Editing IPCC:AR6/WGII/TS (section)

=== Ecosystems and biodiversity ===

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'''TS.B.1 Climate change has altered marine, terrestrial and freshw''' '''ater ecosystems all around the world (''' '''''very high confiden''''' '''''ce''''' '''). Ef''' '''fects were experienced earlier and are more widespread wi''' '''th m''' '''ore far-reaching consequences than anticipated (''' '''''mediu''''' '''''m co''''' '''''nfidence''''' '''). Biological responses, including changes in''' '''physio''' '''logy, growth, abundance, geographic placement and shifti''' '''ng se''' '''asonal timing, are often not sufficient to cope with rece''' '''nt''' '''climate''' '''change (''' '''''very high confidence''''' '''). Climate change has caused local species losses, increases in disease (''' '''''high''''' '''''confidence''''' ''') and mass mortality events of plants and animals (''' '''''very high confidence''''' '''), resulting in the first climate-driven''' '''extinctions''' '''(''' '''''medium confidence''''' '''), ecosystem restructuring, increases in areas burned by wildfire (''' '''''high confidence''''' ''') and declines in key ecosystem services (''' '''''high confidence''''' '''). Climate-driven''' '''impacts''' '''on ecosystems have caused measurable economic and livelihood losses and altered cultural practices and recreational activities around the world (''' '''''high confidence''''' ''').''' (Figure TS.3, Figure TS.5 ECOSYSTEMS) { 2.3.1, 2.3.3, 2.4.2, 2.4.3, 2.4.4, 2.4.5, 3.2, 3.3.2, 3.3.3, 3.4.2, 3.4.3, Box 3.2, 3.5.3, 3.5.5, 3.5.6, 4.3.5, 9.6.1, 9.6.3, 10.4.2., 11.3.1, 11.3.2, 11.3.11, 11.3.2, 11.3.11, 12.3, 13.3.1, 13.4.1, 13.10.1, 14.2.1, 14.5.1, 14.5.2; 15.3.3., 15.3.4, 16.2.3, [https://www.ipcc.ch/chapter/ts#CCP1.2.1 CCP1.2.1] ; [https://www.ipcc.ch/chapter/ts#CCP1.2.2 CCP1.2.2] , [https://www.ipcc.ch/chapter/ts#CCP1.2.4 CCP1.2.4] , Box [https://www.ipcc.ch/chapter/ts#CCP1.1 CCP1.1] , [https://www.ipcc.ch/chapter/ts#CCP3.2.1 CCP3.2.1] , [https://www.ipcc.ch/chapter/ts#CCP4.1.3 CCP4.1.3] , [https://www.ipcc.ch/chapter/ts#CCP5.2.1 CCP5.2.1] , [https://www.ipcc.ch/chapter/ts#CCP5.2.7 CCP5.2.7] , CP6.1, [https://www.ipcc.ch/chapter/ts#CCP6.2.1 CCP6.2.1] , [https://www.ipcc.ch/chapter/ts#CCP7.2.1 CCP7.2.1] , [https://www.ipcc.ch/chapter/ts#CCP7.3.2 CCP7.3.2] , Table 2.2, Table 2.3, Table 2.S. 1, [https://www.ipcc.ch/chapter/ts#CCP5.2.1 CCP5.2.1] , CCB EXTREMES, CCB ILLNESS, CCB NATURAL, CCB SLR }

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'''Figure TS.3 |''' '''Observed global and regional impacts on ecosystems and human systems attributed to climate change.''' Confidence levels reflect uncertainty in attribution of the observed impact to climate change. Global assessments focus on large studies, multi-species, meta-analyses and large reviews. For that reason they can be assessed with higher confidence than regional studies, which may often rely on smaller studies that have more limited data. Regional assessments consider evidence on impacts across an entire region and do not focus on any country in particular.

'''(a)''' Climate change has already altered terrestrial, freshwater and ocean ecosystems at global scale, with multiple impacts evident at regional and local scales where there is sufficient literature to make an assessment. Impacts are evident on ecosystem structure, species geographic ranges and timing of seasonal life cycles (phenology) (for methodology and detailed references to chapters and cross-chapter papers see SMTS.1 and SMTS.1.1).

'''(b)''' Climate change has already had diverse adverse impacts on human systems, including on water security and food production, health and well-being, and cities, settlements and infrastructure. The + and – symbols indicate the direction of observed impacts, with a – denoting an increasing adverse impact and a ± denoting that, within a region or globally, both adverse and positive impacts have been observed (e.g., adverse impacts in one area or food item may occur with positive impacts in another area or food item). Globally, ‘–’ denotes an overall adverse impact; ‘Water scarcity’ considers, e.g., water availability in general, groundwater, water quality, demand for water, drought in cities. Impacts on food production were assessed by excluding non-climatic drivers of production increases; Global assessment for agricultural production is based on the impacts on global aggregated production; ‘Reduced animal and livestock health and productivity’ considers, e.g., heat stress, diseases, productivity, mortality; ‘Reduced fisheries yields and aquaculture production’ includes marine and freshwater fisheries/production; ‘Infectious diseases’ include, e.g., water-borne and vector-borne diseases; ‘Heat, malnutrition and other’ considers, e.g., human heat-related morbidity and mortality, labour productivity, harm from wildfire, nutritional deficiencies; ‘Mental health’ includes impacts from extreme weather events, cumulative events, and vicarious or anticipatory events; ‘Displacement’ assessments refer to evidence of displacement attributable to climate and weather extremes; ‘Inland flooding and associated damages’ considers, e.g., river overflows, heavy rain, glacier outbursts, urban flooding; ‘Flood/storm induced damages in coastal areas’ include damages due to, e.g., cyclones, sea level rise, storm surges. Damages by key economic sectors are observed impacts related to an attributable mean or extreme climate hazard or directly attributed. Key economic sectors include standard classifications and sectors of importance to regions (for methodology and detailed references to chapters and cross-chapter papers see SMTS.1 and SMTS.1.2).

'''TS.B.1.1 Anthropogenic climate change has exposed ecosystems to conditions that are unprecedented over millennia (''' '''''high confidence''''' '''), which has greatly impacted species on land and in the ocean (''' '''''very high confidence''''' ''').''' Consistent with expectations, species in all ecosystems have shifted their geographic ranges and altered the timing of seasonal events ( ''very high confidence'' ). Among thousands of species spread across terrestrial, freshwater and marine systems, half to two-thirds have shifted their ranges to higher latitudes ( ''very high confidence'' ), and approximately two-thirds have shifted towards earlier spring life events ( ''very high confidence'' ) in response to warming. The move of diseases and their vectors has brought new diseases into the high Arctic and at higher elevations in mountain regions to which local wildlife and humans are not resistant ( ''high confidence'' ) ''.'' These processes have led to emerging hybridisation, competition, temporal or spatial mismatches in predator–prey, insect–plant and host–parasite relationships and invasion of alien plant pests or pathogens ( ''medium confidence'' ). (Figure TS.5 ECOSYSTEMS) { 2.4.2, 2.4.3, 2.5.2, 2.5.4, 2.6.1, 3.2.4, 3.4.2, 3.4.3, 3.5.2, 4.3.5, 9.6.1, 10.4.2, 11.3.1, 11.3.2; 11.3.11, 12.3.1, 12.3.2, 12.3.7, 13.3.1, 13.4.1, 13.10.2, 14.5.1, 14.5.2; 15.3.3. 16.2.3, 16.2.3, [https://www.ipcc.ch/chapter/ts#CCP1.2.1 CCP1.2.1] , CCP 1.2.2, [https://www.ipcc.ch/chapter/ts#CCP1.2.4 CCP1.2.4] , [https://www.ipcc.ch/chapter/ts#CCP3.2.1 CCP3.2.1] , [https://www.ipcc.ch/chapter/ts#CCP4.1.3 CCP4.1.3] , [https://www.ipcc.ch/chapter/ts#CCP5.2.1 CCP5.2.1] , CCP.5.2.7, [https://www.ipcc.ch/chapter/ts#CCP6.2.1 CCP6.2.1] , [https://www.ipcc.ch/chapter/ts#CCP7.3.2 CCP7.3.2] , CCB EXTREMES, CCB ILLNESS, CCB MOVING PLATE }

'''TS.B.1.2 Observed responses of species to climate change have altered biodiversity and impacted ecosystem structure and resilience in most regions (''' '''''very high confidence''''' ''').''' Range shifts reduce biodiversity in the warmest regions and locations as adaptation limits are exceeded ( ''high confidence'' ). Simultaneously, these shifts homogenise biodiversity ( ''medium confidence'' ) in regions receiving climate-migrant species, alter food webs and eliminate the distinctiveness of communities ( ''medium confidence'' ). Increasing losses of habitat-forming species such as trees, corals, kelp and seagrass have caused irreversible shifts in some ecosystems and threaten associated biodiversity in marine systems ( ''high confidence'' ). Human-introduced invasive (non-native) species can reduce or replace native species and alter ecosystem characteristics if they fare better than endemic species in new climate-altered ecological niches ( ''high confidence'' ). Such invasive species effects are most prominent in geographically constrained areas, including islands, semi-enclosed seas and mountains, and they increase vulnerability in these systems ( ''high confidence'' ). Phenological shifts increase the risks of temporal mismatches between trophic levels within ecosystems ( ''medium confidence'' ), which can lead to reduced food availability and population abundances ( ''medium confidence'' ) and can further destabilise ecosystem resilience. (Figure TS.5 ECOSYSTEMS) { 2.4.2, 2.4.3, 2.4.5, Box 2.1, 2.5.4, 3.3.3, 3.4.2, 3.4.3. Box 3.2, Box 3.4, 3.5.2, 3.5.3, 4.3.5, 9.6.1, 10.4.2, 11.3.1, 11.3.2, 11.3.11, 13.3.1, 13.4.1, 13.10.2, 14.5.1, 15.3.3, 15.3.4, 15.8, Box [https://www.ipcc.ch/chapter/ts#CCP1.1 CCP1.1] , [https://www.ipcc.ch/chapter/ts#CCP1.2.2 CCP1.2.2] , [https://www.ipcc.ch/chapter/ts#CCP1.2.1 CCP1.2.1] , [https://www.ipcc.ch/chapter/ts#CCP3.2.1 CCP3.2.1] , [https://www.ipcc.ch/chapter/ts#CCP5.2.1 CCP5.2.1] , CCB EXTREMES }

'''TS.B.1.3 At the warm (equatorward and lower) edges of distributions, adaptation limits to human-induced warming have led to widespread local population losses (extirpations) that result in range contractions (''' '''''very high confidence''''' ''').''' Among land plants and animals, local population loss was detected in around 50% of studied species and is often attributable to extreme events ( ''high confidence'' ). Such extirpations are most common in tropical habitats (55%) and freshwater systems (74%), but also high in marine (51%) and terrestrial (46%) habitats. Many mountain-top species have suffered population losses along lower elevations, leaving them increasingly restricted to a smaller area and at higher risk of extinction ( ''medium confidence'' ). Global extinctions due to climate change are already being observed, with two extinctions currently attributed to anthropogenic climate change ( ''medium confidence'' ). Climate-induced extinctions, including mass extinctions, are common in the palaeo record, underlining the potential of climate change to have catastrophic impacts on species and ecosystems ( ''high confidence'' ). (Figure TS.5 ECOSYSTEMS) { 2.3.1, 2.3.3, 2.4.2, 2.4.5, 2.5.4, 3.3.3, 3.4.2, 3.4.3, Box 3.2, 9.6.1, 11.3.1, 12.3, 13.4.1, [https://www.ipcc.ch/chapter/ts#CCP1.2.1 CCP1.2.1] , [https://www.ipcc.ch/chapter/ts#CCP5.2.1 CCP5.2.1] , [https://www.ipcc.ch/chapter/ts#CCP5.2.7 CCP5.2.7] , [https://www.ipcc.ch/chapter/ts#CCP7.2.1 CCP7.2.1] , CCB EXTREMES, CCB PALEO }

'''TS.B.1.4 Ecosystem change has led to the loss of specialised ecosystems where warming has reduced thermal habitat, as at the poles, at the tops of mountains and at the equator, with the hottest ecosystems becoming intolerable for many species (''' '''''very high confidence''''' ''').''' For example, warming, reduced ice, thawing permafrost and a changing hydrological cycle have resulted in the contraction of polar and mountain ecosystems. The Arctic is showing increased arrival of species from warmer areas on land and in the sea, with a declining extent of tundra and ice-dependent species, such as the polar bear ( ''high confidence'' ). Similar patterns of change in the Antarctic terrestrial and marine environment are beginning to emerge, such as declining ranges of krill and emperor penguins ( ''medium confidence'' ). Coral reefs are suffering global declines, with abrupt shifts in community composition persisting for years ( ''very high confidence'' ). Deserts and tropical systems are decreasing in diversity due to heat stress and extreme events ( ''high confidence'' ). In contrast, arid lands are displaying varied responses around the globe in response to regional changes in the hydrological cycle ( ''high confidence'' ). { 2.3.1, 2.3.3, 2.4.2, 2.4.3, 3.2.2, 3.4.2, 3.4.3, 3.5.3, 9.6.1, 10.4.3, 11.3.2, 11.3.11, 12.3.1, [https://www.ipcc.ch/chapter/ts#CCP1.2.4 CCP1.2.4] , [https://www.ipcc.ch/chapter/ts#CCP3.2.1 CCP3.2.1] , [https://www.ipcc.ch/chapter/ts#CCP3.2.2 CCP3.2.2] , [https://www.ipcc.ch/chapter/ts#CCP4.3.2 CCP4.3.2] , [https://www.ipcc.ch/chapter/ts#CCP5.2.1 CCP5.2.1] , [https://www.ipcc.ch/chapter/ts#CCP6.1 CCP6.1] , [https://www.ipcc.ch/chapter/ts#CCP6.2 CCP6.2] , CCB EXTREMES }

'''TS.B.1.5 Climate change is affecting ecosystem services connected to human health, livelihoods and well-being (''' '''''medium confidence''''' ''').''' In terrestrial ecosystems, carbon uptake services linked to CO 2 fertilisation effects are being increasingly limited by drought and warming and exacerbated by non-climatic anthropogenic impacts ( ''high confidence'' ) ''.'' Deforestation, draining and burning of peatlands and tropical forests and thawing of Arctic permafrost have already shifted some areas from being carbon sinks to carbon sources ( ''high confidence'' ) ''.'' The severity and outbreak extent of forest insect pests increased in several regions ( ''high confidence'' ) ''.'' Woody plant expansion into grasslands and savannahs, linked to increased CO 2 , has reduced grazing land, while invasive grasses in semiarid lands increased the risk of fire ( ''high confidence'' ). Coastal ‘blue carbon’ systems are already impacted by multiple climate and non-climate drivers ( ''very high confidence'' ). Warming and CO 2 fertilisation have altered coastal ecosystem biodiversity, making carbon storage or release regionally variable ( ''high confidence'' ). { 2.2, Table 2.1, 2.4.2, 2.4.3, 2.4.4, Box 2.1, 3.4.2, 3.5.3, 3.5.5, Table Box 3.4.2, Box 3.4, 9.6.1, 10.4.3, 11.3.11, 11.3.7, 12.3.3, 12.4, Figure 12.8, Figure 12.9, 13.3.1, 13.5.1, 14.5.1, 15.3.3, 15.5.6, [https://www.ipcc.ch/chapter/ts#CCP1.2.2 CCP1.2.2] , [https://www.ipcc.ch/chapter/ts#CCP1.2.4 CCP1.2.4] , [https://www.ipcc.ch/chapter/ts#CCP5.2.1 CCP5.2.1] , [https://www.ipcc.ch/chapter/ts#CCP5.2.3 CCP5.2.3] , [https://www.ipcc.ch/chapter/ts#CCP7.3.1 CCP7.3.1] , Box [https://www.ipcc.ch/chapter/ts#CCP7.1 CCP7.1] }

'''TS.B.1.6 Human communities, especially Indigenous Peoples and those more directly reliant on the environment for subsistence, are already negatively impacted by the loss of ecosystem functions, replacement of endemic species and regime shifts across landscapes and seascapes (''' '''''high confidence''''' ''').''' Indigenous knowledge contains unique information sources about past changes and potential solutions to present issues ( ''medium confidence'' ). Tangible heritage, such as traditional harvesting sites or species and archaeological and cultural heritage sites, and intangible heritage, such as festivals and rites associated with nature-based activities, endemic knowledge and unique insights about plants and animals, are being lost ( ''high confidence'' ). As 80% of the world’s remaining biodiversity is on Indigenous homelands, these losses have cascading impacts on cultural and linguistic diversity and Indigenous knowledge systems, food security, health, and livelihoods, often with irreparable damage and consequences ( ''medium evidence, high agreement'' ). Cultural losses threaten adaptive capacity and may accumulate into intergenerational trauma and irrevocable losses of sense of belonging, valued cultural practices, identity and home ( ''medium confidence'' ). { 2.2, Table 2.1, 2.6.5, 3.5.6, 4.3.5, 4.3.8, 5.4.2, 6.3.3, Box 9.2, 9.12.1, 11.4.1, 11.4.2, 12.5.8, 13.8.1, Box 13.2, 14.4, 15.3.4, [https://www.ipcc.ch/chapter/ts#CCP5.2.5 CCP5.2.5] , [https://www.ipcc.ch/chapter/ts#CCP5.2.7 CCP5.2.7] , [https://www.ipcc.ch/chapter/ts#CCP6.2 CCP6.2] , Box [https://www.ipcc.ch/chapter/ts#CCP7.1 CCP7.1] }

'''TS.B.2 Widespread and severe loss and damage to human and natural systems are being driven by human-induced climate changes increasing the frequency and/or intensity and/or duration of extreme weather events, including droughts, wildfires, terrestrial and marine heatwaves, cyclones (''' '''''high confidence''''' ''') and flood (''' '''''low confidence''''' '''). Extremes are surpassing the resilience of some ecological and human systems and challenging the adaptation capacities of others, including impacts with irreversible consequences (''' '''''high confidence''''' '''). Vulnerable people and human systems and climate-sensitive species and ecosystems are most at risk (''' '''''very high confidence''''' ''').''' (Figure TS.3) { 2.3, 2.3.1, 2.3.1, 2.3.3, 2.4.2, 2.4.5, 2.6.1, 3.2.2, 3.4.2, 3.4.3, 3.5.2, 3.5.3, 4.2.4, 4.2.5, 10.1, 11.2, 12.3, 13.1, 14.1, 15.1, 16.2.3, CCB EXTREMES, WGI AR6 SPM, WGI AR6 9, SROCC SPM }

'''TS.B.2.1 Extreme climate events comprising conditions beyond which many species are adapted are occurring on all continents, with severe impacts (''' '''''very high confidence''''' ''').''' The most severe impacts are occurring in the most climate-sensitive species and ecosystems, characterised by traits that limit their abilities to regenerate between events or to adapt, and those most exposed to climate hazards ( ''high confidence'' ). Losses of local plant and animal populations have been widespread, many associated with large increases in hottest yearly temperatures and heatwave events ( ''very high confidence'' ). Marine heatwave events have led to widespread, abrupt and extensive mortality of key habitat-forming species among tropical corals, kelps, seagrasses and mangroves, as well as mass mortality of wildlife species, including benthic sessile species ( ''high confidence'' ). On land, extreme heat events also have been implicated in the mass mortality of fruit bats and freshwater fish. (Figure TS.3, Figure TS.5 ECOSYSTEMS) { 2.3.1, 2.3.3, 2.4.2, 2.4.4, 2.6, Table 2.2, Table 2.3, Table 2.S. 1, 3.4.2, 3.4.3, 3.5.2, 11.3.2, Figure 12.8, 12.4, Table 11.4, 13.3.1, 13.4.1, CCB EXTREMES }

'''TS.B.2.2 Some extreme events have already emerged which exceeded projected global mean warming conditions for 2100, leading to abrupt changes in marine and terrestrial ecosystems (''' '''''high confidence''''' ''')''' . For some forest types an increase in the frequency, severity and duration of wildfires and droughts has resulted in abrupt and possibly irreversible changes ( ''medium to high confidence'' ). The interplay between extreme events, long-term climate trends and other human pressures has pushed some climate-sensitive ecosystems towards thresholds that exceed their natural regenerative capacity ( ''medium to high confidence'' ). Extreme events can alter or impede evolutionary responses to climate change and the potential for acclimation to extreme conditions both on land and in the ocean ( ''medium to high confidence'' ). (Figure TS.5 ECOSYSTEMS) { 2.3.1, 2.3.3, 2.4.2, 2.4.3, 2.4.5, 2.4.4, 2.6.1, 3.2.2, 3.2.4, 3.4.2, 4.3.5, Table 3.15, 3.6.3, 11.3.1, 11.3.2, 13.3.1, 13.4.1, 14.5.1, CCB MOVING PLATE, CCB EXTREMES }

'''TS.B.2.3 Climate-related extremes have affected the productivity of agricultural, forestry and fishery sectors (''' '''''high confidence''''' '''). Droughts, floods, wildfires and marine heatwaves contribute to reduced food availability and increased food prices, threatening food security, nutrition and livelihoods of millions of people across regions (''' '''''high confidence''''' ''').''' Extreme events caused economic losses in forest productivity and crops and livestock farming, including losses in wheat production in 2012, 2016 and 2018, with the severity of impacts from extreme heat and drought tripling over the last 50 years in Europe ( ''high confidence'' ). Forests were impacted by extreme heat and drought impacting timber sales, for example, in Europe ( ''high confidence'' ). Marine heatwaves, including well-documented events along the west coast of North America (2013–2016) and east coast of Australia (2015–2016, 2016–2017 and 2020), have caused the collapse of regional fisheries and aquaculture ( ''high confidence'' ). Human populations exposed to extreme weather and climate events are at risk of food insecurity with lower diversity in diets, leading to malnutrition and increased risk of disease ( ''high confidence'' ). (Figure TS.6 WATER-FOOD) { 2.4.4, 3.2.2, 3.4.2, 3.4.3, 3.5.3, 4.2.4, 4.2.5, 4.3.1, 5.2.1, 5.4.1, 5.4.2, 5.5.2, 5.8.1, 5.9.1, 5.12.1, 5.14.2, 5.14.6, 7.2.1, 7.2.2, 7.2.3, 7.2.4, 7.2.5, 9.7, 9.8.2, 9.8.5, 11.3.3, 11.5.1, 11.8.1, 12.3, Figure 12.7, Figure 12.9, Table SM12.5, 13.1.1, 13.3.1, 13.5.1, 13.10.2, 14.5.4, CCB MOVING PLATE, WGI AR6 9 }

'''TS.B.2.4 Extreme climatic events have been observed in all inhabited regions, with many regions experiencing unprecedented consequences, particularly when multiple hazards occur at the same time or within the same space (''' '''''very high confidence''''' ''')''' '''''.''''' Since AR5, the impacts of climate change and extreme weather events such as wildfires, extreme heat, cyclones, storms and floods have adversely affected or caused loss and damage to human health, shelter, displacement, incomes and livelihoods, security and inequality ( ''high confidence'' ). Over 20 million people have been internally displaced annually by weather-related extreme events since 2008, with storms and floods the most common drivers ( ''high confidence'' ). Climate-related extreme events are followed by negative impacts on mental health, well-being, life satisfaction, happiness, cognitive performance and aggression in exposed populations ( ''very high confidence'' ). (Figure TS.8 HEALTH, Figure TS.10 COMPLEX RISK) { 2.3.0, 2.3.1, 2.3.3, 4.2.4, 4.2.5, 4.3, 7.1, 7.2.4, 7.2.6, 8.2.1, 8.2.2, 8.3.2, 8.3.3, Box 9.4, Table 9.7, 9.7, 9.9, 9.11, 11.2.1, 11.2.2, 11.3.8, Table 11.2, Table 11.3, Box 11.6, Box 9.8, 12.4.7, 13.1, 13.2.1, 13.7.1, 13.10.2, 14.5.6, 15.1, 15.2.1, 15.3.3, 16.2.3, CCB EXTREMES, CCB HEALTH, CCB MIGRATE }

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