Editing IPCC:AR6/WGII/Cross-Chapter-Paper-6 (section)

===== Observed Impacts and Future Risks =====

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'''Climate change impacts and cascading impacts in polar regions, particularly the Arctic, are already occurring at a magnitude and pace unprecedented in recent history (''' '''''very high confidence''''' '''), and much faster than projected for other world regions (''' '''''high confidence''''' [[#footnote-001|1]] ''').'''

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'''The polar regions, notably the Arctic and maritime Antarctic, are experiencing impacts from climate change at magnitudes and rates that are among the highest in the world, and will become profoundly different in the near-term future (by 2050) under all warming scenarios (''' '''''high confidence''''' ''').''' In the Arctic, accelerated sea ice loss (particularly during summer), increased permafrost thaw and extreme high temperatures have substantially impacted marine, freshwater and terrestrial sociological–ecological systems ( ''very high confidence'' ). Multiple physical, ecological and societal elements of polar regions are approaching a level of change potentially irreversible for hundreds of years, if not millennia ( ''high confidence'' ). Evidence of borealisation of terrestrial and marine systems is emerging ( ''high confidence'' ), and cascading impacts are ongoing and widespread yet challenging to quantify fully due to complexity and lags in ecological expression of change. Loss of multi-year sea ice and the occurrence of a seasonally ice-free Arctic Ocean by the middle of this century will result in substantial range contraction, if not the disappearance of several Arctic fish, crab, bird and marine mammal species, including possible extinction of seals and polar bears in certain regions ( ''high confidence'' ). In the Arctic, permafrost thaw and snowfall decrease lead to profound hydrological changes, an overall greening of the tundra and regional browning of tundra and boreal forests ( ''high confidence'' ). {CCP6.1; Table CCP6.1; Table CCP6.2; CCP6.2.1; CCP6.2.2; Table CCP6.5 }

'''Contractions of the polar climate zones lead to distribution shifts and changes in food webs, induce declines in many species (''' '''''medium confidence''''' ''') with impacts on subsistence harvests and commercial fisheries, and threaten global dependence on polar regions for substantial marine food production (''' '''''high confidence''''' ''').''' Climate change has induced food web changes resulting in population declines in polar sea birds, including penguins, and marine and terrestrial mammals ( ''high confidence'' ). Globally and regionally important harvested fish and invertebrate species are also contracting ranges and declining productivity, including Pacific cod, salmon, snow and king crab in the Arctic and krill in the Antarctic ( ''medium confidence'' ), with implications for global food systems ( ''high confidence'' ). {Table CCP6.2; CCP6.2.1; CCP6.2.3; Table CCP6.3; Table CCP6.4 }

'''Loss of sea ice is rapidly expanding opportunities, but also increasing risks for shipping and other economic industries in polar regions (''' '''''very high confidence''''' ''').''' Reduced sea ice enables greater access to high-latitudinal seas for industries, such as fisheries, shipping, tourism ( ''very high confidence'' ) and Arctic maritime trade and resource extraction ( ''medium confidence'' ). Navigational risks have grown due to increasingly mobile multi-year ice, poor hydrographic charting in newly open areas, and limited weather, water, ice and climate data and services ( ''high confidence'' ). Cascading risks from polar shipping growth include increased air emissions, underwater noise pollution, disruption to subsistence hunting and cultural activities in the Arctic ( ''high confidence'' ) and potential for invasive marine species and geopolitical tensions ( ''medium confidence'' ). {Table CCP6.3; CCP6.2.4; Box CCP6.1; Table CCP6.5; Table CCP6.6}

'''Increased permafrost thaw and flooding will disrupt economically important transportation and supply-chain infrastructure to remote Arctic settlements (''' '''''high confidence''''' '''), increasing risks to economies, Arctic tourism and tourism to cultural heritage sites (''' '''''medium confidence''''' ''').''' Arctic permafrost thaw is projected to impact most infrastructure by the middle of this century, impacting millions of people and their economies, and costing billions in damages ( ''high confidence'' ). {CCP6.2.3; CCP6.2.4; Box CCP6.1; CCP6.2.5; CCP6.3.1; Table CCP6.5; Table CCP6.6}

'''Climate change increasingly threatens many facets of Arctic livelihoods, culture, identity, health and security, particularly for Indigenous Peoples (''' '''''very high confidence''''' ''').''' It has negatively impacted mental health and increased risks of injury, food insecurity and foodborne and waterborne disease, with risks amplified for those reliant on the environment for subsistence, livelihoods and identity ( ''high confidence'' ). Permafrost thaw, sea level rise and reduced sea ice protection have already damaged or destroyed many cultural heritage sites in some Arctic regions ( ''very high confidence'' ) and are projected to continue across all Arctic regions ( ''very high confidence'' ). {CCP6.2.3; Table CCP6.3; CCP6.2.4; CCP6.2.5; CCP6.2.6; Figure CCP6.3; Box CCP6.2; CCP6.3.1; Table CCP6.5; Table CCP6.6}

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