101-489: EEI may refer to: Earth's energy imbalance , the difference between energy arriving at and leaving Earth Edison Electric Institute , an organisation representing parts of the U.S. electric power industry Eindhoven Energy Institute , a department of the Eindhoven University Electrical and Electronics Institute of Thailand , a not-for-profit entity under
202-414: A broad and coordinated attack on the problem of climate and climatic change." While these discussions were ongoing in scientific circles, other accounts appeared in the popular media. In their June 24, 1974, issue, Time presented an article titled "Another Ice Age?" that noted "the atmosphere has been growing gradually cooler for the past three decades" but noted that "Some scientists ... think that
303-544: A decrease in OLR and a warming (restorative) energy imbalance. Ultimately when the amount of greenhouse gases increases or decreases, in-situ surface temperatures rise or fall until the absorbed solar radiation equals the outgoing longwave radiation, or ASR equals OLR. 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
404-607: A factor of at least 20. 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 can then be analyzed over selected timeframes (Δt) as
505-466: A more than 20 times larger imbalance in the incoming/outgoing flows that originate from solar radiation. Photosynthesis also has a significant 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
606-455: A near-balance of the outgoing energy flow to the incoming flow via small changes in the planet's absolute temperatures . As viewed from Earth's surrounding space, greenhouse gases influence the planet's atmospheric emissivity ( ε ). Changes in atmospheric composition can thus shift the overall radiation balance. For example, an increase in heat trapping by a growing concentration of greenhouse gases (i.e. an enhanced greenhouse effect ) forces
707-468: A new glaciation is unlikely to happen within the next approximately 50,000 years, before the next strong drop in Northern Hemisphere summer insolation occurs "if either atmospheric CO 2 concentration remains above 300 ppm or cumulative carbon emissions exceed 1000 Pg C" (i.e. 1000 gigatonnes carbon). "Only for an atmospheric CO 2 content below the preindustrial level may a glaciation occur within
808-565: A paper published in 1975, Schneider corrected the overestimate of aerosol cooling by checking data on the effects of dust produced by volcanoes. When the model included estimated changes in solar intensity, it gave a reasonable match to temperatures over the previous thousand years and its prediction was that "CO 2 warming dominates the surface temperature patterns soon after 1980." The National Science Board 's Patterns and Perspectives in Environmental Science report of 1972 discussed
909-577: A period of several years, such a temperature decrease over the whole globe is believed to be sufficient to trigger an ice age." Both their equations and their data were badly flawed, as was soon pointed out by other scientists and confirmed by Schneider himself. In January 1972, Robert Jay Charlson et al. pointed out that with other reasonable assumptions, the model produced the opposite conclusion. The model made no allowance for changes in clouds or convection, and erroneously indicated that eight times as much CO 2 would only cause 2 °C of warming. In
1010-474: 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: 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/m ), 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
1111-507: A prediction by Carl Sagan and other scientists who had worked on the famous TTAPS study on nuclear winter that massive oil well fires in Kuwait would cause significant effects on climate was incorrect. In January 1999, contrarian Patrick Michaels wrote a commentary offering to "take even money that the 10 years ending on December 31, 2007, will show a statistically significant global cooling trend in temperatures measured by satellite", on
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#17328546849901212-421: A result of cloud seeding activity. Contributions to ΔE C vary regionally and depending upon cloud type. Measurements from satellites are gathered in concert with simulations from models in an effort to improve understanding and reduce uncertainty. The Earth's energy imbalance (EEI) is defined as "the persistent and positive (downward) net top of atmosphere energy flux associated with greenhouse gas forcing of
1313-482: A result of observations and a switch to cleaner fuel burning, this no longer seems likely; current scientific work indicates that global warming is far more likely. Although the temperature drops foreseen by this mechanism have now been discarded in light of better theory and the observed warming, aerosols are thought to have contributed a cooling tendency (outweighed by increases in greenhouse gases) and also have contributed to global dimming . Orbital forcing refers to
1414-424: A steady increase of about 0.18 °C per decade since about year 1970. Ocean waters are especially effective absorbents of solar energy and have a far greater total heat capacity than the atmosphere. Research vessels and stations have sampled sea temperatures at depth and around the globe since before 1960. Additionally, after the year 2000, an expanding network of nearly 4000 Argo robotic floats has measured
1515-448: A sufficiently large amount, the shift is measurable by orbiting satellite-based instruments. Imbalances that 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, sea level, ice mass and related shifts thus also provide measures of EEI. The biggest changes in EEI arise from changes in
1616-502: A tiny contribution compared to solar energy. The energy budget also takes into account how energy moves through the climate system . The Sun heats the equatorial tropics more than the polar regions . Therefore, the amount of solar irradiance received by a certain region 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 . The result
1717-533: A value of about 0.3 for the mean net albedo of Earth, also called its Bond albedo (A): Thermal energy leaves the planet in the form of outgoing longwave radiation (OLR). Longwave radiation is electromagnetic thermal radiation emitted by Earth's surface and atmosphere. Longwave radiation is in the infrared band . But, the terms are not synonymous, as infrared radiation can be either shortwave or longwave . Sunlight contains significant amounts of shortwave infrared radiation. A threshold wavelength of 4 microns
1818-449: Is Earth's climate . Earth's energy budget depends on many factors, such as atmospheric aerosols , greenhouse gases , surface albedo , clouds , and land use patterns. 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
1919-614: Is a warm period of 4 kyr followed by a relatively rapid cooling". Secondly, future orbital variations will not closely resemble those of the past. In 1923, there was concern about a new ice age and Captain Donald Baxter MacMillan sailed toward the Arctic sponsored by the National Geographical Society to look for evidence of advancing glaciers. In 1926, a Berlin astronomer was predicting global cooling but that it
2020-426: Is because excess heat at their surfaces flows inward only by means of thermal conduction , and thus penetrates only several tens of centimeters on the daily cycle and only several tens of meters on the annual cycle. Much of the heat uptake goes either into melting ice and permafrost or into evaporating more water from soils. Several satellites measure the energy absorbed and radiated by Earth, and thus by inference
2121-413: Is designed to measure both solar-reflected (short wavelength) and Earth-emitted (long wavelength) radiation. The CERES data showed increases in EEI from +0.42 ± 0.48 W/m in 2005 to +1.12 ± 0.48 W/m in 2019. Contributing factors included more water vapor, less clouds, increasing greenhouse gases, and declining ice that were partially offset by rising temperatures. Subsequent investigation of
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#17328546849902222-487: Is different from Wikidata All article disambiguation pages All disambiguation pages Earth%27s energy budget#Earth's energy imbalance (EEI) Earth's energy budget (or Earth's energy balance ) is 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
2323-537: Is generally considered to be very low, and the IPCC notes, "even in models where the THC weakens, there is still warming over Europe. For example, in all AOGCM integrations where the radiative forcing is increasing, the sign of the temperature change over north-west Europe is positive." The cooling period is reproduced by current (1999 on) global climate models that include the physical effects of sulfate aerosols , and there
2424-470: 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/m ). Since the absorption varies with location as well as with diurnal, seasonal and annual variations,
2525-432: Is not (yet) possible to measure the absolute magnitude of EEI directly at top of atmosphere, although changes over time as observed by satellite-based instruments are thought to be accurate. The only practical way to estimate the absolute magnitude of EEI is through an inventory of the changes in energy in the climate system. The biggest of these energy reservoirs is the ocean. The planetary heat content that resides in
2626-405: Is now general agreement that aerosol effects were the dominant cause of the mid-20th century cooling. At the time there were two physical mechanisms that were most frequently advanced to cause cooling: aerosols and orbital forcing. Human activity — mostly as a by-product of fossil fuel combustion , partly by land use changes — increases the number of tiny particles ( aerosols ) in
2727-566: Is partially attributable to the fact much less was then known about world climate and causes of ice ages . Climate scientists were aware that predictions based on this trend were not possible - because the trend was poorly studied and not understood (for example see reference ). Despite that, in the popular press the possibility of cooling was reported generally without the caveats present in the scientific reports, and "unusually severe winters in Asia and parts of North America in 1972 and 1973 ... pushed
2828-469: Is possible, or even likely, that human interference has already altered the environment so much that the climatic pattern of the near future will follow a different path." The board's report of 1974, Science And The Challenges Ahead , continued on this theme. "During the last 20-30 years, world temperature has fallen, irregularly at first but more sharply over the last decade." Discussion of cyclic glacial periods does not feature in this report. Instead it
2929-452: Is radiated into space in the form of longwave radiation. The transport of longwave radiation from Earth's surface through its multi-layered atmosphere is governed by radiative transfer equations such as Schwarzschild's equation for radiative transfer (or more complex equations if scattering is present) and obeys Kirchhoff's law of thermal radiation . A one-layer model produces an approximate description of OLR which yields temperatures at
3030-480: Is relatively small. Likewise, Earth's climate system as a whole shows a slow response to shifts in the atmospheric radiation balance. 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 such energy over the planet's surface. Sensible heat also moves into and out of great depths under conditions that favor downwelling or upwelling . Over 90 percent of
3131-432: Is sometimes used to distinguish longwave and shortwave radiation. Generally, absorbed solar energy is converted to different forms of heat energy. Some of the solar energy absorbed by the surface is converted to thermal radiation at wavelengths in the " atmospheric window "; this radiation is able to pass through the atmosphere unimpeded and directly escape to space, contributing to OLR. The remainder of absorbed solar energy
EEI - Misplaced Pages Continue
3232-422: Is the role of humans that is central to the report's analysis. "The cause of the cooling trend is not known with certainty. But there is increasing concern that man himself may be implicated, not only in the recent cooling trend but also in the warming temperatures over the last century". The report did not conclude whether carbon dioxide in warming, or agricultural and industrial pollution in cooling, are factors in
3333-428: Is transported upwards through the atmosphere through a variety of heat transfer mechanisms, until the atmosphere emits that energy as thermal energy which is able to escape to space, again contributing to OLR. For example, heat is transported into the atmosphere via evapotranspiration and latent heat fluxes or conduction / convection processes, as well as via radiative heat transport. Ultimately, all outgoing energy
3434-568: Is undoubtedly near"; but the volume of Quaternary Research reporting on the meeting said that "the basic conclusion to be drawn from the discussions in this section is that the knowledge necessary for understanding the mechanism of climate change is still lamentably inadequate". George Kukla and Robert Matthews, in a Science write-up of a conference, asked when and how the current interglacial would end; concluding that, unless there were impacts from future human activity, "Global cooling and related rapid changes of environment, substantially exceeding
3535-516: The 8.2 kiloyear event , precisely because it was the middle alternative between the Younger Dryas and the Little Ice Age . Scientists said that "abrupt climate change initiated by Greenland ice sheet melting is not a realistic scenario for the 21st century". The concern that cooler temperatures would continue, and perhaps at a faster rate, has been observed to be incorrect, as was assessed in
3636-483: The IPCC Third Assessment Report of 2001. More has to be learned about climate. However, the growing records have shown that short term cooling concerns have not been borne out. As for the prospects of the end of the current interglacial, while the four most recent interglacials lasted about 10,000 years, the interglacial before that lasted around 28,000 years. Milankovitch-type calculations indicate that
3737-463: The Milankovitch theory does not allow the prediction of a "rapid" ice age onset (i.e., less than a century or two) since the fastest orbital period is about 20,000 years. Some creative ways around this were found, notably one championed by Nigel Calder under the name of "snowblitz", but these ideas did not gain wide acceptance. The length of the current interglacial temperature peak is similar to
3838-604: The World Meteorological Organization issued a warning in June 1976 that "a very significant warming of global climate" was probable. Currently, there are some concerns about the possible regional cooling effects of a slowdown or shutdown of thermohaline circulation , which might be provoked by an increase of fresh water mixing into the North Atlantic due to glacial melting . The probability of this occurring
3939-444: The slow, cyclical changes in the tilt of Earth's axis and shape of its orbit . These cycles alter the total amount of sunlight reaching the Earth by a small amount and affect the timing and intensity of the seasons . This mechanism is thought to be responsible for the timing of the ice age cycles , and understanding of the mechanism was increasing rapidly in the mid-1970s. The paper of Hays, Imbrie, and Shackleton "Variations in
4040-484: The 150 years from 1850 to 2000, with a consequent warming trend. The actual increase in this period was 29%. Paul R. Ehrlich mentioned global warming from greenhouse gases as a counterforce to the cooling effect of aerosols in 1968. By the time the idea of global cooling reached the public press in the mid-1970s temperatures had stopped falling, and there was concern in the climatological community about carbon dioxide 's warming effects. In response to such reports,
4141-533: The 1970s were either neutral or showed a warming trend. In 1977, a popular book on the topic was published, called The Weather Conspiracy: The Coming of the New Ice Age . Later in the decade, at a WMO conference in 1979, F. Kenneth Hare reported: Concerns about nuclear winter arose in the early 1980s from several reports. Similar speculations have appeared over effects due to catastrophes such as asteroid impacts and massive volcanic eruptions . In 1991,
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4242-494: The 2006 to 2020 period EEI was about +0.76 ± 0.2 W/m and showed a significant increase above the mean of +0.48 ± 0.1 W/m for the 1971 to 2020 period. EEI has been positive because temperatures have increased almost everywhere for over 50 years. Global surface temperature (GST) is calculated by averaging temperatures measured at the surface of the sea along with air temperatures measured over land. Reliable data extending to at least 1880 shows that GST has undergone
4343-492: The 25-year cooling trend would continue. It stated (Forward, p. v) that, "we do not have a good quantitative understanding of our climate machine and what determines its course [so] it does not seem possible to predict climate", and (p. 2) "The climates of the earth have always been changing, and they will doubtless continue to do so in the future. How large these future changes will be, and where and how rapidly they will occur, we do not know." The Report's "program for action"
4444-559: The Earth's Orbit: Pacemaker of the Ice Ages" qualified its predictions with the remark that "forecasts must be qualified in two ways. First, they apply only to the natural component of future climatic trends - and not to anthropogenic effects such as those due to the burning of fossil fuels . Second, they describe only the long-term trends, because they are linked to orbital variations with periods of 20,000 years and longer. Climatic oscillations at higher frequencies are not predicted ...
4545-519: The Earth's formation. This corresponds to an average flux of 0.087 W/m 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 average 18 TW, corresponding to an estimated 160,000 TW-hr, for all of year 2019. However, consumption is growing rapidly and energy production with fossil fuels also produces an increase in atmospheric greenhouse gases, leading to
4646-583: The Etosha National Park in Namibia Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with the title EEI . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=EEI&oldid=1179320374 " Category : Disambiguation pages Hidden categories: Short description
4747-661: The Foundation for Industrial Development Epoch of Extreme Inundations , a hypothetical epoch during which four landforms in the Pontic–Caspian steppe were widely inundated Essential elements of information , any critical intelligence information required by intelligence consumers to perform their mission (a term used by US and UK ministries of defence and, until 2014, the US Army) Etosha Ecological Institute , an organisation managing research activity in
4848-573: The UAH satellite temperature record showed a slight warming trend. In 2003, the Office of Net Assessment at the United States Department of Defense was commissioned to produce a study on the likely and potential effects of abrupt modern climate change should a shutdown of thermohaline circulation occur. The study, conducted under ONA head Andrew Marshall , modelled its prospective climate change on
4949-411: The atmosphere (34 units from terrestrial energy and 14 from insolation) are then finally radiated back to space. This simplified example neglects some details of 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
5050-505: The atmosphere. These have a direct effect: they effectively increase the planetary albedo , thus cooling the planet by reducing the solar radiation reaching the surface; and an indirect effect: they affect the properties of clouds by acting as cloud condensation nuclei . In the early 1970s some speculated that this cooling effect might dominate over the warming effect of the CO 2 release: see discussion of Rasool and Schneider (1971), below. As
5151-409: The basis of his view that record temperatures in 1998 had been a blip. Indeed, over that period, satellite-measured temperatures never again approached their 1998 peak. Due to a sharp but temporary dip in temperatures in 1999–2000, a least-squares linear regression fit to the satellite temperature record showed little overall trend. The RSS satellite temperature record showed a slight cooling trend, but
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#17328546849905252-476: The behavior using the GFDL CM4/AM4 climate model concluded there was a less than 1% chance that internal climate variability alone 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 analysis showed a forcing rise of +0.53 ± 0.11 W/m from years 2003 to 2018. About 80% of
5353-420: The bulk mass of these components via conduction/convection heat transfer processes. The transformation of water between its solid/liquid/vapor states also acts as a source or sink of potential energy in the form of latent heat . These processes buffer the surface conditions against some of the rapid radiative changes in the atmosphere. As a result, the daytime versus nighttime difference in surface temperatures
5454-457: The calculated small changes in sunlight might somehow trigger ice ages. In 1966, Cesare Emiliani predicted that "a new glaciation will begin within a few thousand years." In his 1968 book The Population Bomb , Paul R. Ehrlich wrote "The greenhouse effect is being enhanced now by the greatly increased level of carbon dioxide ... [this] is being countered by low-level clouds generated by contrails, dust, and other contaminants ... At
5555-455: 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 . In simplest terms, Earth's energy budget is balanced when the incoming flow equals the outgoing flow. Since
5656-623: The cause of cooling; it stated that "what causes the onset of major and minor ice ages remains a mystery" and cited the NAS conclusion that "not only are the basic scientific questions largely unanswered, but in many cases we do not yet know enough to pose the key questions." The article mentioned the alternative solutions of "melting the Arctic ice cap by covering it with black soot or diverting Arctic rivers" but conceded these were not feasible. The Newsweek article concluded by criticizing government leaders: "But
5757-407: The climate system can be compiled given the heat capacity, density and temperature distributions of each of its components. Most regions are now reasonably well sampled and monitored, with the most significant exception being the deep ocean. Estimates of the absolute magnitude of EEI have likewise been calculated using the measured temperature changes during recent multi-decadal time intervals. For
5858-527: The climate system". If Earth's incoming energy flux (ASR) is larger or smaller than the outgoing energy flux (OLR), then the planet will gain (warm) or lose (cool) net heat energy in accordance with the law of energy conservation : Positive EEI thus defines the overall rate of planetary heating and is typically expressed as watts per square meter (W/m ). During 2005 to 2019 the Earth's energy imbalance averaged about 460 TW or globally 0.90 ± 0.15 W per m . When Earth's energy imbalance (EEI) shifts by
5959-498: The composition of the atmosphere through human activities, thereby interfering with the natural flow of energy through the climate system. The main changes are from increases in carbon dioxide and other greenhouse gases, that produce heating (positive EEI), and pollution. The latter refers to atmospheric aerosols of various kinds, some of which absorb energy while others reflect energy and produce cooling (or lower EEI). Square brackets show 90% confidence intervals It
6060-619: The cooling trend may be only temporary." An April 28, 1975, article in Newsweek magazine was titled "The Cooling World", it pointed to "ominous signs that the Earth's weather patterns have begun to change" and pointed to "a drop of half a degree [Fahrenheit] in average ground temperatures in the Northern Hemisphere between 1945 and 1968." The article stated "The evidence in support of these predictions [of global cooling] has now begun to accumulate so massively that meteorologists are hard-pressed to keep up with it." The Newsweek article did not state
6161-427: The cyclical behavior of climate, and the understanding at the time that the planet was entering a phase of cooling after a warm period. "Judging from the record of the past interglacial ages, the present time of high temperatures should be drawing to an end, to be followed by a long period of considerably colder temperatures leading into the next glacial age some 20,000 years from now." But it also continued; "However, it
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#17328546849906262-413: The energy budget to result in any significant changes in the global surface temperature . This is due to the thermal inertia of the oceans , land and cryosphere . Most climate models make accurate calculations of this inertia, energy flows and storage amounts. Earth's energy budget includes the "major energy flows of relevance for the climate system". These are "the top-of-atmosphere energy budget;
6363-556: The energy imbalance. These are located top of atmosphere (TOA) and provide data covering the globe. The NASA Earth Radiation Budget Experiment (ERBE) project involved three such satellites: the Earth Radiation Budget Satellite (ERBS), launched October 1984; NOAA-9, launched December 1984; and NOAA-10, launched September 1986. NASA's Clouds and the Earth's Radiant Energy System (CERES) instruments are part of its Earth Observing System (EOS) since March 2000. CERES
6464-490: The extra energy that has accumulated on Earth from ongoing global warming since 1970 has been stored in the ocean . About one-third 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/m ) as of 2020. That led to about 14 zettajoules (ZJ) of heat gain for the year, exceeding the 570 exajoules (=160,000 TW-hr ) of total primary energy consumed by humans by
6565-465: The fluctuations experienced by man in historical times, must be expected within the next few millennia or even centuries", but many other scientists doubted these conclusions. The 1970 Study of Critical Environmental Problems reported the possibility of warming from increased carbon dioxide, but no concerns about cooling, setting a lower bound on the beginning of interest in "global cooling". By 1971, studies indicated that human caused air pollution
6666-425: The global warming due to greenhouse gases would tend to have less effect with greater densities, and while aerosol pollution could cause warming, it was likely that it would tend to have a cooling effect which increased with density. They concluded that "An increase by only a factor of 4 in global aerosol background concentration may be sufficient to reduce the surface temperature by as much as 3.5 ° K. If sustained over
6767-407: The increase was associated with the rising concentration of greenhouse gases which reduced the outgoing longwave radiation. Further satellite measurements including TRMM and CALIPSO data have 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
6868-413: The issue into the public consciousness". In the 1970s, the compilation of records to produce hemispheric, or global, temperature records had just begun. Spencer R. Weart 's history of The Discovery of Global Warming says that: "While neither scientists nor the public could be sure in the 1970s whether the world was warming or cooling, people were increasingly inclined to believe that global climate
6969-512: The length of the preceding interglacial peak (Sangamon/Eem), and so it could be concluded that we might be nearing the end of this warm period. This conclusion would be mistaken. Firstly, because the lengths of previous interglacials were not particularly regular; see figure. Petit et al. note that "interglacials 5.5 and 9.3 are different from the Holocene , but similar to each other in duration, shape and amplitude. During each of these two events, there
7070-407: The mid 1970s, the limited temperature series available suggested that the temperature had decreased for several decades up to then. As longer time series of higher quality became available, it became clear that global temperature showed significant increases overall. By the 1970s, scientists were becoming increasingly aware that estimates of global temperatures showed cooling since 1945, as well as
7171-419: The moment we cannot predict what the overall climatic results will be of our using the atmosphere as a garbage dump." Concern peaked in the early 1970s, though "the possibility of anthropogenic warming dominated the peer-reviewed literature even then" (a cooling period began in 1945, and two decades of a cooling trend suggested a trough had been reached after several decades of warming). This peaking concern
7272-524: The net change in energy (ΔE) associated with these attributes: Here the term ΔE T , corresponding to the Planck response , is negative-valued when temperature rises due to its strong direct influence on OLR. The recent increase in trace greenhouse gases produces an enhanced greenhouse effect, and thus a positive ΔE G forcing term. By contrast, a large volcanic eruption (e.g. Mount Pinatubo 1991 , El Chichón 1982) can inject sulfur-containing compounds into
7373-409: The next 10 ka. ... Given the continued anthropogenic CO 2 emissions, glacial inception is very unlikely to occur in the next 50 ka, because the timescale for CO 2 and temperature reduction toward unperturbed values in the absence of active removal is very long [IPCC, 2013], and only weak precessional forcing occurs in the next two precessional cycles." (A precessional cycle is around 21,000 years,
7474-539: The next glacial cycle entirely. This is consistent with the prediction of David Archer and colleagues who argued in 2005 that the present level of CO 2 will suspend the next glacial period for the next 500,000 years and will be the longest duration and intensity of the projected interglacial period and are longer than have been seen in the last 2.6 million years. A 2015 report by the Past Global Changes Project, including Berger, says simulations show that
7575-476: The northern hemisphere increased from the 1880s until about 1940 and has been decreasing thereafter." It also stated (p. 44) that, "If both the CO 2 and particulate inputs to the atmosphere grow at equal rates in the future, the widely differing atmospheric residence times of the two pollutants means that the particulate effect will grow in importance relative to that of CO 2 ." The report did not predict whether
7676-440: The numbers quoted are multi-year averages obtained from multiple satellite measurements. Of the ~340 W/m of solar radiation received by the Earth, an average of ~77 W/m is reflected back to space by clouds and the atmosphere and ~23 W/m is reflected by the surface albedo , leaving ~240 W/m of solar energy input to the Earth's energy budget. This amount is called the absorbed solar radiation (ASR). It implies
7777-506: 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 ΔE W 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
7878-532: 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 precedent. The main origin of changes in the Earth's energy is from human-induced changes in the composition of the atmosphere. During 2005 to 2019 the Earth's energy imbalance (EEI) averaged about 460 TW or globally 0.90 ± 0.15 W/m . It takes time for any changes in
7979-526: The planet about a sixth of the way toward the Ice Age." On October 23, 2006, Newsweek issued a correction, over 31 years after the original article, stating that it had been "so spectacularly wrong about the near-term future" (though editor Jerry Adler stated that "the story wasn't 'wrong' in the journalistic sense of 'inaccurate. ' ") Academic analysis of the peer-reviewed studies published at that time shows that most papers examining aspects of climate during
8080-468: The possibility of large scale warming due to emissions of greenhouse gases. In the scientific papers which considered climate trends of the 21st century, fewer than 10% were inclined towards future cooling, while most papers predicted future warming. The general public had little awareness of carbon dioxide's effects on climate, but Science News in May 1959 forecast a 25% increase in atmospheric carbon dioxide in
8181-400: The present interglacial would probably continue for tens of thousands of years naturally in the absence of human perturbations. Other estimates (Loutre and Berger, based on orbital calculations) put the unperturbed length of the present interglacial at 50,000 years. A. Berger expressed the opinion in 2005 (EGU presentation) that the present CO 2 perturbation will last long enough to suppress
8282-473: The recent climatic changes, noting; "Before such questions as these can be resolved, major advances must be made in understanding the chemistry and physics of the atmosphere and oceans , and in measuring and tracing particulates through the system." There also was a Report by the U.S. National Academy of Sciences (NAS) entitled, "Understanding Climate Change: A Program for Action". The report stated (p. 36) that, "The average surface air temperature in
8383-438: The region less reflective, leading to greater absorption of energy and even faster ice melt rates, thus positive influence on ΔE S . Collectively, feedbacks tend to amplify global warming or cooling. 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
8484-474: The results indicate that the long-term trend over the next 20,000 years is towards extensive Northern Hemisphere glaciation and cooler climate". The idea that ice ages cycles were predictable appears to have become conflated with the idea that another one was due "soon" - perhaps because much of this study was done by geologists, who are accustomed to dealing with very long time scales and use "soon" to refer to periods of thousands of years. A strict application of
8585-410: The same amount of energy as it receives via solar insolation (all forms of electromagnetic radiation). The main origin of changes in the Earth's energy is from human-induced changes in the composition of the atmosphere, amounting to about 460 TW or globally 0.90 ± 0.15 W/m . The total amount of energy received per second at the top of Earth's atmosphere (TOA) is measured in watts and
8686-743: The scientists see few signs that government leaders anywhere are even prepared to take the simple measures of stockpiling food or of introducing the variables of climatic uncertainty into economic projections of future food supplies ... The longer the planners (politicians) delay, the more difficult will they find it to cope with climatic change once the results become grim reality." The article emphasized sensational and largely unsourced consequences - "resulting famines could be catastrophic", "drought and desolation", "the most devastating outbreak of tornadoes ever recorded", "droughts, floods, extended dry spells, long freezes, delayed monsoons", "impossible for starving peoples to migrate", "the present decline has taken
8787-403: The sun in order to maintain a net-zero gain of energy by Earth. 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 as sensible heat either into or out of
8888-614: The surface (T s =288 Kelvin ) and at the middle of the troposphere ( T a =242 K) that are close to observed average values: In this expression σ is the Stefan–Boltzmann constant and ε represents the emissivity of the atmosphere, which is less than 1 because the atmosphere does not emit within the wavelength range known as the atmospheric window . Aerosols, clouds, water vapor, and trace greenhouse gases contribute to an effective value of about ε = 0.78 . The strong (fourth-power) temperature sensitivity maintains
8989-415: The surface energy budget; changes in the global energy inventory and internal flows of energy within the climate system". 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
9090-398: 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. Global cooling Global cooling
9191-415: The temperature anomaly, or equivalently the ocean heat content change (ΔOHC). Since at least 1990, OHC has increased at a steady or accelerating rate. ΔOHC represents the largest portion of EEI since oceans have thus far taken up over 90% of the net excess energy entering the system over time (Δt): Earth's outer crust and thick ice-covered regions have taken up relatively little of the excess energy. This
9292-483: The time it takes for the perihelion to move all the way around the tropical year .) As the NAS report indicates, scientific knowledge regarding climate change was more uncertain than it is today. At the time that Rasool and Schneider wrote their 1971 paper, climatologists had not yet recognized the significance of greenhouse gases other than water vapor and carbon dioxide, such as methane , nitrous oxide , and chlorofluorocarbons . Early in that decade, carbon dioxide
9393-557: 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/m ) are absorbed: 14 within the atmosphere and 51 by the Earth's 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
9494-545: The upper atmosphere. High concentrations of stratospheric sulfur aerosols may persist for up to a few years, yielding a negative forcing contribution to ΔE A . Various other types of anthropogenic aerosol emissions make both positive and negative contributions to ΔE A . Solar cycles produce ΔE I smaller in magnitude than those of recent ΔE G trends from human activity. Climate forcings are complex since they can produce direct and indirect feedbacks that intensify ( positive feedback ) or weaken ( negative feedback )
9595-579: Was "ages away". Concerns that a new ice age was approaching was revived in the 1950s. During the Cold War , there were concerns by Harry Wexler that setting off atom bombs could be hastening a new ice age from a nuclear winter scenario. J. Murray Mitchell showed as early as 1963 a multidecadal cooling since about 1940. At a conference on climate change held in Boulder, Colorado in 1965, evidence supporting Milankovitch cycles triggered speculation on how
9696-487: Was a call for creation of a new National Climatic Research Program. It stated (p. 62), "If we are to react rationally to the inevitable climatic changes of the future, and if we are ever to predict their future course, whether they are natural or man-induced, a far greater understanding of these changes is required than we now possess. It is, moreover, important that this knowledge be acquired as soon as possible." For that reason, it stated, "the time has now come to initiate
9797-430: Was a conjecture, especially during the 1970s, of imminent cooling of the Earth culminating in a period of extensive glaciation , due to the cooling effects of aerosols or orbital forcing . Some press reports in the 1970s speculated about continued cooling; these did not accurately reflect the scientific literature of the time, which was generally more concerned with warming from an enhanced greenhouse effect . In
9898-421: Was on the move, and in no small way " [emphasis added]. On January 11, 1970, The Washington Post reported that "Colder Winters Held Dawn of New Ice Age". In 1972, Emiliani warned "Man's activity may either precipitate this new ice age or lead to substantial or even total melting of the ice caps". Also in 1972, a group of glacial-epoch experts at a conference agreed that "the natural end of our warm epoch
9999-473: Was published in the journal Science in July 1971 as a paper by S. Ichtiaque Rasool and Stephen H. Schneider , titled "Atmospheric Carbon Dioxide and Aerosols: Effects of Large Increases on Global Climate". The paper used rudimentary data and equations to compute the possible future effects of large increases in the densities in the atmosphere of two types of human environmental emissions: The paper suggested that
10100-599: Was spreading, but there was uncertainty as to whether aerosols would cause warming or cooling, and whether or not they were more significant than rising CO 2 levels. J. Murray Mitchell still viewed humans as "innocent bystanders" in the cooling from the 1940s to 1970, but in 1971 his calculations suggested that rising emissions could cause significant cooling after 2000, though he also argued that emissions could cause warming depending on circumstances. Calculations were too basic at this time to be trusted to give reliable results. An early numerical computation of climate effects
10201-438: Was the only widely studied human-influenced greenhouse gas. The attention drawn to atmospheric gases in the 1970s stimulated many discoveries in subsequent decades. As the temperature pattern changed, global cooling was of waning interest by 1979. A common argument used to dismiss the significance of human-caused climate change is to allege that scientists showed concerns about global cooling which did not materialise, and there
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