scholarly journals Long-Term Climate Change Commitment and Reversibility: An EMIC Intercomparison

2013 ◽  
Vol 26 (16) ◽  
pp. 5782-5809 ◽  
Author(s):  
Kirsten Zickfeld ◽  
Michael Eby ◽  
Andrew J. Weaver ◽  
Kaitlin Alexander ◽  
Elisabeth Crespin ◽  
...  

Abstract This paper summarizes the results of an intercomparison project with Earth System Models of Intermediate Complexity (EMICs) undertaken in support of the Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report (AR5). The focus is on long-term climate projections designed to 1) quantify the climate change commitment of different radiative forcing trajectories and 2) explore the extent to which climate change is reversible on human time scales. All commitment simulations follow the four representative concentration pathways (RCPs) and their extensions to year 2300. Most EMICs simulate substantial surface air temperature and thermosteric sea level rise commitment following stabilization of the atmospheric composition at year-2300 levels. The meridional overturning circulation (MOC) is weakened temporarily and recovers to near-preindustrial values in most models for RCPs 2.6–6.0. The MOC weakening is more persistent for RCP8.5. Elimination of anthropogenic CO2 emissions after 2300 results in slowly decreasing atmospheric CO2 concentrations. At year 3000 atmospheric CO2 is still at more than half its year-2300 level in all EMICs for RCPs 4.5–8.5. Surface air temperature remains constant or decreases slightly and thermosteric sea level rise continues for centuries after elimination of CO2 emissions in all EMICs. Restoration of atmospheric CO2 from RCP to preindustrial levels over 100–1000 years requires large artificial removal of CO2 from the atmosphere and does not result in the simultaneous return to preindustrial climate conditions, as surface air temperature and sea level response exhibit a substantial time lag relative to atmospheric CO2.

2012 ◽  
Vol 12 (3) ◽  
pp. 1449-1480 ◽  
Author(s):  
D. J. L. Olivié ◽  
D. Cariolle ◽  
H. Teyssèdre ◽  
D. Salas ◽  
A. Voldoire ◽  
...  

Abstract. For the period 1860–2100 (SRES scenario A1B for 2000–2100), the impact of road transport, maritime shipping and aviation on climate is studied using an Atmosphere Ocean General Circulation Model (AOGCM). In addition to carbon dioxide (CO2) emissions from these transport sectors, most of their non-CO2 emissions are also taken into account, i.e. the forcing from ozone, methane, black carbon, organic carbon, sulfate, CFC-12 and HFC-134a from air conditioning systems in cars, and contrails. For the year 2000, the CO2 emissions from all sectors together induce a global annual-mean surface air temperature increase of around 0.1 K. In 2100, the CO2 emissions from road transport induce a global mean warming of 0.3 K, while shipping and aviation each contribute 0.1 K. For road transport, the non-CO2 impact is largest between 2000 and 2050 (of the order of 0.1 K) becoming smaller at the end of the 21st century. The non-CO2 impact from shipping is negative, reaching −0.1 K between 2050 and 2100, while for aviation it is positive and its estimate varies between 0 and 0.15 K in 2100. The largest changes in sea-level from thermal expansion in 2000 are 1.6 mm for the CO2 emissions from road transport, and around −3 mm from the non-CO2 effects of shipping. In 2100, sea-level rises by 18 mm due to the CO2 emissions from road transport and by 4.6 mm due to shipping or aviation CO2 emissions. Non-CO2 changes are of the order of 1 mm for road transport, −6.6 mm for shipping, and the estimate for aviation varies between −1.2 and 4.3 mm. When focusing on the geographical distribution, the non-CO2 impact from road transport and shipping on the surface air temperature is only slightly stronger in northern than in southern mid-latitudes, while the impact from aviation can be a factor of 5 stronger in the northern than in the southern hemisphere. Further it is observed that most of the impacts are more pronounced at high latitudes, and that the non-CO2 emissions from aviation strongly impact the NAO index. The impacts on the oceanic meridional overturning circulation and the Niño3.4 index are also quantified.


2011 ◽  
Vol 11 (7) ◽  
pp. 19769-19850
Author(s):  
D. J. L. Olivié ◽  
D. Cariolle ◽  
H. Teyssèdre ◽  
D. Salas ◽  
A. Voldoire ◽  
...  

Abstract. For the period 1860–2100 (SRES scenario A1B for 2000–2100), the impact of road transport, maritime shipping and aviation on climate is studied using an Atmosphere Ocean General Circulation Model (AOGCM). In addition to carbon dioxide (CO2) emissions from these transport sectors, most of their non-CO2 emissions are also taken into account, i.e., the forcing from ozone, methane, black carbon, organic carbon, sulfate, CFC-12 and HFC-134a from air conditioning systems in cars, and contrails. For the year 2000, the CO2 emissions from all sectors together induce a global annual-mean surface air temperature increase of around 0.1 K. In 2100, the CO2 emissions from road transport induce a global mean warming of 0.3 K, while shipping and aviation each contribute 0.1 K. For road transport, the non-CO2 impact is largest between 2000 and 2050 (of the order of 0.1 K) becoming smaller at the end of the 21st century. The non-CO2 impact from shipping is negative, reaching −0.1 K between 2050 and 2100, while for aviation it is positive and its estimate varies between 0 and 0.15 K in 2100. The largest changes in sea-level from thermal expansion in 2000 are 1.6 mm for the CO2 emissions from road transport, and around −3 mm from the non-CO2 effects of shipping. In 2100, sea-level rises by 18 mm due to the CO2 emissions from road transport and by 4.6 mm due to shipping or aviation CO2 emissions. Non-CO2 changes are of the order of 1 mm for road transport, −6.6 mm for shipping, and the estimate for aviation varies between −1.2 and 4.3 mm. When focusing on the geographical distribution, the non-CO2 impact from road transport and shipping on the surface air temperature is only slightly stronger in northern than in southern mid-latitudes, while the impact from aviation can be a factor of 5 stronger in the northern than in the Southern Hemisphere. Further it is observed that most of the impacts are more pronounced at high latitudes, and that the non-CO2 emissions from aviation strongly impact the NAO index. The impacts on the oceanic meridional overturning circulation and the Niño3.4 index are also quantified.


2015 ◽  
Vol 54 (6) ◽  
pp. 1248-1266 ◽  
Author(s):  
Guoyu Ren ◽  
Jiao Li ◽  
Yuyu Ren ◽  
Ziying Chu ◽  
Aiying Zhang ◽  
...  

AbstractTrends in surface air temperature (SAT) are a critical indicator for climate change at varied spatial scales. Because of urbanization effects, however, the current SAT records of many urban stations can hardly meet the demands of the studies. Evaluation and adjustment of the urbanization effects on the SAT trends are needed, which requires an objective selection of reference (rural) stations. Based on the station history information from all meteorological stations with long-term records in mainland China, an integrated procedure for determining the reference SAT stations has been developed and is applied in forming a network of reference SAT stations. Historical data from the network are used to assess the urbanization effects on the long-term SAT trends of the stations of the national Reference Climate Network and Basic Meteorological Network (RCN+BMN or national stations), which had been used most frequently in studies of regional climate change throughout the country. This paper describes in detail the integrated procedure and the assessment results of urbanization effects on the SAT trends of the national stations applying the data from the reference station network determined using the procedure. The results showed a highly significant urbanization effect of 0.074°C (10 yr)−1 and urbanization contribution of 24.9% for the national stations of mainland China during the time period 1961–2004, which compared well to results that were reported in previous studies by the authors using the predecessor of the present reference network and the reference stations selected but when applying other methods. The authors are thus confident that the SAT data from the updated China reference station network as reported in this paper best represented the baseline SAT trends nationwide and could be used for evaluating and adjusting the urban biases in the historical data series of the SAT from different observational networks.


2013 ◽  
Vol 26 (8) ◽  
pp. 2502-2513 ◽  
Author(s):  
N. Bouttes ◽  
J. M. Gregory ◽  
J. A. Lowe

Abstract During the last century, global climate has been warming, and projections indicate that such a warming is likely to continue over coming decades. Most of the extra heat is stored in the ocean, resulting in thermal expansion of seawater and global mean sea level rise. Previous studies have shown that after CO2 emissions cease or CO2 concentration is stabilized, global mean surface air temperature stabilizes or decreases slowly, but sea level continues to rise. Using idealized CO2 scenario simulations with a hierarchy of models including an AOGCM and a step-response model, the authors show how the evolution of thermal expansion can be interpreted in terms of the climate energy balance and the vertical profile of ocean warming. Whereas surface temperature depends on cumulative CO2 emissions, sea level rise due to thermal expansion depends on the time profile of emissions. Sea level rise is smaller for later emissions, implying that targets to limit sea level rise would need to refer to the rate of emissions, not only to the time integral. Thermal expansion is in principle reversible, but to halt or reverse it quickly requires the radiative forcing to be reduced substantially, which is possible on centennial time scales only by geoengineering. If it could be done, the results indicate that heat would leave the ocean more readily than it entered, but even if thermal expansion were returned to zero, the geographical pattern of sea level would be altered. Therefore, despite any aggressive CO2 mitigation, regional sea level change is inevitable.


2018 ◽  
Vol 29 ◽  
pp. 31-40
Author(s):  
Hadikusumah

Study on mean sea level (MSL) rise has been done on tide data at some locations in the Western Indonesia. To account the effect of climate change, air temperature analyses from some weather stations are also performed. The results showed that air temperature has changed between 0.0 to 0.44°C per ten years. The sea level analysis showed that mean sea level at Western Indonesia rise between 3.10 to 9.27 mm per year. Based on the results, the prediction on mean sea level change in the years of 2000, 2030, 2050 and 2100 for Cirebon location are 17 cm, 39 cm, 55 cm, and 92 cm, respectively.


2021 ◽  
Author(s):  
Clara E Estrela Segrelles ◽  
Miguel Ángel Pérez Martín ◽  
Gabriel Gómez Martínez

<p>Sea level rise produced by climate change severely affects coastal ecosystems. The increase in the area below sea level facilitates the penetration of the marine wedge and causes an increase in soil salinity. Coastal wetlands are areas of great ecological importance due to the richness of flora and fauna that inhabit them. A change in salinity conditions could lead to a reduction or loss of habitat for the wetland biota. Based on RCP4.5 and RCP8.5 CMIP5 multimodel scenarios, in the Western Mediterranean coast, the sea level will rise 0.16 m in the short term (2026 - 2045) and 0.79 m in 2100. Also, high-end scenarios indicate that sea level will rise between 1.35 m and 1.92 m in the long term.</p><p>A sea level rise analysis has been developed in the coastal wetlands of Júcar River Basin District (JRBD). The results show that coastal wetlands are the mainly area affected in the JRBD, so the 90% of the area under the sea level are wetlands. L’Albufera de Valencia is the main wetland in this basin and, also the main wetland affected. It is an anthropized humid zone, regulated by users through gates to preserve the adequate water level for agricultural and environmental purposes such as rice cultivation around the lake and bird habitats conservation, especially in winter. The outcome of the study shows a significative increase in the area below the sea from 507 ha and 4.2 hm<sup>3</sup> of water volume at present to 3,244 ha that represents 42.6 hm<sup>3</sup> of water volume in the short term. In the long term, the area below the sea is 7,253 ha which means 118.4 hm<sup>3</sup> of water volume in the percentile 50 scenario and, in the worst extreme scenario, it is 13,896 ha that represents 289.7 hm<sup>3</sup> of water volume. This leads to a redefinition of the lake management levels as a climate change adaptation measure to prevent the lake salinization and severe impacts in the lake ecosystem. L’Albufera lake levels need to be increased in the next years to avoid the sea water penetration, related to the sea level rise. Thus, in the short term the lake levels must be increased around 0.16 m and, in the long term, L’Albufera levels must be increased around 0.8 m.</p>


2016 ◽  
Vol 113 (10) ◽  
pp. 2597-2602 ◽  
Author(s):  
Matthias Mengel ◽  
Anders Levermann ◽  
Katja Frieler ◽  
Alexander Robinson ◽  
Ben Marzeion ◽  
...  

Sea level has been steadily rising over the past century, predominantly due to anthropogenic climate change. The rate of sea level rise will keep increasing with continued global warming, and, even if temperatures are stabilized through the phasing out of greenhouse gas emissions, sea level is still expected to rise for centuries. This will affect coastal areas worldwide, and robust projections are needed to assess mitigation options and guide adaptation measures. Here we combine the equilibrium response of the main sea level rise contributions with their last century's observed contribution to constrain projections of future sea level rise. Our model is calibrated to a set of observations for each contribution, and the observational and climate uncertainties are combined to produce uncertainty ranges for 21st century sea level rise. We project anthropogenic sea level rise of 28–56 cm, 37–77 cm, and 57–131 cm in 2100 for the greenhouse gas concentration scenarios RCP26, RCP45, and RCP85, respectively. Our uncertainty ranges for total sea level rise overlap with the process-based estimates of the Intergovernmental Panel on Climate Change. The “constrained extrapolation” approach generalizes earlier global semiempirical models and may therefore lead to a better understanding of the discrepancies with process-based projections.


2020 ◽  
Author(s):  
Cornelius Schwarze ◽  
Thomas Jahr ◽  
Andreas Goepel ◽  
Valentin Kasburg ◽  
Nina Kukowski

<p>Longterm geophysical recordings of natural Earth’s parameters besides other signals also may contain past and ongoing temperature fluctuations, as they are occurring e.g. when groundwater moves or when climate changes. Similarly, repeated logs or continuous recordings reveal the amount of ongoing climate fluctuations. However, such thermal signals in the subsurface also may have other causes, e.g. groundwater motion or fluid infiltration after strong rainfall events. The Geodynamic Observatory Moxa of the Friedrich-Schiller University Jena, Germany, is an ideal test site for long-term monitoring of the subsurface temperature distribution in boreholes using optical fibre temperature-sensing, as it is equipped with a variety of complementary sensors.</p><p>A 100 m deep borehole on the ground of the Observatory, is equipped with an optical fibre and a water level gauge. Clearly shown in the records of the first five years of continuous recordings are seasonal temperature fluctuations. Seasonal fluctuations could be identified down to a depth of about 20 m and diurnal temperature signals down to 1.2 m. Precipitation events may influence subsurface temperature still in a depth as deep as 15 m. Besides these, temperature anomalies were detected at two depths, 20 m and 77 m below the surface. These anomalies most probably result from enhanced groundwater flow in aquifers. Recordings of deformation from laser strain meter systems installed in a gallery at Moxa, which are highly sensitive to pore pressure fluctuations, and measuring the physical properties during drilling the borehole, help to identify and quantify the causes of the observed  temperature fluctuations.</p><p>For more than 20 years variations of the Earth’s gravity field have been observed at the Observatory Moxa employing the superconducting gravimeter CD-034. Besides the free oscillations of the Earth and hydrological effects, the tides of the solid Earth are the strongest signals found in the time series. Tidal analysis of the main constituents leads to obtaining the indirect effect for all tidal waves which is mainly controlled by the loading effect of the oceans. Satellite altimetry revealed a mean global sea level rise of about 3.3 mm/a which may be caused amongst others mainly by ice melting processes in the polar regions. However, more detailed analyses and resulting global maps show that the sea level rise is not uniformly distributed over all oceans. This means that actual and future tidal water mass movements could vary regionally and even locally.  As a consequence, the tidal parameter controlled by the ocean loading effect could change over long-term observation periods and it should possibly be detectable as a trend or temporal variation of the tidal gravity parameters locally. Actually, a long-term change of the tidal parameters is observed for the main tidal waves like K1 and O1 in the diurnal and for M2 and K2 in the semi-diurnal frequency band. However, it is not clear if these changes can be correlated with sea level changes as observed from satellite data. On the other hand, surface and subsurface temperature fluctuations directly reveal the size of the thermal signal inherent to climate change.</p>


Author(s):  
Roshanka L.-F. Ranasinghe ◽  
David Wainwright ◽  
Dave Callaghan ◽  
Trang Duong

The potential Climate change (CC) impacts on coasts and associated socio-economic and environmental risks are widely recognised internationally. One of the most talked about CC impacts is coastline recession. Any increase in mean sea level is expected to result in an upward and landward shift of the entire active profile causing net coastline recession (Bruun, 1962). Another phenomenon that can result in net coastline recession is the cumulative effect of storm erosion. This is due to the hysteresis effect in the storm erosion/dune recovery cycle (Ranasinghe et al., 2012). But what causes more recession: storms or sea level rise? This is a commonly asked question, to which science-backed answers have not been presented to date. This paper addresses this question via the application of a physics based, probabilistic numerical model at a typical swell and storm beaches located in SE Australia and The Netherlands, respectively.


2008 ◽  
Vol 21 (12) ◽  
pp. 2721-2751 ◽  
Author(s):  
G.-K. Plattner ◽  
R. Knutti ◽  
F. Joos ◽  
T. F. Stocker ◽  
W. von Bloh ◽  
...  

Abstract Eight earth system models of intermediate complexity (EMICs) are used to project climate change commitments for the recent Intergovernmental Panel on Climate Change’s (IPCC’s) Fourth Assessment Report (AR4). Simulations are run until the year 3000 a.d. and extend substantially farther into the future than conceptually similar simulations with atmosphere–ocean general circulation models (AOGCMs) coupled to carbon cycle models. In this paper the following are investigated: 1) the climate change commitment in response to stabilized greenhouse gases and stabilized total radiative forcing, 2) the climate change commitment in response to earlier CO2 emissions, and 3) emission trajectories for profiles leading to the stabilization of atmospheric CO2 and their uncertainties due to carbon cycle processes. Results over the twenty-first century compare reasonably well with results from AOGCMs, and the suite of EMICs proves well suited to complement more complex models. Substantial climate change commitments for sea level rise and global mean surface temperature increase after a stabilization of atmospheric greenhouse gases and radiative forcing in the year 2100 are identified. The additional warming by the year 3000 is 0.6–1.6 K for the low-CO2 IPCC Special Report on Emissions Scenarios (SRES) B1 scenario and 1.3–2.2 K for the high-CO2 SRES A2 scenario. Correspondingly, the post-2100 thermal expansion commitment is 0.3–1.1 m for SRES B1 and 0.5–2.2 m for SRES A2. Sea level continues to rise due to thermal expansion for several centuries after CO2 stabilization. In contrast, surface temperature changes slow down after a century. The meridional overturning circulation is weakened in all EMICs, but recovers to nearly initial values in all but one of the models after centuries for the scenarios considered. Emissions during the twenty-first century continue to impact atmospheric CO2 and climate even at year 3000. All models find that most of the anthropogenic carbon emissions are eventually taken up by the ocean (49%–62%) in year 3000, and that a substantial fraction (15%–28%) is still airborne even 900 yr after carbon emissions have ceased. Future stabilization of atmospheric CO2 and climate change requires a substantial reduction of CO2 emissions below present levels in all EMICs. This reduction needs to be substantially larger if carbon cycle–climate feedbacks are accounted for or if terrestrial CO2 fertilization is not operating. Large differences among EMICs are identified in both the response to increasing atmospheric CO2 and the response to climate change. This highlights the need for improved representations of carbon cycle processes in these models apart from the sensitivity to climate change. Sensitivity simulations with one single EMIC indicate that both carbon cycle and climate sensitivity related uncertainties on projected allowable emissions are substantial.


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