Editing IPCC:AR6/SYR/Longer-Report (section)

=== 4.3 Near-Term Risks ===

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'''Many changes in the climate system, including extreme events, will become larger in the near term with increasing global warming ( '''''high confidence''''' ) . Multiple climatic and non-climatic risks will interact, resulting in increased compounding and cascading impacts becoming more difficult to manage ( '''''high confidence''''' ) . Losses and damages will increase with increasing global warming ( '''''very''''' '''''high confidence''''' ) , while strongly concentrated among the poorest vulnerable populations ( '''''high confidence''''' ) . Continuing with current unsustainable development patterns would increase exposure and vulnerability of ecosystems and people to climate hazards ( '''''high confidence''''' ) .'''

'''Global warming will continue to increase in the near term (2021''' – '''2040)''' '''mainly due to increased cumulative CO''' '''2''' emissions in nearly all considered scenarios and pathways. In the near term, every region in the world is projected to face further increases in climate hazards ( '''''medium to''''' '''''high confidence , depending on region and hazard), increasing multiple risks to ecosystems and humans (''''' '''''very high confidence).''''' In the near term, natural variability '''[[#footnote-008|149]]''' will modulate human-caused changes, either attenuating or amplifying projected changes, especially at regional scales, with little effect on centennial global warming. Those modulations are important to consider in adaptation planning. Global surface temperature in any single year can vary above or below the long-term human-induced trend, due to natural variability. By 2030, global surface temperature in any individual year could exceed 1.5°C relative to 1850–1900 with a probability between 40% and 60%, across the five scenarios assessed in WGI ( ''medium confidence'' ). The occurrence of individual years with global surface temperature change above a certain level does not imply that this global warming level has been reached. If a large explosive volcanic eruption were to occur in the near term '''[[#footnote-007|150]]''' , it would temporarily and partially mask human-caused climate change by reducing global surface temperature and precipitation, especially over land, for one to three years ( ''medium confidence'' ). { ''WGI SPM B.1.3, WGI SPM B.1.4, WGI SPM C.1, WGI SPM C.2, WGI Cross-Section Box TS.1, WGI Cross-Chapter Box 4.1; WGII SPM B.3, WGII SPM B.3.1; WGIII Box SPM.1 Figure 1'' }

'''The level of risk for humans and ecosystems will depend on near-term trends in vulnerability, exposure, level of socio-economic development and adaptation (''' '''''high confidence).''''' In the near term, many climate-associated risks to natural and human systems depend more strongly on changes in these systems’ vulnerability and exposure than on differences in climate hazards between emissions scenarios ( ''high confidence'' ). Future exposure to climatic hazards is increasing globally due to socio-economic development trends including growing inequality, and when urbanisation or migration increase exposure. ( ''high confidence'' ). Urbanisation increases hot extremes ( ''very high confidence'' ) and precipitation runoff intensity ( ''high confidence'' ). Increasing urbanisation in low-lying and coastal zones will be a major driver of increasing exposure to extreme riverflow events and sea level rise hazards, increasing risks ( ''high confidence'' ) (Figure 4.3). Vulnerability will also rise rapidly in low-lying Small Island Developing States and atolls in the context of sea level rise ( ''high confidence'' ) (see Figure 3.4 and Figure 4.3). Human vulnerability will concentrate in informal settlements and rapidly growing smaller settlements; and vulnerability in rural areas will be heightened by reduced habitability and high reliance on climate-sensitive livelihoods ( ''high confidence'' ). Human and ecosystem vulnerability are interdependent ( ''high confidence'' ). Vulnerability to climate change for ecosystems will be strongly influenced by past, present, and future patterns of human development, including from unsustainable consumption and production, increasing demographic pressures, and persistent unsustainable use and management of land, ocean, and water ( ''high confidence'' ). Several near-term risks can be moderated with adaptation. ( ''high confidence'' ). { ''WGI SPM C.2.6; WGII SPM B.2, WGII SPM B.2.3, WGII SPMB.2.5, WGII SPM B.3, WGII SPM B.3.2, WGII TS.C.5.2'' } . ( ''Section 4.5 and 3.2'' )

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[[File:12ae4572595f5fb24237b1c893b25061 IPCC_AR6_SYR_Figure_4_3.png]]
'''Figure 4.3: Every region faces more''' '''severe or frequent compound and/or''' '''cascading''' '''climate''' '''risks in the near term.''' Changes in risk result from changes in the degree of the hazard, the population exposed, and the degree of vulnerability of people, assets, or ecosystems. '''Panel (a)''' Coastal flooding events affect many of the highly populated regions of the world where large percentages of the population are exposed. The panel shows near-term projected increase of population exposed to 100-year flooding events depicted as the increase from the year 2020 to 2040 (due to sea level rise and population change), based on the intermediate GHG emissions scenario (SSP2-4.5) and current adaptation measures. Out-migration from coastal areas due to future sea level rise is not considered in the scenario. '''Panel (b)''' projected median probability in the year 2040 for extreme water levels resulting from a combination of mean sea level rise, tides and storm surges, which have a historical 1% average annual probability. A peak-over-threshold (99.7%) method was applied to the historical tide gauge observations available in the Global Extreme Sea Level Analysis version 2 database, which is the same information as WGI Figure 9.32, except here the panel uses relative sea level projections under SSP2-4.5 for the year 2040 instead of 2050 The absence of a circle indicates an inability to perform an assessment due to a lack of data, but does not indicate absence of increasing frequencies. '''Panel (c)''' Climate hazards can initiate risk cascades that affect multiple sectors and propagate across regions following complex natural and societal connections. This example of a compound heat wave and a drought event striking an agricultural region shows how multiple risks are interconnected and lead to cascading biophysical, economic, and societal impacts even in distant regions, with vulnerable groups such as smallholder farmers, children and pregnant women particularly impacted. { ''WGI Figure 9.32; WGII SPM B4.3, WGII SPM B1.3, WGII SPM B.5.1, WGII TS Figure TS.9, WGII TS Figure TS.10 (c), WGII Fig 5.2, WGII TS.B.2.3,'' ''WGII TS.B.2.3, WGII TS.B.3.3, WGII 9.11.1.2'' }

[https://www.ipcc.ch/figures/figure-4-3 ]

Principal hazards and associated risks expected in the near term (at 1.5°C global warming) are:

* Increased intensity and frequency of hot extremes and dangerous heat-humidity conditions, with increased human mortality, morbidity, and labour productivity loss. ( ''high confidence'' ). { ''WGI SPM B.2.2, WGI TSFigure TS.6; WGII SPM B.1.4, WGII SPM B.4.4, WGII Figure SPM.2'' } .
* Increasing frequency of marine heatwaves will increase risks of biodiversity loss in the oceans, including from mass mortality events ( ''high confidence'' ). { ''WGI SPM B.2.3; WGII SPM B.1.2, WGII Figure SPM.2; SROCC SPM B.5.1'' }
* Near-term risks for biodiversity loss are moderate to high in forest ecosystems ( ''medium confidence'' ) and kelp and seagrass ecosystems ( ''high'' to ''very high confidence'' ) and are high to very high in Arctic sea-ice and terrestrial ecosystems ( ''high confidence'' ) and warm-water coral reefs ( ''very high confidence'' ). { ''WGII SPM B.3.1'' } .
* More intense and frequent extreme rainfall and associated flooding in many regions including coastal and other low-lying cities ( ''medium'' to ''high confidence'' ), and increased proportion of and peak wind speeds of intense tropical cyclones. ( ''high confidence'' ). { ''WGI SPM B.2.4, WGI SPM C.2.2, WGI SPM C.2.6, WGI 11.7'' }
* High risks from dryland water scarcity, wildfire damage, and permafrost degradation ( ''medium confidence'' ). { ''SRCCL SPM A.5.3.'' }
* Continued sea level rise and increased frequency and magnitude of extreme sea level events encroaching on coastal human settlements and damaging coastal infrastructure ''(high confidence)'' , committing low-lying coastal ecosystems to submergence and loss ( ''medium confidence'' ), expanding land salinization ( ''very high confidence'' ), with cascading to risks to livelihoods, health, well-being, cultural values, food and water security ( ''high confidence'' ). { ''WGI SPM C.2.5, WGI SPM C.2.6; WGII SPM B.3.1, WGII SPM B.5.2; SRCCL SPM A.5.6; SROCC SPM B.3.4, SROCC SPM 3.6, SROCC SPM B.9.1'' } . ( ''Figure 3.4, 4.3'' )
* Climate change will significantly increase ill health and premature deaths from the near to long term ( ''high confidence'' ). Further warming will increase climate-sensitive food-borne, water-borne, and vector-borne disease risks ( ''high confidence'' ), and mental health challenges including anxiety and stress ( ''very high confidence'' ). { ''WGII SPM B.4.4'' }
* Cryosphere-related changes in floods, landslides, and water availability have the potential to lead to severe consequences for people, infrastructure and the economy in most mountain regions ( ''high confidence'' ). { ''WGII TS C.4.2'' }
* The projected increase in frequency and intensity of heavy precipitation ( ''high confidence'' ) will increase rain-generated local flooding ( ''medium confidence'' ). { ''WGI Figure SPM.6, WGI SPM B.2.2; WGII TS C.4.5'' }

'''Multiple climate change risks will increasingly compound and cascade in the near term (''' '''''high confidence).''''' Many regions are projected to experience an increase in the probability of compound events with higher global warming ( ''high confidence'' ) including concurrent heatwaves and drought. Risks to health and food production will be made more severe from the interaction of sudden food production losses from heat and drought, exacerbated by heat-induced labour productivity losses ( ''high confidence'' ) (Figure 4.3). These interacting impacts will increase food prices, reduce household incomes, and lead to health risks of malnutrition and climate-related mortality with no or low levels of adaptation, especially in tropical regions ( ''high confidence'' ). Concurrent and cascading risks from climate change to food systems, human settlements, infrastructure and health will make these risks more severe and more difficult to manage, including when interacting with non-climatic risk drivers such as competition for land between urban expansion and food production, and pandemics ( ''high confidence'' ). Loss of ecosystems and their services has cascading and long-term impacts on people globally, especially for Indigenous Peoples and local communities who are directly dependent on ecosystems, to meet basic needs ( ''high confidence'' ). Increasing transboundary risks are projected across the food, energy and water sectors as impacts from weather and climate extremes propagate through supply-chains, markets, and natural resource flows ( ''high confidence'' ) and may interact with impacts from other crises such as pandemics. Risks also arise from some responses intended to reduce the risks of climate change, including risks from maladaptation and adverse side effects of some emissions reduction and carbon dioxide removal measures, such as afforestation of naturally unforested land or poorly implemented bioenergy compounding climate-related risks to biodiversity, food and water security, and livelihoods ( ''high confidence'' ) (see [[#3.4.1|Section 3.4.1]] and 4.5). { ''WGI SPM.2.7; WGII SPM B.2.1, WGII SPM B.5, WGII SPM B.5.1, WGII SPM B.5.2, WGII SPM B.5.3, WGII SPM B.5.4,'' . ''WGII Cross-Chapter Box COVID in Chapter 7; WGIII SPM C.11.2; SRCCL SPM A.5, SRCCL SPM A.6.5'' } ( ''Figure 4.3'' )

'''With every increment of global warming losses and damages will increase (''' '''''very''''' '''''high confidence), become increasingly difficult to avoid and be strongly concentrated among the poorest vulnerable populations (''''' '''''high confidence).''''' Adaptation does not prevent all losses and damages, even with effective adaptation and before reaching soft and hard limits. Losses and damages will be unequally distributed across systems, regions and sectors and are not comprehensively addressed by current financial, governance and institutional arrangements, particularly in vulnerable developing countries. ( ''high confidence'' ). { ''WGII SPM B.4, WGII SPM C.3, WGII SPM C.3.5'' }

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