IPCC AR6 Synthesis Report LR Figure 2.3 (a): Synthesis of assessment of observed change in hot extremes, heavy precipitation and drought and confidence in human contribution in the world’s regions

The IPCC AR6 WGI inhabited regions are displayed as hexagons with identical size in their approximate geographical location (see legend for regional acronyms). All assessments are made for each region as a whole and for the 1950s to the present. Assessments made on different time scales or more local spatial scales might differ from what is shown in the figure. The colours in each panel represent the four outcomes of the assessment on observed changes. Striped hexagons (white and light-grey) are used where there is low agreement in the type of change for the region as a whole, and grey hexagons are used when there is limited data and/or literature that prevents an assessment of the region as a whole. Other colours indicate at least medium confidence in the observed change. The confidence level for the human influence on these observed changes is based on assessing trend detection and attribution and event attribution literature, and it is indicated by the number of dots: three dots for high confidence, two dots for medium confidence and one dot for low confidence (single, filled dot: limited agreement; single, empty dot: limited evidence). For hot extremes, the evidence is mostly drawn from changes in metrics based on daily maximum temperatures; regional studies using other indices (heatwave duration, frequency and intensity) are used in addition. For heavy precipitation, the evidence is mostly drawn from changes in indices based on one-day or five-day precipitation amounts using global and regional studies. Agricultural and ecological droughts are assessed based on observed and simulated changes in total column soil moisture, complemented by evidence on changes in surface soil moisture, water balance (precipitation minus evapotranspiration) and indices driven by precipitation and atmospheric evaporative demand.政府间气候变化专门委员会（Intergovernmental Panel on Climate Change, IPCC）第六次评估报告（Sixth Assessment Report, AR6）第一工作组（Working Group I, WGI）划定的有人居住区域，以尺寸统一的六边形标记于其近似地理位置上，区域缩写含义详见图例。所有评估均以各区域为整体单元，时间跨度为1950年代至今。基于不同时间尺度或更精细局地空间尺度开展的评估结果，或与本图展示内容存在差异。各子图中的颜色对应观测变化评估的四类结果。带条纹的六边形（白色与浅灰色）用于标注区域整体变化类型共识度较低的区域；灰色六边形则用于标注因数据和/或文献不足，无法开展区域整体评估的区域。其余颜色则代表对观测变化具备至少中等置信水平。人类活动对上述观测变化影响的置信水平，基于趋势检测与归因、事件归因相关文献评估得出，以圆点数量表示：三个圆点代表高置信水平，两个圆点代表中等置信水平，一个圆点代表低置信水平（单个实心圆点：共识度有限；单个空心圆点：证据有限）。针对高温极端事件，其证据主要来源于基于日最高气温的指标变化；此外还补充纳入了采用其他指数（热浪持续时长、发生频率与强度）的区域研究成果。针对强降水事件，其证据主要来源于全球及区域研究中基于单日或五日降水量的指数变化。农业与生态干旱的评估以观测及模拟得到的全土层土壤湿度变化为基础，同时补充纳入表层土壤湿度变化、水量平衡（降水量减去蒸散量）以及由降水与大气蒸发需求驱动的相关指数变化等证据。