copenlu/druid huggingface dataset:
Claim: Solar forcings are not too small to explain twentieth century warming. In fact, their effect could be equal to or greater than the effect of CO2 in the atmosphere. (Craig Idso, Robert Carter, S. Fred Singer, 2017-03-05)
Evidence (2013-12-22): The climate of the past millennium was marked by substantial decadal and centennial scale variability in the Northern Hemisphere1. Low solar activity has been linked to cooling during the Little Ice Age (AD 1450–1850; ref. 1) and there may have been solar forcing of regional warmth during the Medieval Climate Anomaly2,3,4,5 (AD 950–1250; ref. 1). The amplitude of the associated changes is, however, poorly constrained5,6, with estimates of solar forcing spanning almost an order of magnitude7,8,9. Numerical simulations tentatively indicate that a small amplitude best agrees with available temperature reconstructions10,11,12,13. Here we compare the climatic fingerprints of high and low solar forcing derived from model simulations with an ensemble of surface air temperature reconstructions14 for the past millennium. Our methodology15 also accounts for internal climate variability and other external drivers such as volcanic eruptions, as well as uncertainties in the proxy reconstructions and model output. We find that neither a high magnitude of solar forcing nor a strong climate effect of that forcing agree with the temperature reconstructions. We instead conclude that solar forcing probably had a minor effect on Northern Hemisphere climate over the past 1,000 years, while, volcanic eruptions and changes in greenhouse gas concentrations seem to be the most important influence over this period. [...] Hind, A. & Moberg, A. Past millennial solar forcing magnitude. Clim. Dynam.41, 2527–2537 (2012).
Claim: Solar forcings are not too small to explain twentieth century warming. In fact, their effect could be equal to or greater than the effect of CO2 in the atmosphere. (Craig Idso, Robert Carter, S. Fred Singer, 2017-03-05)
Evidence (2012-05-16): Thus, to explain the warming with GHG forcing alone requires feedbacks to account for a forcing of Δf − ΔfG ≈ 2.67 W m−2, that is, a (positive) feedback factor of aG = Δf/ΔfG ≈ 2.1. To explain 60% of the warming with solar forcing requires a feedback factor of aS = 0.6 × Δf/ΔfS ≈ 12.8 and a feedback factor of aG = 0.4 × Δf/ΔfG ≈ 0.8 for greenhouse gases. In other words, the fit of Scafetta (2009) requires a huge positive feedback for the solar forcing but a negative feedback for the greenhouse forcing. Thus, this fit raises much bigger problems than it solves and makes no sense physically. [...] Meehl GA, Washington WM, Wigley TML, Arblaster JM, Dai A (2003) Solar and greenhouse gas forcing and climate response in the twentieth century. J Clim 16:426–444. doi:10.1175/15200442
Claim: Solar forcings are not too small to explain twentieth century warming. In fact, their effect could be equal to or greater than the effect of CO2 in the atmosphere. (Craig Idso, Robert Carter, S. Fred Singer, 2017-03-05)
Evidence (2023-12-19): Furthermore, solar cycle has a separate external forcing than CO2. The response to this external forcing is amplified by the climate feedback processes of the Earth system. It is hoped that by examining the solar-cycle response at the Earth’s surface, we can estimate the effect of the climate feedback involved, and hence the climate sensitivity of the Earth system. This is a different approach than some of the current ones, for example, of using the effect of Arctic snow-albedo12, or tropical low clouds13,14 to provide a constraint on the climate sensitivity (ECS in the cited cases). Using a component of the feedback process to constrain ECS or TCR requires an additional assumption that the other feedback components are "unbiased", e.g. not compensating9. This structural uncertainty has so far not been assessed.
Claim: Solar forcings are not too small to explain twentieth century warming. In fact, their effect could be equal to or greater than the effect of CO2 in the atmosphere. (Craig Idso, Robert Carter, S. Fred Singer, 2017-03-05)
Evidence (2004-10-01): As noted by Meehl et al. (2003), solar was likely the dominant forcing that produced the temperature increases in the first part of the twentieth century. Thus, in PC1 and PC2, explaining 90% and 8%, respectively, of the variance of the original time series, the elements of the two major features of the globally averaged surface air temperature over the twentieth century are represented: the early century warming in the model associated mainly with solar forcing, and the late-century warming produced mainly by increased GHGs in the model. PC3, representing only 1% of the variance, shows low-amplitude variations that have elements of both the early century and late-century warming and cannot be associated directly with any single forcing time series in Fig. 1. Had the PC analysis shown a gradual decay of variance explained among the 13 PCs with no obvious cutoff, we would not advocate this approach over a simple mean standard error computation between original forcings and residuals. But the obvious dominance of just three components seems to us to justify this simple additional step, and adds insight to the analysis of linearity. [...] Meehl, G. A., W. M. Washington, T. M. L. Wigley, J. M. Arblaster, and A. Dai, 2003: Solar and greenhouse gas forcing and climate response in the twentieth century. J. Climate, 16 , 426–444.
Claim: Solar forcings are not too small to explain twentieth century warming. In fact, their effect could be equal to or greater than the effect of CO2 in the atmosphere. (Craig Idso, Robert Carter, S. Fred Singer, 2017-03-05)
Evidence (2024-04-09): Natural increases in carbon dioxide concentrations have periodically warmed Earth’s temperature during ice age cycles over the past million years or more. The warm episodes (interglacials) began with a small increase in incoming sunlight in the Northern Hemisphere due to variations in Earth’s orbit around the Sun and its axis of rotation. (For more details, see the "Milankovitch cycles and ice ages" section of our Climate change: incoming sunlight article.) That little bit of extra sunlight caused a little bit of warming. As the oceans warmed, they outgassed carbon dioxide—like a can of soda going flat in the heat of a summer day. The extra carbon dioxide in the atmosphere greatly amplified the initial, solar-driven warming. Based on air bubbles trapped in mile-thick ice cores and other paleoclimate evidence, we know that during the ice age cycles of the past million years or so, atmospheric carbon dioxide never exceeded 300 ppm. Before the Industrial Revolution started in the mid-1700s, atmospheric carbon dioxide was 280 ppm or less. [...] More on carbon dioxide
Claim: Solar forcings are not too small to explain twentieth century warming. In fact, their effect could be equal to or greater than the effect of CO2 in the atmosphere. (Craig Idso, Robert Carter, S. Fred Singer, 2017-03-05)
Evidence (2011-03-06): For downloadable pdfs of factsheets and graphic assets, see the Digital Library. [...] Sources: IPCC (1), WMO (4, 7, 10), WMO (4), IPCC (4, 7), UN Climate Action (8, 10), World Bank (11). [...] - Global surface temperature has increased faster since 1970 than in any other 50-year period over at least the last 2000 years.
Claim: Solar forcings are not too small to explain twentieth century warming. In fact, their effect could be equal to or greater than the effect of CO2 in the atmosphere. (Craig Idso, Robert Carter, S. Fred Singer, 2017-03-05)
Evidence (2019-07-30): CO2 makes up only about 0.04% of the atmosphere, and water vapor can vary from 0 to 4%. But while water vapor is the dominant greenhouse gas in our atmosphere, it has "windows" that allow some of the infrared energy to escape without being absorbed. In addition, water vapor is concentrated lower in the atmosphere, whereas CO2 mixes well all the way to about 50 kilometers up. The higher the greenhouse gas, the more effective it is at trapping heat from the Earth’s surface. The burning of fossil fuels affects the concentration of CO2 in the atmosphere. Before the industrial revolution, the amount of CO2 in the atmosphere was about 288 ppm. We have now reached about 414 ppm, so we are on the way to doubling the amount of CO2 in the atmosphere by the end of this century. Scientists say that if CO2 doubles, it could raise the average global temperature of the Earth between two and five degrees Celsius. We are already increasing the amount of energy that bounces back to the Earth. Because of the greenhouse effect, this is causing global warming with its many destructive impacts.
Claim: Solar forcings are not too small to explain twentieth century warming. In fact, their effect could be equal to or greater than the effect of CO2 in the atmosphere. (Craig Idso, Robert Carter, S. Fred Singer, 2017-03-05)
Evidence (2022-06-09): Water vapor is also a product of jet fuel consumption, making up about 30 percent of the exhaust. With its short lifespan in the atmosphere as part of the water cycle, water vapor from aircraft has a minimal direct warming impact. However, its presence in the exhaust plume has an indirect impact by contributing to the formation of contrails. Water vapor in the exhaust instantly freezes when the ambient temperature is cold enough, as particulates in the exhaust form the nucleus of ice crystals. When the ambient atmosphere is sufficiently humid and cold, the small ice crystals expand as they draw water vapor from the atmosphere and are sustained as contrails that can spread horizontally and vertically to form contrail-induced cirrus clouds. These lingering contrails and contrail-induced cirrus clouds trap infrared rays, producing a warming effect up to three times the impact of CO2. Even though these cirrus clouds have a relatively short life span, usually a matter of hours, their collective influence, produced by thousands of flights, have a serious warming effect. The effect is so large today that it exceeds the total warming influence of all the CO2 emitted by aircraft since the beginning of powered flight.
Claim: Solar forcings are not too small to explain twentieth century warming. In fact, their effect could be equal to or greater than the effect of CO2 in the atmosphere. (Craig Idso, Robert Carter, S. Fred Singer, 2017-03-05)
Evidence (2021-10-11): The effect of the orbital features on the total sunlight reaching the Earth is almost zero; the sunshine is just moved between areas and seasons. But, the whole world cools into an ice age, and the whole world warms coming out of an ice age, despite half the world getting less sun when the other half gets more. And, so far, all the explanations of this require the effects of the CO2, which beautifully explain it. A recent study by Dr Daniel Baggenstos at the University of Bern and colleagues examined the relative contribution of different factors during the transition from the last ice age to the current interglacial period. They found that albedo – changing reflectivity of the surface as ice sheets shrink – was the largest factor responsible for about half of the warming, while changing CO2 concentrations and other greenhouse gases was responsible for 37%, while reductions of the amount of reflective dust and other aerosols in the atmosphere made up the remaining 13%. [...] However, if CO2 only contributed around 35% of the warming at the end of the last ice age – with changing albedo from melting ice sheets playing a major role – this would imply a climate sensitivity of around 3C – much more in-line with current model estimates, though with a very large uncertainty given the limits to how accurately models simulate global changes over that period.
Claim: Solar forcings are not too small to explain twentieth century warming. In fact, their effect could be equal to or greater than the effect of CO2 in the atmosphere. (Craig Idso, Robert Carter, S. Fred Singer, 2017-03-05)
Evidence (2024-07-01): A summary of radiative forcings of climate in 2019 resulting from the increases in the principal long-lived and short-lived GHGs from human activities since 1750 is shown in Figure Q17-1. Positive forcings lead to warming and negative forcings lead to cooling of Earth’s surface. Climate forcings also lead to other changes, for example reductions in glacier and sea-ice extent, variations in precipitation patterns, and more extreme weather events. International climate assessments conclude that much of the observed surface warming and changes in other climate parameters over the last several decades are due to increases in the atmospheric abundances of CO2 and other GHGs, which result from a variety of human activities.
Claim: Solar forcings are not too small to explain twentieth century warming. In fact, their effect could be equal to or greater than the effect of CO2 in the atmosphere. (Craig Idso, Robert Carter, S. Fred Singer, 2017-03-05)
Evidence (2022-01-31): The combination of all radiative forcings generally matches longer-term changes in observed temperatures quite well. There is some year-to-year variability, primarily from El Niño events, that is not driven by changes in forcings. There are also periods from 1900-1920 and 1930-1950 where some larger disagreements are evident between projected and observed warming, both in this simple model and in more complex climate models. [...] Future radiative forcing from CO2 is expected to continue to increase if emissions rise. Aerosols, on the other hand, are projected to peak at today’s levels and decline significantly by 2100, driven in large part by concerns about air quality. This reduction in aerosols will enhance overall warming, bringing total warming from all radiative forcing closer to warming from greenhouse gases alone. The RCP scenarios assume no specific future volcanic eruptions, as the timing of these is unknowable, while solar output continues its 11-year cycle. [...] While natural forcings from solar and volcanoes do not seem to play much of a role in long-term warming, there is also natural variability associated with ocean cycles and variations in ocean heat uptake.
Claim: Solar forcings are not too small to explain twentieth century warming. In fact, their effect could be equal to or greater than the effect of CO2 in the atmosphere. (Craig Idso, Robert Carter, S. Fred Singer, 2017-03-05)
Evidence (2020-06-22): Information from ice cores
Claim: Solar forcings are not too small to explain twentieth century warming. In fact, their effect could be equal to or greater than the effect of CO2 in the atmosphere. (Craig Idso, Robert Carter, S. Fred Singer, 2017-03-05)
Evidence (2013-02-19): While a ton-for-ton comparison of emissions is useful, it is more helpful to understand the overall influence each type of emission has on climate change. The best method to compare the total effect of very different climate pollutants is radiative forcing. This measures the change in Earth’s energy budget (i.e., the warming effect) caused by the total atmospheric concentration of a GHG or particulate. The radiative forcing of CO2 (over pre-industrial conditions) is 1.66 watts per square meter (W/m2)*. Methane’s radiative forcing is 0.48 W/m2. In other words, the current atmospheric concentration of methane causes a warming effect equal to 29 percent of the effect caused by the current concentration of CO2. *Radiative forcing measures the change in energy, in watts, at the top of the atmosphere averaged over each square meter of the planet. Emissions that have a cooling effect, such as sulfates, have a negative radiative forcing.
Claim: Solar forcings are not too small to explain twentieth century warming. In fact, their effect could be equal to or greater than the effect of CO2 in the atmosphere. (Craig Idso, Robert Carter, S. Fred Singer, 2017-03-05)
Evidence (2022-07-20): This amount of warming (∼0.1 ∘C) is also equal to the amount of warming projected in 2100 from carbon dioxide emissions from international shipping and aviation combined in the absence of climate action (Ivanovich et al., 2019). However, if leakage does not exceed 1 %, the temperature response could be an order of magnitude smaller. [...] This research has been supported by Robertson Foundation, the Heising-Simons Foundation, and ClimateWorks Foundation. [...] Rahn, T., Eiler, J. M., Boering, K. A., Wennberg, P. O., McCarthy, M. C., Tyler, S., Schauffler, S., Donnelly, S., and Atlas, E.: Extreme deuterium enrichment in stratospheric hydrogen and the global atmospheric budget of H2, Nature, 424, 915–918, https://doi.org/10.1038/nature01917, 2003.
Claim: Solar forcings are not too small to explain twentieth century warming. In fact, their effect could be equal to or greater than the effect of CO2 in the atmosphere. (Craig Idso, Robert Carter, S. Fred Singer, 2017-03-05)
Evidence (2017-05-03): Factually Inaccurate: No estimate of 20th century climate forcings (warming or cooling influences) shows the solar forcing to be close to the effect of increased CO2. [...] There is strong evidence that solar forcing cannot explain much of the observed warming at all. The "fingerprint" of solar forcing does not match the observed changes at all, neither over time nor space. Solar forcing would warm both the stratosphere and the surface of the Earth, whereas CO2 warms the surface (and the troposphere) but cools the stratosphere. Using radiosondes and (more recently) satellites, we have observed a warming surface and troposphere together with a cooling stratosphere. See Santer et al (2013)* for one of many studies providing this evidence. [...] Solar forcing is much smaller than CO2 forcing. As this figure from the latest IPCC report shows, CO2 radiative forcing (1.68 W/m2) dwarfs solar forcing (0.05 W/m2). Along with other greenhouse gases, CO2 dominates the total radiative forcing when all positive and negative factors are taken into account.
Claim: Solar forcings are not too small to explain twentieth century warming. In fact, their effect could be equal to or greater than the effect of CO2 in the atmosphere. (Craig Idso, Robert Carter, S. Fred Singer, 2017-03-05)
Evidence (2015-01-01): Several eruptions during the past century have caused a decline in the average temperature at the Earth's surface of up to half a degree (Fahrenheit scale) for periods of one to three years. The climactic eruption of Mount Pinatubo on June 15, 1991, was one of the largest eruptions of the twentieth century and injected a 20-million ton (metric scale) sulfur dioxide cloud into the stratosphere at an altitude of more than 20 miles. The Pinatubo cloud was the largest sulfur dioxide cloud ever observed in the stratosphere since the beginning of such observations by satellites in 1978. It caused what is believed to be the largest aerosol disturbance of the stratosphere in the twentieth century, though probably smaller than the disturbances from eruptions of Krakatau in 1883 and Tambora in 1815. Consequently, it was a standout in its climate impact and cooled the Earth's surface for three years following the eruption, by as much as 1.3 degrees F at the height of the impact. [...] For additional information about this subject, please read the American Geophysical Union's Eos article "Volcanic Versus Anthropogenic Carbon Dioxide" written by USGS scientist Terrence M. Gerlach. [...] **Ratio of annual anthropogenic CO2 (approximately 35 Gt) to maximum preferred estimate for annual volcanic CO2.
Claim: Solar forcings are not too small to explain twentieth century warming. In fact, their effect could be equal to or greater than the effect of CO2 in the atmosphere. (Craig Idso, Robert Carter, S. Fred Singer, 2017-03-05)
Evidence (2023-05-11): Almost all of the water on Earth is stored in two places: in the oceans (currently 97 percent of all water) and in glaciers (currently about 2.7 percent). How much water is in the oceans—and thus how high sea level is—largely depends on how much water is trapped in glacial ice. [...] Fifth Assessment Report from the Intergovernmental Panel on Climate Change [...] Probabilistic reanalysis of twentieth-century sea-level rise – Carling C. Hay, Eric Morrow, Robert E. Kopp and Jerry X. Mitrovica
Claim: Solar forcings are not too small to explain twentieth century warming. In fact, their effect could be equal to or greater than the effect of CO2 in the atmosphere. (Craig Idso, Robert Carter, S. Fred Singer, 2017-03-05)
Evidence (2017-02-09): Neither the rate nor the magnitude of the reported late twentieth century surface warming (1979–2000) lay outside normal natural variability. [...] Forward projections of solar cyclicity imply the next few decades may be marked by global cooling rather than warming, despite continuing CO2 emissions. [...] Increases in atmospheric CO2 followed increases in temperature. Therefore, CO2 levels could not have forced temperatures to rise.
Claim: Solar forcings are not too small to explain twentieth century warming. In fact, their effect could be equal to or greater than the effect of CO2 in the atmosphere. (Craig Idso, Robert Carter, S. Fred Singer, 2017-03-05)
Evidence (2006-06-01): There is a degree of uncertainty regarding these different solar forcing reconstructions (e.g., Foukal et al. 2004) that is reflected in the climate model simulations. That is, Foukal et al. (2004), Lean et al. (2002), and others have questioned the earlier solar reconstructions of Hoyt and Schatten (1993) and Lean et al. (1995) in that low-frequency variation of solar output may be manifested only as amplitude modulation of the 11-yr solar cycle. This could reduce the amplitude of the low-frequency solar forcing that was present in the earlier reconstructions. We are currently performing sensitivity experiments with solar forcing that includes only amplitude modulation of the 11-yr solar cycle. Preliminary results show that the early century warming in the coupled model still occurs, but with somewhat reduced amplitude.
Claim: Solar forcings are not too small to explain twentieth century warming. In fact, their effect could be equal to or greater than the effect of CO2 in the atmosphere. (Craig Idso, Robert Carter, S. Fred Singer, 2017-03-05)
Evidence (2011-06-16): Shifts in Earth’s orbit are happening constantly, in predictable cycles. In about 30,000 years, Earth’s orbit will have changed enough to reduce sunlight in the Northern Hemisphere to the levels that led to the last ice age. [...] Carbon dioxide, on the other hand, remains a gas at a wider range of atmospheric temperatures than water. Carbon dioxide molecules provide the initial greenhouse heating needed to maintain water vapor concentrations. When carbon dioxide concentrations drop, Earth cools, some water vapor falls out of the atmosphere, and the greenhouse warming caused by water vapor drops. Likewise, when carbon dioxide concentrations rise, air temperatures go up, and more water vapor evaporates into the atmosphere—which then amplifies greenhouse heating. So while carbon dioxide contributes less to the overall greenhouse effect than water vapor, scientists have found that carbon dioxide is the gas that sets the temperature. Carbon dioxide controls the amount of water vapor in the atmosphere and thus the size of the greenhouse effect.