Editing IPCC:AR6/WGII/TS (section)

=== Temporary overshoot ===

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'''TS.C.13 Warming pathways that imply a temporary temperature increase over ‘well below 2°C above pre-industrial’ for multi-decadal time spans imply severe risks and irreversible impacts in many natural and human systems (e.g., glacier melt, loss of coral reefs, loss of human lives due to heat) even if the temperature goals are reached later (''' '''''high confidence''''' ''').''' { 2.5.2, 2.5.3, 4.6.1 }

'''TS.C.13.1 Projected warming pathways may entail exceeding 1.5°C or 2°C around mid-century.''' Even if the Paris temperature goal is still reached by 2100, this ‘overshoot’ entails severe risks and irreversible impacts on many natural and human systems (e.g., glacier melt, loss of coral reefs, loss of human life due to heat) ( ''high confidence'' ). { 2.5, 3.4, 16.6, WGI AR6 SPM }

'''TS.C.13.2 Overshoot substantially increases risk of carbon stored in the biosphere being released into the atmosphere due to increases in processes such as wildfires, tree mortality, insect pest outbreaks, peatland drying and permafrost thaw (''' '''''high confidence''''' ''').''' These phenomena exacerbate self-reinforcing feedbacks between emissions from high-carbon ecosystems (which currently store around 3030–4090 GtC) and increasing global temperatures. Complex interactions of climate change, land use change, carbon dioxide fluxes and vegetation changes, combined with insect outbreaks and other disturbances, will regulate the future carbon balance of the biosphere, processes incompletely represented in current Earth system models. The exact timing and magnitude of climate–biosphere feedbacks and potential tipping points of carbon loss are characterised by large uncertainty, but studies of feedbacks indicate increased ecosystem carbon losses can cause large future temperature increases ( ''medium confidence'' ). { 2.5.2, 2.5.2, 2.5.3, Figure 2.10, Figure 2.11, Table 2.4, Table 2.5, Table 2.S. 2, Table 2.S. 4, Table 5.4, Figure 5.29, WGI AR6 5.4 }

'''TS.C.13.3 Extinction of species is an irreversible impact of climate change whose risk increases sharply with rises in global temperature (''' '''''high confidence''''' ''').''' Even the lowest estimates of species extinctions (9% lost) are 1000 times the natural background rates ( ''medium confidence'' ). Projected species extinctions at future global warming levels are consistent with projections from AR4, but assessed on many more species with much greater geographic coverage and a broader range of climate models, giving higher confidence. (see also TS.C.1) { 2.5.1, Figure 2.6, Figure 2.7, Figure 2.8, CCP1, CCB DEEP }

'''TS.C.13.4 Solar radiation modification (SRM) approaches have the potential to offset warming and ameliorate other climate hazards, but their potential to reduce risk or introduce novel risks to people and ecosystems is not well understood (''' '''''high confidence''''' ''').''' SRM effects on climate hazards are highly dependent on deployment scenarios, and substantial residual climate change or overcompensating change would occur at regional scales and seasonal time scales ( ''high confidence'' ). Due in part to limited research, there is low confidence in projected benefits or risks to crop yields, economies, human health or ecosystems. Large negative impacts are projected from rapid warming for a sudden and sustained termination of SRM in a high-CO 2 scenario. SRM would not stop CO 2 from increasing in the atmosphere or reduce resulting ocean acidification under continued anthropogenic emissions ( ''high confidence'' ). There is high agreement in the literature that for addressing climate change risks SRM is, at best, a supplement to achieving sustained net zero or net negative CO 2 emission levels globally. Co-evolution of SRM governance and research provides a chance for responsibly developing SRM technologies with broader public participation and political legitimacy, guarding against potential risks and harms relevant across a full range of scenarios. { CWGB SRM }

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'''Figure TS.5 ECOSYSTEMS |''' '''(a)''' '''Left:''' '''Observed global and regional impacts on ecosystems and human systems attributed to climate change.''' C onfidence levels reflect uncertainty in attribution of the observed impact to climate change. For more details and line of sight to chapters and cross-chapter papers see Figure TS.3a, SMTS.1 and Table SMTS.1. '''Right:''' Observed species richness across latitude for three historical periods. { 3.4.3, Figure 3.18 } .

'''(b)''' '''Left:''' Global warming levels (GMST) modelled across the ranges of more than 30,000 marine and terrestrial species. '''Middle:''' Global warming levels (GSAT); change indicated by the proportion of species (modelled n=119,813 species globally) for which the climate is projected to become unsuitable across their current distributions. '''Right:''' Modelled 12,796 marine species globally. { 2.5.1, Figure 2.6, 3.4.3, Figure 3.18, Figure 3.20a, [https://www.ipcc.ch/chapter/ts#CCP1.2.4 CCP1.2.4] , Figures AI.6, AI.15, AI.16 } .

'''(c)''' { 2.6.2, Table 2.6, 3.6.2, Figure 3.24 } .

'''(d)''' Some actions facilitate sustainable use but also increase space for nature. { 2.4 2, 2.6.2, 2.6.3, 2.6.5, 2.6.7, 2.6.8, 3.6.2, 3.6.5, Table 3.30, 5.6.3, Box 5.11, 9.3.1, 9.3.2, 9.6.3, 9.6.4, 9.12 .3, 10.4.2, 10.4.3, 11.3.1, 11 .3.2, 11 .7.3, 12.5. 1, 12. 5.2, 12.5.9, 12.6.1, 13.3.2, 13.4.2, 13.5 .2, 13.10.2, 14.5.1, 14.5.2, Box 14.2, Box 14.7, 15.5.4, 15.3.3, Table 15 .6, 16.5.2, 16.6.3, [https://www.ipcc.ch/chapter/ts#CCP1.3 CCP1.3] , CCP3. 2.2, [https://www.ipcc.ch/chapter/ts#CCP4.4.1 CCP4.4.1] , CCP5 .2.5, [https://www.ipcc.ch/chapter/ts#CCP5.4.1 CCP5.4.1] , [https://www.ipcc.ch/chapter/ts#CCP6.3.2 CCP6.3.2] , [https://www.ipcc.ch/chapter/ts#CCP7.5 CCP7.5] , CCP7 .5. 1, CCPBox7.1, Table CCP7 .3, CCB EXTREMES, CCB NATURAL }

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'''Figure TS.6 FOOD-WATER |''' '''(a)''' '''5''' '''.''' 4.1.1, Box 5.1, FAQ 5.1, SM5.1, Figure Al.20.

'''(b)''' Projected increase in the global share of area and population impacted from droughts. Changes are calculated based on the RCP6.0 concentration pathway for Terrestrial Water Storage (TWS) droughts, which can be considered to be a combination of agricultural, ecological and hydrological droughts. TWS is the sum of continental water stored in canopies, snow and ice, rivers, lakes and reservoirs, wetlands, soil and groundwater. { Figure 4.19; 4.4.5 } .

'''(c)''' Projected impacts are for RCP4.5 mid 21st century, taking into account adaptation and CO 2 fertilisation for the crop yield productivity { 4.3.1, 4.2.7, 4.5.1, Figure 4.2, 5.5.3, 5.4.1, Figure 5.3, Figure 9.22, 15.3.3, 15.3.4 } .

'''(d)''' Projections used five CMIP5 climate models, three global hydrological models from ISIMIP, and three Shared Socioeconomic Pathways (SSPs). { Box 4.1, Figure Box 4.1.1, Figure AI.48 } . '''(e)''' { 4.6.2, Figure 4.29, Figure 4.28, SM4.7, SM4.8, 5.5.4, 5.6.3 } .

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'''Figure TS.7 VULNERABILITY |''' '''(a)''' '''The global map of vulnerability is based on two comprehensive global indicator systems, namely INFORM Risk Index and WorldRiskIndex (2019).''' Climate change hazards and exposure levels are not included in this figure. The relative level of average national vulnerability is shown by the colours. Vulnerability values are based on the average of the two indices, classified into 5 classes using the quantile method. A hexagon binning method was used to simplify the global map and enlarge small states. The map combines information about the level of vulnerability (independent of the population size) with two classes of population density (high density ≥ 20 people/km2 and low density &lt; 20 people/km 2 ). The selected examples of local vulnerable populations underscore that there are also highly vulnerable populations in countries with overall low relative vulnerability { 8.3.2, Figure 8.6 }

'''(b)''' This figure shows regional averages for selected aspects of human vulnerability. The indicators are a selection of the indicator systems used within the global vulnerability map (panel a). The colours represent the average value of the respective indicator for the regional level; classified into three classes using natural breaks. This regional information reveals that within all regions challenges exist in terms of different aspects of vulnerability, however, in some regions these challenges are more severe and accumulate in multiple-dimensions. For example, the indicator “dependency ratio” measures the ratio of the number of children (0–14 years old) and older persons (65 years or over) to the working-age population (15–64 years old). { 8.3.2, Figure 8.7 }

'''(c)''' The pie charts show the number of deaths (mortality) per hazard (storm, flood, drought, heatwaves and wildfires) event per continental region based on Emergency Events Database (EM-DAT) (Centre for Research on the Epidemiology of Disasters, 2020). The size of the pie chart represents the average mortality per hazard event while slices of each pie chart show the absolute number of deaths from each hazard. This reveals that significantly more fatalities per hazard (storms, floods, droughts, heatwaves and wildfires) did occur in the past decade in more vulnerable regions, e.g. Africa and Asia. { Figure 8.6 }

'''(d)''' The figure shows constraints that make it harder to plan and implement human adaptation. Across regions and sectors, the most significant challenges to human adaptation are financial, governance, institutional and policy constraints. The ability of actors to overcome these socio-economic constraints largely influences whether additional adaptation is able to be implemented and prevent limits to adaptation from being reached. Low: &lt;20% of assessed literature identifies this constraint; Medium: 20–40% of assessed literature identifies this constraint; High: &gt;40% of assessed literature identifies this constraint. { 9.3, 16.4.3, Figure 16.8 }

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'''Figure TS.8 HEALTH |''' '''Multiple socio-economic and environmental factors interact with climate risks to shape human health and well-being.''' Achieving climate resilient development requires leveraging opportunities in the solution space within health systems and across other sectors. { 7.1.4, 7.1.6, 7.1.7, 7.2.1, 7.2.2, 7.2.3, 7.2.4, 7.2.5, 7.2.6, 7.2.7, 7.3.1, 7.3.3, 7.4.1, 7.4.2, 7.4.3, 7.4.6, 7.4.7, Box 7.1, Box 7.2, Figure 7.6, Figure 7.7, Figure 7.16, Table 7.1,Table 7.3, Table 7.6, Table 7.7, Table 7.8, Table 7.10, Table 7.11, CCB COVID, CCB HEALTH, CCB MIGRATE }

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'''Figure TS.9 URBAN |''' '''(a)''' The regions shown are reflecting the original dataset from UN Habitat and vary from IPCC regions. (6.1.4, 9.9.3, 10.4.6, 12.5.5)

'''(b)''' Heat is a growing health risk due to increasing urbanization and rising temperature extremes. Within cities the urban heat island effect elevates temperatures further, with some populations in cities being disproportionately at risk including low income communities in informal settlements, children, the elderly, disabled, people who work outdoors and ethnic minorities. The data does not consider heatwaves which are also projected to increase and can cause thousands of deaths in higher latitudes. { 6.1.4, 7.2.4, 7.3.1, 10.4.6, 13.6.1, Annex I: Global to Regional Atlas }

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'''(c)''' The size of the circle represents the number of people at risk per IPCC region and the colours show the timing of risk based on projected population change and sea level rise under SSP2-4.5. Darker colours indicate earlier in setting risks. The left side of the circles shows absolute projected population at risk and the right side the share of the population in percentage. (Figure 13.6, Figure 15.3, Figure [https://www.ipcc.ch/chapter/ts#CCP2.4 CCP2.4] , Annex I: Global to Regional Atlas).

'''(d)''' The figure is based on Table 6.6 which is an assessment of 21 urban adaptation mechanisms. Supplementary Material 6.3 provides a detailed analysis including definitions for each component of climate resilient development and the evidences. { 6.3.1, 6.3.2, 6.3.3, Table 6.6, SM6.3 }

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'''Figure TS.10 COMPLEX RISK |''' '''Compound, cascading and transboundary impacts for humans and ecosystems result from exposure to the complex interactions of (1) multiple climatic hazards, including with non-climatic stressors (as seen in panels a, b, c, d), (2) multiple vulnerabilities compounding the effect of risks (as seen in panel a, b, c), and (3) multiple impacts/risks that compound and cascade to spread across sectors and boundaries (panels b, c, d, e, f)'''

'''(a)''' Climate and land use change result in cumulative impacts on traditional, semi-nomadic Sámi reindeer herding. Impacts cascade due to a lack of access to key ecosystems, lakes and rivers, thereby increasing costs and threatening traditional livelihoods, food security, cultural heritage, and mental health. { Box 7.1, Figure Box 9.7.1, 13.8.1.2, Box 13.2, Figure 13.14. Table SM13.7, Figure 16.2, Figure CCP6.7 }

'''(b)''' Risks compound from deforestation, wildfires, urbanization, and climate change in Amazonia impacts biodiversity, livelihoods, medicinal, spiritual, and cultural sites; increasing migration patterns, loss of place-based attachments, and culture, causing health problems and mental and emotional distress of vulnerable traditional communities and Indigenous People dependent on the forest ecosystem. { Box 8.7, Figure Box 9.7.1, 12.4, Figure 12.11, Table 12.6, Figure 16.2 }

'''(c)''' Complex pathways from climate hazards to malnutrition in subsistence farming households. The factors involved in and the probable impacts of weather variables on food yields and of production on malnutrition. { Figure 1.3, Figure 1.4, 5.2.1, 5.2.2, 5.12.3, 5.12.4, Box 5.10, Figure 5.2, 7.2.2, 7.3.1, Figure Box 9.7.1, 13.5.1, 13.5.2, 13.10.2, 16.5.2, 16.5.3, Figure 16.2 }

'''(d)''' Risk compounds and amplifies through cascading effects due to interconnectedness of island systems. Loss of marine, coastal, terrestrial biodiversity and ecosystem services can cause submergence of reef islands, increase water insecurity, destroy settlements and infrastructure, degrade health and well-being, reduce economy and livelihoods, and result in loss of cultural resources and heritage. { 15.3.4.9, Figure Box 15.1, Figure 15.5, Figure 16.2 }

'''(e)''' Climate impacts can cascade through interconnected infrastructure in cities and settlements impacting on social well-being and economic activities, spreading loss and risk through lost economic productivity disrupting the distribution of goods and provision of basic services, spreading widely, into rural places and across international borders as supply chains, financial investment and remittance flows are disrupted. { 6.1.3, 6.2.2, 6.2.4, Figure 6.2, Figure 16.2, Figure CCB INTEREG.1 }

'''(f)''' Cascading, compounding and transboundary impacts on people’s mortality and physical and mental health, economic activity, built assets, ecosystems and mass species mortality and with smoke and ash transported to New Zealand affecting air quality and glaciers, arising from the “Black Summer” fires of 2019–2020 which burned over a five-month period in eastern and southern Australia. Fire weather is projected to worsen across Australasia. { Figure 1.3, Figure 1.4, 11.3.1.3, Box 11.1, Figure Box 11.1.2, Figure 16.2, WGI AR6 Figure SPM.9 }

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