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All Observed Anthropogenic:

• Represent a direct or indirect observation demonstrating why the warming trend since the mid-20th century is anthropogenic (i.e. the result of an enhanced greenhouse effect.)
• Are built upon an established framework of several assumed facts:
• That greenhouse gases are rising.
• That this rise is due to anthropogenic activities.
• That the planet has warmed since the mid-20th Century.
• That the presence of greenhouse gases in the atmosphere will (at least theoretically) cause a planet's temperature at its surface and lower atmosphere to be greater than if they were not present.
As an established baseline, the sources below are not focused on establishing the validity on any of the above given facts. They are instead focused specifically on the lines of evidence which attribute the observed temperature rise since the mid-20th century to this human-driven rise in greenhouse gases.

Decreasing DTR

Diurnal Temperature Range (DTR)

A shrinking diurnal temperature range (the difference between the hottest [daytime] and coldest [nighttime]...

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A shrinking diurnal temperature range (the difference between the hottest [daytime] and coldest [nighttime] temperature at a particular location) is a predicted effect of warming as a result of a strengthening greenhouse effect.

This can be intuitive. Consider that the majority of the radiation that interacts with greenhouse gases comes from the Earth's surface, as longwave infrared, rather than shortwave from the sun. Since the Earth's surface is emitting longwave IR day and night, the greenhouse effect works both day and night at any particular location, while the sun's energy only makes a contribution during the day.

Imagine a hypothetical, very weak, greenhouse effect. Take solar energy to be 1300 at high noon, 0 at night, with a greenhouse effect of 1 all the time. From day:night then, the planet receives 1301x more energy during the day than at night.

Now, increase the strength of the greenhouse effect to 500. During the day the combined incoming energy to the surface becomes (1301 + 500), compared to 500 at night. Now, the difference between day and night is only 3.6x. Both daytime and nighttime temperatures are higher with the stronger greenhouse effect, but it is the night that has gained by far the most proportionally, and this is true regardless of what the actual greenhouse gas contributions may be. It should be clear from this example too that increasing the solar component alone (either by increasing the sun's output, reducing cloud cover, or other global brightening factor) would *increase* the ratio from day to night by warming only daytime temperatures and keeping nighttime unaffected, thus producing the opposite signature of days warming faster than nights.

Astronomical analogies emphasize the point: Venus, with a greenhouse effect much stronger than Earth's, is a dramatic example of this effect, with a diurnal temperature range of effectively 0. Bodies with no greenhouse effect, however, such as the Moon and Mercury, have DTRs of approximately 300 C and 600 C, respectively.

Thus, a planetary warming driven by an enhanced greenhouse effect has a relatively unique expected signature: a multi-year warming rate that is greater at night than at daytime, or (in other words) an expected reduction in the mean difference between daytime maximum and nighttime minimum temperature. The multiple studies below which present evidence that this reduction is being observed thus represent a strong line of empirical evidence that the warming since the mid-20th century is being driven by an enhanced greenhouse effect.
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Upper Atmosphere Cooling

Upper Atmosphere Cooling

The cooling of the upper atmosphere in response to an increase in CO2 was predicted over 50 years ago...

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The cooling of the upper atmosphere in response to an increase in CO2 was predicted over 50 years ago:

The larger the mixing ratio of carbon dioxide…
1) …the warmer is the equilibrium temperature of the earth's surface and troposphere.
2) …the colder is the equilibrium temperature of the stratosphere.

(Manabe and Wetherald, 1966; Journal of the Atmospheric Sciences, p251)

One reason for this is that greenhouse gases absorb infrared radiation that is emitted by the Earth’s surface; without them, infrared radiation emitted by Earth would proceed uninterrupted to space. As the concentration of greenhouse gases increase, any particular photon has a greater chance of being absorbed by a greenhouse gas molecule. Since a greenhouse gas molecule which absorbed the photon can re-radiate it in a random direction, this has the immediate effect of preventing its energy from reaching the upper atmosphere. Until equilibrium is re-established by surface warming (which generates more IR photons to compensate), the stratosphere receives less energy with an increase in the strength of the greenhouse effect in the troposphere, and therefore cools.

It is not necessary for a lack of equilibrium to exist, however. Consider that CO2 is less abundant in the stratosphere than it is in the troposphere. Put another way, more of the stratosphere is composed of gases that are not greenhouse gases, like O2 and N2, than it is by greenhouse gasses. Although N2 and O2 do not absorb longwave IR, they are able to absorb shorter wavelengths (from the sun). This increases their energy and they move faster, which is synonymous with being warmer. Because these molecules cannot emit longwave IR, energy transfer between molecules can only happen s via collisions (conduction). When an O2 or N2 molecule collides with another O2 or N2 molecule, kinetic energy can be transferred from one to the other.

CO2 is also capable of moving, but it is also able to vibrate in an excited state when it absorbs energy. When an N2 or O2 collides with a CO2 molecule, then, the N2/O2 will cool after transferring its energy to the CO2. But if the collision results not in a 1:1 transfer of kinetic energy, and instead the CO2 molecule moves to an excited vibrational state, kinetic energy (temperature) is no longer conserved and thus the average temperature of the collided molecules is less. The excited state is then relaxed by the emission of an IR photon. And because of the lower concentration of greenhouse gases in the upper atmosphere, any emitted photon has a greater chance of reaching space than would a photon emitted by a CO2 molecule in the troposphere.

Increasing CO2 concentrations in the troposphere will also increase them in the stratosphere, wherein they enable a more effective radiation of the photons, and thus lead to a cooler temperature.

By contrast, a warming caused by an increase in solar forcing, for example – either directly from the sun being more active, or from an increase in clouds (which would reflect shortwave, rather than longwave, back to the upper atmosphere) – would increase the shortwave absorption by N2 and O2 and therefore warm the stratosphere. Only a greenhouse-gas induced warming produces the signature of a warming lower atmosphere and cooling upper atmosphere.
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Warming Anomalous Historically

Warming Anomalous Historically

In general, any trend in Earth’s temperature has an underlying physical cause. Without a driving, or forcing, of temperature change…

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In general, any trend in Earth’s temperature has an underlying physical cause. Without a driving, or forcing, of temperature change, the temperature would remain constant. There can be multiple possible causes of any temperature change, and so two different temperature changes in history – even of similar rate and magnitude – may not necessarily be due to the same underlying cause. Because of this, there is no reason to demand perfectly stable temperatures – or no record of similar temperature change events – in Earth’s geological past as a pre-requisite to attributing the current warming to man-made causes, if the causes underlying previous warming events are known to be nonexistent today.

In other words, the fact that the Earth's temperature *can* change naturally is not evidence that it can only ever change naturally. This would be no more logical than observing an animal dying naturally and concluding that humans are incapable of killing an animal. The question, therefore, is not whether the Earth's average temperature can vary naturally, because it certainly can: it is whether the observed increase in temperature since the mid-20th century is *also* natural.

What the recent stability of temperatures does do is show that the rate of warming observed since the mid-20th century has not been observed in the past 2,000 years and therefore any ‘natural’ cycle that could produce it must have a frequency that is longer than this. It also shows that something must have changed since the mid-20th century. Indeed, the overall trend from the proxy records tends to show that over many millenia the long-term trend was one of gradual cooling. A forcing must have been introduced that was not only not naturally present over the past 2,000 years, but which was sufficient to reverse the underlying cooling trend.

What this does not do is prove that the warming since the mid-20th century is due to human activities – this is only able to be demonstrated by ruling out other possible natural causes, and finding unique fingerprints in the way in which the planet is warming that are exclusively consistent with a warming caused by an increase in greenhouse gas concentrations. These fingerprints are presented as the other lines of evidence here.

Simplified figure originally from Mann et al., 2008, reproduced under educational use license. Copyright 2008 National Academy of Sciences.
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Quick filter by anthropogenic evidence type:

Quality Category Year Cite As DOI Key Quote
9 Radiative GHE Observed2001(Harries et al., 2001)https://doi.org/10.1038/35066553Here we analyse the difference between the spectra of the outgoing longwave radiation of the Earth as measured by orbiting spacecraft in 1970 and 1997. We find differences in the spectra that point to long-term changes in atmospheric CH4, CO2 and O3 as well as CFC-11 and CFC-12. Our results provide direct experimental evidence for a significant increase in the Earth's greenhouse effect that is consistent with concerns over radiative forcing of climate.
10 Radiative GHE Observed2015(Feldman et al., 2015)https://doi.org/10.1038/nature14240Here we present observationally based evidence of clear-sky CO2 surface radiative forcing that is directly attributable to the increase, between 2000 and 2010, of 22 parts per million atmospheric CO2
10 Radiative GHE Observed2004(Philipona et al., 2004)https://doi.org/10.1029/2003GL018765The resulting temperature corrected cloud-free longwave downward radiation (LDRcf,tc) shown in Figure 3b) has, due to the high correlation, now much less variability and a quite uniform increase between 2.1 and 2.9 Wm−2 over all stations. The average LDRcf,tc increase is +2.4 (0.9) Wm−2 and most of the stations show a trend at the 95% significance level.

The resulting uniform increase of longwave downward radiation manifests radiative forcing that is induced by increased greenhouse gas concentrations and water vapor feedback, and proves the -theory- of greenhouse warming with direct observations.
10 Upper Atmosphere Cooling2013(Santer et al., 2013)https://doi.org/10.1073/pnas.1305332110Since the late 1970s, satellite-based instruments have monitored global changes in atmospheric temperature. These measurements reveal multidecadal tropospheric warming and stratospheric cooling...We show that a human-caused latitude/altitude pattern of atmospheric temperature change can be identified with high statistical confidence in satellite data
10 Decreasing DTR2006(Alexander et al., 2006)https://doi.org/10.1029/2005JD006290Trends in the gridded fields were computed and tested for statistical significance. Results showed widespread significant changes in temperature extremes associated with warming, especially for those indices derived from daily minimum temperature...Daily maximum temperature indices showed similar changes but with smaller magnitudes.
10 Decreasing DTR2016(Davy et al., 2016)https://doi.org/10.1002/joc.4688Here, we review the observed diurnal asymmetry in the global warming trend: the night-time temperatures have increased more rapidly than day-time temperatures...we demonstrate that the night-time temperatures are inherently more sensitive to perturbations to the radiation balance and will warm more rapidly on a uniform forcing (such as that from the build-up of greenhouse-gases).
9 Upper Atmosphere Cooling2014(Ogawa et al., 2014)https://doi.org/10.1002/2014GL060591The European Incoherent Scatter radar has gathered data in the polar ionosphere above Tromso for over 33-years. Using this long-term data set, we have estimated the first significant trends of ion temperature at altitudes between 200 and 450-km. The estimated trends indicate a cooling of 10-15-K/decade near the F region peak (220-380-km altitude)
9 Upper Atmosphere Cooling1997(Ulich and Turunen, 1997)https://doi.org/10.1029/97GL50896We find a close to linear decrease in the altitude of the F2 layer peak during the last 39 years, when the effect of solar cycle variations is removed from the data. This local trend is qualitatively consistent with the model predictions of a cooling of the lower thermosphere.
8 Decreasing DTR2005(Vose et al., 2005)https://doi.org/10.1029/2005GL024379New data acquisitions are used to examine recent global trends in maximum temperature, minimum temperature, and the diurnal temperature range (DTR)...minimum temperature increased more rapidly than maximum temperature (0.204 vs. 0.141 C dec−1) from 1950-2004, resulting in a significant DTR decrease (−0.066 C dec−1).
8 Radiative GHE Observed2009(Wang and Liang, 2009)https://doi.org/10.1029/2009JD011800We found that daily Ld increased at an average rate of 2.2 W m^2 per decade from 1973 to 2008. The increase in Ld is mainly due to the increase in air temperature, water vapor and CO2 concentration.
8 Radiative GHE Observed2008(Wild, Grieser and Schär, 2008)https://doi.org/10.1029/2008GL034842Here we present a first-order trend estimate for the 15-year period 1986-2000, which suggests that surface net radiation over land has rapidly increased by about 2 Wm^2 per decade, after several decades with no evidence for an increase. This recent increase is caused by increases in both downward solar radiation (due to a more transparent atmosphere) and downward thermal radiation (due to enhanced concentrations of atmospheric greenhouse gases)
7 Radiative GHE Observed2007(Prata, 2007)https://doi.org/10.1080/01431160802036508Here long-term (more than 25 years) mean monthly profiles obtained from globally distributed land-based radiosonde stations are subjected to detailed radiative transfer computations and Fourier time series analysis. The results indicate that over the period 1964-1990, there has been a global increase in the clear-sky longwave flux at the surface. The global trend is approximately +1.7 W m^2 per decade
7 Decreasing DTR1995(Plummer et al., 1995)https://doi.org/10.1016/0169-8095(94)00070-TTrends in maximum and minimum temperatures over Australia from 1951 to 1992 have been examined using data adjusted for inhomogeneities....showing a decrease in the diurnal temperature range (DTR) over large areas of the Australian continent...largely a consequence of the minimum temperatures increasing more than the maximum temperatures
7 Upper Atmosphere Cooling1992(Bremer, 1992)https://doi.org/10.1016/0021-9169(92)90157-GUsing long-term ionosonde measurements in mid-latitudes (Juliusruh: 54.6N, 13.4E; 1957-1990), the first experimental hints of a decrease of the peak height of the ionospheric F2-layer were found...These results qualitatively agree with the predictions of Rishbeth [(1990) Planet. Space Sci.38, 945] who expected a lowering of the E- and F2-layer caused by a global cooling of the strato, meso- and thermosphere due to the increasing greenhouse effect.
9 Upper Atmosphere Cooling2004(Emmert et al., 2004)https://doi.org/10.1029/2003JA010176The results cover all levels of solar activity during the period 1996-2001, and each object indicates a long-term decrease of total mass density...The trends that we obtain are qualitatively, and in some cases quantitatively, consistent with available theoretical predictions of density decreases associated with the cooling effect of increased greenhouse gas concentrations.
9 Upper Atmosphere Cooling2008(Emmert et al., 2008)https://doi.org/10.1029/2007GL032809We use orbit data on ∼5000 near-Earth space objects to investigate long-term trends in thermospheric total mass density, which has been predicted to decrease with time due to increasing CO2 concentrations...At 400 km, we estimate an overall trend of -2.68 +/- 0.49 % per decade and trends of ∼-5 and -2 % per decade at solar minimum and maximum, respectively, in fair quantitative agreement with theoretical predictions
5 Upper Atmosphere Cooling2008(Holt and Zhang, 2008)https://doi.org/10.1029/2007GL031148Temperature data from the Millstone Hill incoherent scatter radar (46.2N, 288.5E) from 1978 to 2007 have been analyzed to provide a direct estimate of the temperature trend above the radar. The long-term trend in the directly measured ion temperature Ti at 375 km is found to be −4.7 K/year with a 95% confidence interval of −3.6 to −5.8 K
8 Upper Atmosphere Cooling2011(Zhang et al., 2011)https://doi.org/10.1029/2010JA016414A cooling trend at altitudes above 200 km and an apparent warming trend below 200 km are found...these changes appear to be suggestive of a long-term greenhouse gas effect.
9 Warming Anomalous Historically2019(Neukom, R. et al., 2019)https://doi.org/10.1038/s41586-019-1401-2Here we use global palaeoclimate reconstructions for the past 2,000 years, and find no evidence for preindustrial globally coherent cold and warm epochs... This provides strong evidence that anthropogenic global warming is not only unparalleled in terms of absolute temperatures, but also unprecedented in spatial consistency within the context of the past 2,000 years.
7 Warming Anomalous Historically2013(Ahmed et al., 2013)https://doi.org/10.1038/ngeo1834Recent warming reversed the long-term cooling; during the period AD 1971-2000, the area-weighted average reconstructed temperature was higher than any other time in nearly 1,400 years.
7 Warming Anomalous Historically2008(Mann et al., 2008)https://doi.org/10.1073/pnas.0805721105We find that the hemispheric-scale warmth of the past decade for the NH is likely anomalous in the context of not just the past 1,000 years, as suggested in previous work, but longer.
7 Decreasing DTR2009(Choi et al., 2009)https://doi.org/10.1002/joc.1979In this study, spatial and temporal patterns of changes in extreme events of temperature and precipitation at 143 weather stations in ten Asia-Pacific Network (APN) countries and their associations with changes in climate means are examined for the 1955-2007 period. Averaged over the APN region, annual frequency of cool nights (days) has decreased by 6.4 days/decade (3.3 days/decade), whereas the frequency of warm nights (days) has increased by 5.4 days/decade (3.9 days/decade)
6 Decreasing DTR2006(Klein Tank et al., 2006)https://doi.org/10.1029/2005JD006316This smaller warming of daytime versus nighttime extremes is consistent with the observed decrease in diurnal temperature range (DTR) shown in Figure 4 (0.12C/decade).
5 Upper Atmosphere Cooling2011(Seidel et al., 2011)https://doi.org/10.1002/wcc.125Observations show overall cooling of the stratosphere during the period for which they are available (since the late 1950s and late 1970s from radiosondes and satellites, respectively)
7 Decreasing DTR2013(Skansi et al., 2013)https://doi.org/10.1016/j.gloplacha.2012.11.0...Nighttime (minimum) temperature indices show the largest rates of warming (e.g. for tropical nights, cold and warm nights), while daytime (maximum) temperature indices also point to warming (e.g. for cold days, summer days, the annual lowest daytime temperature), but at lower rates than for minimums.
7 Decreasing DTR1997(Easterling et al., 1997)https://doi.org/10.1126/science.277.5324.364Analysis of the global mean surface air temperature has shown that its increase is due, at least in part, to differential changes in daily maximum and minimum temperatures, resulting in a narrowing of the diurnal temperature range (DTR)
7 Upper Atmosphere Cooling2005(Thorne et al., 2005)https://doi.org/10.1029/2004JD005753Within the lower stratosphere, at 100 hPa...Over the entire period of 1958 to 2002 there is an overall global cooling at 100 hPa...Zonal mean trends over the full period 1958-2002 exhibit warming throughout the troposphere, and cooling in the stratosphere
6 Decreasing DTR1993(Karl et al., 1993)https://doi.org/10.1175/1520-0477(1993)074%3C...Monthly mean maximum and minimum temperatures for over 50% (10%) of the Northern (Southern) Hemisphere landmass, accounting for 37% of the global landmass, indicate that the rise of the minimum temperature has occurred at a rate three times that of the maximum temperature during the period 1951-90 (0.84C versus 0.28C)
4 Warming Anomalous Historically2007(Juckes et al., 2007)https://doi.org/10.5194/cp-3-591-2007A reconstruction using 13 proxy records extending back to AD 1000 shows a maximum pre-industrial temperature of 0.25 K (relative to the 1866 to 1970 mean)...Instrumental temperatures for two recent years (1998 and 2005) have exceeded the pre-industrial estimated maximum by more than 4 standard deviations of the calibration period residual.
6 Warming Anomalous Historically2012(Leclercq and Oerlemans, 2012)https://doi.org/10.1007/s00382-011-1145-7The rate of temperature change over the period 1980-2000, with a linear trend of 0.16 K per decade, is the highest over the last 400 years...Our reconstruction supports the conclusion of Mann et al. (2008) that the high global average temperatures of the 1990-2000 decade are unprecedented in at least the last four centuries.
4 Warming Anomalous Historically2010(Ljungqvist, 2010)https://doi.org/10.1111/j.1468-0459.2010.0039...The temperature of the last two decades, however, is possibly higher than during any previous time in the past two millennia
4 Warming Anomalous Historically2009(Mann et al., 2009)https://doi.org/10.1126/science.1177303The Medieval period is found to display warmth that matches or exceeds that of the past decade in some regions, but which falls well below recent levels globally
6 Warming Anomalous Historically2000(Huang et al., 2000)https://doi.org/10.1038/35001556We use present-day temperatures in 616 boreholes from all continents except Antarctica to reconstruct century-long trends in temperatures over the past 500 years at global, hemispheric and continental scales. The results confirm the unusual warming of the twentieth century revealed by the instrumental record
8 Warming Anomalous Historically1999(Mann et al., 1999)https://doi.org/10.1029/1999GL900070our results suggest that the latter 20th century is anomalous in the context of at least the past millennium...20th century warming counters a millennial-scale cooling trend which is consistent with long-term astronomical forcing.
7 Warming Anomalous Historically2011(Mann et al., 2011)https://doi.org/10.1029/2003EO270003A number of reconstructions of large-scale temperature changes over the past millennium support the conclusion that late-20th century warmth was unprecedented over at least the past millennium.
5 Warming Anomalous Historically1995(Briffa et al., 1995)https://doi.org/10.1038/376156a0Here we report a tree-ring-based reconstruction of mean summer temperatures over the northern Urals since AD 914. This record shows that the mean temperature of the twentieth century (1901-90) is higher than during any similar period since AD 914.
6 Decreasing DTR2008(Dufek et al., 2008;)https://doi.org/10.1196/annals.1446.010All over South America, the climate indices related to the minimum temperature (warm or cold nights) have clearly shown a warming tendency; however, no consistent changes in maximum temperature extremes (warm and cold days) have been observed
8 Upper Atmosphere Cooling2009(Randel et al., 2009)https://doi.org/10.1029/2008JD010421Trends in the middle and upper stratosphere have been derived from updated SSU data, taking into account changes in the SSU weighting functions due to observed atmospheric CO2 increases. The results show mean cooling of 0.5-1.5 K/decade during 1979-2005, with the greatest cooling in the upper stratosphere near 40-50 km.
6 Decreasing DTR1995(Horton, 1995)https://doi.org/10.1016/0169-8095(94)00083-PSeasonal trends of maximum and minimum temperature, and diurnal range, are presented, revealing a marked decrease in diurnal temperature range in 1981-1990 compared with 1951-1980 over a large area of the world.
4 Decreasing DTR1991(Karl et al., 1991)https://doi.org/10.1029/91GL02900Three large countries in the Northern Hemisphere (the contiguous United States, the Soviet Union, and the People's Republic of China)...most of the warming which has occurred in these regions over the past four decades can be attributed to an increase of mean minimum (mostly nighttime) temperatures. Mean maximum (mostly daytime) temperatures display little or no warming.
5 Decreasing DTR2008(Soltani and Soltani, 2008)https://dx.doi.org/10.3923/rjes.2008.316.322Minimum temperature (0.29°C/decade) at Bojnord and both minimum (0.45°C/decade) and maximum (0.24°C/decade) temperatures at Mashhad indicated significant positive trend. The positive trend for minimum temperature at Bojnord and Mashhad could be ascribed to greenhouse effect.
7 Upper Atmosphere Cooling2020(French et al., 2020)https://doi.org/10.5194/acp-2019-1001Hydroxyl rotational temperatures are a layer-weighted proxy for kinetic temperatures near 87 km altitude and have been used for many decades to monitor trends in the mesopause region in response to increasing greenhouse gas emissions...a record low winter-average temperature of 198.3 K is obtained for 2018...a long term cooling trend of 1.2 K/decade persists
6 Decreasing DTR2016(Cao et al., 2016)https://doi.org/10.1002/joc.4639Based on the new homogenized data set, linear trends in the annual and seasonal temperature series from 1960 to 2014 were calculated...The updated nationwide mean warming rate reached 0.22 C per 10 years for the Tmax...and 0.38 C per 10 years for the Tmin.
6 Decreasing DTR2018(Tong et al., 2018)https://doi.org/10.1016/j.scitotenv.2018.08.2...Temporal and spatial variations in extreme temperature and precipitation events in Inner Mongolia were analyzed...nighttime warming was higher than daytime warming.
6 Decreasing DTR2019(Fallah-Ghalhari et al., 2019)https://doi.org/10.1007/s00704-019-02906-9In this paper, trends of minimum and maximum temperatures in Iran were studied...the slope of the trend line for maximum and minimum temperature was obtained 0.23 and 0.39 C decade -1, respectively.
7 Decreasing DTR2019(Liu et al., 2019)https://doi.org/10.3390/atmos10120815Over the Yarlung Tsangpo River Basin (1970-2017)...increases in daily minimum and maximum temperature were detected, and the magnitude of daily minimum temperature change was greater than that of the daily maximum temperature, revealing an obvious decrease in the diurnal temperature range.
5 Warming Anomalous Historically2001(Briffa et al., 2001)https://doi.org/10.1029/2000JD900617We describe new reconstructions of northern extratropical summer temperatures for nine subcontinental?scale regions and a composite series representing quasi "Northern Hemisphere" temperature change over the last 600 years...the 20th century is clearly shown by all of the palaeoseries composites to be the warmest during this period.
8 Warming Anomalous Historically2003(Mann & Jones, 2003)https://doi.org/10.1029/2003GL017814We present reconstructions of Northern and Southern Hemisphere mean surface temperature over the past two millennia based on high?resolution ?proxy? temperature data which retain millennial?scale variability. These reconstructions indicate that late 20th century warmth is unprecedented for at least roughly the past two millennia for the Northern Hemisphere.
6 Warming Anomalous Historically2001(Jones et al., 2001)https://doi.org/10.1126/science.1059126Average temperatures during the last three decades were likely the warmest of the last millennium, about 0.2?C warmer than during warm periods in the 11th and 12th centuries. The 20th century experienced the strongest warming trend of the millennium (about 0.6?C per century)
5 Decreasing DTR2020(Fathian et al., 2020)https://doi.org/10.1007/s00704-020-03269-2Data of 76 synoptic stations were selected for trend analysis throughout Iran during the period 1981-2010...the monthly maximum value of daily maximum (TXx) and minimum (TNx) temperatures increased by 0.3 and 0.4 C/decade on average, respectively; and the monthly minimum value of daily maximum (TXn) and minimum (TNn) temperatures increased by 0.1 and 0.3 C/decade, respectively
5 Decreasing DTR1998(Gaffen & Ross, 1998)https://doi.org/10.1038/25030In the past half century, the mean summertime temperature in the United States has increased, with nights warming more than days.
6 Decreasing DTR2014(Stephenson et al., 2014)https://doi.org/10.1002/joc.3889This study presents the trends in daily and extreme temperature and precipitation indices in the Caribbean region for records spanning the 1961-2010 and 1986-2010 intervals...in general, the indices based on minimum temperature show stronger warming trends than indices calculated from maximum temperature.
9 Upper Atmosphere Cooling2006(Lastovicka et al., 2006)https://doi.org/10.1126/science.1135134Over the past three decades, the global temperature at Earth?s surface has increased by 0.2 to 0.4 C, compared with a 5 to 10 C decrease in the lower and middle mesosphere.. The upper atmosphere is generally cooling and contracting, and related changes in chemical composition are affecting the ionosphere. The dominant driver of these trends is increasing greenhouse forcing.