中国沿海响应气候变化的复杂性

在过去的一个世纪,中国海岸已明显观测到气候变暖和海平面上升所造成的危害。气候变化对中国海岸带的影响和海岸系统对气候变化的适应性具有明显的区域性差异。海岸自然条件复杂,海岸不同生态环境的自修复能力各异。人类活动对海岸带的影响巨大,在适应气候变化方面具有明显的能动性,适应能力受社会经济发展水平的制约,从而具有明显的区域特征。海岸系统与气候变化之间并不是简单的线性关系。未来气候变暖和海平面加速上升无疑将加大对海岸带的影响,但目前尚难以确定海岸生态系统的气候变化阈值。     

气候变化科学方面的几个最新认知

IPCC第六次评估报告（AR6）第一工作组报告主要从以下几个方面的进展提升了我们对气候系统变化、气候变化原因以及预估未来气候系统变化等方面的认知,对过去气候变化及其与人类活动的关系有了更加清晰、可靠的认识。综合多重证据评估指出,全球气候正经历着前所未有的变化;包括极端事件在内的归因进展已把人类活动对气候系统影响的认识从大气圈扩展到水圈、冰冻圈和生物圈,进一步强化了人类活动影响全球和区域气候的认识;有关区域气候变化信息的内容更加丰富,与各行业和敏感地区的气候变化影响联系更加紧密,使这些信息能更好地为气候变化风险评估和气候变化区域适应提供支持;气候模式和约束预估方法的发展以及对气候敏感度认识的深化,减少了未来不同排放情景下全球地表温度（Global Surface Temperature,GST)、海平面上升和海洋热含量的变化预估的不确定性。这份最新报告对我国提升气候变化研究水平和防灾减灾应对能力具有十分重要的指导意义。     

气候变化对黑龙江省农业的影响

IPCC（政府间气候变化专门委员会）第二工作组第四次评估报告Il】指出,全球气候变暖,对自然生态和人类生存环境产生显著影响．并将对未来自然生态和经济社会的发展产生长期的影响,其中对农牧业、生态系统、水资源及沿海岸带社会经济的影响最为严重,而农业则是受气候和天气制约最大的领域。     

海洋的变化及其对生态系统和人类社会的影响、风险及应对

IPCC《气候变化中的海洋和冰冻圈特别报告》评估了全球和区域海洋的气候变化及其对生态系统和人类社会的影响、风险及应对措施。结果表明,近几十年来,海洋的物理和化学性质发生了明显变化,如升温、酸化、脱氧和营养盐减少等气候致灾因子（事件）的危害（险）性不断加剧（高信度）。这种变化正在影响从上层到底层的海洋生态系统和人类社会的可持续发展,如海洋初级生产力的下降、物种地理分布的变迁、渔业资源潜在渔获量的下降以及食品供应的减少（高信度）。在气候变化与非气候人为干扰因素的综合影响下,随着温室气体排放的增加（从RCP2.6到RCP8.5情景）,到21世纪末,几乎所有类型的海洋和海岸带生态系统将处于高或很高的风险水平（高信度);其中,暖水珊瑚礁生态系统尤其严重,如果全球升温1.5℃和2℃,将分别消失70%~90%和99%以上（很高信度）。然而,当前多种减缓气候变化的海洋应对措施的作用较小,有的可能带来生态危险,而许多降低气候风险的海洋适应措施的作用也很有限,特别是在RCP8.5情景下的作用更小;未来海洋生态系统的风险水平在RCP2.6情景下均低于RCP8.5情景（很高信度)。因此,这凸显了减缓气候变化尤其是减缓和适应气候变化综合治理的重要性。     

气候变化与海洋生态系统：影响、适应和脆弱性——IPCC AR6 WGⅡ报告之解读

IPCC第六次评估报告(AR6)第二工作组报告第三章开展了气候变化对海洋的影响和风险,以及生态系统及其服务功能、脆弱性和适应评估。AR6明确指出,人为气候变化已经并将继续显著地改变全球和区域海洋的气候影响驱动因子,包括海温升高、海平面上升、海洋酸化和缺氧,以及营养盐浓度变化等海洋物理和化学因子。例如,20世纪80年代以来全球海洋热浪发生的频率已增加了1倍,到21世纪末期可能增加4～8倍。气候影响驱动因子的变化已经对海洋和海岸带生态系统造成了广泛而深远的影响:1)海洋变暖使得海洋物种自1950年代以来以(59.2±15.5) km/(10 a)的速率向极地方向迁移,导致热带海域生物量减少,中纬度海区热带化,极地和亚极地海区浮游植物生长期提前;2)频繁发生的海洋热浪事件已经接近甚至超过了某些海洋生物的耐受极限或其气候临界点,如暖水珊瑚的大规模白化、死亡,海草和大型海藻的大面积消失;3)海洋变暖、缺氧和酸化使得河口区生物群落结构改变,赤潮等有害藻华事件频发,近海和大洋浮游植物生物量和初级生产力下降;4)海平面上升导致海岸带红树林、盐沼和海草床等生态系统的退化;5)未来全球海洋生态系统面临的风险将不断加剧,尤其是在热带和北冰洋海区。其中,当全球升温1.5℃时(最快到21世纪40年代,SSP5-8.5情景),暖水珊瑚礁预计将减少70％～90％;当升温2℃时,几乎所有的(>99％)暖水珊瑚礁将会消失。目前人类社会采取的一些措施(如建立海洋保护区和红树林生态修复)已越来越不能应对日益增长的气候风险,迫切需要发展变革性的行动措施,推动海洋生态系统恢复力的发展,并需尽快采取强有力的减排措施以减缓全球变暖的影响。     

气候变化国家评估报告（II）：气候变化的影响与适应

已经观测到的气候变化影响是显著的、多方面的。各个领域和地区都存在有利和不利影响,但以不利影响为主,未来的气候变暖将会对中国的生态系统、农业以及水资源等部门和沿海地区产生重大的不利影响。采取适应措施可以减轻气候变化的不利影响,应将适应气候变化的行动逐步纳入国民经济和社会发展的中长期规划中。由于我国科学研究的相对不足和科学认识能力的局限,目前的气候变化影响评估方法和结果还存在很大的不确定性。应当加强区域适应气候变化的案例研究、扩大研究领域、加强极端天气、气候事件影响的研究,以降低影响评估的不确定性,并提出切实可行的适应对策。     

气候变化及其未来情景

论述了百余年来气候变化的事实及对未来情景的预估。1861年以来,全球平均温度升高了0.6±0.2℃。20世纪90年代是20世纪最暖的10a。近百年来,降水分布也发生了变化,大陆地区尤其是中高纬地区降水增加,非洲等一些地区降水减少。气候模式模拟表明:全球平均地表气温到2100年时将比1990年上升1.4￣5.8℃。21世纪全球平均降水将会增加,但大部分年平均降水增加的区域很可能同时出现大的年际变化。全球平均海平面到2100年时将比1990年上升0.09￣0.88m。北半球雪盖和海冰范围将进一步缩小。未来,若干极端事件发生的频率会增加。     

IPCC AR6报告解读：气候变化与水安全

保障水安全是应对和缓解气候变化的核心问题,也是实现可持续发展的前提。IPCC第六次评估报告（AR6）第二工作组报告单独设立第四章“水”,分析了气候变化对全球水循环的影响,评估了水循环变化对人类社会和生态系统的影响,指出了当前与未来的水安全风险,分析了与水相关适应措施的收益与成效。报告显示,人类活动导致的气候变化加速了全球水文循环,对水安全产生负面影响,面临水安全风险的人口与地区增多,并增加了由社会经济因素造成的水资源脆弱性。水安全风险随全球升温水平的升高而增加,在水安全脆弱地区表现更为显著。将全球升温限制在1.5℃可有效降低未来的水安全风险,有助于实现水安全、可持续发展和具有气候恢复力的发展三重目标。我国水安全问题突出,急需在“灰-绿”基础设施生态水文效应、三维水资源短缺、水-粮食-能源耦合、地球系统模拟器研发应用等方面重点开展研究工作。     

全球气候变化对中国森林生态系统的影响

人类活动所引起的温室效应及由此造成的全球气候变化和对全球生态环境的影响正引起人们越来越多的重视.作为全球陆地生态系统一个重要组分,中国的森林生态系统对未来全球气候变化的响应更是人们关注的重点.作者系统地总结了全球气候变化对中国森林生态系统分布、生态系统生产力、森林树种以及森林土壤的影响,指出了现阶段该领域研究中存在的一些问题,并对今后需要加强的一些核心问题与研究重点作了展望.     

广东气候变化评估报告(节选)

IPCC第4次报告指出:近100年全球平均气温升高了0.74℃,最近50年有加速之势,而且很可能主要由人类活动引起;预计21世纪,全球仍将表现为明显的增温,极端天气气候事件及其引发的气象灾害可能更加严重。近50年,广东气温升高与全球平均水平相当,其中珠江三角洲地区是主要增温区域,其次是东南部沿海地区。预计广东在2011~2040年、2041~2070年和2071~2100年的年平均气温可能分别升高约1.0、1.9和2.8℃。在全球变暖的背景下,广东地区气候变化的特征主要表现在:降水变率加大,旱涝灾害频繁;登陆台风的个数减少,初台登陆时间异常;高温日数增加,高温酷热、热浪愈发频繁;低温日数减少,暖冬突出;极端最低气温变化不稳定性增加,寒冷灾害加重;灰霾天气增多,日照时数减少;极端天气气候事件及其引发的气象灾害造成的经济损失显著增大。广东近50年的增暖在很大程度上可能归因于温室气体浓度增加造成的温室效应,这种温室效应已经对增暖做出了实质性的贡献;城市化导致的热岛效应加剧了局部地区的气温上升。气候变暖既有负面影响也有正面影响,但负面影响可能超过正面影响。气候变暖将导致海平面上升,继而可能对广东沿海低洼地区带来严重的负面影响。在过去近100年全球海平面上升约10~20 cm,广东海平面上升速率为1.7 mm/年,海平面上升会使海岸侵蚀加重,咸潮海水入侵加剧;温度上升可能使广东近海珊瑚礁生态系统退化,且变得更加脆弱;珠江口的咸潮上溯的现象可能更加频繁;广东沿海的赤潮可能更加频发。气候变暖将导致农业生产的不稳定性增加,产量波动大,农业成本和投资将增加。此外,气候变化对我省国民经济的一些方面(如水资源、人类健康、人类居住环境、保险和其它金融业)的影响可能以负面为主。为适应和减缓气候变化的影响,建议:通过节能降耗,减缓温室气体排放;采取措施,适应已经发生了变化的气候;提高对气候系统的监测能力;加强气候变化领域的科学研究、适应对策研究及技术开发;在经济社会发展规划中统筹考虑应对气候变化问题;提高公众的气候保护意识;加大资金投入;积极开展合作与交流。     

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.     

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).     

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.     

A megacity in a changing climate: the case of Kolkata

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 %.     

Regional impact assessment of flooding under future climate and socio-economic scenarios for East Anglia and North West England

Interactive tools developed within the RegIS project for assessing the impacts of flooding provide information to support flood management policies and analyse the performance of possible adaptation activities to climate change. This paper describes the methodologies used in the development of these tools including tidal and fluvial flooding processes with different levels of climate pressures, represented by changes in sea level and peak river flows. Potential impacts of climate change for East Anglia and North West England are explored to the 2050s using four socio-economic scenarios to represent plausible futures. This includes changes in urban land use as well as adaptive responses to flooding comprising dike upgrade and realignment options. The results indicate that future climate will increase flood risk in both regions. East Anglia is more vulnerable to climate change than North West England at the present level of protection, especially in the extensive coastal lowlands of the Fens and Broads because of the combined effects of sea-level rise and increased fluvial flows. Although the present adaptive policy of upgrading defences in East Anglia will reduce the impacts of flooding, this policy is not effective in the case of the more extreme climate change scenarios by 2050s. In this case, more extensive adaptation would be required.     

海平面加速上升对低海拔岛屿、沿海地区及社会的影响和风险

IPCC《气候变化中的海洋和冰冻圈特别报告》评估了气候变化对全球、区域海平面变化和极端海面（极值水位）升高的贡献,以及海平面上升对低海拔（小鱼10 m）岛屿、沿海地区和社会的影响及相关的风险。评估表明,全球变暖背景下,全球平均海平面上升的证据是确凿的,且明显加速（高信度),极端海面高度升高,主要是由陆地冰川和冰盖融化以及海洋热膨胀引起,且前者的贡献已大于后者（很高信度);与此同时,海洋变暖速率倍增,强热带气旋、风暴潮增多,极值水位重现期缩短;至21世纪末,全球海平面还将上升约0.43 m（温室气体低排放情景,RCP2.6）和0.84 m（高排放情景,RCP8.5）（中等信度）,很多沿海地区当前较少发生的百年一遇的极值水位将变为一年一遇或更频繁,而对于许多沿海低洼地而言,类似事件甚至在21世纪中叶就可能发生（高信度)。评估还表明,持续上升的海平面、趋于频发的极值水位,以及人为地面沉降等因素,增加了沿海社会-生态系统的暴露度和脆弱性;并且,与海平面上升有关的危害（险）性事件,如海岸侵蚀、洪灾、盐碱化和生境退化等将显著增加（高信度)。报告指出,如未采取充分的适应海平面上升的措施,在RCP8.5情景下,沿海大城市、城市环礁群岛、热带农业三角洲地区和北极沿岸社区将处于高或很高的灾害风险中（高信度)。     

California coastal management with a changing climate

With over 2,000 miles (3,218 km) of ocean and estuarine coastline, California faces significant coastal management challenges as a result of climate change-induced sea level rise. Under high emission scenarios, recent models predict 1.4 m or more of sea level rise by 2100, accompanied by increasing storm surges. This article investigates the most important issues facing coastal managers, explores the policy tools available for adapting to the impacts of climate change, assesses institutional constraints to adaptation, and identifies priorities for future research and policy action. We find that adaptation tools exist for dealing with anticipated increases in coastal erosion and flooding, but they involve significant costs and tradeoffs. In particular, coastal armoring, such as seawalls, can protect developed coastal lands, but destroys beaches and habitat. Although California already has policies and institutions that aim to balance the competing objectives for coastal development, management agencies are at the early stages of understanding how to facilitate adaptation. Research priorities to inform coastal adaptation planning include: (i) inventorying coastal resources to provide a firmer basis for balancing decisions on property and habitat protection, (ii) identifying opportunities for coastal habitat migration, (iii) assessing the vulnerabilities of existing and planned coastal infrastructure, and (iv) experimenting with alternatives to armoring as a way of managing the changing coastline.     

The economic impact of climate change in the 20th and 21st centuries

The national version of FUND3.6 is used to backcast the impacts of climate change to the 20th century and extrapolate to the 21st century. Carbon dioxide fertilization of crops and reduced energy demand for heating are the main positive impacts. Climate change had a negative effect on water resources and, in most years, human health. Most countries benefitted from climate change until 1980, but after that the trend is negative for poor countries and positive for rich countries. The global average impact was positive in the 20th century. In the 21st century, impacts turn negative in most countries, rich and poor. Energy demand, water resources, biodiversity and sea level rise are the main negative impacts; the impacts of climate change on human health and agriculture remain positive until 2100.     

IPCC SROCC的主要结论和启示

2019年9月,IPCC正式发布《气候变化中的海洋和冰冻圈特别报告》（SROCC）,这是IPCC首次以高山地区与极区冰冻圈和海洋为主题的评估报告。报告全面评估气候变化背景下海洋和冰冻圈变化及其广泛影响与风险,其核心结论包括：气候系统变暖背景下高山地区和极区的冰冻圈普遍退缩,未来冰冻圈将继续消融,高山地区和极区将面临更高的灾害风险;20世纪70年代以来全球海洋持续增暖,未来海洋将继续变暖、加速酸化,影响海洋生物多样性并危及海洋生态系统服务功能和人类社会;近几十年全球平均海平面加速上升,未来数百年海平面仍将持续上升,极端海面事件频发将加剧沿海地区社会-生态系统的灾害风险。报告强调,采取及时、积极、协调和持久的适应与减缓行动,是有效应对海洋和冰冻圈变化,实现气候恢复力发展路径和可持续发展目标的关键所在。本研究认为,需要高度重视海洋和冰冻圈在气候系统变化中的长期和不可逆影响,强化应对气候变化紧迫性认识;高度重视我国冰冻圈和沿海地区面临的气候风险,强化适应能力建设;推动我国牵头的国际大科学计划,强化跨学科、跨领域协同创新,持续提升我国在相关领域的国际影响力和科技支撑能力。     

Projection of economic impacts of climate change in sectors of Europe based on bottom up analysis: human health

This paper scopes a number of the health impacts of climate change in Europe (EU-27) quantitatively, using physical and monetary metrics. Temperature-related mortality effects, salmonellosis and coastal flooding-induced mental health impacts resulting from climate change are isolated from the effects of socio-economic change for the 2011–2040 and 2071–2100 time periods. The temperature-induced mortality effects of climate change include both positive and negative effects, for winter (cold) and summer (heat) effects, respectively, and have welfare costs (and benefits) of up to 100 billion Euro annually by the later time-period, though these are unevenly distributed across countries. The role of uncertainty in quantifying these effects is explored through sensitivity analysis on key parameters. This investigates climate model output, climate scenario, impact function, the existence and extent of acclimatisation, and the choice of physical and monetary metrics. While all of these lead to major differences in reported results, acclimatisation is particularly important in determining the size of the health impacts, and could influence the scale and form of public adaptation at the EU and national level. The welfare costs for salmonellosis from climate change are estimated at potentially several hundred million Euro annually by the period 2071–2100. Finally, a scoping assessment of the health costs of climate change from coastal flooding, focusing on mental health problems such as depression, are estimated at up to 1.5 billion Euro annually by the period 2071–2100.