中国冰冻圈变化的适应研究：进展与展望

冰冻圈变化的适应研究是冰冻圈科学领域的新兴研究方向,是当今自然科学与社会科学交叉融合跨学科集成研究的典型代表。起步于2007年的中国冰冻圈变化适应研究,经历了早期的探索,研究重点由评价脆弱性发展为量化冰冻圈变化的影响,形成以影响/风险—脆弱性—适应全链条的完善的研究体系,研究方法突破传统的指标体系赋权法的不足,初步实现了定量化,有机结合影响/风险、脆弱性、适应三方面的研究结果,使冰冻圈变化的适应措施由偏重宏观性、普适性开始转向更有针对性。未来中国冰冻圈变化的适应研究应拓展、完善和深化现有的理论体系,构建冰冻圈与社会经济耦合模型,科学量化冰冻圈全要素变化的影响,建立不同利益相关者与科学家共同参与的研究新模式,科学有效应对与适应冰冻圈变化及其影响。     

海洋和冰冻圈变化有关的极端事件、突变及其影响与风险

《气候变化中的海洋和冰冻圈特别报告》（SROCC）于2019年9月在IPCC第一工作组和第二工作组第二次联合大会上得到审议通过,并得到了IPCC第51届全会接受和批准。文中主要对该报告中海洋和冰冻圈变化有关的极端事件、突变及其影响与风险的有关评估内容进行了综合分析。SROCC评估得到的最新结果显示：气候变化背景下冰冻圈变化引起的山体滑坡、雪崩和冰川洪水事件频发。海洋有关的海洋热浪频发,极端El Niño事件加强,大西洋经向翻转环流减弱。同时,沿海地区极端海平面上升,极端海浪增高,极端热带气旋影响增加。这些变化,比如海洋热浪等,是可以归因于人为增暖的。预估结果表明,海洋和冰冻圈变化引起的极端事件未来会进一步加剧。而这些变化已经影响了高山、极地以及沿海地区人群的生产和生活,以及海洋和冰冻圈的生态系统服务功能。应对这一系列变化,需要更加精准的预测和预警,包括对极端事件和突变的季节预测和年际、年代际预测,以便做好充足的准备来降低极端事件风险。同时,加强应对极端事件的科普教育和提供因地制宜的灾害重建措施等也是风险管理的重要环节。     

IPCC《全球1.5℃增暖特别报告》冰冻圈变化及其影响解读

在气候系统五大圈层中,冰冻圈对气候变化高度敏感,近几十年来气候变暖已引起全球冰川、冻土、积雪和海冰等冰冻圈要素加速退缩,进而对区域水资源、生态环境、社会经济发展和人类福祉产生了深远影响。2018年10月,IPCC在韩国仁川公布了《全球1.5℃增暖特别报告》（SR1.5）。报告较系统地呈现了关于全球1.5℃温升目标的基本科学认知,并探讨了可持续发展及消除贫困目标下加强全球响应的路径。在冰冻圈相关内容方面,报告呈现了有关全球1.5℃和2℃温升下冰冻圈（主要是海冰和多年冻土）变化及其对大气圈、水圈、生物圈、岩石圈和人类圈影响的一些亮点结论,还关注了全球1.5℃和2℃温升下冰冻圈相关的气候变化热点（区）和地球系统临界因素。报告指出,随着温度不断升高,冰冻圈及其相关要素和热点（区）面临的风险将不断增加,但将全球温升控制在1.5℃而不是2℃或更高时的风险将大大降低。     

Adaptation in Canadian Agriculture to Climatic Variability and Change

The effects of climatic variability and change on Canadian agriculture have become an important research field since the early 1980s. In this paper, we seek to synthesize this research, focusing on agricultural adaptation, a purposeful proactive or reactive response to changes associated with climate, and influenced by many factors. A distinctive feature of methods used in research on adaptation in Canadian agriculture is the focus on the important role of human agency. Many individual farmers perceive they are well adapted to climate, because of their extensive 'technological' tool-kit, giving them confidence in dealing with climatic change. In many regions, little concern is expressed over climatic change, except where there are particular types of climatic vulnerability. Farmers respond to biophysical factors, including climate, as they interact with a complex of human factors. Several of these, notably institutional and political ones, have tended to diminish the farm-level risks stemming from climatic variability and change, but may well increase the long term vulnerability of Canadian agriculture. Notwithstanding the technological and management adaptation measures available to producers, Canadian agriculture remains vulnerable to climatic variability and to climate change.     

Trends and Variability in Sea Ice and Icebergs off the Canadian East Coast

ABSTRACT

Seasonal time series of sea-ice area or extent in several regions along the east coast of Canada were compiled from several sources for the period 1901 to 2013 and compared with an index of ice extent off southwest Greenland, iceberg season length south of 48°N, air temperature, and other climate indices. Trends in winter ice area and iceberg season length are significant over the past 100 years and 30 years. Variability of winter ice area and iceberg season length is associated with a combination of the North Atlantic Oscillation (NAO) and the Atlantic Multidecadal Oscillation (AMO) indices superimposed on a negative trend. Thus, large declines in ice area and iceberg season length in the 1920s and 1990s can be attributed to a decreasing NAO index and a shift to the positive phase of the AMO at the end of these decades. Ice extent in southern areas such as the Scotian Shelf is more strongly correlated with the Western Atlantic index than with the NAO. Ice area trends (in percent per decade) are larger in magnitude and account for twice as much of the variance in ice area for summer than for winter, with summer trends significant over 30-, 60- and 100-year periods. Sea-ice variability is generally consistent with air temperature variability in the various regions; in the 1930s, during the early twentieth-century warming period, ice anomalies were higher and temperature anomalies were lower along the coast of eastern Canada than along the coast of southwestern Greenland.     

全球山地冰冻圈变化、影响与适应

冰冻圈是高山地区不可或缺的重要组成部分,居住着全球约10%的人口。近几十年来,冰冻圈变化对山区和周围地区的自然和人类系统产生了广泛而深远的影响,对海洋也发挥着重要作用。IPCC最新发布的《气候变化中的海洋和冰冻圈特别报告》（SROCC）指出,过去几十年全球高山区气温显著升高,使山地冰冻圈发生了大范围显著退缩。观测到的山地（特别是低海拔山区）积雪期缩短、雪深和积雪覆盖范围减小;冰川物质持续亏损,其中全球最大的冰川负物质平衡出现在南安第斯山、高加索山和欧洲中部,亚洲高山区冰川负物质平衡最小;多年冻土温度升高、厚度减薄,地下冰储量减少;河、湖冰持续时间缩短。随着气候持续变暖,山地冰冻圈在21世纪仍将呈继续退缩状态。到21世纪末,低海拔山区积雪深度和积雪期将减少,冰川物质损失继续增加,多年冻土持续退化。冰冻圈变化已经或将改变山地灾害发生频率和强度,并对水资源、生态系统和经济社会系统产生重要影响。应对山地冰冻圈变化应从管理和优化利用冰冻圈资源、加强冰冻圈变化灾害风险的有效治理、增强国际合作及公约制定等适应策略着手开展,增强适应能力,从而有益于推动山地生态系统和经济社会系统可持续发展。     

Farm-Level Adaptation to Climatic Variability and Change: Crop Diversification in the Canadian Prairies

Among other foci, recent research on adaptation to climatic variability and change has sought to evaluate the merit of adaptation generally, as well as the suitability of particular adaptations. Additionally, there is a need to better understand the likely uptake of adaptations. For example, diversification is one adaptation that has been identified as a potential farm-level response to climatic variability and change, but its adoption by farmers for this reason is not well understood. This paper serves two purposes. The first is to document the adoption of crop diversification in Canadian prairie agriculture for the period 1994–2002, reflect upon its strengths and limitations for managing a variety of risks, including climatic ones, and gauge its likely adoption by producers in response to anticipated climate change. The second purpose is to draw on this case to refine our current understanding of climate change adaptation more generally. Based upon data from over 15 000 operations, it was determined that individual farms have become more specialized in their cropping patterns since 1994, and this trend is unlikely to change in the immediate future, notwithstanding anticipated climate change and the known risk-reducing benefits of crop diversification. More broadly, the analysis suggests that suitable and even possible climate change adaptations need to be more rigorously assessed in order to understand their wider strengths and limitations.     

Surface air temperature in the Canadian Arctic: scaling and pattern change

We analyze minimum and maximum daily temperature records from weather stations situated in the Canadian Arctic area and investigate scaling properties and their change over time. Detrended fluctuation analysis is applied to the entire available records, as well as to successive non-overlapping temporal windows. Scaling is found for intervals of 1–2?months to 5–8?years, with most exponents in the range 0.70?±?0.05. Exponents are subject to temporal change that is found significant when compared with 95?% confidence intervals. Patterns of change are shared by groups of stations in spite of the distances separating their locations. Defining regions characterized by similar patterns of change may be possible, but such a classification should not be expected to be constant: region boundaries shift over time.     

ENSO and Sea Surface Temperature Anomalies in Association with Canadian Wheat Yield Variability

Interannual variations of spring wheat yields in Canadian agricultural regions are analyzed, together with the associated sea surface temperature (SST) anomalies in the northern hemisphere tropics and extratropics, from 1961 to 2015. The cubic trend is calculated and used to represent the trend related to advances in agricultural technology over this time period. The correlations between Canadian wheat yields at regional scales and the tropical El Niño–Southern Oscillation (ENSO) variability are not robust at any stage of the evolution of ENSO. Based on the power spectrum and cross-spectrum analysis, the most prominent yield variance is found in the Canadian Prairies, with a significant power peak of 4.5 years but does not co-vary significantly with interannual ENSO variability. ENSO weakly affects temperature and precipitation anomalies in the Canadian Prairie Region in summer—two important agroclimatic conditions for crop growth—and hence insignificantly impacts wheat yields. This indicates that there would be little benefit to including tropical ENSO indices in the operational wheat yield forecasting system. For Canadian wheat yield forecasting, attention should be paid to the preceding winter and spring SST anomalies in the northern extratropics. The SST anomalies associated with yields in the Canadian Prairie region and Central Region are generally stronger than those associated with yields in the Canadian Pacific Coast Region and eastern Maritime Region. In association with the Prairie Region and Central Region yields, SST shows pronounced anomalies in the mid-high latitudes of the North Pacific from winter to summer. The non-linearity of the SST anomalies associated with the Canadian yields is also clearly evident. Stronger (weaker) SST anomalies in the extratropical North Pacific correspond to low wheat yields in the Prairie (Central) Region, while weaker (stronger) SST anomalies correspond to high yields in the Prairie (Central) Region.     

Atmospheric and Oceanic Variability Associated with Growing Season Droughts and Pluvials on the Canadian Prairies

Abstract

The importance of measurements of the vertical distribution of odd nitrogen in studies of ozone chemistry and climate change has long being recognized. In this paper, we use the optimal estimation method developed by Rodgers (1976, 1990) to retrieve NO₂ vertical profiles from slant column observations made with a portable ultraviolet (UV)‐visible zenith‐sky spectrometer operated on the ground during the Middle Atmosphere Nitrogen TRend Assessment (MANTRA) balloon campaign carried out at Vanscoy, Saskatchewan, Canada (52°N, 107°W), from 18 to 25 August 1998. Late summer was chosen for the campaign because the stratospheric zonal wind velocity changes sign at that time. Under such conditions the stratospheric winds are at a minimum, leaving the stratosphere in a dynamically quiescent state and closer to photochemical control (Fahey et al., 2001; Fioletov and Shepherd, 2003). The NO₂ profile retrieved from the ground‐based observations is compared with the co‐located and simultaneous NO₂ profile measured by a balloon‐borne UV‐visible spectrometer during sunrise on 24 August. Good agreement is observed, giving us confidence in the retrieval technique adopted. The retrieved NO₂ profiles are also compared with the output of the Model for Evaluating oZONe trends (MEZON) 3D stratospheric chemical transport model. It is observed that, for altitudes below the peak concentration, the model underestimates the NO₂ amount, and at the altitude of peak concentration, the model values lie between the values measured from the balloon and those retrieved from the ground‐based measurements. Nevertheless, the model reproduces the general shape of the retrieved profiles, including the altitude of the NO₂ maximum, for both sunrise and sunset conditions.     

Long-term observations for monitoring of the cryosphere

Variations of the cryosphere over decadal-to-century timescales are assessed by a survey of data on sea ice, snow cover, glaciers and ice sheets, permafrost and lake ice. The recent variations are generally consistent across the different cryospheric variables, especially when placed into the context of variations of temperature and precipitation. The recent warming over northern land areas has been accompanied by a decrease of snow cover, particularly during spring; the retreat of mountain glaciers is, in an aggregate sense, compatible with the observed warming; permafrost extent and lake ice duration show similar variations in areas for which data are available. Corresponding trends are not apparent, however, in data for some regions such as eastern Canada, nor in hemispheric sea ice data, especially for winter. The data also suggest an increase of snowfall over high latitudes, including the Antarctic ice sheet.Estimates of both the climatic and the statistical significance of the recent variations are hampered by data inhomogeneities, the shortness of the records of many variables and the absence of central archives for data on several variables. The potential of monitoring by satellite remote sensing has been realized with several variables (extent of sea ice, snow cover). Other cryospheric variables (snow depth, ice sheet elevation, lake ice, mountain glaciers) may be amenable to routine monitoring by satellites pending advances in instrumentation, modifications of satellite orbit, and further developments in signal detection algorithms. The survey of recent variations leads to recommendations concerning the use of historical data,in situ measurements, and remote sensing applications in the monitoring of the cryosphere.     

Climate and climate change in western canada as simulated by the Canadian regional climate model

Abstract

A þrst climate simulation performed with the novel Canadian Regional Climate Model (CRCM) is presented. The CRCM is based on fully elastic non‐hydrostatic þeld equations, which are solved with an efþcient semi‐implicit semi‐Lagrangian (SISL) marching algorithm, and on the parametrization package of subgrid‐scale physical effects of the second‐generation Canadian Global Climate Model (GCMII). Two 5‐year integrations of the CRCM nested with GCMII simulated data as lateral boundary conditions are made for conditions corresponding to current and doubled CO₂ scenarios. For these simulations the CRCM used a grid size of 45 km on a polar‐stereographic projection, 20 scaled‐height levels and a time step of 15 min; the nesting GCMII has a spectral truncation of T32, 10 hybrid‐pressure levels and a time step of 20 min. These simulations serve to document: (1) the suitability of the SISL numerical scheme for regional climate modelling, (2) the use of GCMII physics at much higher resolution than in the nesting model, (3) the ability of the CRCM to add realistic regional‐scale climate information to global model simulations, and (4) the climate of the CRCM compared to that of GCMII under two greenhouse gases (GHG) scenarios.     

Adaptation options for the near term: climate change and the Canadian water sector

Climate change poses significant challenges for the Canadian water sector. This paper discusses issues relating to the selection of proactive, planned adaptation measures for the near term (next decade). A set of selection criteria is offered, and these are used in three cases to illustrate how stakeholders can identify measures appropriate for the near term. Cases include municipal water supply in the Grand River basin, Ontario; irrigation in southern Alberta; and commercial navigation on the Great Lakes. In all three cases, it is possible to identify adaptations to climate change that also represent appropriate responses to existing conditions; these should be pursued first.     

Variability of modeled runoff over China and its links to climate change

Runoff is a key component of the water cycle over land, with direct impact on regional ecosystems and water resources. This study investigates historical runoff variability and change over China in 1951–2008 using the Community Land Model and in situ observations of atmospheric forcing fields. Model simulations are first evaluated against in situ observations of streamflow for four major rivers, as well as soil moisture and water table depths, before further analysis is conducted. Then, quantile regression is used to analyze runoff variability and its relation to precipitation and temperature. The spatial pattern of monthly climatological runoff over China is characterized by maxima in the humid south and a gradual decrease toward the arid northwest. Runoff increases in the humid south, slightly decreases in the transition zone, and shows nonsignificant trends in the arid northwest. The footprint of decadal variability can be seen from 1951 to 2008. The annual precipitation advances the spatiotemporal variability of runoff despite locally distinct runoff–precipitation responses. The runoff-temperature relationship shows complex spatiotemporal characteristics that depend on the feedback from precipitation.     

Learning with practitioners: climate change adaptation priorities in a Canadian community

Adaptation is already a necessary response to climate change for northern communities. The City of Prince George, in British Columbia, Canada, has been adjusting to impacts for years and there is a high level of local awareness of climate change. The purpose of this study was to collaborate with City staff and other organizations to undertake action-oriented research with the goal of creating a local adaptation strategy. Steps taken toward this goal included: producing downscaled climate scenarios; facilitating a workshop with local practitioners to prioritize impacts; gathering public feedback regarding impacts; and triangulating sources of information to determine community adaptation priorities. Changes to forests and increased flooding are the top local adaptation priorities, and impacts related to transportation, severe weather and water supply are high priorities. Other impacts, such as health effects and agricultural changes, are also important but did not rank highly using a risk framework focused on negative physical effects. Local impacts, actions the City is undertaking to address them and suggestions for implementing adaptation measures are summarized. The process of creating an adaptation strategy has proven highly valuable in Prince George and has precipitated further engagement and action. Due to the low profile of adaptation and limited resources in many communities, researchers and practitioners must capitalize on opportunities to incorporate adaptation into existing plans and processes. Lessons from the Prince George experience can be applied to other communities as they strive to effectively adapt to climate change.     

Canadian vegetation sensitivity to projected climatic change at three organizational levels

The potential equilibrium response of Canadian vegetation under two doubled-CO₂ climatic scenarios was investigated at three levels in the vegetation mosaic using the rule-based, Canadian Climate-Vegetation Model (CCVM) and climatic response surfaces. The climatic parameters employed as model drivers (i.e., degree-days, minimum temperature, snowpack, actual evapotranspiration, and soil moisture deficit) have a more direct influence on the distribution of vegetation than those commonly used in equilibrium models. Under both scenarios, CCVM predicted reductions in the extent of the tundra and subarctic woodland formations, a northward shift and some expansion in the distributions of boreal and the temperate forest, and an expansion of the dry woodland and prairie formations that was especially pronounced under one of the scenarios. Results of the response surface analysis suggest the potential for significant changes in the probability of dominance for eight boreal tree species. A dissimilarity coefficient was used to identify forest-types under the future climatic scenarios that were analogous to boreal forest-types derived from cluster analysis of the current probabilities of species dominance. All of the current forest-types persisted under the doubled-CO₂ scenarios, but no-analog areas were also identified within which an empirically derived threshold of the distance coefficient was exceeded. Maps showing the highest level in the vegetation hierarchy where change was predicted suggest the relative impact of the response under the two climatic scenarios.     

Patterns of controversy and consensus in German,Canadian, and US online news on climate change

Individual action and support for policy to tackle climate change have been linked to perceptions of political and scientific controversy and consensus concerning the issue. Recent media effects research indicates that presentation of agreement or conflict between actors’ opinions influences how audiences respond to news about climate change and policy. While some national case studies have investigated portrayals of actors’ positions on important questions regarding climate change in the media, they are largely absent from comparative research. This study addresses this gap by analysing portrayals of actor-issue-positions and the emerging patterns of controversy and consensus in German, Canadian, and US coverage. Studying a sample of occurrences of climate change-related issues (N = 902) in-depth, the results show German media present political consensus about the need to limit emissions and societal controversy about the efficacy of specific mitigation measures. Presenting mainly consensus, Canadian media report more on climate change’s impact, leaving aside the issue of efficacy. In the US, media emphasise political controversy — about the need to limit emissions and occasionally about climate change’s impact on humans. The findings, consistent with other recent publications, can best be explained by journalists selectively indexing of seemingly relevant actor-issue-positions.     

Effects of a melted greenland ice sheet on climate, vegetation, and the cryosphere

This paper investigates the possible implications for the earth-system of a melting of the Greenland ice-sheet. Such a melting is a possible result of increased high latitude temperatures due to increasing anthropogenic greenhouse gas emissions. Using an atmosphere-ocean general circulation model (AOGCM), we investigate the effects of the removal of the ice sheet on atmospheric temperatures, circulation, and precipitation. We find that locally over Greenland, there is a warming associated directly with the altitude change in winter, and the altitude and albedo change in summer. Outside of Greenland, the largest signal is a cooling over the Barents sea in winter. We attribute this cooling to a decrease in poleward heat transport in the region due to changes to the time mean circulation and eddies, and interaction with sea-ice. The simulated climate is used to force a vegetation model and an ice-sheet model. We find that the Greenland climate in the absence of an ice sheet supports the growth of trees in southern Greenland, and grass in central Greenland. We find that the ice sheet is likely to regrow following a melting of the Greenland ice sheet, the subsequent rebound of its bedrock, and a return to present day atmospheric CO₂ concentrations. This regrowth is due to the high altitude bedrock in eastern Greenland which allows the growth of glaciers which develop into an ice sheet.     

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。