than half of warming. Methane (CH 4 ) emissions have almost the same short-term impact. Nitrous oxide (N 2 O) and fluorinated gases (F-gases) play

2072-418: The fossil-fuel industry . The largest agricultural methane source is livestock . Agricultural soils emit nitrous oxide partly due to fertilizers . Similarly, fluorinated gases from refrigerants play an outsized role in total human emissions. The current CO 2 -equivalent emission rates averaging 6.6 tonnes per person per year, are well over twice the estimated rate 2.3 tons required to stay within

2146-407: The thermal inertia of the climate system resists changes both day and night, as well as for longer periods. Diurnal temperature changes decrease with height in the atmosphere. In the lower portion of the atmosphere, the troposphere , the air temperature decreases (or "lapses") with increasing altitude. The rate at which temperature changes with altitude is called the lapse rate . On Earth,

2220-520: The 2030 Paris Agreement increase of 1.5 °C (2.7 °F) over pre-industrial levels. 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. A 2017 survey of corporations responsible for global emissions found that 100 companies were responsible for 71% of global direct and indirect emissions , and that state-owned companies were responsible for 59% of their emissions. China is, by

2294-407: The 2030 Paris Agreement increase of 1.5 °C (2.7 °F) over pre-industrial levels. Annual per capita emissions in the industrialized countries are typically as much as ten times the average in developing countries. The carbon footprint (or greenhouse gas footprint ) serves as an indicator to compare the amount of greenhouse gases emitted over the entire life cycle from the production of

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2368-532: The 20th century average of about 14 °C (57 °F). In addition to naturally present greenhouse gases, burning of fossil fuels has increased amounts of carbon dioxide and methane in the atmosphere. As a result, global warming of about 1.2 °C (2.2 °F) has occurred since the Industrial Revolution , with the global average surface temperature increasing at a rate of 0.18 °C (0.32 °F) per decade since 1981. All objects with

2442-495: The EU, the agricultural sector presently accounts for roughly 10% of total greenhouse gas emissions, with methane from livestock accounting for slightly more than half of 10%. Estimates of total CO 2 emissions do include biotic carbon emissions, mainly from deforestation. Including biotic emissions brings about the same controversy mentioned earlier regarding carbon sinks and land-use change. The actual calculation of net emissions

2516-420: The Earth are important because radiative transfer is the only process capable of exchanging energy between Earth and the rest of the universe. The temperature of a planet depends on the balance between incoming radiation and outgoing radiation. If incoming radiation exceeds outgoing radiation, a planet will warm. If outgoing radiation exceeds incoming radiation, a planet will cool. A planet will tend towards

2590-474: The Earth can cool off. The major anthropogenic (human origin) sources of greenhouse gases are carbon dioxide (CO 2 ), nitrous oxide ( N 2 O ), methane and three groups of fluorinated gases ( sulfur hexafluoride ( SF 6 ), hydrofluorocarbons (HFCs) and perfluorocarbons (PFCs, sulphur hexafluoride (SF 6 ), and nitrogen trifluoride (NF 3 )). Though the greenhouse effect is heavily driven by water vapor , human emissions of water vapor are not

2664-443: The Earth's surface than reaches space. Currently, longwave radiation leaves the surface at an average rate of 398 W/m , but only 239 W/m reaches space. Thus, the Earth's greenhouse effect can also be measured as an energy flow change of 159 W/m . The greenhouse effect can be expressed as a fraction (0.40) or percentage (40%) of the longwave thermal radiation that leaves Earth's surface but does not reach space. Whether

2738-404: The Earth's surface. In response, the Earth's surface emits longwave radiation that is mostly absorbed by greenhouse gases. The absorption of longwave radiation prevents it from reaching space, reducing the rate at which the Earth can cool off. Without the greenhouse effect, the Earth's average surface temperature would be as cold as −18 °C (−0.4 °F). This is of course much less than

2812-451: The Earth’s surface and elsewhere in the atmosphere." The enhanced greenhouse effect describes the fact that by increasing the concentration of GHGs in the atmosphere (due to human action), the natural greenhouse effect is increased. The term greenhouse effect comes from an analogy to greenhouses . Both greenhouses and the greenhouse effect work by retaining heat from sunlight, but

2886-712: 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%. The European Commission adopted a set of legislative proposals targeting a reduction of the CO 2 emissions by 55% by 2030. Overall, developed countries accounted for 83.8% of industrial CO 2 emissions over this time period, and 67.8% of total CO 2 emissions. Developing countries accounted for industrial CO 2 emissions of 16.2% over this time period, and 32.2% of total CO 2 emissions. However, what becomes clear when we look at emissions across

2960-548: The US are gradually decreasing over time. Emissions in Russia and Ukraine have decreased fastest since 1990 due to economic restructuring in these countries. 2015 was the first year to see both total global economic growth and a reduction of carbon emissions. Annual per capita emissions in the industrialized countries are typically as much as ten times the average in developing countries. Due to China's fast economic development, its annual per capita emissions are quickly approaching

3034-419: The ability of oceans and land sinks to absorb these gases. Short-lived climate pollutants (SLCPs) including methane, hydrofluorocarbons (HFCs) , tropospheric ozone and black carbon persist in the atmosphere for a period ranging from days to 15 years; whereas carbon dioxide can remain in the atmosphere for millennia. Reducing SLCP emissions can cut the ongoing rate of global warming by almost half and reduce

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3108-471: The air is less dense, there is less water vapor, and reduced pressure broadening of absorption lines limits the wavelengths that gas molecules can absorb. For any given wavelength, the longwave radiation that reaches space is emitted by a particular radiating layer of the atmosphere. The intensity of the emitted radiation is determined by the weighted average air temperature within that layer. So, for any given wavelength of radiation emitted to space, there

3182-416: The air temperature decreases by about 6.5 °C/km (3.6 °F per 1000 ft), on average, although this varies. The temperature lapse is caused by convection . Air warmed by the surface rises. As it rises, air expands and cools . Simultaneously, other air descends, compresses, and warms. This process creates a vertical temperature gradient within the atmosphere. This vertical temperature gradient

3256-463: The case of Jupiter , or from its host star as in the case of the Earth . In the case of Earth, the Sun emits shortwave radiation ( sunlight ) that passes through greenhouse gases to heat the Earth's surface. In response, the Earth's surface emits longwave radiation that is mostly absorbed by greenhouse gases. The absorption of longwave radiation prevents it from reaching space, reducing the rate at which

3330-667: 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. The main sources of greenhouse gases due to human activity (also called carbon sources ) are: Global greenhouse gas emissions are about 50 Gt per year and for 2019 have been estimated at 57 Gt CO 2 eq including 5 Gt due to land use change. In 2019, approximately 34% [20 GtCO 2 -eq] of total net anthropogenic GHG emissions came from

3404-439: The concentration of the gases increases the amount of absorption and emission, and thereby causing more heat to be retained at the surface and in the layers below. The power of outgoing longwave radiation emitted by a planet corresponds to the effective temperature of the planet. The effective temperature is the temperature that a planet radiating with a uniform temperature (a blackbody ) would need to have in order to radiate

3478-410: The decreasing concentration of water vapor, an important greenhouse gas. Rather than thinking of longwave radiation headed to space as coming from the surface itself, it is more realistic to think of this outgoing radiation as being emitted by a layer in the mid- troposphere , which is effectively coupled to the surface by a lapse rate . The difference in temperature between these two locations explains

3552-413: 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

3626-689: The difference between surface emissions and emissions to space, i.e., it explains the greenhouse effect. A greenhouse gas (GHG) is a gas which contributes to the trapping of heat by impeding the flow of longwave radiation out of a planet's atmosphere. Greenhouse gases contribute most of the greenhouse effect in Earth's energy budget . Gases which can absorb and emit longwave radiation are said to be infrared active and act as greenhouse gases. Most gases whose molecules have two different atoms (such as carbon monoxide, CO ), and all gases with three or more atoms (including H 2 O and CO 2 ), are infrared active and act as greenhouse gases. (Technically, this

3700-481: The dip in outgoing radiation (and associated rise in the greenhouse effect) at around 667 cm (equivalent to a wavelength of 15 microns). Each layer of the atmosphere with greenhouse gases absorbs some of the longwave radiation being radiated upwards from lower layers. It also emits longwave radiation in all directions, both upwards and downwards, in equilibrium with the amount it has absorbed. This results in less radiative heat loss and more warmth below. Increasing

3774-440: The energy supply sector, 24% [14 GtCO 2 -eq] from industry, 22% [13 GtCO 2 -eq]from agriculture, forestry and other land use (AFOLU), 15% [8.7 GtCO 2 -eq] from transport and 6% [3.3 GtCO 2 -eq] from buildings. Global carbon dioxide emissions by country in 2023: The current CO 2 -equivalent emission rates averaging 6.6 tonnes per person per year, are well over twice the estimated rate 2.3 tons required to stay within

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3848-399: The evidence were further strengthened by Claude Pouillet in 1827 and 1838. In 1856 Eunice Newton Foote demonstrated that the warming effect of the sun is greater for air with water vapour than for dry air, and the effect is even greater with carbon dioxide. She concluded that "An atmosphere of that gas would give to our earth a high temperature..." John Tyndall was the first to measure

3922-553: The first quantitative prediction of global warming due to a hypothetical doubling of atmospheric carbon dioxide. The term greenhouse was first applied to this phenomenon by Nils Gustaf Ekholm in 1901. Matter emits thermal radiation at a rate that is directly proportional to the fourth power of its temperature . Some of the radiation emitted by the Earth's surface is absorbed by greenhouse gases and clouds. Without this absorption, Earth's surface would have an average temperature of −18 °C (−0.4 °F). However, because some of

3996-431: The geological record maxima (≈300 ppm) from ice core data. Over the past 800,000 years, ice core data shows that carbon dioxide has varied from values as low as 180 ppm to the pre-industrial level of 270 ppm. Paleoclimatologists consider variations in carbon dioxide concentration to be a fundamental factor influencing climate variations over this time scale. Hotter matter emits shorter wavelengths of radiation. As

4070-497: The greenhouse effect is expressed as a change in temperature or as a change in longwave thermal radiation, the same effect is being measured. Strengthening of the greenhouse effect through additional greenhouse gases from human activities is known as the enhanced greenhouse effect . As well as being inferred from measurements by ARGO , CERES and other instruments throughout the 21st century, this increase in radiative forcing from human activity has been observed directly, and

4144-824: The importing country, rather than the exporting, country. A substantial proportion of CO 2 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. 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. Emission intensities may be calculated using market exchange rates (MER) or purchasing power parity (PPP). Calculations based on MER show large differences in intensities between developed and developing countries, whereas calculations based on PPP show smaller differences. Carbon accounting (or greenhouse gas accounting)

4218-483: The incoming sunlight, and absorbs the rest (240 W/m ). The Earth and its atmosphere emit longwave radiation , also known as thermal infrared or terrestrial radiation . Informally, longwave radiation is sometimes called thermal radiation . Outgoing longwave radiation (OLR) is the radiation from Earth and its atmosphere that passes through the atmosphere and into space. The greenhouse effect can be directly seen in graphs of Earth's outgoing longwave radiation as

4292-402: The infrared absorption and emission of various gases and vapors. From 1859 onwards, he showed that the effect was due to a very small proportion of the atmosphere, with the main gases having no effect, and was largely due to water vapor, though small percentages of hydrocarbons and carbon dioxide had a significant effect. The effect was more fully quantified by Svante Arrhenius in 1896, who made

4366-468: The lapse of formerly declining trends in carbon 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 more efficient energy use , made necessary by the increasing proportion of it that

4440-707: The levels of those in the Annex I group of the Kyoto Protocol (i.e., the developed countries excluding the US). 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. There are several ways of measuring greenhouse gas emissions. Some variables that have been reported include: These measures are sometimes used by countries to assert various policy/ethical positions on climate change. The use of different measures leads to

4514-496: The main international treaty on climate change (the UNFCCC ), countries report on emissions produced within their borders, e.g., the emissions produced from burning fossil fuels. 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

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4588-456: The major source of greenhouse gas emissions in the EU . 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 passenger vehicles and vans. Road travel

4662-492: The projected Arctic warming by two-thirds. Greenhouse effect The greenhouse effect occurs when greenhouse gases in a planet's atmosphere insulate the planet from losing heat to space, raising its surface temperature. Surface heating can happen from an internal heat source as in the case of Jupiter , or from its host star as in the case of the Earth . In the case of Earth, the Sun emits shortwave radiation ( sunlight ) that passes through greenhouse gases to heat

4736-418: The radiation is absorbed, Earth's average surface temperature is around 15 °C (59 °F). Thus, the Earth's greenhouse effect may be measured as a temperature change of 33 °C (59 °F). Thermal radiation is characterized by how much energy it carries, typically in watts per square meter (W/m ). Scientists also measure the greenhouse effect based on how much more longwave thermal radiation leaves

4810-422: The range of 4–100 microns. Greenhouse gases that were largely transparent to incoming solar radiation are more absorbent for some wavelengths in this range. The atmosphere near the Earth's surface is largely opaque to longwave radiation and most heat loss from the surface is by evaporation and convection . However radiative energy losses become increasingly important higher in the atmosphere, largely because of

4884-408: The retained energy goes into warming the oceans, with much smaller amounts going into heating the land, atmosphere, and ice. A simple picture assumes a steady state, but in the real world, the day/night ( diurnal ) cycle, as well as the seasonal cycle and weather disturbances, complicate matters. Solar heating applies only during daytime. At night the atmosphere cools somewhat, but not greatly because

4958-474: The same amount of energy. This concept may be used to compare the amount of longwave radiation emitted to space and the amount of longwave radiation emitted by the surface: Earth's surface temperature is often reported in terms of the average near-surface air temperature. This is about 15 °C (59 °F), a bit lower than the effective surface temperature. This value is 33 °C (59 °F) warmer than Earth's overall effective temperature. Energy flux

5032-607: The summit of the United Nations Environment Programme reached a legally binding accord to phase out hydrofluorocarbons (HFCs) in the Kigali Amendment to the Montreal Protocol . The use of CFC-12 (except some essential uses) has been phased out due to its ozone depleting properties. The phasing-out of less active HCFC-compounds will be completed in 2030. Starting about 1750, industrial activity powered by fossil fuels began to significantly increase

5106-468: The warming effect of the sun is greater for air with water vapour than for dry air, and the effect is even greater with carbon dioxide. The term greenhouse was first applied to this phenomenon by Nils Gustaf Ekholm in 1901. The greenhouse effect on Earth is defined as: "The infrared radiative effect of all infrared absorbing constituents in the atmosphere. Greenhouse gases (GHGs), clouds , and some aerosols absorb terrestrial radiation emitted by

5180-423: The way they retain heat differs. Greenhouses retain heat mainly by blocking convection (the movement of air). In contrast, the greenhouse effect retains heat by restricting radiative transfer through the air and reducing the rate at which thermal radiation is emitted into space. The existence of the greenhouse effect, while not named as such, was proposed as early as 1824 by Joseph Fourier . The argument and

5254-452: 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. In comparison, humans have emitted more greenhouse gases than the Chicxulub meteorite impact event which caused the extinction of the dinosaurs . Transport, together with electricity generation , is

5328-582: The year 1995). 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. Per capita emissions may be based on historical or annual emissions. One way of attributing greenhouse gas emissions is to measure the embedded emissions (also referred to as "embodied emissions") of goods that are being consumed. Emissions are usually measured according to production, rather than consumption. For example, in

5402-406: Was at about the time of the 1970s energy crisis . Percent changes per year were estimated by piecewise linear regression on the log data and are shown on the plot; the data are from The Integrated Carbon Observation system. The sharp acceleration in CO 2 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

5476-569: Was occurring within a country, so more operational factories would increase carbon emission levels. 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 the United Nations Framework Convention on Climate Change (UNFCCC) as the base year for emissions, and is also used in the Kyoto Protocol (some gases are also measured from

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