气候变化对陆地生态系统和海岸带地区的影响解读

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。     

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。     

IPCC AR6报告解读：气候变化对城市、住区和关键基础设施的影响与适应

IPCC AR6 WGII评估了气候变化对城市、住区和关键基础设施的影响、风险及应对。气候变化对城市影响的程度和范围逐渐增加,全球城市化的过程与气候变化相互作用加剧了城市和住区的风险。通过社会基础设施、基于自然的解决方案和灰色/工程基础设施所采取的适应措施对气候恢复力发展均有贡献,而城市适应差距在世界各地普遍存在。气候恢复力发展需要多方协作、弥合政策行动差距、提升适应能力。评估报告的经验和案例为我国城乡地区适应和应对气候变化风险提供借鉴。     

IPCC AR6报告关于气候变化适应措施的解读

适应举措对降低人类和生态系统的气候变化风险有着积极的影响。IPCC第六次评估报告（AR6）第二工作组（WGII）报告全面评估了适应的可行性和有效性,深入评估了适应局限性和不良适应。报告认为,个人、地方、区域和国家各级的适应行动都在增加,但是在做决策时需考虑不良适应的风险。报告从经济、技术、制度、社会、环境和地球物理这6个维度,对23个适应措施的可行性进行了评估;这些适应措施分布在陆地、海洋与生态系统,城乡与基础设施系统,能源系统以及跨部门等四大系统,其中,基于森林的适应、具有恢复力的电力系统、能源可靠性等适应措施具有高信度的高可行性。适应措施的可行性和有效性会随着气候变暖的增加而降低,需要采用多种措施来降低未来气候变化风险。     

气候变化影响的最新认知

政府间气候变化专门委员会（IPCC）第二工作组于2007年4月6日正式发布了第四次评估报告,该报告客观、全面而审慎地评估了气候变化已有的和未来的可能影响。现有观测证据表明,人为增暖可能已对许多自然和生物系统产生了可辨别的影响,但由于适应以及非气候因子的作用,许多影响还难以辨别。21世纪中期,某些中纬度和热带干旱地区年平均河流径流量和可用水量会减少10%～30%;如果全球平均温度增幅超过1.5～2.5℃,目前所评估的20%～30%动植物物种可能面临灭绝的风险会增大;从全球角度看,局地平均温度增加1～3℃,预计粮食生产潜力会增加,但若超过这一范围,则会减少。兼顾适应和减缓的措施能够降低气候变化相关风险。     

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。     

IPCC AR6报告关于气候恢复力发展的解读

文中对IPCC第六次评估报告（AR6）第二工作组（WGII）报告关于气候恢复力发展（CRD）相关内容进行解读。CRD的概念最初由IPCC第五次评估报告（AR5）引入,AR6在AR5的基础上进行了更新,正式将CRD定义为实施温室气体减缓和适应措施的过程,以支持所有人的可持续发展。新的定义更加强调了公平性原则,并且在评估内容中对不同社会选择进行了细致的描述,增强了CRD的可操作性,也强调了其紧迫性与不可逆性。报告主要从适应的角度阐述了如何在人类系统和自然系统中促成CRD的实现：城市化趋势为CRD同时带来了机遇与挑战,城市化在加剧气候变化风险的同时也会通过带动周边乡村地区的适应行动来推动CRD;保护生态系统多样性有助于保护生态系统也有助于提高其自身的恢复力,但在较高温升水平下部分适应行动将会无法实施。AR6 WGII报告评估显示,比起AR5报告的时间节点（2014年）的评估结论,当前全球CRD行动更紧迫,实行有效的、公平的应对气候变化措施迫在眉睫。     

冰冻圈影响区恢复力研究和实践:进展与展望

气候变化引起全球冰冻圈各要素普遍退缩,进而深刻影响着区域生态安全和社会经济发展。恢复力(resilience)以降低脆弱性为目标,维持和培育社会-生态系统应对外界胁迫和干扰的能力,为应对冰冻圈变化引起的负面影响、实现区域可持续发展提供了重要的理论和实践框架。文中辨识了全球变暖背景下冰冻圈过程和功能变化对主要社会-生态系统的影响,综述了当前冰冻圈影响区恢复力相关的主要研究和实践进展,探讨了加强冰冻圈影响区社会-生态系统恢复力的路径。我们认为未来要进一步加强区域和全球冰冻圈变化及其影响综合评估,深入研究冰冻圈影响区社会-生态系统变化的驱动机制、级联效应和稳态转换;在实践上将减缓、适应和转型有机结合,建立管控区域社会-生态系统演化的综合监测、评估、预警和决策系统,从而促进系统朝着更具恢复力和可持续的路径发展。     

IPCC第五次评估报告对气候变化风险及风险管理的新认知

IPCC第五次评估报告第二工作组报告在气候变化风险及风险管理方面聚焦于气候变化对领域和区域的不利影响。在综合分析与气候变化相关危害、暴露度和脆弱性的基础上,提出了气候变化风险的评估框架。风险不仅来自气候变化本身,同时也来自人类社会发展和治理过程。报告首次提出了新生风险,归纳总结了气候变化带来的关键风险,评估了不同温升下气候变化5个“关注理由”的风险水平。在风险管理过程中,由于适应和减缓的局限性,剩余风险是不可避免的。未来,若全球平均温度升高4℃（较工业革命以前）将加剧人类和社会生态系统广泛的、严重的和不可逆影响的风险。     

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。     

Modeling the Impact of Black Spruce on the Fire Regime of Alaskan Boreal Forest

In the boreal biome, fire is the major disturbance agent affecting ecosystem change, and fire dynamics will likely change in response to climatic warming. We modified a spatially explicit model of Alaskan subarctic treeline dynamics (ALFRESCO) to simulate boreal vegetation dynamics in interior Alaska. The model is used to investigate the role of black spruce ecosystems in the fire regime of interior Alaska boreal forest. Model simulations revealed that vegetation shifts caused substantial changes to the fire regime. The number of fires and the total area burned increased as black spruce forest became an increasingly dominant component of the landscape. The most significant impact of adding black spruce to the model was an increase in the frequency and magnitude of large-scale burning events (i.e., time steps in which total area burned far exceeded the normal distribution of area burned). Early successional deciduous forest vegetation burned more frequently when black spruce was added to the model, considerably decreasing the fire return interval of deciduous vegetation. Ecosystem flammability accounted for the majority of the differences in the distribution of the average area burned. These simulated vegetation effects and fire regime dynamics have important implications for global models of vegetation dynamics and potential biotic feedbacks to regional climate.     

Forest ecosystems, disturbance, and climatic change in Washington State, USA

Climatic change is likely to affect Pacific Northwest (PNW) forests in several important ways. In this paper, we address the role of climate in four forest ecosystem processes and project the effects of future climatic change on these processes across Washington State. First, we relate Douglas-fir growth to climatic limitation and suggest that where Douglas-fir is currently water-limited, growth is likely to decline due to increased summer water deficit. Second, we use existing analyses of climatic controls on tree species biogeography to demonstrate that by the mid twenty-first century, climate will be less suitable for key species in some areas of Washington. Third, we examine the relationships between climate and the area burned by fire and project climatically driven regional and sub-regional increases in area burned. Fourth, we suggest that climatic change influences mountain pine beetle (MPB) outbreaks by increasing host-tree vulnerability and by shifting the region of climate suitability upward in elevation. The increased rates of disturbance by fire and mountain pine beetle are likely to be more significant agents of changes in forests in the twenty-first century than species turnover or declines in productivity, suggesting that understanding future disturbance regimes is critical for successful adaptation to climate change.     

适应与绿色复苏：应对新冠疫情和气候复合风险的协同

作为全球性危机,新冠疫情和气候危机在影响范围、效果、原因等方面的相似之处可能使两种危机的效果叠加,而二者的不同之处又可能导致应对政策的相互干扰,带来更加严峻的复合风险。文中全面分析了全球面临的新冠疫情和气候危机的复合风险,识别了新冠疫情对全球气候变化适应进程的影响,以及适应在各国疫后绿色复苏计划中的地位。研究表明,目前全球的绿色复苏中较少考虑适应,而绿色复苏为同时恢复经济和增强气候恢复力提供了机会,如果能在绿色复苏中考虑变革性适应,将显著提升社会经济系统对气候变化等冲击的抵御能力与恢复力,实现疫情后更持续和更有韧性的经济发展。     

California’s local health agencies and the state’s climate adaptation strategy

A changing climate will exacerbate many of the problems currently faced by California’s public health institutions. The public health impacts of climate change include: an increase in extreme heat events and associated increases in heat-related morbidity and mortality, increases in the frequency and severity of air pollution episodes, shifts in the range and incidence of vector-borne diseases, increases in the severity of wildfire, increased risks of drought and flooding, and other extreme events. This article assesses the readiness of California’s public health institutions to cope with the changes that will accompany a changing climate and how they relate to strategies laid out in the state’s Climate Adaptation Strategy. County-level health offices are the front line actors to preserve public health in the face of numerous threats, including climate change. Survey results show that local health officers in California believe that climate change is a serious threat to public health, but feel that they lack the funding and resources to reduce this risk. Local health agencies also have a number of tools in place that will be helpful for preparing for a changing climate.     

Wildfire preparedness,community cohesion and social–ecological systems

The consequences of wildfires are felt in susceptible communities around the globe on an annual basis. Climate change predictions in places like the south-east of Australia and western United States suggest that wildfires may become more frequent and more intense with global climate change. Compounding this issue is progressive urban development at the peri-urban fringe (wildland–urban interface), where continued infrastructure development and demographic changes are likely to expose more people and property to this potentially disastrous natural hazard. Preparing well in advance of the wildfire season is seen as a fundamental behaviour that can both reduce community wildfire vulnerability and increase hazard resilience – it is an important element of adaptive capacity that allows people to coexist with the hazardous environment in which they live. We use household interviews and surveys to build and test a substantive model that illustrates how social cohesion influences the decision to prepare for wildfire. We demonstrate that social cohesion, particularly community characteristics like ‘sense of community’ and ‘collective problem solving’, are community-based resources that support both the adoption of mechanical preparations, and the development of cognitive abilities and capacities that reduce vulnerability and enhance resilience to wildfire. We use the results of this work to highlight opportunities to transfer techniques and approaches from natural hazards research to climate change adaptation research to explore how the impacts attributed to the social components of social–ecological systems can be mitigated more effectively.     

IPCC AR6粮食系统的影响与适应的新认知和新趋势

解读政府间气候变化专门委员会(IPCC)第六次评估报告(AR6)粮食系统的影响与适应,对科学认识国际气候变化对农业影响学科前沿动态具有重要意义。最新发布的IPCC AR6在深化阐述粮食生产能力、种植布局、病虫害影响的基础上,高度确信人类活动导致的气候变暖对粮食系统产生了负面影响,论述了粮食运输及消费中的气候风险,解析了粮食生产-存储-运输-消费的全链条气候变化影响,延展了影响评估归因内容并丰富了农业环境影响等相关科学认识。对于粮食系统的适应能力,强调适应及减缓协同发展的气候恢复力发展路径,适应评估从适应能力、适应方式等理论逐步转向适应实施行动和成效评估,并注重适应行动的区域特异性和有效性。本次评估强调了气候变化对作物影响的检测和归因、关注了气候和农业环境变化复合影响、倡导基于生态系统的适应方案和技术,评估了现有适应技术的可行性和成效。报告内容对中国强化农业影响评估能力及把握国际学科动态具有参考价值。     

Climate change vulnerability and social development for remote indigenous communities of South Australia

There is a strong contemporary research and policy focus on climate change risk to communities, places and systems. While the need to understand how climate change will impact on society is valid, the challenge for many vulnerable communities, especially some of the most marginalised, such as remote indigenous communities of north-west South Australia, need to be couched in the context of both immediate risks to livelihoods and long-term challenges of sustainable development. An integrated review of climate change vulnerability for the Alinytjara Wilurara Natural Resources Management region, with a focus on the Anangu Pitjantjatjara Yankunytjatjara lands, suggests that targeted analysis of climate change impacts and adaptation options can overlook broader needs both for people and the environment. Climate change will add to a range of complex challenges for indigenous communities, especially in relation to hazards, such as fire and floods, and local environmental management issues, especially in association with invasive species. To respond to future socio-ecological risk, some targeted responses will need to focus on climate change impacts, but there also needs to be a better understanding of what risk is already apparent within socio-ecosystems and how climate interacts with such systems. Other environmental, social and economic risks may need to be prioritised, or at least strongly integrated into climate change vulnerability assessments. As the capacity to learn how to adapt to risk is developed, the value attributed to traditional ecological knowledge and local indigenous natural resource management must increase, both to provide opportunities for strong local engagement with the adaptation response and to provide broader social development opportunities.     

Facilitating adaptation of biodiversity to climate change: a conceptual framework applied to the world’s largest Mediterranean-climate woodland

The importance of ecological management for reducing the vulnerability of biodiversity to climate change is increasingly recognized, yet frameworks to facilitate a structured approach to climate adaptation management are lacking. We developed a conceptual framework that can guide identification of climate change impacts and adaptive management options in a given region or biome. The framework focuses on potential points of early climate change impact, and organizes these along two main axes. First, it recognizes that climate change can act at a range of ecological scales. Secondly, it emphasizes that outcomes are dependent on two potentially interacting and countervailing forces: (1) changes to environmental parameters and ecological processes brought about by climate change, and (2) responses of component systems as determined by attributes of resistance and resilience. Through this structure, the framework draws together a broad range of ecological concepts, with a novel emphasis on attributes of resistance and resilience that can temper the response of species, ecosystems and landscapes to climate change. We applied the framework to the world’s largest remaining Mediterranean-climate woodland, the ‘Great Western Woodlands’ of south-western Australia. In this relatively intact region, maintaining inherent resistance and resilience by preventing anthropogenic degradation is of highest priority and lowest risk. Limited, higher risk options such as fire management, protection of refugia and translocation of adaptive genes may be justifiable under more extreme change, hence our capacity to predict the extent of change strongly impinges on such management decisions. These conclusions may contrast with similar analyses in degraded landscapes, where natural integrity is already compromised, and existing investment in restoration may facilitate experimentation with higher risk?options.     

An assessment of climate change impacts and adaptation for the Torres Strait Islands, Australia

Adaptive practices are taking place in a range of sectors and regions in Australia in response to existing climate impacts, and in anticipation of future unavoidable impacts. For a rich economy such as Australia’s, the majority of human systems have considerable adaptive capacity. However, the impacts on human systems at the intra-nation level are not homogenous due to their differing levels of exposure, sensitivity and capacity to adapt to climate change. Despite past resilience to changing climates, many Indigenous communities located in remote areas are currently identified as highly vulnerable to climate impacts due to their high level of exposure and sensitivity, but low capacity to adapt. In particular, communities located on low-lying islands have particular vulnerability to sea level rise and increasingly intense storm surges caused by more extreme weather. Several Torres Strait Island community leaders have been increasingly concerned about these issues, and the ongoing risks to these communities’ health and well-being posed by direct and indirect climate impacts. A government agency is beginning to develop short-term and long-term adaptation plans for the region. This work, however, is being developed without adequate scientific assessment of likely ‘climate changed futures.’ This is because the role that anthropogenic climate change has played, or will play, on extreme weather events for this region is not currently clear. This paper draws together regional climate data to enable a more accurate assessment of the islands’ exposure to climate impacts. Understanding the level of exposure and uncertainty around specific impacts is vital to gauge the nature of these islands’ vulnerability, in so doing, to inform decisions about how best to develop anticipatory adaptation strategies over various time horizons, and to address islanders’ concerns about the likely resilience and viability of their communities in the longer term.