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1.
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   

2.
The Sundarbans mangrove ecosystem, shared by India and Bangladesh, is recognized as a global priority for biodiversity conservation. Sea level rise, due to climate change, threatens the long term persistence of the Sundarbans forests and its biodiversity. Among the forests’ biota is the only tiger (Panthera tigris) population in the world adapted for life in mangrove forests. Prior predictions on the impacts of sea level rise on the Sundarbans have been hampered by coarse elevation data in this low-lying region, where every centimeter counts. Using high resolution elevation data, we estimate that with a 28 cm rise above 2000 sea levels, remaining tiger habitat in Bangladesh’s Sundarbans would decline by 96% and the number of breeding individuals would be reduced to less than 20. Assuming current sea level rise predictions and local conditions do not change, a 28 cm sea level rise is likely to occur in the next 50–90 years. If actions to both limit green house gas emissions and increase resilience of the Sundarbans are not initiated soon, the tigers of the Sundarbans may join the Arctic’s polar bears (Ursus maritimus) as early victims of climate change-induced habitat loss.  相似文献   

3.
Global warming may result in substantial sea level rise and more intense hurricanes over the next century, leading to more severe coastal flooding. Here, observed climate and sea level trends over the last century (c. 1900s to 2000s) are used to provide insight regarding future coastal inundation trends. The actual impacts of Hurricane Katrina (2005) in New Orleans are compared with the impacts of a similar hypothetical hurricane occurring c. 1900. Estimated regional sea level rise since 1900 of 0.75 m, which contains a dominant land subsidence contribution (0.57 m), serves as a ‘prototype’ for future climate-change induced sea level rise in other regions. Landform conditions c. 1900 were estimated by changing frictional resistance based on expected additional wetlands at lower sea levels. Surge simulations suggest that flood elevations would have been 15 to 60 % lower c. 1900 than the conditions observed in 2005. This drastic change suggests that significantly more flood damage occurred in 2005 than would have occurred if sea level and climate conditions had been like those c. 1900. We further show that, in New Orleans, sea level rise dominates surge-induced flooding changes, not only by increasing mean sea level, but also by leading to decreased wetland area. Together, these effects enable larger surges. Projecting forward, future global sea level changes of the magnitude examined here are expected to lead to increased flooding in coastal regions, even if the storm climate is unchanged. Such flooding increases in densely populated areas would presumably lead to more widespread destruction.  相似文献   

4.
Thresholds for irreversible decline of the Greenland ice sheet   总被引：1，自引：0，他引：1  
The Greenland ice sheet will decline in volume in a warmer climate. If a sufficiently warm climate is maintained for a few thousand years, the ice sheet will be completely melted. This raises the question of whether the decline would be reversible: would the ice sheet regrow if the climate cooled down? To address this question, we conduct a number of experiments using a climate model and a high-resolution ice-sheet model. The experiments are initialised with ice sheet states obtained from various points during its decline as simulated in a high-CO2 scenario, and they are then forced with a climate simulated for pre-industrial greenhouse gas concentrations, to determine the possible trajectories of subsequent ice sheet evolution. These trajectories are not the reverse of the trajectory during decline. They converge on three different steady states. The original ice-sheet volume can be regained only if the volume has not fallen below a threshold of irreversibility, which lies between 80 and 90% of the original value. Depending on the degree of warming and the sensitivity of the climate and the ice-sheet, this point of no return could be reached within a few hundred years, sooner than CO2 and global climate could revert to a pre-industrial state, and in that case global sea level rise of at least 1.3 m would be irreversible. An even larger irreversible change to sea level rise of 5 m may occur if ice sheet volume drops below half of its current size. The set of steady states depends on the CO2 concentration. Since we expect the results to be quantitatively affected by resolution and other aspects of model formulation, we would encourage similar investigations with other models.  相似文献   

5.
This paper presents a scenario-based study that investigates the interaction between sea-level rise and land subsidence on the storm tides induced fluvial flooding in the Huangpu river floodplain. Two projections of relative sea level rise (RSLR) were presented (2030 and 2050). Water level projections at the gauging stations for different return periods were generated using a simplified algebraic summation of the eustatic sea-level rise, land subsidence and storm tide level. Frequency analysis with relative sea level rise taken into account shows that land subsidence contributes to the majority of the RSLR (between 60 % and 70 %). Furthermore, a 1D/2D coupled flood inundation model (FloodMap) was used to predict the river flow and flood inundation, after calibration using the August 1997 flood event. Numerical simulation with projected RSLR suggests that, the combined impact of eustatic sea-level rise and land subsidence would be a significantly reduced flood return period for a given water level, thus effective degradation of the current flood defences. In the absence of adaptation measures, storm flooding will cause up to 40 % more inundation, particularly in the upstream of the river.  相似文献   

6.
The sea level history of the northern Gulf of Mexico during recent geologic time has closely followed global eustatic sea level change. Regional effects due to tectonics and glacio-isostasy have been minimal. Over the past several million years the northern Gulf coast, like most stable coastal regions of the globe, has experienced major swings of sea level below and above present level, accompanied by major shifts in shoreline position. During advances of the northern hemisphere ice sheets, sea level dropped by more than 100 m, extending the shoreline in places more than 100 km onto the shelf. For much of the period since the last glacial maximum (LGM), 20,000 years ago, the region has seen rates of sea level rise far in excess of those experienced during the period represented by long-term tide gauges. The regional tide gauge record reveals that sea level has been rising at about 2 mm/year for the past century, while the average rate of rise since the LGM has been 6 mm/year, with some periods of abrupt rise exceeding 40 mm/year. During times of abrupt rise, Gulf of Mexico shorelines were drowned in place and overstepped. The relative stability of modern coastal systems is due primarily to stabilization of sea level approximately 6,000 years ago, resulting in the slow rates of rise experienced during historic time. Recent model projections of sea level rise over the next century and beyond may move northern Gulf coastal environments into a new equilibrium regime, more similar to that experienced during the deglaciation than that which has existed during historic time.  相似文献   

7.
Tens of millions of people around the world are already exposed to coastal flooding from tropical cyclones. Global warming has the potential to increase hurricane flooding, both by hurricane intensification and by sea level rise. In this paper, the impact of hurricane intensification and sea level rise are evaluated using hydrodynamic surge models and by considering the future climate projections of the Intergovernmental Panel on Climate Change. For the Corpus Christi, Texas, United States study region, mean projections indicate hurricane flood elevation (meteorologically generated storm surge plus sea level rise) will, on average, rise by 0.3 m by the 2030s and by 0.8 m by the 2080s. For catastrophic-type hurricane surge events, flood elevations are projected to rise by as much as 0.5 m and 1.8 m by the 2030s and 2080s, respectively.  相似文献   

8.
Martin Wolf 《Climate Policy》2013,13(6):772-783
Is it possible for all of humanity to enjoy the standards of living of today's high-income countries? What would happen if these limits were reached, perhaps because of climate change or a shortage of natural resources essential to production? How would society manage – or fail to manage – such limits? Notwithstanding the current financial and economic crises, these are perhaps the biggest questions confronting our species (and of a host of other species, who are the victims of our decisions). The article begins by considering the biggest economic event of our lifetimes – the ‘great convergence’ and its implications for the demand for resources. The discussion then turns to a specific limit on our development, climate change, which is different from most other limits, because it involves a global public good: the atmosphere. What such limits might mean for our civilization is discussed. One can persuade people to tackle climate change only if those concerned with the dangers persuade ordinary people that action will not come at the expense of their prosperity.  相似文献   

9.
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   

10.
A mathematical model was used to predict the effect of climate change on soft and hard rock coasts in a 2 m tidal environment. Erosional equations represented the effect of wave impact and bottom generated shear stresses in the intertidal and subtidal zones. Model runs were made for: 2900 years with constant sea level; a further 100 years, representing the last century, with either constant or slow sea level rise (0.2 m per century); and another 100 years, representing the present century, with either slow or fast (1 m per century) sea level rise, and with either no change in storm frequency or with a 10% increase in the frequency of the highest waves. The results suggest that rising sea level will trigger faster rates of cliff recession, whereas increased storm wave frequency may have only a fairly minor effect on erosional efficacy. Model runs were used to derive a series of predictive equations relating cliff recession during the present and last centuries.  相似文献   

11.
The threat of an abrupt and extreme rise in sea level is widely discussed in the media, but little understood in practise, especially the likely impacts of such a rise including a potential adaptation response. This paper explores for the first time the global impacts of extreme sea-level rise, triggered by a hypothetical collapse of the West Antarctic Ice Sheet (WAIS). As the potential contributions remain uncertain, a wide range of scenarios are explored: WAIS contributions to sea-level rise of between 0.5 and 5 m/century. Together with other business-as-usual sea-level contributions, in the worst case this gives an approximately 6-m rise of global-mean sea level from 2030 to 2130. Global exposure to extreme sea-level rise is significant: it is estimated that roughly 400 million people (or about 8% of global population) are threatened by a 5-m rise in sea level, just based on 1995 data. The coastal module within the Climate Framework for Uncertainty, Negotiation and Distribution (FUND) model is tuned with global data on coastal zone characteristics concerning population, land areas and land use, and then used for impact analysis under the extreme sea-level rise scenarios. The model considers the interaction of (dry)land loss, wetland loss, protection costs and human displacement, assuming perfect adaptation based on cost-benefit analysis. Unlike earlier analyses, response costs are represented in a non-linear manner, including a sensitivity analysis based on response costs. It is found that much of the world’s coast would be abandoned given these extreme scenarios, although according to the global model, significant lengths of the world’s coast are worth defending even in the most extreme case. This suggests that actual population displacement would be a small fraction of the potential population displacement, and is consistent with the present distribution of coastal population, which is heavily concentrated in specific areas. Hence, a partial defence can protect most of the world’s coastal population. However, protection costs rise substantially diverting large amounts of investment from other sectors, and large areas of (dry)land and coastal wetlands are still predicted to be lost. Detailed case studies of the WAIS collapse in the Netherlands, Thames Estuary and the Rhone delta suggest greater abandonment than shown by the global model, probably because the model assumes perfect implementation of coastal protection and does not account for negative feedbacks when implementation is imperfect. The significant impacts found in the global model together with the potential for greater impacts as found in the detailed case studies shows that the response to abrupt sea-level rise is worthy of further research.  相似文献   

12.
Projections by the Intergovernmental Panel on Climate Change suggest that there will be an increase in the frequency and intensity of climate extremes in the 21st century. Kolkata, a megacity in India, has been singled out as one of the urban centers vulnerable to climate risks. Modest flooding during monsoons at high tide in the Hooghly River is a recurring hazard in Kolkata. More intense rainfall, riverine flooding, sea level rise, and coastal storm surges in a changing climate can lead to widespread and severe flooding and bring the city to a standstill for several days. Using rainfall data, high and low emissions scenarios, and sea level rise of 27 cm by 2050, this paper assesses the vulnerability of Kolkata to increasingly intense precipitation events for return periods of 30, 50, and 100 years. It makes location-specific inundation depth and duration projections using hydrological, hydraulic, and urban storm models with geographic overlays. High resolution spatial analysis provides a roadmap for designing adaptation schemes to minimize the impacts of climate change. The modeling results show that de-silting of the main sewers would reduce vulnerable population estimates by at least 5 %.  相似文献   

13.
Sea level rise is one of the most pressing climate adaptation issues around the world. Often, coastal communities are interdependent in their exposure to sea level rise – if one builds a seawall, it will push water to another – and would benefit from a coordinated adaptive response. The literature on social-ecological systems (SES) calls for actors placed at higher levels of governance (e.g. regional government in a metropolitan area) to improve coordination between local managers by serving as brokers. However, we lack empirical insight on how higher-level actors might improve coordination in practice, and theoretical development on the implications of their intermediation. To address these gaps, we study the case of adaptation to sea level rise in the San Francisco Bay Area. We build a social-ecological network of social actors and shoreline segments using original survey data and simulated scenarios of tidal and traffic interdependencies between shoreline segments. We perform a frequency analysis of network motifs that operationalize social-ecological ‘fit’ in the context of the Bay Area. We find that regional actors and non-governmental organizations increase social-ecological fit by providing intermediation between actors who work on different shoreline segments, whether interdependent or not. This shows that these actors provide adaptive social-ecological fit, future-proofing the Bay Area to current and future climate adaptation challenges.  相似文献   

14.
In the fall of 2009 the City of Satellite Beach (City), Florida, authorized a study designed to assess municipal vulnerability to rising sea level and facilitate discussion of potential adaptation strategies. The project is one of the first in Florida to seriously address the potential consequences of global sea level rise, now forecast to rise a meter or more by the year 2100. Results suggest the tipping point between relatively benign impacts and those that disrupt important elements of the municipal landscape is +?2 ft (0.6 m) above present. Seasonal flooding to an elevation of +?2 ft is forecast to begin around 2050 and thus the City has about 40 years to formulate and implement an adaptation plan. As an initial step, the Comprehensive Planning Advisory Board, a volunteer citizen committee serving as the City??s local planning authority, has recommended a series of updates and revisions to the City??s Comprehensive Plan. If approved by the City Council and Florida??s Department of Community Affairs, the amendments will provide a legal basis for implementing specific policies designed to reduce the City??s vulnerability to sea level rise.  相似文献   

15.
Risk policy and public attitudes appear disconnected from research predicting warmer climate partially due to human activity. To step out of this stalled situation, a worst case scenario of a 5- to 6-m sea level rise (SLR) induced by the collapse of the WAIS and occurring during the period 2030–2130 is constructed and applied to the Rhone delta. Physical and socio-economic scenarios developed with data from the Rhone delta context are developed and submitted to stakeholders for a day-long workshop. Group process analysis shows a high level of trust and cooperation mobilized to face the 5–6 m SLR issue, despite potentially diverging interests. Two sets of recommendations stem from the scenario workshop. A conservative “wait and see” option is decided when the risk of the WAIS collapse is announced in 2030. After WAIS collapse generates an effective 1 m SLR rise by 2050, decisions are taken for total retreat and rendering of the Rhone delta to its hydrological function. The transposition of these results into present-day policy decisions could be considered. The methodology developed here could be applied to other risk objects and situations, and serve for policy exercises and crisis prevention.  相似文献   

16.
With an increasing political focus on limiting global warming to less than 2 °C above pre-industrial levels it is vital to understand the consequences of these targets on key parts of the climate system. Here, we focus on changes in sea level and sea ice, comparing twenty-first century projections with increased greenhouse gas concentrations (using the mid-range IPCC A1B emissions scenario) with those under a mitigation scenario with large reductions in emissions (the E1 scenario). At the end of the twenty-first century, the global mean steric sea level rise is reduced by about a third in the mitigation scenario compared with the A1B scenario. Changes in surface air temperature are found to be poorly correlated with steric sea level changes. While the projected decreases in sea ice extent during the first half of the twenty-first century are independent of the season or scenario, especially in the Arctic, the seasonal cycle of sea ice extent is amplified. By the end of the century the Arctic becomes sea ice free in September in the A1B scenario in most models. In the mitigation scenario the ice does not disappear in the majority of models, but is reduced by 42 % of the present September extent. Results for Antarctic sea ice changes reveal large initial biases in the models and a significant correlation between projected changes and the initial extent. This latter result highlights the necessity for further refinements in Antarctic sea ice modelling for more reliable projections of future sea ice.  相似文献   

17.
ABSTRACT

Consideration of solar geoengineering as a potential response to climate change will demand complex decisions. These include not only the choice of whether to deploy solar engineering, but decisions regarding how to deploy, and ongoing decision-making throughout deployment. Research on the governance of solar geoengineering to date has primarily engaged only with the question of whether to deploy. We examine the science of solar geoengineering in order to clarify the technical dimensions of decisions about deployment – both strategic and operational – and how these might influence governance considerations, while consciously refraining from making specific recommendations. The focus here is on a hypothetical deployment rather than governance of the research itself. We first consider the complexity surrounding the design of a deployment scheme, in particular the complicated and difficult decision of what its objective(s) would be, given that different choices for how to deploy will lead to different climate outcomes. Next, we discuss the on-going decisions across multiple timescales, from the sub-annual to the multi-decadal. For example, feedback approaches might effectively manage some uncertainties, but would require frequent adjustments to the solar geoengineering deployment in response to observations. Other decisions would be tied to the inherently slow process of detection and attribution of climate effects in the presence of natural variability. Both of these present challenges to decision-making. These considerations point toward particular governance requirements, including an important role for technical experts – with all the challenges that entails.

Key policy insights

  • Decisions about solar geoengineering deployment will be informed not only by political choices, but also by climate science and engineering.

  • Design decisions will pertain to the spatial and temporal goals of a climate intervention and strategies for achieving those goals.

  • Some uncertainty can be managed through feedback, but this would require frequent operational decisions.

  • Some strategic decisions will depend on the detection and attribution of climatic effects from solar geoengineering, which may take decades.

  • Governance for solar geoengineering deployment will likely need to incorporate technical expertise for making short-term adjustments to the deployment and conducting attribution analysis, while also slowing down decisions made in response to attribution analysis to avoid hasty choices.

  相似文献   

18.
Sea-level variability in the South China Sea was investigated based on satellite altimetry, tide-gauge data, and temperature and salinity climatology. The altimetric sea-level results clearly reveal three distinct amphidromes associated with the annual cycle. The annual sea level is higher in fall/winter in the coast and shelf region and lower in summer/fall in the central sea, agreeing well with independent tide-gauge data. Averaged over the deep basin (bottom depth?>?2,000 m), the annual cycle can be approximately accounted for by the steric height relative to 700 db. Significant interannual sea-level change is observed from altimetry and tide-gauge data. The interannual and longer-term sea-level variability in the altimetric data is negatively correlated (significant at the 95% confidence level) with the El Niño - Southern Oscillation (ENSO), attributed in part to the steric height change. The altimetric sea-level rise rate is 1.0 cm/year for the period from 1993 to 2001, which is consistent with the rate derived from coastal tide-gauge data and approximately accountable for by the steric height calculated relative to 700 db. The tide-gauge sea-level (steric height) rise rate of 1.05 (0.9) cm/year from 1993 to 2001 is much larger than that of 0.22 (0.12) cm/year for the period from 1979 to 2001, implying the sensitivity to the length of data as a result of the decadal variability. Potential roles of the ENSO in the interannual and longer-term sea-level variability are discussed in terms of regional manifestations such as the ocean temperature and salinity.  相似文献   

19.
“When I was born – in 1956 – the chance of realizing a Frisian Eleven City Ice Skating Marathon in Netherlands was 1 in 4. When my daughter was born – in 1999 – this chance had diminished to 1 in 10. An enormous change in one generation!” This quote was taken from a speech by J. P. Balkenende, prime minister of the Netherlands. It illustrates how a seemingly odd indicator of climate change, the chance of organizing large-scale outdoor ice-skating marathons, can play a role in the public and political debate on climate change. Outdoor skating has a very strong public appeal in the Netherlands, and the diminishing chances of holding such events provide an additional Dutch motive for introducing climate-policy measures. Here, “ice skating marathons” are approached from three angles: (1) the societal/political angle as described above, (2) the more technical angle, of how to derive annual chances for holding large-scale marathons such as the Eleven City Marathon (‘Elfstedentocht’), and (3) the role of (communicating) uncertainties. Since the statistical approach was developed in response to communicational needs, both statistical and communicative aspects are reported on in this article.  相似文献   

20.
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