# 地球能量收支

Earth's climate is largely determined by the planet's energy budget, i.e., the balance of incoming and outgoing radiation. It is measured by satellites and shown in W/m2.[1]

Earth's energy budget accounts for the balance between the energy that Earth receives from the Sun and the energy the Earth loses back into outer space. Smaller energy sources, such as Earth's internal heat, are taken into consideration, but make a tiny contribution compared to solar energy. The energy budget also accounts for how energy moves through the climate system.[2] Because the Sun heats the equatorial tropics more than the polar regions, received solar irradiance is unevenly distributed. As the energy seeks equilibrium across the planet, it drives interactions in Earth's climate system, i.e., Earth's water, ice, atmosphere, rocky crust, and all living things.[3] The result is Earth's climate.

Earth's energy budget accounts for the balance between the energy that Earth receives from the Sun and the energy the Earth loses back into outer space. Smaller energy sources, such as Earth's internal heat, are taken into consideration, but make a tiny contribution compared to solar energy. The energy budget also accounts for how energy moves through the climate system. "energy budget" Because the Sun heats the equatorial tropics more than the polar regions, received solar irradiance is unevenly distributed. As the energy seeks equilibrium across the planet, it drives interactions in Earth's climate system, i.e., Earth's water, ice, atmosphere, rocky crust, and all living things. "climate system" The result is Earth's climate.

Earth's energy budget depends on many factors, such as atmospheric aerosols, greenhouse gases, the planet's surface albedo (reflectivity), clouds, vegetation, land use patterns, and more. When the incoming and outgoing energy fluxes are in balance, Earth is in radiative equilibrium and the climate system will be relatively stable. Global warming occurs when earth receives more energy than it gives back to space, and global cooling takes place when the outgoing energy is greater.[4] Multiple types of measurements and observations show a warming imbalance since at least year 1970.[5][6] The rate of heating from this human-caused event is without precedence.[7]

Earth's energy budget depends on many factors, such as atmospheric aerosols, greenhouse gases, the planet's surface albedo (reflectivity), clouds, vegetation, land use patterns, and more. When the incoming and outgoing energy fluxes are in balance, Earth is in radiative equilibrium and the climate system will be relatively stable. Global warming occurs when earth receives more energy than it gives back to space, and global cooling takes place when the outgoing energy is greater. Multiple types of measurements and observations show a warming imbalance since at least year 1970. The rate of heating from this human-caused event is without precedence.

When the energy budget changes, there is a delay before average global surface temperature changes significantly. This is due to the thermal inertia of the oceans, land and cryosphere.[8] Accurate quantification of these energy flows and storage amounts is a requirement within most climate models.

When the energy budget changes, there is a delay before average global surface temperature changes significantly. This is due to the thermal inertia of the oceans, land and cryosphere. Accurate quantification of these energy flows and storage amounts is a requirement within most climate models.

## Earth's energy flows

Incoming, top-of-atmosphere (TOA) shortwave flux radiation, shows energy received from the sun (26–27 Jan 2012).

In spite of the enormous transfers of energy into and from the Earth, it maintains a relatively constant temperature because, as a whole, there is little net gain or loss: Earth emits via atmospheric and terrestrial radiation (shifted to longer electromagnetic wavelengths) to space about the same amount of energy as it receives via solar insolation (all forms of electromagnetic radiation).

thumb|upright=1.3|Incoming, top-of-atmosphere (TOA) shortwave flux radiation, shows energy received from the sun (26–27 Jan 2012). In spite of the enormous transfers of energy into and from the Earth, it maintains a relatively constant temperature because, as a whole, there is little net gain or loss: Earth emits via atmospheric and terrestrial radiation (shifted to longer electromagnetic wavelengths) to space about the same amount of energy as it receives via solar insolation (all forms of electromagnetic radiation).

= = = 地球能量流 = = 拇指 | 竖直 = 1.3 | 入射的大气顶部短波通量辐射，显示了从太阳接收到的能量(2012年1月26日至27日)。尽管有大量能量进出地球，但地球的温度保持相对恒定，因为总体而言，净增益或净损失很小: 地球通过大气和地面辐射向太空释放的能量(转换为更长的电磁波长)与通过太阳辐射(所有形式的电磁辐射)接收的能量大致相同。

The total amount of energy received per second at the top of Earth's atmosphere (TOA) is measured in watts and is given by the solar constant times the cross-sectional area of the Earth corresponded to the radiation. Because the surface area of a sphere is four times the cross-sectional area of a sphere (i.e. the area of a circle), the globally and yearly averaged TOA flux is one quarter of the solar constant and so is approximately 340 watts per square meter (W/m2).[1][9] Since the absorption varies with location as well as with diurnal, seasonal and annual variations, the numbers quoted are multi-year averages obtained from multiple satellite measurements.[1]

The total amount of energy received per second at the top of Earth's atmosphere (TOA) is measured in watts and is given by the solar constant times the cross-sectional area of the Earth corresponded to the radiation. Because the surface area of a sphere is four times the cross-sectional area of a sphere (i.e. the area of a circle), the globally and yearly averaged TOA flux is one quarter of the solar constant and so is approximately 340 watts per square meter (W/m2). Since the absorption varies with location as well as with diurnal, seasonal and annual variations, the numbers quoted are multi-year averages obtained from multiple satellite measurements.

= = = 入射辐射能(短波) = = = 地球大气层顶部每秒接收的总能量(TOA)以瓦为单位，用太阳常数乘以地球截面积与辐射相对应的面积得出。因为一个球体的表面积是一个球体横截面积的四倍(即。圆的面积) ，全球和年平均 TOA 通量是太阳常数的四分之一，因此大约是每平方米340瓦(w/m2)。由于吸收随地点以及日变化、季节变化和年变化而变化，所引用的数字是多次卫星测量得到的多年平均值。

Of the ~340 W/m2 of solar radiation received by the Earth, an average of ~77 W/m2 is reflected back to space by clouds and the atmosphere and ~23 W/m2 is reflected by the surface albedo, leaving ~240 W/m2 of solar energy input to the Earth's energy budget. This amount is called the absorbed solar radiation (ASR). It implies a mean net albedo for Earth (specifically, its Bond albedo) of 0.306.[1]

Of the ~340 W/m2 of solar radiation received by the Earth, an average of ~77 W/m2 is reflected back to space by clouds and the atmosphere and ~23 W/m2 is reflected by the surface albedo, leaving ~240 W/m2 of solar energy input to the Earth's energy budget. This amount is called the absorbed solar radiation (ASR). It implies a mean net albedo for Earth (specifically, its Bond albedo) of 0.306.

Outgoing, longwave flux radiation at the top-of-atmosphere (26–27 Jan 2012). Heat energy radiated from Earth (in watts per square metre) is shown in shades of yellow, red, blue and white. The brightest-yellow areas are the hottest and are emitting the most energy out to space, while the dark blue areas and the bright white clouds are much colder, emitting the least energy.

thumb|upright=1.3|Outgoing, longwave flux radiation at the top-of-atmosphere (26–27 Jan 2012). Heat energy radiated from Earth (in watts per square metre) is shown in shades of yellow, red, blue and white. The brightest-yellow areas are the hottest and are emitting the most energy out to space, while the dark blue areas and the bright white clouds are much colder, emitting the least energy.

= = = 地球长波辐射 = = = 拇指 | 竖直 = 1.3 | 大气层顶部向外的长波通量辐射(2012年1月26-27日)。地球辐射的热能(每平方米瓦特)以黄色、红色、蓝色和白色的阴影显示。最亮的黄色区域是最热的，向太空释放的能量最多，而深蓝色区域和明亮的白色云层则要冷得多，释放的能量最少。

Outgoing longwave radiation (OLR) is usually defined as outgoing energy leaving the planet, most of which is in the infrared band. Generally, absorbed solar energy is converted to different forms of heat energy. Some of this energy is emitted as OLR directly to space, while the rest is first transported through the climate system as radiant and other forms of thermal energy. For example, indirect emissions occur following heat transport from the planet's surface layers (land and ocean) to the atmosphere via evapotranspiration and latent heat fluxes or conduction/convection processes.[1] Ultimately, all of outgoing energy is radiated in the form of longwave radiation back into space.

Outgoing longwave radiation (OLR) is usually defined as outgoing energy leaving the planet, most of which is in the infrared band. Generally, absorbed solar energy is converted to different forms of heat energy. Some of this energy is emitted as OLR directly to space, while the rest is first transported through the climate system as radiant and other forms of thermal energy. For example, indirect emissions occur following heat transport from the planet's surface layers (land and ocean) to the atmosphere via evapotranspiration and latent heat fluxes or conduction/convection processes. Ultimately, all of outgoing energy is radiated in the form of longwave radiation back into space.

Despite multiple other influences, the Stefan-Boltzmann law of radiation describes the fundamental dependence of OLR upon Earth's surface skin temperature (Tskin):

$\displaystyle{ OLR = \sigma T_{skin}^{4}. }$

Tskin has been globally measured from satellite observations of OLR in the infrared and microwave bands, and is approximated by in-situ surface temperatures.[10] The strong (fourth-power) temperature sensitivity acts to maintain a near-balance of the outgoing energy flow to the incoming flow via small changes in absolute temperature.

Despite multiple other influences, the Stefan-Boltzmann law of radiation describes the fundamental dependence of OLR upon Earth's surface skin temperature (Tskin):

OLR = \sigma T_{skin}^{4}.

Tskin has been globally measured from satellite observations of OLR in the infrared and microwave bands, and is approximated by in-situ surface temperatures. The strong (fourth-power) temperature sensitivity acts to maintain a near-balance of the outgoing energy flow to the incoming flow via small changes in absolute temperature.

$\displaystyle{ OLR = \sigma T_{skin}^{4}. }$ 。通过对 OLR 的红外和微波波段的卫星观测，对 Tskin 进行了全球测量，并用地表温度进行了近似计算。强大的(四次方)温度敏感性行为，以保持一个近乎平衡的能量流出的流入通过微小的变化，在绝对温度。

### Earth's internal heat sources and other small effects

The geothermal heat flow from the Earth's interior is estimated to be 47 terawatts (TW)[11] and split approximately equally between radiogenic heat and heat left over from the Earth's formation. This corresponds to an average flux of 0.087 W/m2 and represents only 0.027% of Earth's total energy budget at the surface, being dwarfed by the 173,000 TW of incoming solar radiation.[12]

The geothermal heat flow from the Earth's interior is estimated to be 47 terawatts (TW) and split approximately equally between radiogenic heat and heat left over from the Earth's formation. This corresponds to an average flux of 0.087 W/m2 and represents only 0.027% of Earth's total energy budget at the surface, being dwarfed by the 173,000 TW of incoming solar radiation.

Human production of energy is even lower at an estimated 160,000 TW-hr for all of year 2019. This corresponds to an average continuous heat flow of about 18 TW.[13]

Human production of energy is even lower at an estimated 160,000 TW-hr for all of year 2019. This corresponds to an average continuous heat flow of about 18 TW.

2019年全年，人类的能源产量估计为每小时160000 TW-hr，甚至更低。这相当于大约18太瓦的平均连续热流。

Photosynthesis has a larger effect: An estimated 140 TW (or around 0.08%) of incident energy gets captured by photosynthesis, giving energy to plants to produce biomass.[14] A similar flow of thermal energy is released over the course of a year when plants are used as food or fuel.

Photosynthesis has a larger effect: An estimated 140 TW (or around 0.08%) of incident energy gets captured by photosynthesis, giving energy to plants to produce biomass. A similar flow of thermal energy is released over the course of a year when plants are used as food or fuel.

Other minor sources of energy are usually ignored in the calculations, including accretion of interplanetary dust and solar wind, light from stars other than the Sun and the thermal radiation from space. Earlier, Joseph Fourier had claimed that deep space radiation was significant in a paper often cited as the first on the greenhouse effect.[15]

Other minor sources of energy are usually ignored in the calculations, including accretion of interplanetary dust and solar wind, light from stars other than the Sun and the thermal radiation from space. Earlier, Joseph Fourier had claimed that deep space radiation was significant in a paper often cited as the first on the greenhouse effect.

## Budget analysis

A Sankey diagram illustrating the Earth's energy budget described in this section – line thickness is linearly proportional to relative amount of energy.[16]

In simplest terms, Earth's energy budget is balanced when the incoming flow equals the outgoing flow. Since a portion of incoming energy is directly reflected, the balance can also be stated as absorbed incoming solar (shortwave) radiation equal to outgoing longwave radiation:

$\displaystyle{ ASR = OLR. }$

In simplest terms, Earth's energy budget is balanced when the incoming flow equals the outgoing flow. Since a portion of incoming energy is directly reflected, the balance can also be stated as absorbed incoming solar (shortwave) radiation equal to outgoing longwave radiation:

ASR = OLR.

### Internal flow analysis

To describe some of the internal flows within the budget, let the insolation received at the top of the atmosphere be 100 units (=340 W/m2), as shown in the accompanying Sankey diagram. Called the albedo of Earth, around 35 units in this example are directly reflected back to space: 27 from the top of clouds, 2 from snow and ice-covered areas, and 6 by other parts of the atmosphere. The 65 remaining units (ASR=220 W/m2) are absorbed: 14 within the atmosphere and 51 by the Earth's surface.

To describe some of the internal flows within the budget, let the insolation received at the top of the atmosphere be 100 units (=340 W/m2), as shown in the accompanying Sankey diagram. Called the albedo of Earth, around 35 units in this example are directly reflected back to space: 27 from the top of clouds, 2 from snow and ice-covered areas, and 6 by other parts of the atmosphere. The 65 remaining units (ASR=220 W/m2) are absorbed: 14 within the atmosphere and 51 by the Earth's surface.

= = = 内部流动分析 = = = 为了描述预算内的一些内部流动，设大气层顶部收到的日照为100单位(= 340 w/m2) ，如附带的桑基图所示。在这个例子中，被称为地球反照率的大约35个单位被直接反射回太空: 27个单位来自云层顶部，2个单位来自冰雪覆盖的地区，6个单位来自大气的其他部分。其余65个单位(ASR = 220 w/m2)被吸收: 14个在大气层内，51个在地球表面。

The 51 units reaching and absorbed by the surface are emitted back to space through various forms of terrestrial energy: 17 directly radiated to space and 34 absorbed by the atmosphere (19 through latent heat of vaporisation, 9 via convection and turbulence, and 6 as absorbed infrared by greenhouse gases). The 48 units absorbed by the atmosphere (34 units from terrestrial energy and 14 from insolation) are then finally radiated back to space. This simplified example neglects mechanisms that recirculate, store, and thus lead to further buildup of heat near the surface.

The 51 units reaching and absorbed by the surface are emitted back to space through various forms of terrestrial energy: 17 directly radiated to space and 34 absorbed by the atmosphere (19 through latent heat of vaporisation, 9 via convection and turbulence, and 6 as absorbed infrared by greenhouse gases). The 48 units absorbed by the atmosphere (34 units from terrestrial energy and 14 from insolation) are then finally radiated back to space. This simplified example neglects mechanisms that recirculate, store, and thus lead to further buildup of heat near the surface.

Ultimately the 65 units (17 from the ground and 48 from the atmosphere) are emitted as OLR. They approximately balance the 65 units (ASR) absorbed from the sun in order to maintain a net-zero gain of energy by Earth.[16]

Ultimately the 65 units (17 from the ground and 48 from the atmosphere) are emitted as OLR. They approximately balance the 65 units (ASR) absorbed from the sun in order to maintain a net-zero gain of energy by Earth.

### Role of the greenhouse effect

The greenhouse effect traps infrared heat, and ultimately raises Earth's surface temperatures.

The major atmospheric gases (oxygen and nitrogen) are transparent to incoming sunlight but are also transparent to outgoing longwave (thermal/infrared) radiation. However, water vapor, carbon dioxide, methane and other trace gases are opaque to many wavelengths of thermal radiation.[17]

thumb|upright=1.35|right|The greenhouse effect traps infrared heat, and ultimately raises Earth's surface temperatures.

The major atmospheric gases (oxygen and nitrogen) are transparent to incoming sunlight but are also transparent to outgoing longwave (thermal/infrared) radiation. However, water vapor, carbon dioxide, methane and other trace gases are opaque to many wavelengths of thermal radiation.

= = = 温室效应的作用 = = = 拇指 | 直立 = 1.35 | 右 | 温室效应捕获红外线热量，并最终提高地球表面温度。大气中的主要气体(氧气和氮气)对入射的阳光是透明的，但对出射的长波(热/红外线)辐射也是透明的。然而，水蒸气、二氧化碳、甲烷和其他示踪气体对于许多波长的热辐射是不透明的。

When greenhouse gas molecules absorb thermal infrared energy, their temperature rises. Those gases then radiate an increased amount of thermal infrared energy in all directions. Heat radiated upward continues to encounter greenhouse gas molecules; those molecules also absorb the heat, and their temperature rises and the amount of heat they radiate increases. The atmosphere thins with altitude, and at roughly 5–6 kilometres, the concentration of greenhouse gases in the overlying atmosphere is so thin that heat can escape to space.[17]

When greenhouse gas molecules absorb thermal infrared energy, their temperature rises. Those gases then radiate an increased amount of thermal infrared energy in all directions. Heat radiated upward continues to encounter greenhouse gas molecules; those molecules also absorb the heat, and their temperature rises and the amount of heat they radiate increases. The atmosphere thins with altitude, and at roughly 5–6 kilometres, the concentration of greenhouse gases in the overlying atmosphere is so thin that heat can escape to space.

Because greenhouse gas molecules radiate infrared energy in all directions, some of it spreads downward and ultimately returns to the Earth's surface, where it is absorbed. The Earth's surface temperature is thus higher than it would be if it were heated only by direct solar heating. This supplemental heating is the natural greenhouse effect.[17] It is as if the Earth is covered by a blanket that allows high frequency radiation (sunlight) to enter, but slows the rate at which the longwave infrared radiation leaves.

Because greenhouse gas molecules radiate infrared energy in all directions, some of it spreads downward and ultimately returns to the Earth's surface, where it is absorbed. The Earth's surface temperature is thus higher than it would be if it were heated only by direct solar heating. This supplemental heating is the natural greenhouse effect. It is as if the Earth is covered by a blanket that allows high frequency radiation (sunlight) to enter, but slows the rate at which the longwave infrared radiation leaves.

Ultimately, the surface temperature rises until the ASR = OLR balance is restored.

Ultimately, the surface temperature rises until the ASR = OLR balance is restored.

### Heat storage reservoirs

The rising accumulation of thermal energy in the oceanic, land, ice, and atmospheric components of Earth's climate system since 1960.[6]

Land, ice, and oceans are active material constituents of Earth's climate system along with the atmosphere. They have far greater mass and heat capacity, and thus much more thermal inertia. When radiation is directly absorbed or the surface temperature changes, thermal energy will flow either into or out of the bulk mass of these components via additional heat transfer processes like conduction and convection. Such flows partially counteract the more rapid changes from solar-driven radiative processes in the atmosphere. As a result, the daytime versus nightime difference in surface temperatures is reduced, and the Earth system exhibits climate inertia over the long term.[18]

thumb|320px|The rising accumulation of thermal energy in the oceanic, land, ice, and atmospheric components of Earth's climate system since 1960. Land, ice, and oceans are active material constituents of Earth's climate system along with the atmosphere. They have far greater mass and heat capacity, and thus much more thermal inertia. When radiation is directly absorbed or the surface temperature changes, thermal energy will flow either into or out of the bulk mass of these components via additional heat transfer processes like conduction and convection. Such flows partially counteract the more rapid changes from solar-driven radiative processes in the atmosphere. As a result, the daytime versus nightime difference in surface temperatures is reduced, and the Earth system exhibits climate inertia over the long term.

The top few meters of Earth's oceans harbor more thermal energy than its entire atmosphere.[19] Like atmospheric gases, fluidic ocean waters transport vast amounts of thermal energy over the planet's surface. Heat is also distributed into and out of great depths under conditions that favor downwelling or upwelling.[20][21]

The top few meters of Earth's oceans harbor more thermal energy than its entire atmosphere. Like atmospheric gases, fluidic ocean waters transport vast amounts of thermal energy over the planet's surface. Heat is also distributed into and out of great depths under conditions that favor downwelling or upwelling.

Over 90 percent of the heat that has accumulated on Earth from ongoing global warming since 1970 has been stored in the ocean.[19] About one-third of this energy has propagated to depths below 700 meters. The overall rate of growth has also risen during recent decades, reaching close to 500 TW (1 W/m2) as of 2020.[6][22] That led to about 14 zettajoules (ZJ) of heat gain, exceeding all other human production of energy by a factor of 20 for the year.[23]

Over 90 percent of the heat that has accumulated on Earth from ongoing global warming since 1970 has been stored in the ocean. About one-third of this energy has propagated to depths below 700 meters. The overall rate of growth has also risen during recent decades, reaching close to 500 TW (1 W/m2) as of 2020. That led to about 14 zettajoules (ZJ) of heat gain, exceeding all other human production of energy by a factor of 20 for the year.

### Heating/cooling rate analysis

Generally speaking, changes to Earth's energy flux balance can be thought of as being the result of external forcings (both natural and anthropogenic, radiative and non-radiative), system feedbacks, and internal system variability.[24] Such changes are primarily expressed as observable shifts in temperature (T), clouds (C), water vapor (W), aerosols (A), trace greenhouse gases (G), land/ocean/ice surface reflectance (S), and as minor shifts in insolaton (I) among other possible factors. Earth's heating/cooling rate (ΔE) can then be analyzed over selected timeframes as the net change in energy associated with these attributes:

$\displaystyle{ \Delta E = \Delta E_T + \Delta E_C + \Delta E_W + \Delta E_A + \Delta E_G + \Delta E_S + \Delta E_I +... = ASR - OLR }$.

Here the term ΔET is negative-valued when temperature rises due to the strong direct influence on OLR.[25][22]

Generally speaking, changes to Earth's energy flux balance can be thought of as being the result of external forcings (both natural and anthropogenic, radiative and non-radiative), system feedbacks, and internal system variability. Such changes are primarily expressed as observable shifts in temperature (T), clouds (C), water vapor (W), aerosols (A), trace greenhouse gases (G), land/ocean/ice surface reflectance (S), and as minor shifts in insolaton (I) among other possible factors. Earth's heating/cooling rate (ΔE) can then be analyzed over selected timeframes as the net change in energy associated with these attributes:

\Delta E = \Delta E_T + \Delta E_C + \Delta E_W + \Delta E_A + \Delta E_G + \Delta E_S + \Delta E_I +... = ASR - OLR.

Here the term ΔET is negative-valued when temperature rises due to the strong direct influence on OLR.

= = = = 加热/冷却速率分析 = = = 一般而言，地球能量通量平衡的变化可以被认为是外部强迫(自然和人为的，辐射和非辐射的)、系统反馈和内部系统变化的结果。这些变化主要表现为温度(t)、云(c)、水汽(w)、气溶胶(a)、微量温室气体(g)、陆地/海洋/冰面反射率(s)的可观测变化，以及日照(i)等可能因素的微小变化。地球的加热/冷却速率(ΔE)可以随着与这些属性有关的能量的净变化在选定的时间框架内进行分析: Delta e = ΔE _ t + ΔE _ c + ΔE _ w + ΔE _ a + ΔE _ g + ΔE _ s + ΔE _ i + ... = ASR-OLR。这里 ΔET 项在温度升高时为负值，因为它对 OLR 有很强的直接影响。

The recent increase in trace greenhouse gases produces an enhanced greenhouse effect, and thus a positive ΔEG forcing term. By contrast, a large volcanic eruption (e.g. Mount Pinatubo 1991, El Chichón 1982) can inject sulfur-containing compounds into the upper atmosphere. High concentrations of stratospheric sulfur aerosols may persist for up to a few years, yielding a negative forcing contribution to ΔEA.[26][27] Various other types of anthropogenic aerosol emissions make both positive and negative contributions to ΔEA. Solar cycles produce ΔEI smaller in magnitude than those of recent ΔEG trends from human activity.[28][29]

The recent increase in trace greenhouse gases produces an enhanced greenhouse effect, and thus a positive ΔEG forcing term. By contrast, a large volcanic eruption (e.g. Mount Pinatubo 1991, El Chichón 1982) can inject sulfur-containing compounds into the upper atmosphere. High concentrations of stratospheric sulfur aerosols may persist for up to a few years, yielding a negative forcing contribution to ΔEA. Various other types of anthropogenic aerosol emissions make both positive and negative contributions to ΔEA. Solar cycles produce ΔEI smaller in magnitude than those of recent ΔEG trends from human activity.

Climate forcings are complex since they can produce direct and indirect feedbacks that intensify (positive feedback) or weaken (negative feedback) the original forcing. These often follow the temperature response. Water vapor trends as a positive feedback with respect to temperature changes due to evaporation shifts and the Clausius-Clapeyron relation. An increase in water vapor results in positive ΔEW due to further enhancement of the greenhouse effect. A slower positive feedback is the ice-albedo feedback. For example, the loss of Arctic ice due to rising temperatures makes the region less reflective, leading to greater absorption of energy and even faster ice melt rates, thus positive influence on ΔES.[30] Collectively, feebacks tend to amplify global warming.[31]

Climate forcings are complex since they can produce direct and indirect feedbacks that intensify (positive feedback) or weaken (negative feedback) the original forcing. These often follow the temperature response. Water vapor trends as a positive feedback with respect to temperature changes due to evaporation shifts and the Clausius-Clapeyron relation. An increase in water vapor results in positive ΔEW due to further enhancement of the greenhouse effect. A slower positive feedback is the ice-albedo feedback. For example, the loss of Arctic ice due to rising temperatures makes the region less reflective, leading to greater absorption of energy and even faster ice melt rates, thus positive influence on ΔES. Collectively, feebacks tend to amplify global warming.

Clouds are responsible for about half of Earth's albedo and are powerful expressions of internal variability of the climate system.[32][33] They may also act as feedbacks to forcings, and could be forcings themselves if for example a result of cloud seeding activity. Contributions to ΔEC vary regionally and depending upon cloud type. Measurements from satellites are gathered in concert with simulations from models in the effort to improve understanding and reduce uncertainty.[34]

Clouds are responsible for about half of Earth's albedo and are powerful expressions of internal variability of the climate system. They may also act as feedbacks to forcings, and could be forcings themselves if for example a result of cloud seeding activity. Contributions to ΔEC vary regionally and depending upon cloud type. Measurements from satellites are gathered in concert with simulations from models in the effort to improve understanding and reduce uncertainty.

## Earth's energy imbalance

Schematic drawing of Earth's excess heat inventory as it relates to the planet's energy imbalance for two recent time periods.[6]

If Earth's incoming energy flux is larger or smaller than the outgoing energy flux, then the planet will gain (warm) or lose (cool) net heat energy in accordance with the law of energy conservation:

$\displaystyle{ EEI = ASR - OLR }$.

When Earth's energy imbalance (EEI) shifts by a sufficiently large amount, it is directly measurable by orbiting satellite-based radiometric instruments.[27][35] Imbalances which fail to reverse over time will also drive long-term temperature changes in the atmospheric, oceanic, land, and ice components of the climate system.[36][37] Temperature changes and their related effects may thus provide indirect measures of EEI. From mid-2005 to mid-2019, satellite and ocean temperature observations have each independently shown an approximate doubling of the (global) warming imbalance in Earth's energy budget.[6][22]

thumb|upright=1.3|Schematic drawing of Earth's excess heat inventory as it relates to the planet's energy imbalance for two recent time periods.

If Earth's incoming energy flux is larger or smaller than the outgoing energy flux, then the planet will gain (warm) or lose (cool) net heat energy in accordance with the law of energy conservation:

EEI = ASR - OLR.

When Earth's energy imbalance (EEI) shifts by a sufficiently large amount, it is directly measurable by orbiting satellite-based radiometric instruments. Imbalances which fail to reverse over time will also drive long-term temperature changes in the atmospheric, oceanic, land, and ice components of the climate system. Temperature changes and their related effects may thus provide indirect measures of EEI. From mid-2005 to mid-2019, satellite and ocean temperature observations have each independently shown an approximate doubling of the (global) warming imbalance in Earth's energy budget.

### Direct measurement

Animation of the orbits of NASA's 2011 fleet of Earth remote sensing observatories.

Several satellites directly measure the energy absorbed and radiated by Earth, and thus by inference the energy imbalance. The NASA Earth Radiation Budget Experiment (ERBE) project involves three such satellites: the Earth Radiation Budget Satellite (ERBS), launched October 1984; NOAA-9, launched December 1984; and NOAA-10, launched September 1986.[38]

thumb|upright=1.3|Animation of the orbits of NASA's 2011 fleet of Earth remote sensing observatories. Several satellites directly measure the energy absorbed and radiated by Earth, and thus by inference the energy imbalance. The NASA Earth Radiation Budget Experiment (ERBE) project involves three such satellites: the Earth Radiation Budget Satellite (ERBS), launched October 1984; NOAA-9, launched December 1984; and NOAA-10, launched September 1986.

= = = 直接测量 = = 拇指 | 竖直 = 1.3 | 美国宇航局2011年地球遥感天文台轨道动画。几颗卫星直接测量地球吸收和辐射的能量，从而推断能量不平衡。美国航天局的地球辐射预算实验项目涉及三颗这样的卫星: 1984年10月发射的地球辐射预算卫星(ERBS) ; 1984年12月发射的 NOAA-9; 以及1986年9月发射的 NOAA-10。

NASA's Clouds and the Earth's Radiant Energy System (CERES) instruments are part of the NASA's Earth Observing System (EOS) since 1998. CERES is designed to measure both solar-reflected (short wavelength) and Earth-emitted (long wavelength) radiation.[39] Analysis of CERES data by its principal investigators showed a linearly increasing trend in EEI, from +0.42 W m−2 (+/-0.48 W m−2) in 2005 to +1.12 W m−2 (+/-0.48 W m−2) in 2019.[22][40] Subsequent investigation of the behavior using the GFDL CM4/AM4 climate model concluded there was a less than 1% chance that internal climate variability caused the trend.[41]

NASA's Clouds and the Earth's Radiant Energy System (CERES) instruments are part of the NASA's Earth Observing System (EOS) since 1998. CERES is designed to measure both solar-reflected (short wavelength) and Earth-emitted (long wavelength) radiation. Analysis of CERES data by its principal investigators showed a linearly increasing trend in EEI, from +0.42 W m−2 (+/-0.48 W m−2) in 2005 to +1.12 W m−2 (+/-0.48 W m−2) in 2019. Subsequent investigation of the behavior using the GFDL CM4/AM4 climate model concluded there was a less than 1% chance that internal climate variability caused the trend.

Other researchers have used data from CERES, AIRS, CloudSat, and other EOS instruments to look for trends of radiative forcing embedded within the EEI data. Their data analysis showed a forcing rise of +0.53 W m−2 (+/-0.11 W m−2) from years 2003 to 2018. About 80% of the increase was associated with the rising concentration of greenhouse gases which reduced the outgoing longwave radiation.[42][43][44]

Other researchers have used data from CERES, AIRS, CloudSat, and other EOS instruments to look for trends of radiative forcing embedded within the EEI data. Their data analysis showed a forcing rise of +0.53 W m−2 (+/-0.11 W m−2) from years 2003 to 2018. About 80% of the increase was associated with the rising concentration of greenhouse gases which reduced the outgoing longwave radiation.

Satellite observations have also indicated additional precipitation, which is sustained by increased energy leaving the surface through evaporation (the latent heat flux), offsetting some of the increase in the longwave greenhouse flux to the surface.[45]

Satellite observations have also indicated additional precipitation, which is sustained by increased energy leaving the surface through evaporation (the latent heat flux), offsetting some of the increase in the longwave greenhouse flux to the surface.

It is noteworthy that radiometric calibration uncertainties limit the capability of the current generation of satellite-based instruments, which are otherwise stable and precise. As a result, relative changes in EEI are quantifiable with an accuracy which is not also achievable for any single measurement of the absolute imbalance.[46][47]

It is noteworthy that radiometric calibration uncertainties limit the capability of the current generation of satellite-based instruments, which are otherwise stable and precise. As a result, relative changes in EEI are quantifiable with an accuracy which is not also achievable for any single measurement of the absolute imbalance.

### Indirect measurements

Global surface temperature (GST) is calculated by averaging atmospheric temperatures measured over the surface of the sea along with temperatures measured over land. Reliable data extending to at least 1880 shows that GST has undergone a steady increase of about 0.18°C per decade since about year 1970.[48]

Global surface temperature (GST) is calculated by averaging atmospheric temperatures measured over the surface of the sea along with temperatures measured over land. Reliable data extending to at least 1880 shows that GST has undergone a steady increase of about 0.18°C per decade since about year 1970.

= = = 间接测量 = = = 全球表面温度(GST)是通过平均测量到的海洋表面的大气温度和测量到的陆地温度计算出来的。至少1880年的可靠数据显示，自1970年以来，商品及服务税每十年稳步上升约0.18摄氏度。

Ocean waters are especially effective absorbents of solar energy and have far greater total heat capacity than the atmosphere.[49] Research vessels and stations have sampled sea temperatures around the globe since before 1960. Additionally after year 2000, an expanding network of over 3000 Argo robotic floats has measured the temperature anomaly, or equivalently the change in ocean heat content (OHC). Since at least 1990, OHC has increased at a steady or accelerating rate. Changes in OHC provide the most robust indirect measure of EEI since the oceans take up 90% of the excess heat.[6][50]

Ocean waters are especially effective absorbents of solar energy and have far greater total heat capacity than the atmosphere. Research vessels and stations have sampled sea temperatures around the globe since before 1960. Additionally after year 2000, an expanding network of over 3000 Argo robotic floats has measured the temperature anomaly, or equivalently the change in ocean heat content (OHC). Since at least 1990, OHC has increased at a steady or accelerating rate. Changes in OHC provide the most robust indirect measure of EEI since the oceans take up 90% of the excess heat.

The extent of floating and grounded ice is measured by satellites, while the change in mass is then inferred from measured changes in sea level in concert with computational models that account for thermal expansion and other factors. Observations since 1994 show that ice has retreated from every part of Earth at an accelerating rate.[51]

GST since 1850
OHC since 1958 in the top 2000 meters
Global ice loss since 1994

The extent of floating and grounded ice is measured by satellites, while the change in mass is then inferred from measured changes in sea level in concert with computational models that account for thermal expansion and other factors. Observations since 1994 show that ice has retreated from every part of Earth at an accelerating rate.

## Importance as a climate change metric

Long-time climate researchers Kevin Trenberth, James Hansen, and colleagues have identified the monitoring of Earth's energy imbalance as an imperative to help policymakers guide the pace of planning for climate change adaptation. Because of climate system inertia, longer-term EEI trends can forecast further changes that are "in the pipeline".[36][37][52]

Long-time climate researchers Kevin Trenberth, James Hansen, and colleagues have identified the monitoring of Earth's energy imbalance as an imperative to help policymakers guide the pace of planning for climate change adaptation. Because of climate system inertia, longer-term EEI trends can forecast further changes that are "in the pipeline".

In 2012, NASA scientists reported that to stop global warming atmospheric CO2 concentration would have to be reduced to 350 ppm or less, assuming all other climate forcings were fixed.[53] As of 2020, atmospheric CO2 reached 415 ppm and all long-lived greenhouse gases exceeded a 500 ppm [[CO2-eq|模板:CO2-equivalent]] concentration due to continued growth in human emissions.[54]

In 2012, NASA scientists reported that to stop global warming atmospheric CO2 concentration would have to be reduced to 350 ppm or less, assuming all other climate forcings were fixed. As of 2020, atmospheric CO2 reached 415 ppm and all long-lived greenhouse gases exceeded a 500 ppm -equivalent concentration due to continued growth in human emissions.

2012年，美国宇航局的科学家报告说，要阻止全球变暖，大气中的二氧化碳浓度必须降低到350ppm 或更低，假设所有其他气候影响都是固定的。截至2020年，由于人类排放量的持续增长，大气中的二氧化碳含量达到了415 ppm，所有长期存在的温室气体都超过了500 ppm 当量的浓度。

• Lorenz energy cycle
• Planetary equilibrium temperature
• Climate sensitivity
• Tipping points in the climate system
• Anthropogenic metabolism

# = =

• Lorenz 能量循环
• 行星平衡温度
• 气候敏感性
• 气候系统的临界点
• 人类新陈代谢

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## Additional bibliography for cited sources

### IPCC reports

#### AR6 Working Group I Report

• (pb: ).
• Global Warming of 1.5 ºC —.

# = = = = = = = = = IPCC 报告附加书目 = = = = = = = = = = = 第五工作组第一报告 = = = = = = = = =

• (pb:)。
• = = = = 全球变暖1.5 ° c = = = =
• 全球变暖1.5 ° c ー。
• = = = ar6第一工作组报告 = = = =