scholarly journals Solar and Anthropogenic Influences on Climate: Regression Analysis and Tentative Predictions

Climate ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 163
Author(s):  
Frank Stefani
Keyword(s):  
Climate Sensitivity ◽  
Temperature Drop ◽  
Carbon Dioxide Concentration ◽  
High Sensitivity ◽  
Simultaneous Occurrence ◽  
Anthropogenic Influences ◽  
Linear Combinations ◽  
The 19Th Century ◽  
Near Future ◽  
Aa Index

The paper aims to quantify solar and anthropogenic influences on climate change, and to make some tentative predictions for the next hundred years. By means of double regression, we evaluate linear combinations of the logarithm of the carbon dioxide concentration and the geomagnetic aa index as a proxy for solar activity. Thereby, we reproduce the sea surface temperature (HadSST) since the middle of the 19th century with an adjusted R2 value of around 87 percent for a climate sensitivity (of TCR type) in the range of 0.6 K until 1.6 K per doubling of CO2. The solution of the double regression is quite sensitive: when including data from the last decade, the simultaneous occurrence of a strong El Niño and of low aa values leads to a preponderance of solutions with relatively high climate sensitivities around 1.6 K. If these later data are excluded, the regression delivers a significantly higher weight of the aa index and, correspondingly, a lower climate sensitivity going down to 0.6 K. The plausibility of such low values is discussed in view of recent experimental and satellite-borne measurements. We argue that a further decade of data collection will be needed to allow for a reliable distinction between low and high sensitivity values. In the second part, which builds on recent ideas about a quasi-deterministic planetary synchronization of the solar dynamo, we make a first attempt to predict the aa index and the resulting temperature anomaly for various typical CO2 scenarios. Even for the highest climate sensitivities, and an unabated linear CO2 increase, we predict only a mild additional temperature rise of around 1 K until the end of the century, while for the lower values an imminent temperature drop in the near future, followed by a rather flat temperature curve, is prognosticated.

Climate Sensitivity and the Direct Effect of Carbon Dioxide in a Limited-Area Cloud-Resolving Model

2020 ◽  
Vol 33 (9) ◽  
pp. 3413-3429 ◽  
Author(s):  
David M. Romps
Keyword(s):  
Carbon Dioxide ◽  
Direct Effect ◽  
Climate Sensitivity ◽  
Convective Available Potential Energy ◽  
Carbon Dioxide Concentration ◽  
Limited Area ◽  
Equilibration Time ◽  
Feedback Parameter ◽  
Wide Range ◽  
Cloud Resolving Model

AbstractEven in a small domain, it can be prohibitively expensive to run cloud-resolving greenhouse gas warming experiments due to the long equilibration time. Here, a technique is introduced that reduces the computational cost of these experiments by an order of magnitude: instead of fixing the carbon dioxide concentration and equilibrating the sea surface temperature (SST), this technique fixes the SST and equilibrates the carbon dioxide concentration. Using this approach in a cloud-resolving model of radiative–convective equilibrium (RCE), the equilibrated SST is obtained as a continuous function of carbon dioxide concentrations spanning 1 ppmv to nearly 10 000 ppmv, revealing a dramatic increase in equilibrium climate sensitivity (ECS) at higher temperatures. This increase in ECS is due to both an increase in forcing and a decrease in the feedback parameter. In addition, the technique is used to obtain the direct effects of carbon dioxide (i.e., the rapid adjustments) over a wide range of SSTs. Overall, the direct effect of carbon dioxide offsets a quarter of the increase in precipitation from warming, reduces the shallow cloud fraction by a small amount, and has no impact on convective available potential energy (CAPE).

scholarly journals On the variability of return periods of European winter precipitation extremes over the last five centuries

2006 ◽  
Vol 2 (2) ◽  
pp. 157-189 ◽  
Author(s):  
A. Pauling ◽  
H. Paeth
Keyword(s):  
19Th Century ◽  
18Th Century ◽  
Winter Precipitation ◽  
Precipitation Extremes ◽  
Anthropogenic Influences ◽  
Return Periods ◽  
Before And After ◽  
Last 300 Years ◽  
The 19Th Century ◽  
Early 18Th Century

Abstract. We investigate the changes of extreme European winter (December–February) precipitation over the last half millennium and show for various European regions that return periods of extremely wet and dry winters are subject to significant changes both before and after the onset of anthropogenic influences. Additionally, we examine the spatial pattern of the changes of the extremes covering the last 300 years where data quality is sufficient. Over central and eastern Europe dry winters occurred more frequently during the 18th and the second part of the 19th century relative to 1951–2000. Dry winters were less frequent during both the 18th and 19th century over the British Isles and the Mediterranean. Wet winters have been less abundant during the last three centuries compared to 1951–2000 except during the early 18th century in central Europe. Although winter precipitation extremes are affected by climate change, no obvious connection of these changes was found to solar, volcanic or anthropogenic forcing. However, physically meaningful interpretation with atmospheric circulation changes was possible.

scholarly journals Climate sensitivity and meridional overturning circulation in the late Eocene using GFDL CM2.1

2018 ◽  
Author(s):  
David K. Hutchinson ◽  
Agatha M. de Boer ◽  
Helen K. Coxall ◽  
Rodrigo Caballero ◽  
Johan Nilsson ◽  
...  
Keyword(s):  
Climate Sensitivity ◽  
North Atlantic ◽  
Climate Model ◽  
Hydrological Cycle ◽  
High Sensitivity ◽  
Late Eocene ◽  
Meridional Overturning Circulation ◽  
Climate History ◽  
Model Studies ◽  
The North

Abstract. The Eocene–Oligocene Transition (EOT), approximately 34 Ma ago, is an interval of great interest in Earth's climate history, due to the inception of the Antarctic ice sheet and major global cooling at the time. Climate simulations of the transition are needed to help us interpret proxy data, test mechanistic hypotheses for the transition, and determine the climate sensitivity at the time. However, model studies of the EOT thus far typically employ control states designed for a different time period, or ocean resolution on the order of 3 degrees. Here we developed a new higher resolution paleoclimate model configuration based on the GFDL CM2.1 climate model adapted to a late Eocene (38 Ma) paleogeography reconstruction. We employ an ocean resolution of 1 × 1.5 degrees, and an atmosphere resolution of 3 × 3.75 degrees. This represents a significant step forward in resolving the ocean geography, gateways and circulation in a coupled climate model of this period. We simulate the model under 3 different levels of CO2; 400, 800 and 1600 ppm. The model exhibits relatively high sensitivity to CO2 compared with other recent model studies, and thus can capture the expected Eocene high latitude warmth within observed estimates of atmospheric CO2. However, the model does not capture the low meridional temperature gradient seen in proxies. Equatorial sea surface temperatures are too high in the model (30–37 degrees C) compared with observations (max 32 degrees C), though observations are lacking in the warmest regions of the western Pacific. The model exhibits robust bipolar sinking in the North Pacific and Southern Ocean, which persists under all levels of CO2. North Atlantic salinities are too fresh to permit sinking (25–30 psu), due to surface transport from the very fresh Arctic (~ 20 psu), whose salinities approximately agree with Eocene proxy estimates. North Atlantic salinity increases by 1–2 psu when CO2 is halved, and similarly freshens when CO2 is doubled, due to changes in the hydrological cycle.

scholarly journals Estimating Remaining Carbon Budgets Using Emulators of CMIP6 Models

2021 ◽  
Author(s):  
Martin Rypdal ◽  
Niklas Boers ◽  
Hege-Beate Fredriksen ◽  
Kai-Uwe Eiselt ◽  
Andreas Johansen ◽  
...  
Keyword(s):  
Co2 Emissions ◽  
Climate Sensitivity ◽  
Carbon Budget ◽  
Climate Models ◽  
Coupled Model ◽  
High Sensitivity ◽  
Earth System ◽  
Transient Climate Response ◽  
Uncertainty Range ◽  
Intercomparison Project

Abstract A remaining carbon budget (RCB) estimates how much CO2 we can emit and still reach a specific temperature target. The RCB concept is attractive since it easily communicates to the public and policymakers, but RCBs are also subject to uncertainties. The expected warming levels for a given carbon budget has a wide uncertainty range, which we show here to increase with less ambitious targets, i.e., with higher CO2 emissions and temperatures. Leading causes of RCB uncertainty are the future non-CO2 emissions, Earth system feedbacks, and the spread in the climate sensitivity among climate models. The latter is investigated in this paper, using simple emulators of Earth System Models in the Coupled Model Intercomparison Project Phase 6 (CMIP6) ensemble. It is shown that the transient climate response to cumulative emissions of carbon (TCRE) is approximately proportional to the effective equilibrium climate sensitivity (ECS). For temperature targets between 1.5-3.0 degrees C, the models exhibiting low ECS increase RCB by a factor two compared to those with high sensitivity, suggesting that observational constraints imposed on the ECS in the model ensemble also will reduce uncertainty in the RCB estimates.

scholarly journals Climate sensitivity and meridional overturning circulation in the late Eocene using GFDL CM2.1

2018 ◽  
Vol 14 (6) ◽  
pp. 789-810 ◽  
Author(s):  
David K. Hutchinson ◽  
Agatha M. de Boer ◽  
Helen K. Coxall ◽  
Rodrigo Caballero ◽  
Johan Nilsson ◽  
...  
Keyword(s):  
Climate Sensitivity ◽  
North Atlantic ◽  
Climate Model ◽  
Hydrological Cycle ◽  
High Sensitivity ◽  
Late Eocene ◽  
Meridional Overturning Circulation ◽  
Atmospheric Co2 ◽  
Climate History ◽  
Model Studies

Abstract. The Eocene–Oligocene transition (EOT), which took place approximately 34 Ma ago, is an interval of great interest in Earth's climate history, due to the inception of the Antarctic ice sheet and major global cooling. Climate simulations of the transition are needed to help interpret proxy data, test mechanistic hypotheses for the transition and determine the climate sensitivity at the time. However, model studies of the EOT thus far typically employ control states designed for a different time period, or ocean resolution on the order of 3∘. Here we developed a new higher resolution palaeoclimate model configuration based on the GFDL CM2.1 climate model adapted to a late Eocene (38 Ma) palaeogeography reconstruction. The ocean and atmosphere horizontal resolutions are 1∘ × 1.5∘ and 3∘ × 3.75∘ respectively. This represents a significant step forward in resolving the ocean geography, gateways and circulation in a coupled climate model of this period. We run the model under three different levels of atmospheric CO2: 400, 800 and 1600 ppm. The model exhibits relatively high sensitivity to CO2 compared with other recent model studies, and thus can capture the expected Eocene high latitude warmth within observed estimates of atmospheric CO2. However, the model does not capture the low meridional temperature gradient seen in proxies. Equatorial sea surface temperatures are too high in the model (30–37 ∘C) compared with observations (max 32 ∘C), although observations are lacking in the warmest regions of the western Pacific. The model exhibits bipolar sinking in the North Pacific and Southern Ocean, which persists under all levels of CO2. North Atlantic surface salinities are too fresh to permit sinking (25–30 psu), due to surface transport from the very fresh Arctic (∼ 20 psu), where surface salinities approximately agree with Eocene proxy estimates. North Atlantic salinity increases by 1–2 psu when CO2 is halved, and similarly freshens when CO2 is doubled, due to changes in the hydrological cycle.

scholarly journals ALGORITHMIC COOLING OF SPINS: A PRACTICABLE METHOD FOR INCREASING POLARIZATION

2004 ◽  
Vol 02 (04) ◽  
pp. 461-477 ◽  
Author(s):  
JOSÉ M. FERNANDEZ ◽  
SETH LLOYD ◽  
TAL MOR ◽  
VWANI ROYCHOWDHURY
Keyword(s):  
Nmr Spectroscopy ◽  
Low Temperatures ◽  
Open Systems ◽  
High Sensitivity ◽  
Quantum Gates ◽  
Quantum Computers ◽  
Short Term ◽  
Near Future ◽  
Practicable Method ◽  
Far Future

An efficient technique to generate ensembles of spins that are highly polarized by external magnetic fields is the Holy Grail in Nuclear Magnetic Resonance (NMR) spectroscopy. Since spin-half nuclei have steady-state polarization biases that increase inversely with temperature, spins exhibiting high polarization biases are considered cool, even when their environment is warm. Existing spin-cooling techniques are highly limited in their efficiency and usefulness. Algorithmic cooling is a promising new spin-cooling approach that employs data compression methods in open systems. It reduces the entropy of spins on long molecules to a point far beyond Shannon's bound on reversible entropy manipulations, thus increasing their polarization. Here we present an efficient and experimentally feasible algorithmic cooling technique that cools spins to very low temperatures even on short molecules. This practicable algorithmic cooling could lead to breakthroughs in high-sensitivity NMR spectroscopy in the near future, and to the development of scalable NMR quantum computers in the far future. Moreover, while the cooling algorithm itself is classical, it uses quantum gates in its implementation, thus representing the first short-term application of quantum computing devices.

scholarly journals Effects of Ocean Acidification on Calcification of the Sub-Antarctic Pteropod Limacina retroversa

2021 ◽  
Vol 8 ◽  
Author(s):  
Lisette Mekkes ◽  
Guadalupe Sepúlveda-Rodríguez ◽  
Gintarė Bielkinaitė ◽  
Deborah Wall-Palmer ◽  
Geert-Jan A. Brummer ◽  
...  
Keyword(s):  
Ocean Acidification ◽  
Leading Edge ◽  
High Sensitivity ◽  
Ct Scanning ◽  
Carbonate Chemistry ◽  
Shell Weight ◽  
Oceanic Surface ◽  
Antarctic Waters ◽  
Near Future ◽  
Past Conditions

Ocean acidification is expected to impact the high latitude oceans first, as CO2 dissolves more easily in colder waters. At the current rate of anthropogenic CO2 emissions, the sub-Antarctic Zone will start to experience undersaturated conditions with respect to aragonite within the next few decades, which will affect marine calcifying organisms. Shelled pteropods, a group of calcifying zooplankton, are considered to be especially sensitive to changes in carbonate chemistry because of their thin aragonite shells. Limacina retroversa is the most abundant pteropod in sub-Antarctic waters, and plays an important role in the carbonate pump. However, not much is known about its response to ocean acidification. In this study, we investigated differences in calcification between L. retroversa individuals exposed to ocean carbonate chemistry conditions of the past (pH 8.19; mid-1880s), present (pH 8.06), and near-future (pH 7.93; predicted for 2050) in the sub-Antarctic. After 3 days of exposure, calcification responses were quantified by calcein staining, shell weighing, and Micro-CT scanning. In pteropods exposed to past conditions, calcification occurred over the entire shell and the leading edge of the last whorl, whilst individuals incubated under present and near-future conditions mostly invested in extending their shells, rather than calcifying over their entire shell. Moreover, individuals exposed to past conditions formed larger shell volumes compared to present and future conditions, suggesting that calcification is already decreased in today’s sub-Antarctic waters. Shells of individuals incubated under near-future conditions did not increase in shell weight during the incubation, and had a lower density compared to past and present conditions, suggesting that calcification will be further compromised in the future. This demonstrates the high sensitivity of L. retroversa to relatively small and short-term changes in carbonate chemistry. A reduction in calcification of L. retroversa in the rapidly acidifying waters of the sub-Antarctic will have a major impact on aragonite-CaCO3 export from oceanic surface waters to the deep sea.

THE STUDY OF AIR TEMPERATURE IN THE LAST DECADE IN THE BUCHAREST METROPOLITAN AREA

2021 ◽  
Vol 07 (01) ◽  
Author(s):  
CHICHIREZ CRISTINA-MIHAELA ◽  
Keyword(s):  
Air Temperature ◽  
Metropolitan Area ◽  
Cold Season ◽  
Absolute Maximum ◽  
Mean Annual Temperature ◽  
Reference Period ◽  
Hot Season ◽  
The Mean ◽  
The 19Th Century ◽  
Near Future

Multiple paleoclimatic studies indicate that the Earth has warmed significantly since the end of the 19th century. The mean temperature of the Earth's surface is rising unnaturally and frighteningly fast, having a large impact and threatening the very near future of human civilization. This paper presents an analysis of the variability of air temperature in the Bucharest metropolitan area in the decade 2011-2020, related to the 1901-2000 period in the context of the global warming. The research includes the study of the mean annual and monthly temperature, the absolute maximum and minimum temperature, the frequency of the thermal character in the cold season and in the hot season and the frequency of days with characteristic temperatures. The 2011-2020 decade was the hottest one since the beginning of meteorological measurements. Related to the 1901-2000- reference period, the air temperature increased by 1.6°C, from 11.1°C to 12.7°C, the mean of the 10 years. The year 2020 was the hottest year, marking the end of the hottest decade since the meteorological measurements were made, the mean annual temperature being 13.5°C, by 2.4°C higher than the mean of the 1901-2010 reference period.

Constraints on Climate Sensitivity from Radiation Patterns in Climate Models

2011 ◽  
Vol 24 (4) ◽  
pp. 1034-1052 ◽  
Author(s):  
Markus Huber ◽  
Irina Mahlstein ◽  
Martin Wild ◽  
John Fasullo ◽  
Reto Knutti
Keyword(s):  
Climate Sensitivity ◽  
Radiative Forcing ◽  
Climate Models ◽  
Radiant Energy ◽  
Carbon Dioxide Concentration ◽  
Energy System ◽  
Surface Radiation ◽  
Radiation Budget ◽  
Radiation Patterns ◽  
Strong Constraint

Abstract The estimated range of climate sensitivity, the equilibrium warming resulting from a doubling of the atmospheric carbon dioxide concentration, has not decreased substantially in past decades. New statistical methods for estimating the climate sensitivity have been proposed and provide a better quantification of relative probabilities of climate sensitivity within the almost canonical range of 2–4.5 K; however, large uncertainties remain, in particular for the upper bound. Simple indices of spatial radiation patterns are used here to establish a relationship between an observable radiative quantity and the equilibrium climate sensitivity. The indices are computed for the Coupled Model Intercomparison Project phase 3 (CMIP3) multimodel dataset and offer a possibility to constrain climate sensitivity by considering radiation patterns in the climate system. High correlations between the indices and climate sensitivity are found, for example, in the cloud radiative forcing of the incoming longwave surface radiation and in the clear-sky component of the incoming surface shortwave flux, the net shortwave surface budget, and the atmospheric shortwave attenuation variable β. The climate sensitivity was estimated from the mean of the indices during the years 1990–99 for the CMIP3 models. The surface radiative flux dataset from the Clouds and the Earth’s Radiant Energy System (CERES) together with its top-of-atmosphere Energy Balanced and Filled equivalent (CERES EBAF) are used as a reference observational dataset, resulting in a best estimate for climate sensitivity of 3.3 K with a likely range of 2.7–4.0 K. A comparison with other satellite and reanalysis datasets show similar likely ranges and best estimates of 1.7–3.8 (3.3 K) [Earth Radiation Budget Experiment (ERBE)], 2.9–3.7 (3.3 K) [International Satellite Cloud Climatology Project radiative surface flux data (ISCCP-FD)], 2.8–4.1 (3.5 K) [NASA’s Modern Era Retrospective-Analysis for Research and Application (MERRA)], 3.0–4.2 (3.6 K) [Japanese 25-yr Reanalysis (JRA-25)], 2.7–3.9 (3.4 K) [European Centre for Medium-Range Weather Forecasts Re-Analysis (ERA-Interim)], 3.0–4.0 (3.5 K) [ERA-40], and 3.1–4.7 (3.6 K) for the NCEP reanalysis. For each individual reference dataset, the results suggest that values for the sensitivity below 1.7 K are not likely to be consistent with observed radiation patterns given the structure of current climate models. For the aggregation of the reference datasets, the climate sensitivity is not likely to be below 2.9 K within the framework of this study, whereas values exceeding 4.5 K cannot be excluded from this analysis. While these ranges cannot be interpreted properly in terms of probability, they are consistent with other estimates of climate sensitivity and reaffirm that the current climatology provides a strong constraint on the lower bound of climate sensitivity even in a set of structurally different models.

Russian-Egyptian economic relations: history and mоdernity

2018 ◽  
pp. 23-37
Author(s):  
Sergey Volkov
Keyword(s):  
Mediterranean Coast ◽  
Spent Fuel ◽  
Strong Base ◽  
Economic Relations ◽  
Current State ◽  
Operational Lifetime ◽  
High Level ◽  
Vladimir Putin ◽  
The 19Th Century ◽  
Near Future

The author for the first time generalized information on the Russian-Egyptian economic relations since the beginning of the 60th years of the 19th century so far and allocated a number of stages of their development. However, he pays the main attention to the analysis of the current state of bilateral cooperation and long-term projects, which will define the level of development of trade and economic relations in the near future. The largest of them is the project of the NPP “Dabaa”. Four commercial contracts on this project make nearly $60 bln. According to the signed contracts, Rosatom will build till 2029 four VVER-1200 units generation 3+ of the NPP “Dabaa” in the Matrouh region on the Mediterranean coast, as well as supplying nuclear fuel throughout the plant’s entire operational lifetime. In addition, Rosatom will be conduct personnel training and will assist its Egyptian partners in the operation and maintenance of the NPP for the first ten years of its operation. Besides, the Russian side will construct a purpose-built storage and supply containers for storing spent fuel. Life cycle of this project can make 100 years. Presidents of Russia and Egypt Vladimir Putin and Abdel Fattah el-Sisi accepted the decision in principle on implementation of other large project – the Russian industrial zone (RIZ) in Egypt – at a meeting in 2014. During this time, the parties chose the location of a zone, developed the business plan and the master plan of the RIZ taking into account stage-by-stage development of the territory and coordinated conditions of the special intergovernmental agreement on creation of the RIZ. Implementation of this project has to begin in the nearest future. The research showed the high level of complementarity of economies of two countries, which creates strong base of further development of different forms of mutually beneficial economic relations.

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