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1.
To reveal the steric sea level change in 20th century historical climate simulations and future climate change projections under the IPCC’s Representative Concentration Pathway 8.5 (RCP8.5) scenario, the results of two versions of LASG/IAP’s Flexible Global Ocean-Atmosphere-Land System model (FGOALS) are analyzed. Both models reasonably reproduce the mean dynamic sea level features, with a spatial pattern correlation coefficient of 0.97 with the observation. Characteristics of steric sea level changes in the 20th century historical climate simulations and RCP8.5 scenario projections are investigated. The results show that, in the 20th century, negative trends covered most parts of the global ocean. Under the RCP8.5 scenario, global-averaged steric sea level exhibits a pronounced rising trend throughout the 21st century and the general rising trend appears in most parts of the global ocean. The magnitude of the changes in the 21st century is much larger than that in the 20th century. By the year 2100, the global-averaged steric sea level anomaly is 18 cm and 10 cm relative to the year 1850 in the second spectral version of FGOALS (FGOALS-s2) and the second grid-point version of FGOALS (FGOALS-g2), respectively. The separate contribution of the thermosteric and halosteric components from various ocean layers is further evaluated. In the 20th century, the steric sea level changes in FGOALS-s2 (FGOALS-g2) are largely attributed to the thermosteric (halosteric) component relative to the pre-industrial control run. In contrast, in the 21st century, the thermosteric component, mainly from the upper 1000 m, dominates the steric sea level change in both models under the RCP8.5 scenario. In addition, the steric sea level change in the marginal sea of China is attributed to the thermosteric component.  相似文献   

2.
The MIT 2D climate model is used to make probabilistic projections for changes in global mean surface temperature and for thermosteric sea level rise under a variety of forcing scenarios. The uncertainties in climate sensitivity and rate of heat uptake by the deep ocean are quantified by using the probability distributions derived from observed twentieth century temperature changes. The impact on climate change projections of using the smallest and largest estimates of twentieth century deep ocean warming is explored. The impact is large in the case of global mean thermosteric sea level rise. In the MIT reference (“business as usual”) scenario the median rise by 2100 is 27 and 43 cm in the respective cases. The impact on increases in global mean surface air temperature is more modest, 4.9 and 3.9 C in the two respective cases, because of the correlation between climate sensitivity and ocean heat uptake required by twentieth century surface and upper air temperature changes. The results are also compared with the projections made by the IPCC AR4’s multi-model ensemble for several of the SRES scenarios. The multi-model projections are more consistent with the MIT projections based on the largest estimate of ocean warming. However, the range for the rate of heat uptake by the ocean suggested by the lowest estimate of ocean warming is more consistent with the range suggested by the twentieth century changes in surface and upper air temperatures, combined with the expert prior for climate sensitivity.  相似文献   

3.
Sea level rise, especially combined with possible changes in storm surges and increased river discharge resulting from climate change, poses a major threat in low-lying river deltas. In this study we focus on a specific example of such a delta: the Netherlands. To evaluate whether the country’s flood protection strategy is capable of coping with future climate conditions, an assessment of low-probability/high-impact scenarios is conducted, focusing mainly on sea level rise. We develop a plausible high-end scenario of 0.55 to 1.15 m global mean sea level rise, and 0.40 to 1.05 m rise on the coast of the Netherlands by 2100 (excluding land subsidence), and more than three times these local values by 2200. Together with projections for changes in storm surge height and peak river discharge, these scenarios depict a complex, enhanced flood risk for the Dutch delta.  相似文献   

4.
Past and future sea-level rise along the coast of North Carolina,USA   总被引:1,自引:1,他引:0  
We evaluate relative sea level (RSL) trajectories for North Carolina, USA, in the context of tide-gauge measurements and geological sea-level reconstructions spanning the last ~11,000 years. RSL rise was fastest (~7 mm/yr) during the early Holocene and slowed over time with the end of the deglaciation. During the pre-Industrial Common Era (i.e., 0–1800 CE), RSL rise (~0.7 to 1.1 mm/yr) was driven primarily by glacio-isostatic adjustment, though dampened by tectonic uplift along the Cape Fear Arch. Ocean/atmosphere dynamics caused centennial variability of up to ~0.6 mm/yr around the long-term rate. It is extremely likely (probability P=0.95) that 20th century RSL rise at Sand Point, NC, (2.8 ± 0.5 mm/yr) was faster than during any other century in at least 2,900 years. Projections based on a fusion of process models, statistical models, expert elicitation, and expert assessment indicate that RSL at Wilmington, NC, is very likely (P=0.90) to rise by 42–132 cm between 2000 and 2100 under the high-emissions RCP 8.5 pathway. Under all emission pathways, 21st century RSL rise is very likely (P>0.90) to be faster than during the 20th century. Due to RSL rise, under RCP 8.5, the current ‘1-in-100 year’ flood is expected at Wilmington in ~30 of the 50 years between 2050-2100.  相似文献   

5.
Dynamic sea level changes following changes in the thermohaline circulation   总被引:3,自引:2,他引:1  
Using the coupled climate model CLIMBER-3, we investigate changes in sea surface elevation due to a weakening of the thermohaline circulation (THC). In addition to a global sea level rise due to a warming of the deep sea, this leads to a regional dynamic sea level change which follows quasi-instantaneously any change in the ocean circulation. We show that the magnitude of this dynamic effect can locally reach up to ~1 m, depending on the initial THC strength. In some regions the rate of change can be up to 20–25 mm/yr. The emerging patterns are discussed with respect to the oceanic circulation changes. Most prominent is a south-north gradient reflecting the changes in geostrophic surface currents. Our results suggest that an analysis of observed sea level change patterns could be useful for monitoring the THC strength.  相似文献   

6.
Sea level rise (SLR) is one of the major socioeconomic risks associated with global warming. Mass losses from the Greenland ice sheet (GrIS) will be partially responsible for future SLR, although there are large uncertainties in modeled climate and ice sheet behavior. We used the ice sheet model SICOPOLIS (Simulation COde for POLythermal Ice Sheets) driven by climate projections from 20 models in the fifth phase of the Coupled Model Intercomparison Project (CMIP5) to estimate the GrlS contribution to global SLR. Based on the outputs of the 20 models, it is estimated that the GrIS will contribute 0-16 (0-27) cm to global SLR by 2100 under the Representative Concentration Pathways (RCP) 4.5 (RCP 8.5) scenarios. The projected SLR increases further to 7-22 (7-33) cm with 2~basal sliding included. In response to the results of the multimodel ensemble mean, the ice sheet model projects a global SLR of 3 cm and 7 cm (10 cm and 13 cm with 2~basal sliding) under the RCP 4.5 and RCP 8.5 scenarios, respectively. In addition, our results suggest that the uncertainty in future sea level projection caused by the large spread in climate projections could be reduced with model-evaluation and the selective use of model outputs.  相似文献   

7.
Four accelerated sea level rise scenarios, 30 and 100 cm by the year 2100, and 10 and 30 cm by the year 2030, have been assumed as boundary conditions (along with some wind climate changes) for the entire Polish coast, under two recent programmes completed in 1992 and 1995. Three adaptation strategies, i.e., retreat, limited protection and full protection have been adopted and compared in physical and socio-economic terms. Over 2,200 km2 and 230,000 people are found vulnerable in the most severe case of 100-cm rise by 2100. The total cost of land at loss in that case is estimated at nearly 30 USD billion (plus some 18 USD billion at risk of flooding), while the cost of full protection reaches 6 USD billion. Particular features of vulnerability and adaptation schemes have been examined as well, including specific sites and the effects of not only sea level rise but also other climate change factors, and interactions with other climate change studies in Poland. Planning of coastal zone management facing climate change can be facilitated by the use of a GIS-supported coastal information and analysis system. An example of the application of such a system for a selected Polish coastal site is shown to illustrate the most recent smaller-scale research activities undertaken in the wake of the overall assessment of the vulnerability to climate change for the entire Polish coastal zone.  相似文献   

8.
Relative sea level rise (RSLR) due to climate change and geodynamics represents the main threat for the survival of Venice, emerging today only 90 cm above the Northern Adriatic mean sea level (msl). The 25 cm RSLR occurred over the 20th century, consisting of about 12 cm of land subsidence and 13 cm of sea level rise, has increased the flood frequency by more than seven times with severe damages to the urban heritage. Reasonable forecasts of the RSLR expected to the century end must be investigated to assess the suitability of the Mo.S.E. project planned for the city safeguarding, i.e., the closure of the lagoon inlets by mobile barriers. Here we consider three RSLR scenarios as resulting from the past sea level rise recorded in the Northern Adriatic Sea, the IPCC mid-range A1B scenario, and the expected land subsidence. Available sea level measurements show that more than 5 decades are required to compute a meaningful eustatic trend, due to pseudo-cyclic 7–8 year long fluctuations. The period from 1890 to 2007 is characterized by an average rate of 0.12 ± 0.01 cm/year. We demonstrate that linear regression is the most suitable model to represent the eustatic process over these 117 year. Concerning subsidence, at present Venice is sinking due to natural causes at 0.05 cm/year. The RSLR is expected to range between 17 and 53 cm by 2100, and its repercussions in terms of flooding frequency are associated here to each scenario. In particular, the frequency of tides higher than 110 cm, i.e., the value above which the gates would close the lagoon to the sea, will increase from the nowadays 4 times per year to a range between 20 and 250. These projections provide a large spread of possible conditions concerning the survival of Venice, from a moderate nuisance to an intolerable aggression. Hence, complementary solutions to Mo.S.E. may well be investigated.  相似文献   

9.
Attention is focused here on the effect of additional sources of uncertainty derived from climate change on the cost-benefit procedures applied by coastal planners to evaluate shoreline protection projects. The largest effect would be felt if planners were trying to achieve the first best economic optimum. Given the current view that the seas will rise by significantly less than one meter through the year 2100, present procedures should work reasonably well assuming (1) informed vigilance in monitoring the pace of future greenhouse induced sea level rise, (2) careful attention to the time required for market-based adaptation to minimize the economic cost of abandonment, and (3) firm support of the credibility of an announced policy to proceed with plans to retreat from the sea when warranted. Assumptions (1) and (2) might be satisfied in reality, even cursory review of existing policy makes it clear that meeting (3) is a "long shot" at the very best. In any case, planners should periodically revisit potential protection sites, especially in the wake of catastrophic events, to assess the impact of the most recent information on sea level rise trajectories, local development patterns, and protection costs on the decision calculus.  相似文献   

10.
Against a background of climate change, Macau is very exposed to sea level rise(SLR) because of its low elevation,small size, and ongoing land reclamation. Therefore, we evaluate sea level changes in Macau, both historical and, especially,possible future scenarios, aiming to provide knowledge and a framework to help accommodate and protect against future SLR. Sea level in Macau is now rising at an accelerated rate: 1.35 mm yr-1over 1925–2010 and jumping to 4.2 mm yr-1over 1970–2010, which outpaces the rise in global mean sea level. In addition, vertical land movement in Macau contributes little to local sea level change. In the future, the rate of SLR in Macau will be about 20% higher than the global average, as a consequence of a greater local warming tendency and strengthened northward winds. Specifically, the sea level is projected to rise 8–12, 22–51 and 35–118 cm by 2020, 2060 and 2100, respectively, depending on the emissions scenario and climate sensitivity. Under the +8.5 W m-2Representative Concentration Pathway(RCP8.5) scenario the increase in sea level by2100 will reach 65–118 cm—double that under RCP2.6. Moreover, the SLR will accelerate under RCP6.0 and RCP8.5, while remaining at a moderate and steady rate under RCP4.5 and RCP2.6. The key source of uncertainty stems from the emissions scenario and climate sensitivity, among which the discrepancies in SLR are small during the first half of the 21 st century but begin to diverge thereafter.  相似文献   

11.
Here we present a set of regional climate scenarios of sea level rise for the northeast Atlantic Ocean. In this study, the latest observations and results obtained with state-of-the-art climate models are combined. In addition, regional effects due to ocean dynamics and changes in the Earth’s gravity field induced by melting of land-based ice masses have been taken into account. The climate scenarios are constructed for the target years 2050 and 2100, for both a moderate and a large rise in global mean atmospheric temperature (2 °C and 4 °C in 2100 respectively). The climate scenarios contain contributions from changes in ocean density (global thermal expansion and local steric changes related to changing ocean dynamics) and changes in ocean mass (melting of mountain glaciers and ice caps, changes in the Greenland and Antarctic ice sheets, and (minor) terrestrial water-storage contributions). All major components depend on the global temperature rise achieved in the target periods considered. The resulting set of climate scenarios represents our best estimate of twenty-first century sea level rise in the northeast Atlantic Ocean, given the current understanding of the various contributions. For 2100, they yield a local rise of 30 to 55 cm and 40 to 80 cm for the moderate and large rise in global mean atmospheric temperature, respectively.  相似文献   

12.
The future rate of Greenland Ice Sheet (GrIS) deglaciation and the future contribution of GrIS deglaciation to sea level rise will depend critically on the magnitude of northern hemispheric polar amplification and global equilibrium climate sensitivity. Here, these relationships are analyzed using an ensemble of multi-century coupled ice-sheet/climate model simulations seeded with observationally-constrained initial conditions and then integrated forward under tripled preindustrial CO2. Polar amplifications and climate sensitivities were varied between ensemble members in order to bracket current uncertainty in polar amplification and climate sensitivity. A large inter-ensemble spread in mean GrIS air temperature, albedo and surface mass balance trends stemming from this uncertainty resulted in GrIS ice volume loss ranging from 5 to 40 % of the original ice volume after 500 years. The large dependence of GrIS deglaciation on polar amplification and climate sensitivity that we find indicates that the representation of these processes in climate models will exert a strong control on any simulated predictions of multi-century GrIS evolution. Efforts to reduce polar amplification and equilibrium climate sensitivity uncertainty will therefore play a critical role in constraining projections of GrIS deglaciation and sea level rise in a future high-CO2 world.  相似文献   

13.
Coastal sector impacts from sea level rise (SLR) are a key component of the projected economic damages of climate change, a major input to decision-making and design of climate policy. Moreover, the ultimate global costs to coastal resources will depend strongly on adaptation, society’s response to cope with the local impacts. This paper presents a new open-source optimization model to assess global coastal impacts from SLR from the perspective of economic efficiency. The Coastal Impact and Adaptation Model (CIAM) determines the optimal strategy for adaptation at the local level, evaluating over 12,000 coastal segments, as described in the DIVA database (Vafeidis et al. 2006), based on their socioeconomic characteristics and the potential impacts of relative sea level rise and uncertain sea level extremes. A deterministic application of CIAM demonstrates the model’s ability to assess local impacts and direct costs, choose the least-cost adaptation, and estimate global net damages for several climate scenarios that account for both global and local components of SLR (Kopp et al. 2014). CIAM finds that there is large potential for coastal adaptation to reduce the expected impacts of SLR compared to the alternative of no adaptation, lowering global net present costs through 2100 by a factor of seven to less than $1.7 trillion, although this does not include initial transition costs to overcome an under-adapted current state. In addition to producing aggregate estimates, CIAM results can also be interpreted at the local level, where retreat (e.g., relocate inland) is often a more cost-effective adaptation strategy than protect (e.g., construct physical defenses).  相似文献   

14.
15.
IPCC第五次评估报告认为,受气候变化影响,许多生物种及生态系统已经发生显著变化,未来这些变化还将继续。气候变化和人类活动的共同作用将对21世纪的陆地生态系统和内陆水系统产生重要影响,大部分陆地和淡水物种灭绝的风险都将增加,部分地区可能会发生不可逆转的变化。未来仅依靠生态系统自身的适应能力将不足以应对这些变化,需要辅以适应措施帮助生态系统适应气候变化。海岸带系统和低洼地区除了受气候变化的影响,还受到人类活动的强烈影响,并且影响的方式和结果因地而异。预计到2100年,全球平均海平面将上升0.28~0.98 m,相对海平面上升差异较大。到2100年,数以亿计的人将受到沿海洪水的影响。未来海岸带地区适应的相对成本会有很大的区域差异。在全球尺度上,采取防御措施取得的效益仍要高于不作为而付出的社会经济成本。发达国家比发展中国家具有更强的适应气候变化能力,可持续发展的气候恢复力也更大。  相似文献   

16.
This study concerns effects along the Illinois shoreline resulting from the record-low levels of Lake Michigan during 1964–65, and the potential impacts of future low water levels at Chicago resulting from potential climate changes. The low lake levels of the 1960s did not cause major impacts at Chicago when they occurred. The two major impacts discerned (damage to shoreline protection structures and the encroachment of structures onto areas too close to the lake) resulted from a sequence of low-water levels followed by high-water levels a few years later. Climate scenarios, derived from general circulation models (GCMs) and extreme historical precipitation values, were used in a basin hydrologic model to determine potential future lake levels. Possible impacts were then estimated by 29 lakeshore experts. If the average lake level were reduced 1.0 m during the next 50 yr, shoreline impacts would not be severe and cost about $ 100 million. Many of the adjustment costs could be offset by normal maintenance and replacement costs. If the average lake level was reduced more than 1.5 m during the next 50 yr, very sizable economic impacts would occur, costing between $3 and $35 billion (1988 dollars). Some of the adjustment cost could be offset by normal replacement costs, particularly if a master plan for changing affected facilities were implemented in advance. The type of climate change and degree of lakelevel change will greatly affect the severity of the effects at Chicago.  相似文献   

17.
IPCC第六次评估报告第一工作组报告第九章综合评估了与海平面相关的最新监测和数值模拟结果,指出目前(2006—2018年)的海平面上升速率处于加速状态(3.7 mm/a),并会在未来持续上升,且呈现不可逆的趋势。其中低排放情景(SSP1-1.9)和高排放情景(SSP5-8.5)下,到2050年,预估全球平均海平面(GMSL)分别上升0.15~0.23 m和0.20~0.30 m;到2100年,预估GMSL分别上升0.28~0.55 m和0.63~1.02 m。南极冰盖不稳定性是影响未来海平面上升预估的最大不确定性来源之一。区域海平面变化是影响沿海极端静水位的重要因素。  相似文献   

18.
2030年上海地区相对海平面变化趋势的研究和预测   总被引:1,自引:0,他引:1  
从全球气候变化区域响应角度,依据1912-2000年吴淞验潮站年平均潮位资料,构建灰色线性回归组合模型,并将其与最小二乘法和小波变换相结合,分析以吴淞为代表的上海绝对海平面长期变化趋势和周期变化规律。由此预测2030年上海绝对海平面相对2011年的上升值为4 cm,结合已公布的构造沉降和城市地面沉降、流域水土保持和大型水利工程及人工挖沙导致的河口河槽冲刷、河口围海造地和深水航道及跨江跨海大桥导致水位抬升等叠加效应及其变化趋势,预测2030年上海市相对海平面上升10~16 cm,陆地海平面上升有7个风险分区。  相似文献   

19.
We use a physically plausible four parameter linear response equation to relate 2,000 years of global temperatures and sea level. We estimate likelihood distributions of equation parameters using Monte Carlo inversion, which then allows visualization of past and future sea level scenarios. The model has good predictive power when calibrated on the pre-1990 period and validated against the high rates of sea level rise from the satellite altimetry. Future sea level is projected from intergovernmental panel on climate change (IPCC) temperature scenarios and past sea level from established multi-proxy reconstructions assuming that the established relationship between temperature and sea level holds from 200 to 2100 ad. Over the last 2,000 years minimum sea level (−19 to −26 cm) occurred around 1730 ad, maximum sea level (12–21 cm) around 1150 ad. Sea level 2090–2099 is projected to be 0.9 to 1.3 m for the A1B scenario, with low probability of the rise being within IPCC confidence limits.  相似文献   

20.
G. Jordà  D. Gomis  M. Marcos 《Climatic change》2012,113(3-4):1081-1087
Troccoli et al. (Climatic Change, published online 14th May, DOI: 10.1007/s10584-011-0093-x), analysed different projections from global climate models in order to assess the frequency of storm surges in Venice during the 21st century under a climate change context. They concluded that the frequency of storm surges would decrease by about 30%, and that this reduction would compensate the expected mean sea level rise. Their final statement was that “the frequency of extreme tides in Venice might largely remain unaltered”. Although we agree in the expected reduction of storm surges, we strongly disagree in their final conclusion. First, because the impact of storm surges not only depends on the number of extreme surge events, but also on their intensity, that was not explicitely addressed. Second, because their estimates of mean sea level change for the 21st century are largely underestimated, as they miss some of the components driving sea level variability. Using state-of-the-art estimates for the thermosteric, mass and tidal contributions we show that the flooding events in Venice are expected to dramatically increase in a climate change scenario.  相似文献   

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