Global assessment of the effectiveness of adaptation in coastal areas based on RCP/SSP scenarios

Climatic Change - The objective of this study is to assess the global impact of sea level rise and to evaluate the effectiveness of adaptation. Global areas of inundation due to sea level rise are...     

Assessing climate change impacts,sea level rise and storm surge risk in port cities: a case study on Copenhagen

This study illustrates a methodology to assess the economic impacts of climate change at a city scale and benefits of adaptation, taking the case of sea level rise and storm surge risk in the city of Copenhagen, capital of Denmark. The approach is a simplified catastrophe risk assessment, to calculate the direct costs of storm surges under scenarios of sea level rise, coupled to an economic input–output (IO) model. The output is a risk assessment of the direct and indirect economic impacts of storm surge under climate change, including, for example, production and job losses and reconstruction duration, and the benefits of investment in upgraded sea defences. The simplified catastrophe risk assessment entails a statistical analysis of storm surge characteristics, geographical-information analysis of population and asset exposure combined with aggregated vulnerability information. For the city of Copenhagen, it is found that in absence of adaptation, sea level rise would significantly increase flood risks. Results call for the introduction of adaptation in long-term urban planning, as one part of a comprehensive strategy to manage the implications of climate change in the city. Mitigation policies can also aid adaptation by limiting the pace of future sea level rise.     

Fern species richness and abundance are indicators of climate change on high-elevation islands: evidence from an elevational gradient on Tahiti (French Polynesia)

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).     

Between the devil and the deep blue sea: Florida��s unenviable position with respect to sea level rise

This paper introduces and summarizes a series of articles on the potential impacts of sea level rise on Florida??s natural and human communities and what might be done to reduce the severity of those impacts. Most of the papers in this special issue of Climatic Change were developed from presentations at a symposium held at Archbold Biological Station in January 2010, sponsored by the Florida Institute for Conservation Science. Symposium participants agreed that adaptation to sea level rise for the benefit of human communities should be planned in concert with adaptation to reduce vulnerability and impacts to natural communities and native species. The papers in this special issue discuss both of these categories of impacts and adaptation options. In this introductory paper, I place the subject in context by noting that that the literature in conservation biology related to climate change has been concerned largely about increasing temperatures and reduced moisture availability, rather than about sea level rise. The latter, however, is the most immediate and among the most severe impacts of global warming in low-lying regions such as Florida. I then review the content of this special issue by summarizing and interpreting the following 10 papers. I conclude with a review of the recommendations for research and policy that were developed from group discussions at the Archbold symposium. The main lesson that emerges from this volume is that sea level rise, combined with human population growth, urban development in coastal areas, and landscape fragmentation, poses an enormous threat to human and natural well-being in Florida. How Floridians respond to sea level rise will offer lessons, for better or worse, for other low-lying regions worldwide.     

Using El Niño/Southern Oscillation Climate Data to Predict Rice Production in Indonesia

Despite the strong signal of El Niño/Southern Oscillation (ENSO) events on climate in the Indo-Pacific region, models linking ENSO-based climate variability to seasonal rice production and food security in the region have not been well developed or widely used in a policy context. This study successfully measures the connections among sea surface temperature anomalies (SSTAs), rainfall, and rice production in Indonesia during the past three decades. Regression results show particularly strong connections on Java, where 55% of the country's rice is grown. Two-thirds of the interannual variance in rice plantings and 40% of the interannual variance in rice production during the main (wet) season on Java are explained by year-to-year fluctuations in SSTAs measured 4 and 8 months in advance, respectively. These effects are cumulative; during strong El Niño years, production shortfalls in the wet season are not made up later in the crop year. The analysis demonstrates that quantitative predictions of ENSO's effects on rice harvests can provide an additional tool for managing food security in one of the world's most populous and important rice-producing countries.     

Global estimates of the impact of a collapse of the West Antarctic ice sheet: an application of FUND

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.     

Regional sea level changes projected by the NASA/GISS Atmosphere-Ocean Model

Sea level has been rising for the past century, and coastal residents of the Earth will want to understand and predict future sea level changes. In this study we present sea level changes from new simulations of the Goddard Institute for Space Studies (GISS) global atmosphere-ocean model from 1950 to 2099. The free surface, mass conserving ocean model leads to a straightforward calculation of these changes. Using observed levels of greenhouse gases between 1950 and 1990 and a compounded 0.5% annual increase in CO₂ after 1990, model projections show that global sea level measured from 1950 will rise by 61?mm in the year 2000, by 212?mm in 2050, and by 408?mm in 2089. By 2089, 64% of the global sea level rise will be due to thermal expansion and 36% will be due to ocean mass changes. The Arctic Ocean will show a greater than average sea level rise, while the Antarctic circumpolar region will show a smaller rise in agreement with other models. Model results are also compared with observed sea level changes during the past 40 years at 12 coastal stations around the world.     

Economic impacts of climate change in Europe: sea-level rise

This paper uses two models to examine the direct and indirect costs of sea-level rise for Europe for a range of sea-level rise scenarios for the 2020s and 2080s: (1) the DIVA model to estimate the physical impacts of sea-level rise and the direct economic cost, including adaptation, and (2) the GTAP-EF model to assess the indirect economic implications. Without adaptation, impacts are quite significant with a large land loss and increase in the incidence of coastal flooding. By the end of the century Malta has the largest relative land loss at 12% of its total surface area, followed by Greece at 3.5% land loss. Economic losses are however larger in Poland and Germany (483 and483 and 391 million, respectively). Coastal protection is very effective in reducing these impacts and optimally undertaken leads to protection levels that are higher than 85% in the majority of European states. While the direct economic impact of sea-level rise is always negative, the final impact on countries’ economic performances estimated with the GTAP-EF model may be positive or negative. This is because factor substitution, international trade, and changes in investment patterns interact with possible positive implications. The policy insights are (1) while sea-level rise has negative and huge direct economic effects, overall effects on GDP are quite small (max −0.046% in Poland); (2) the impact of sea-level rise is not confined to the coastal zone and sea-level rise indirectly affects landlocked countries as well (Austria for instance loses −0.003% of its GDP); and (3) adaptation is crucial to keep the negative impacts of sea-level rise at an acceptable level.     

The potential impacts of sea level rise on the coastal region of New Jersey,USA

This study presents an assessment of the potential impacts of sea level rise on the New Jersey, USA coastal region. We produce two projections of sea level rise for the New Jersey coast over the next century and apply them to a digital elevation model to illustrate the extent to which coastal areas are susceptible to permanent inundation and episodic flooding due to storm events. We estimate future coastline displacement and its consequences based on direct inundation only, which provides a lower bound on total coastline displacement. The objective of this study is to illustrate methodologies that may prove useful to policy makers despite the large uncertainties inherent in analysis of local impacts of climate and sea level change. Our findings suggest that approximately 1% to 3% of the land area of New Jersey would be permanently inundated over the next century and coastal storms would temporarily flood low-lying areas up to 20 times more frequently. Thus, absent human adaptation, by 2100 New Jersey would experience substantial land loss and alteration of the coastal zone, causing widespread impacts on coastal development and ecosystems. Given the results, we identify future research needs and suggest that an important next step would be for policy makers to explore potential adaptation strategies.     

Assessing municipal vulnerability to predicted sea level rise: City of Satellite Beach, Florida

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.     

The risk of sea level rise

The United Nations Framework Convention on Climate Change requires nations to implement measures for adapting to rising sea level and other effects of changing climate. To decide upon an appropriate response, coastal planners and engineers must weigh the cost of these measures against the likely cost of failing to prepare, which depends on the probability of the sea rising a particular amount.This study estimates such a probability distribution, using models employed by previous assessments, as well as the subjective assessments of twenty climate and glaciology reviewers about the values of particular model coefficients. The reviewer assumptions imply a 50 percent chance that the average global temperature will rise 2 °C, as well as a 5 percent chance that temperatures will rise 4.7 °C by 2100. The resulting impact of climate change on sea level has a 50 percent chance of exceeding 34 cm and a 1% chance of exceeding one meter by the year 2100, as well as a 3 percent chance of a 2 meter rise and a 1 percent chance of a 4 meter rise by the year 2200.The models and assumptions employed by this study suggest that greenhouse gases have contributed 0.5 mm/yr to sea level over the last century. Tidal gauges suggest that sea level is rising about 1.8 mm/yr worldwide, and 2.5–3.0 mm/yr along most of the U.S. Coast. It is reasonable to expect that sea level in most locations will continue to rise more rapidly than the contribution from climate change alone.We provide a set of normalized projections which express the extent to which climate change is likely to accelerate the rate of sea level rise. Those projections suggest that there is a 65 percent chance that sea level will rise 1 mm/yr more rapidly in the next 30 years than it has been rising in the last century. Assuming that nonclimatic factors do not change, there is a 50 percent chance that global sea level will rise 45 cm, and a 1 percent chance of a 112 cm rise by the year 2100; the corresponding estimates for New York City are 55 and 122 cm.Climate change impact assessments concerning agriculture, forests, water resources, and other noncoastal resources should also employ probability-based projections of regional climate change. Results from general circulation models usually provide neither the most likely scenario nor the full range of possible outcomes; probabilistic projections do convey this information. Moreover, probabilistic projections can make use of all the available knowledge, including the views of skeptics; the opinions of those who study ice cores, fossils, and other empirical evidence; and the insights of climate modelers, which may be as useful as the model results themselves.The U.S. Government right to retain a non-exclusive royalty-free license in and to any copyright is acknowledged.     

Sea level history of the northern Gulf of Mexico coast and sea level rise scenarios for the near future

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.     

Sea level rise,consequences and policies

Accelerated sea-level rise and the effects on coastal areas represent one of the most important impacts of global climate warming as a large part of the world's population and food production is situated along low-lying coasts. Coastal nations of the world should now be planning for one-half to a meter rise in sea level during the next century. While the actual extent of sea rise realized may be larger or perhaps smaller, this amount establishes a reasonable baseline for coastal zone planning activities. With respect to actual measures, priority should be given to projects that are beneficial to presently existing problems in coastal areas.The lowlands along the world's seas will be the areas most vulnerable to impact. They include the deltaic, barrier island, atoll, and marshy coastlines. Increased storm-induced flooding represents the major danger in developing countries because of loss of life. In western countries, beach erosion will be a primary concern, requiring substantial expenditure of public funds to maintain existing recreational beaches. Marshlands will probably be left to their own destiny, which signals a marked decline in most places.The responses to accelerated sea-level rise must be based on more than a simple cost-benefit ratio; a host of important considerations cannot be expressed in simple dollar terms. Each area must be considered on a site-specific basis as there is considerable geographic variation in the environmental (e.g., hydrologic, geologic) and cultural (e.g., population, human development) factors. The problem is further compounded by the time lag of several decades that exists between public recognition of the problem and actual construction and full operation of major coastal protective devices. It may be necessary to retreat from the eroding shore in some areas, while fortifying and even reclaiming land in others. Clearly a global response is required in that international research and cooperative efforts represent the only reasonable approach.     

CLIMATE CHANGE VULNERABILITY AND RESPONSE STRATEGIES FOR THE COASTAL ZONE OF POLAND

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.     

Redistribution of sea level rise associated with enhanced greenhouse warming: a simple model study

Future sea level rise from thermal expansion of the World Ocean due to global warming has been explored in several recent studies using coupled ocean-atmosphere models. These coupled models show that the heat input by the model atmosphere to the ocean in such an event could be quite non-uniform in different areas of the ocean. One of the most significant effects predicted by some of the models is a weakening of the thermohaline circulation, which normally transports heat poleward. Since the greatest heat input from enhanced greenhouse warming is in the higher latitudes, a weakening of the poleward heat transport effectively redistributes the heat anomaly and the associated sea level rise to lower latitudes. In this study, the mechanism of ocean circulation spindown and heat redistribution was studied in the context of a much simpler, linearized shallow water model. Although the model is much simpler than the three-dimensional ocean circulation models used in the coupled model experiments, and neglects several important physical effects, it has a nearly 10-fold increase in horizontal resolution and clearer dynamical interpretations. The results indicated that advanced signals of sea level rise propagated rapidly through the action of Kelvin and Rossby waves, but the full adjustment toward a more uniform sea level rise took place much more slowly. Long time scales were required to redistribute mass through narrow currents trapped along coasts and the equatorial wave guide. For realistic greenhouse warming, the model showed why the sea level rise due to ocean heating could be far from uniform over the globe and hence difficult to estimate from coastal tide gauge stations.     

IPCC AR6解读：全球和区域海平面变化的监测和预估

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。     

Multipurpose agroforestry as a climate change resiliency option for farmers: an example of local adaptation in Vietnam

Increasing frequency, intensity and duration of severe weather events are posing major challenges to global food security and livelihoods of rural people. Agriculture has evolved through adaptation to local circumstances for thousands of years. Local experience in responding to severe weather conditions, accumulated over generations and centuries, is valuable for developing adaptation options to current climate change. This study aimed to: (i) identify tree species that reduce vulnerability of cropping systems under climate variability; and (ii) develop a method for rapidly assessing vulnerability and exploring strategies of smallholder farmers in rural areas exposed to climate variability. Participatory Rural Appraisal methods in combination with Geographical Information Systems tools and statistical analysis of meteorological data were used to evaluate local vulnerability to climate change and to investigate local adaptation measures in two selected villages in Vietnam, one of the countries most vulnerable to climate change. The low predictability of severe weather events makes food crops, especially grain production, insecure. This study shows that while rice and rain-fed crops suffered over 40 % yield losses in years of extreme drought or flood, tree-based systems and cattle were less affected. 13 tree species performed well under the harsh local climate conditions in home and forest gardens to provide income, food, feed and other environmental benefits. Thus, this research suggests that maintenance and enhancement of locally evolved agroforestry systems, with high resilience and multiple benefits, can contribute to climate change adaptation.     

IPCC特别报告SRCCL关于气候变化与粮食安全的新认知与启示

气候变化对粮食安全的影响是广泛的,不但影响粮食产量和品质,还会影响到农户的生计以及农业相关的产业发展等;而粮食系统在保障粮食安全的同时,又会产生一系列的环境问题,其中农业源温室气体（GHG）的排放加剧全球变暖。IPCC在2019年8月份发布的《气候变化与土地特别报告》（SRCCL）,从粮食生产、加工、储存、运输及消费的各个环节评估气候变化对粮食安全的影响及粮食系统的温室气体排放对气候系统的影响;系统梳理粮食系统供给侧和需求侧的适应与减缓措施、适应与减缓的协同和权衡问题,以及气候变化条件下保障粮食安全的政策环境等。SRCCL评估结论认为,由于大量施用氮肥和消耗水资源,目前粮食系统GHG排放占全球总排放的21%~37%;农业和粮食系统是全球应对气候变化的重要方面,供给侧和需求侧的综合措施可以减少食物浪费、减少GHG排放、增加粮食系统的恢复力。未来工作的重点应丰富和扩展气候变化影响评估内容,量化适应效果,加深对适应、减缓及其协同和权衡的科学认知,大力加强应对气候变化能力建设。     

Sea level responses to climatic variability and change in northern British Columbia

Abstract

Sea level responses to climatic variability (CV) and change (CC) signals at multiple temporal scales (interdecadal to monthly) are statistically examined using long‐term water level records from Prince Rupert (PR) on the north coast of British Columbia. Analysis of observed sea level data from PR, the longest available record in the region, indicates an annual average mean sea level (MSL) trend of +1.4±0.6 mm yr^?1 for the period (1939–2003), as opposed to the longer term trend of 1±0.4 mm yr^?1 (1909–2003). This suggests a possible acceleration in MSL trends during the latter half of the twentieth century. According to the results of this study, the causes behind this acceleration can be attributed not only to the effects of global warming but also to cyclic climate variability patterns such as the strong positive Pacific Decadal Oscillation (PDO) phase that has been present since the mid‐1970s. The linear regression model based on highest sea levels (MAXSL) of each calendar year showed a trend exceeding twice that (3.4 mm yr^?1) of MSL. Previous work shows that the influence of vertical crustal motions on relative sea level are negligible at PR.

Relations between sea levels and known CV indices (e.g., the Multivariate ENSO Index (MEI), PDO, Northern Oscillation Index (NOI), and Aleutian Low Pressure Index (ALPI)) are explored to identify potential controls of CV phenomena (e.g., the El Niño Southern Oscillation (ENSO), PDO) on regional MSL and MAXSL. Linear and non‐linear statistical methods including correlation analyses, multiple regression, Cumulative Sum (CumSum) analysis, and Superposed Epoch Analysis (SEA) are used. Results suggest that ENSO forcing (as shown by the MEI and NOI indices) exerts significant influence on winter sea level fluctuations, while the PDO dominates summer sea level variability. The observational evidence at PR also shows that, during the period 1939–2003, these cyclic shorter temporal scale sea level fluctuations in response to CV were significantly greater than the longer term sea‐level rise trend by as much as an order of magnitude and with trends over twice that of MSL. Such extreme sea level fluctuations related to CV events should be the immediate priority for the development of coastal adaptation strategies, as they are superimposed on long‐term MSL trends, resulting in greater hazard than longer term MSL rise trends alone.