rlacombe/ClimateX · Datasets at Hugging Face

statement_idx int64 0 8.09k	report stringclasses 3 values	page_num int64 18 2.84k	sent_num int64 0 78	statement stringlengths 13 4.29k	confidence stringclasses 4 values	score int64 0 3	split stringclasses 2 values
6,500	AR6_WGII	2,332	6	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	2	train
6,501	AR6_WGII	2,332	8	Climate change has induced food web changes resulting in population declines in polar sea birds, including penguins, and marine and terrestrial mammals	high	2	train
6,502	AR6_WGII	2,332	9	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	2	train
6,503	AR6_WGII	2,332	13	For a given evidence and agreement statement, different confidence levels can be assigned, but increasing levels of evidence and degrees of agreement are correlated with increasing confidence.shipping, tourism (very high confidence) and Arctic maritime trade and resource extraction	medium	1	train
6,504	AR6_WGII	2,332	14	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	2	train
6,505	AR6_WGII	2,332	15	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	1	train
6,506	AR6_WGII	2,332	17	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	2	train
6,507	AR6_WGII	2,332	19	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	2	train
6,508	AR6_WGII	2,332	20	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	3	train
6,509	AR6_WGII	2,332	22	Polar zones will continue to contract and diminish in extent under climate change, and local adaptations will be insufficient to achieve long-term resilience of polar systems	medium	1	train
6,510	AR6_WGII	2,332	23	The pace and extent of change in polar regions is challenging the ability of social and natural systems to adapt	medium	1	train
6,511	AR6_WGII	2,333	0	CCP6 2322Cross-Chapter Paper 6 Polar Regions biodiversity	medium	1	train
6,512	AR6_WGII	2,333	2	Governance around climate change planning, preparation and response has been limited in scope, and has often not considered interacting effects of climate change with other risks	high	2	train
6,513	AR6_WGII	2,333	3	Reactive management strategies will not succeed in reducing risks in polar regions given the rapid change and increasing potential for extreme events	high	2	train
6,514	AR6_WGII	2,333	4	Greater inclusivity of stakeholders and communities, along with using diverse sources of information, including Indigenous knowledge and local knowledge, can benefit robust planning and decision making, and uptake of adaptations	high	2	train
6,515	AR6_WGII	2,333	5	Effectiveness in preparing for and adapting to climate risks can benefit from improved climate, weather and ice forecasting services, tools for integrating climate change data and different types of knowledge into management processes and enhanced polar search, rescue and emergency response capabilities	high	2	train
6,516	AR6_WGII	2,333	7	Development of robust pathways for climate resilience in the Arctic can be accelerated by adaptation strategies and governance that reflect local conditions, cultures and adaptive capacities of communities and sectors	high	2	train
6,517	AR6_WGII	2,333	8	Effectiveness of adaptation strategies will be enhanced by accounting for the geographic, climatic, ecological and cultural uniqueness of the polar regions	medium	1	train
6,518	AR6_WGII	2,333	9	Colonialism can inhibit the development of robust climate adaptation strategies, and exacerbate climate risks	very high	3	train
6,519	AR6_WGII	2,333	10	Inclusive decision making in establishing climate adaptations can foster resilience, reflect the unique environmental, cultural and economic imperatives of the region and support both market-based and sharing economies	high	2	train
6,520	AR6_WGII	2,333	12	Arctic Indigenous self-determination in decision making can establish robust climate resilience, especially in Indigenous communities, incorporating locally derived definitions of social and economic success, culturally legitimate institutions of government, strategic visioning and thinking and public-spirited, nation-building leadership	very high	3	train
6,521	AR6_WGII	2,334	2	These changes are causing a suite of direct and cascading risks for all polar ecosystems with larger effects to date in the Arctic than the Antarctic	high	2	train
6,522	AR6_WGII	2,335	3	Driver Region Observed changes Projected changes Marine and sea ice Sea level (relative) ArcticNo consistent trend (increase in northwest America, decrease in northeast America, stable in Greenland and Arctic Russia) (WG1-12)Rise in all polar regions (except areas of substantial land uplift in northeast Canada, the west coast of Greenland) (high confidence); Increase of extreme sea levels in Russian Arctic and northwest America (high confidence) Greenland/Iceland and northeast America (given glacial isostatic adjustment) (medium confidence, WG1-12) AntarcticRise in all polar regions (except areas of substantial land uplift in west Antarctica) (high confidence, WG1-12) Sea surface temperature ArcticIncrease of ~0.5°C per decade during 1982–2017 in ice-free regions in summer (high confidence, SROCC-3)Further increases (high confidence, WG1-12) AntarcticWarmed in northern areas of Southern Ocean but cooled in its southernmost regions since the 1980s (high confidence, SROCC-3)Circumpolar increases (high confidence, WG1-12) Sea ice cover ArcticLoss (particularly of multi-year sea ice) accelerated since 2001 (very likely, WG1-9)Will become sea ice free (< 1 × 106 km2) during summer before 2050, irrespective of global warming level (likely, WG1-9) AntarcticNo significant circumpolar trend from 1979–2018 (very high confidence), but decrease off the Antarctic Peninsula	high	2	train
6,523	AR6_WGII	2,336	6	Warming and wetting have persisted as key climatic impact drivers in polar regions	very high	3	train
6,524	AR6_WGII	2,336	20	CCP6.2 Observed Impacts and Future Risks CCP6.2.1 Marine and Coastal Ecosystems CCP6.2.1.1 Warming and sea ice retreat cause shifts in distribution ranges of species In Arctic seas, warming and other climate impact drivers, primarily sea ice retreat, have led to range contractions of Arctic marine and ice-associated species and poleward expansions of boreal species	very high	3	train
6,525	AR6_WGII	2,336	21	Altered conditions allow more microorganisms to move poleward and provide opportunities for invasive species (Cavicchioli et al., 2019; Nielsen et al., 2020; Driver Region Observed changes Projected changes Permafrost ArcticRising permafrost temperatures over past three to four decades (high confidence, WG1-9); decreases in permafrost active layer thickness	very high	3	train
6,526	AR6_WGII	2,336	22	Submarine permafrost warming (medium confidence, WG1-9)Increases in temperature and active layer thickness (WG1-9); near-surface terrestrial permafrost extent will reduce under all scenarios by 2100 (virtually certain, WG1-9) AntarcticRising permafrost temperatures over past three to four decades (high confidence, WG1-9) Lake, river ice ArcticDeclines in seasonal lake ice cover thickness and duration over most Arctic lakes; declines in cold-season river ice extent (high confidence, WG1-12)Many lakes will lose >1 month lake ice cover by 2050	medium	1	train
6,527	AR6_WGII	2,338	1	Affected systemHazard Cascading effectObserved impacts, future risks and natural adaptations identified in SROCC (confidence level) Arctic marine ecosystems Primary producers (PP-1)Sea ice loss Freshening * StratificationImpact: timing (earlier and later blooms), distribution and magnitude (>30% increase in annual net primary production since 1998) (high confidence) Acidification Adaptation: phytoplankton may compensate for decrease in pH Zooplankton * PP-1 Impact: changing production and community composition (medium confidence) Benthos * PP-1 Impact: changing production and biodiversity	medium	1	train
6,528	AR6_WGII	2,339	4	Numerous mammals and sea birds respond to changes in the distribution of their preferred habitats and prey by shifting their range, altering the timing or pathways for migration or switching prey	very high	3	train
6,529	AR6_WGII	2,339	5	Ice-breeding seals (e.g., harp seals – Pagophilus groenlandicus) often have little scope to shift distribution, leading to increases in strandings and pup mortality in years with little ice cover	medium	1	train
6,530	AR6_WGII	2,339	6	Recent studies confirm that polar bears (Ursus maritimus) are negatively affected by changing ice and snow conditions with decreases in denning, foraging, reproduction, genetic diversity and survival rates	very high	3	train
6,531	AR6_WGII	2,339	8	Such shifts have so far only been detected for Antarctic krill (Euphausia superba), with a poleward contraction of the highest densities of krill in the Atlantic sector	medium	1	train
6,532	AR6_WGII	2,339	9	Ocean warming is expected to put pressure on Antarctic phytoplankton (Pinkerton et al., 2021) and fish species unable to move further south in shelf areas, including waters off sub-Antarctic islands	low	0	train
6,533	AR6_WGII	2,339	10	Off the Antarctic Peninsula and sub-Antarctic islands, invasive benthic invertebrates and macroalgae have already been detected	medium	1	train
6,534	AR6_WGII	2,339	11	On a local to regional scale, the benthic recolonisation of the newly exposed seabed after the disintegration of ice shelves shows typical succession patterns, with mass occurrences of few pioneer species followed by gradual shifts to a more diverse typical shelf community, driven by increasing pelagic primary production upon ice-shelf collapse and strengthening of the pelagic–benthic coupling	high	2	train
6,535	AR6_WGII	2,339	12	Range changes of Antarctic birds and marine mammals have been observed, which vary among sub- regions and are mostly attributable to changes in sea ice extent and food availability	high	2	train
6,536	AR6_WGII	2,339	13	With projected sea ice retreat and associated change in prey distribution (Henley et al., 2020), foraging areas of sub-Antarctic sea birds and marine mammals will shift southwards, leading to elevated pressure on populations due to higher foraging costs during the breeding season	medium	1	train
6,537	AR6_WGII	2,339	14	These changes are particularly impacting emperor penguins (Aptenodytes forsteri) (Table CCP6.2), with the projected population declining close to extinction by 2100 under Business-As-Usual climate scenarios (medium confidence) (Jenouvrier et al., 2020; Trathan et al., 2020; Jenouvrier et al., 2021), whereas population decline is halted by 2060 under the 1.5°C climate scenario	low	0	train
6,538	AR6_WGII	2,339	15	CCP6.2.1.2 Ocean warming and sea ice changes affect marine primary productivity In the central Arctic Ocean, primary productivity remains low	medium	1	train
6,539	AR6_WGII	2,339	16	In inflowing (Barents and Chukchi Sea) and interior shelf regions (Laptev, Kara, and Siberian Sea), changes in sea ice extent, thickness and seasonal timing have altered light and mixing regimes, causing increasing overall productivity in open-water and under-ice habitats, and in leads	high	2	train
6,540	AR6_WGII	2,339	17	Productivity changes are associated with the earlier- onset phytoplankton spring blooms and the increasing occurrence of autumn blooms, particularly at lower latitudes of the Arctic	high	2	train
6,541	AR6_WGII	2,339	18	Ice algal communities are expected to change in productivity and species composition in response to the transition from a predominantly multi-year to a seasonal sea ice pack	high	2	train
6,542	AR6_WGII	2,340	0	CCP6 2329Polar Regions Cross-Chapter Paper 6 in Greenland	medium	1	train
6,543	AR6_WGII	2,340	1	Macroalgae and seagrass are generally expanding in the Arctic	medium	1	test
6,544	AR6_WGII	2,340	2	In the future Arctic Ocean, higher light availability in response to further sea ice decline and reduced deep mixing is projected to generally increase primary productivity	medium	1	train
6,545	AR6_WGII	2,340	3	However, productivity may increase less than predicted and eventually even decrease once nutrient limitation outweighs the benefits of higher light availability	low	0	train
6,546	AR6_WGII	2,340	4	Despite large-scale environmental changes in the Southern Ocean, such as the deepening of the summer mixed layer (medium confidence) (Panassa et al., 2018; Sallée et al., 2021), and the expected impacts via altered nutrient entrainment, light availability and grazer encounter rates (Chapter 3) (Behrenfeld and Boss, 2014; Llort et al., 2019), assessments indicated no consistent changes in primary production at the circumpolar scale, as sectors and regions show different trends	medium	1	test
6,547	AR6_WGII	2,340	6	Primary productivity has increased in the Pacific sector and decreased in the Atlantic sector and the Ross Sea	low	0	test
6,548	AR6_WGII	2,340	7	Higher productivity has also been observed in regions where rapid environmental changes occurred, such as in the vicinity of retreating IS and declining sea ice cover off the Antarctic Peninsula	medium	1	train
6,549	AR6_WGII	2,340	10	Such an increase in Southern Ocean productivity will lead to a decline in global ocean productivity	medium	1	train
6,550	AR6_WGII	2,340	11	CCP6.2.1.3 Impacts of ocean acidification vary spatially and among biotas In Arctic seas, areas with acidification levels corrosive to organisms forming CaCO 3 shells or skeletons expanded between the 1990s and 2010	high	2	train
6,551	AR6_WGII	2,340	12	Key species of diatom and picoeukaryote phytoplankton species yet appear relatively resilient to decreasing pH levels over a range of temperature and light conditions	medium	1	train
6,552	AR6_WGII	2,340	13	In contrast, there is evidence for species- and stage-specific sensitivities of zooplankton, pteropods and fishes	high	2	train
6,553	AR6_WGII	2,340	14	Warming, rising river-sediment discharge and coastal erosion in Arctic shelf regions are expected to increase the input of labile, often permafrost-derived organic carbon, the remineralisation of which further increases acidification rates	medium	1	train
6,554	AR6_WGII	2,340	16	In the Southern Ocean, calcifying organisms are also most vulnerable to ocean acidification	high	2	train
6,555	AR6_WGII	2,340	17	Calcifying species with low- magnesium calcite or mechanisms to protect their skeletons are less vulnerable to the corrosive effects of acidification than those using aragonite or high-magnesium calcite	high	2	train
6,556	AR6_WGII	2,340	18	In diatom-dominated communities, silicification diminishes with reduced pH levels, albeit with rates differing among taxa	low	0	train
6,557	AR6_WGII	2,340	19	Species-specific responses exist regarding growth and primary production, which are further strongly modulated by iron and light availability	high	2	train
6,558	AR6_WGII	2,340	23	CCP6.2.1.4 Climate change alters food web dynamics Climate change has transformed Arctic marine ecosystems from sea ice- associated to open-water production regimes, with profound impacts on trophic energy transfer efficiencies and pathways (high confidence) (Behrenfeld et al., 2017; Meredith et al., 2019; Huntington et al., 2020) as well as benthic–pelagic coupling	medium	1	train
6,559	AR6_WGII	2,340	24	Shifts in bloom phenology favour small phytoplankton and smaller zooplankton over large lipid-rich macro-zooplankton, leading to longer, less efficient food chains	medium	1	train
6,560	AR6_WGII	2,341	1	Species range shifts have restructured higher trophic levels in Arctic food webs	high	2	train
6,561	AR6_WGII	2,341	5	Climate impacts on Arctic marine food webs will be profound and intensify with GWL	high	2	train
6,562	AR6_WGII	2,341	6	However, the exact nature of these impacts remains unclear due to attenuating and amplifying dynamics of both top-down and bottom-up processes in polar food webs and the management of fisheries	high	2	train
6,563	AR6_WGII	2,341	8	Warming is expected to reduce the quantity and quality of lipid-rich copepod prey (high confidence) (Aarflot et al., 2018; Kimmel et al., 2018; Bouchard and Fortier, 2020; Møller and Nielsen, 2020; Mueter et al., 2020), leading to declines in survival and growth of multiple upper-trophic level fish species; these impacts are amplified over time under low mitigation scenarios (RCP8.5)	high	2	train
6,564	AR6_WGII	2,341	9	Marine mammals and sea birds will continue to attenuate climate change impacts by shifting their diets and behaviour	medium	1	train
6,565	AR6_WGII	2,341	10	However, sea birds generally have low temperature-mediated plasticity of reproductive timing, making them vulnerable to mismatches with their prey and limiting long-term adaptation	medium	1	train
6,566	AR6_WGII	2,341	15	The optimum habitat for Antarctic krill is expected to decline with a shortening of suitable season for krill growth and reproduction, particularly in the northern Scotia and Bellingshausen Seas	medium	1	train
6,567	AR6_WGII	2,341	18	Although salps have long been considered to be competitors of Antarctic krill (Suprenand and Ainsworth, 2017; Rogers et al., 2020), they provide a third energy pathway in pelagic food webs and, given the changing ocean conditions and their preference for smaller phytoplankton, may increase in importance for copepods	low	0	train
6,568	AR6_WGII	2,341	20	CCP6.2.2 Terrestrial and Freshwater Ecosystems Since the publication of AR5 (IPCC, 2014) and SROCC (IPCC, 2019) and their findings (Table CCP6.2), more studies confirm rapid changes in Arctic terrestrial and freshwater systems including increased permafrost thaw, changes to tundra hydrology and vegetation (overall greening of the tundra, regional browning of tundra and boreal forests), coastal and riverbank erosion	high	2	train
6,569	AR6_WGII	2,341	23	Further evidence shows that warming and changes to the Arctic hydrologic cycle increase the risk of wildfire	medium	1	train
6,570	AR6_WGII	2,341	24	Both the frequency of and the area burned by wildfires during recent years are unprecedented compared with the last 10,000 years	high	2	train
6,571	AR6_WGII	2,342	0	CCP6 2331Polar Regions Cross-Chapter Paper 6 most tundra and boreal regions, and interactions between climate and shifting vegetation (Song et al., 2018) will influence future fire intensity and frequency	medium	1	train
6,572	AR6_WGII	2,342	2	Even though the overall regional water cycle will intensify, including increased precipitation, evapotranspiration and river discharge to the Arctic Ocean (Table CCP6.1), snow and permafrost decline may lead to further soil drying	medium	1	train
6,573	AR6_WGII	2,342	5	Soil temperatures along the Antarctic Peninsula are now sufficient for germination of non-native plants; invasions by non- endemic species are expected to increase with rising temperatures (high confidence) (Bokhorst et al., 2021), posing a risk to endemic polar species	medium	1	train
6,574	AR6_WGII	2,342	6	Vegetation responses to warming are contingent on water availability and local temperature	medium	1	train
6,575	AR6_WGII	2,342	8	West Antarctica is showing evidence of greening in the dominant cryptogrammic vegetation, with greater growth in mosses	high	2	train
6,576	AR6_WGII	2,342	9	Peatland ecosystems may increase on the west Antarctic Peninsula with future warming	low	0	train
6,577	AR6_WGII	2,342	10	In contrast, some parts of East Antarctica and the subantarctic islands to the north have been experiencing a drying climate, with declining health of mosses and other vegetation	high	2	train
6,578	AR6_WGII	2,342	15	However, this trend is not as great in southern colder locations (medium confidence) (e.g., Kim et al., 2018; Newsham et al., 2019), as the microbial community structure is affected by vegetation cover and water availability	high	2	train
6,579	AR6_WGII	2,342	16	Antarctic terrestrial invertebrate communities on the West Antarctic Peninsula may be controlled more by vegetation and water availability than by air temperature	medium	1	train
6,580	AR6_WGII	2,342	17	Evidence from laboratory studies, field programmes and sedimentary records indicate that Antarctic freshwater ecosystems may become more productive under climate warming scenarios	medium	1	train
6,581	AR6_WGII	2,342	19	Since SROCC, there is further evidence that climate change alterations of polar ecosystems increasingly challenge production of, and access to, sufficient, healthy and nutritious food, posing risks to future food and nutritional security within and beyond polar regions	high	2	train
6,582	AR6_WGII	2,342	21	Climate change has impacted Indigenous subsistence resources across the Arctic (very high confidence) (SMCCP6.2), and future food systems and ecological connections are at risk from future climate change hazards interacting with non-climate pressures, some of which are mediated or amplified by novel conditions and opportunities in Arctic regions	high	2	train
6,583	AR6_WGII	2,342	22	Increasing heatwaves, wildfires, extreme precipitation, permafrost loss and rapid seasonal snow and ice thaw events will further threaten terrestrial subsistence food resources across the Arctic	high	2	train
6,584	AR6_WGII	2,344	3	Shifting spatial distributions of fish stocks have led to transboundary management challenges in the Atlantic, Bering Sea and Arctic areas previously inaccessible due to sea ice (Table CCP6.6) (Gullestad et al., 2020).Cascading and interacting effects of climate change impacts in polar regions (Table CCP6.1) will reduce access to, and productivity of, future fisheries, and pose significant risks to regional and global food and nutritional security that increase with atmospheric carbon levels and declines in sea ice	high	2	train
6,585	AR6_WGII	2,344	5	Some global- scale models project increases in potential fishery yields in Arctic Canada (Cheung, 2018; Bindoff et al., 2019; Tai et al., 2019), whereas many observational studies and high-resolution regional projections suggest overall declines in biomass, productivity and yield associated with warming and loss of sea ice in multiple regions such as the Bering Sea	medium	1	test
6,586	AR6_WGII	2,344	6	Reduced production of macronutrients and protein by polar marine sources will disproportionately impact people already experiencing food and nutritional scarcity (Myers et al., 2017), marine-dependent communities within and beyond polar regions, and women and children who require higher quantities of macronutrients	high	2	train
6,587	AR6_WGII	2,345	0	CCP6 2334Cross-Chapter Paper 6 Polar Regions Large-scale commercial fisheries are expected to continue to operate in polar regions (high confidence) (Barange et al., 2018; Cavanagh et al., 2021; Grant et al., 2021), and will shift poleward (high confidence) toward geopolitical and management boundaries	high	2	train
6,588	AR6_WGII	2,345	2	Increased distances from ports to redistributed fishing grounds as well as increased frequency of storms and other extreme events are expected to increase risks and costs for fishery operations	medium	1	train
6,589	AR6_WGII	2,345	4	There will be increased demand for new port infrastructure across the Arctic	high	2	train
6,590	AR6_WGII	2,346	2	Coupling adaptation measures with global carbon mitigation strategies substantially decreases climate change risks to polar fisheries	very high	3	train
6,591	AR6_WGII	2,346	3	CCP6.2.4 Economic Activities Climate change presents significant risks to economic activities in the polar regions (very high confidence) and simultaneously enables development possibilities for fisheries (CCP6.2.3.3), agriculture (CCP6.2.3.2), the sharing and subsistence economy (CCP6.2.3.1) (SMCCP6.2) (high confidence), maritime trade (Box CCP6.1), natural resource development (CCP6.2.4.1)	medium	1	train
6,592	AR6_WGII	2,346	5	CCP6.2.4.1 Changing access to natural resources with consequences for safety, economic development and climate mitigation Climate change is improving access to natural resources in the Arctic with consequences for human safety (high confidence), economic development (very high confidence) and global mitigation efforts	medium	1	train
6,593	AR6_WGII	2,346	13	Climate change has increased risks to, and demand for, polar tourism experiences with the development of a ‘last chance tourism market’	medium	1	test
6,594	AR6_WGII	2,346	21	Climate hazards create risks to transportation sectors with consequences for economic development	high	2	test
6,595	AR6_WGII	2,347	2	Fog (low confidence) and an increase in precipitation falling as ice pellets or hail	high	2	train
6,596	AR6_WGII	2,347	4	Polar settlements are at significant risk from climate change through shoreline erosion, permafrost thaw and flooding	high	2	train
6,597	AR6_WGII	2,347	6	Degradation of ice-rich permafrost can threaten the structural stability and functional capacities of community-based infrastructure (i.e., airports and roads; CCP6.2.5) and can have implications for local economies with coupled impacts for local livelihoods, health and well- being (CCP6.2.5, CCP6.2.6)	high	2	train
6,598	AR6_WGII	2,350	9	Permafrost thaw, sea-level rise and reduced sea ice protection also presents the potential for the introduction and propagation of invasive species (Chan et al., 2019; Rosenhaim et al., 2019), and sovereignty tensions with implications for global geopolitics (Drewniak et al., 2018)	medium	1	test
6,599	AR6_WGII	2,351	4	CCP6.2.6 Human Health and Wellness in the Arctic Climate change continues to have wide-ranging physical human health risks in the Arctic, particularly for Indigenous Peoples	high	2	train

6,500

AR6_WGII

2,332

6

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

2

train

6,501

AR6_WGII

2,332

8

Climate change has induced food web changes resulting in population declines in polar sea birds, including penguins, and marine and terrestrial mammals

high

2

train

6,502

AR6_WGII

2,332

9

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

2

train

6,503

AR6_WGII

2,332

13

For a given evidence and agreement statement, different confidence levels can be assigned, but increasing levels of evidence and degrees of agreement are correlated with increasing confidence.shipping, tourism (very high confidence) and Arctic maritime trade and resource extraction

medium

1

train

6,504

AR6_WGII

2,332

14

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

2

train

6,505

AR6_WGII

2,332

15

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

1

train

6,506

AR6_WGII

2,332

17

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

2

train

6,507

AR6_WGII

2,332

19

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

2

train

6,508

AR6_WGII

2,332

20

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

3

train

6,509

AR6_WGII

2,332

22

Polar zones will continue to contract and diminish in extent under climate change, and local adaptations will be insufficient to achieve long-term resilience of polar systems

medium

1

train

6,510

AR6_WGII

2,332

23

The pace and extent of change in polar regions is challenging the ability of social and natural systems to adapt

medium

1

train

6,511

AR6_WGII

2,333

0

CCP6 2322Cross-Chapter Paper 6 Polar Regions biodiversity

medium

1

train

6,512

AR6_WGII

2,333

2

Governance around climate change planning, preparation and response has been limited in scope, and has often not considered interacting effects of climate change with other risks

high

2

train

6,513

AR6_WGII

2,333

3

Reactive management strategies will not succeed in reducing risks in polar regions given the rapid change and increasing potential for extreme events

high

2

train

6,514

AR6_WGII

2,333

4

Greater inclusivity of stakeholders and communities, along with using diverse sources of information, including Indigenous knowledge and local knowledge, can benefit robust planning and decision making, and uptake of adaptations

high

2

train

6,515

AR6_WGII

2,333

5

Effectiveness in preparing for and adapting to climate risks can benefit from improved climate, weather and ice forecasting services, tools for integrating climate change data and different types of knowledge into management processes and enhanced polar search, rescue and emergency response capabilities

high

2

train

6,516

AR6_WGII

2,333

7

Development of robust pathways for climate resilience in the Arctic can be accelerated by adaptation strategies and governance that reflect local conditions, cultures and adaptive capacities of communities and sectors

high

2

train

6,517

AR6_WGII

2,333

8

Effectiveness of adaptation strategies will be enhanced by accounting for the geographic, climatic, ecological and cultural uniqueness of the polar regions

medium

1

train

6,518

AR6_WGII

2,333

9

Colonialism can inhibit the development of robust climate adaptation strategies, and exacerbate climate risks

very high

3

train

6,519

AR6_WGII

2,333

10

Inclusive decision making in establishing climate adaptations can foster resilience, reflect the unique environmental, cultural and economic imperatives of the region and support both market-based and sharing economies

high

2

train

6,520

AR6_WGII

2,333

12

Arctic Indigenous self-determination in decision making can establish robust climate resilience, especially in Indigenous communities, incorporating locally derived definitions of social and economic success, culturally legitimate institutions of government, strategic visioning and thinking and public-spirited, nation-building leadership

very high

3

train

6,521

AR6_WGII

2,334

2

These changes are causing a suite of direct and cascading risks for all polar ecosystems with larger effects to date in the Arctic than the Antarctic

high

2

train

6,522

AR6_WGII

2,335

3

Driver Region Observed changes Projected changes Marine and sea ice Sea level (relative) ArcticNo consistent trend (increase in northwest America, decrease in northeast America, stable in Greenland and Arctic Russia) (WG1-12)Rise in all polar regions (except areas of substantial land uplift in northeast Canada, the west coast of Greenland) (high confidence); Increase of extreme sea levels in Russian Arctic and northwest America (high confidence) Greenland/Iceland and northeast America (given glacial isostatic adjustment) (medium confidence, WG1-12) AntarcticRise in all polar regions (except areas of substantial land uplift in west Antarctica) (high confidence, WG1-12) Sea surface temperature ArcticIncrease of ~0.5°C per decade during 1982–2017 in ice-free regions in summer (high confidence, SROCC-3)Further increases (high confidence, WG1-12) AntarcticWarmed in northern areas of Southern Ocean but cooled in its southernmost regions since the 1980s (high confidence, SROCC-3)Circumpolar increases (high confidence, WG1-12) Sea ice cover ArcticLoss (particularly of multi-year sea ice) accelerated since 2001 (very likely, WG1-9)Will become sea ice free (< 1 × 106 km2) during summer before 2050, irrespective of global warming level (likely, WG1-9) AntarcticNo significant circumpolar trend from 1979–2018 (very high confidence), but decrease off the Antarctic Peninsula

high

2

train

6,523

AR6_WGII

2,336

6

Warming and wetting have persisted as key climatic impact drivers in polar regions

very high

3

train

6,524

AR6_WGII

2,336

20

CCP6.2 Observed Impacts and Future Risks CCP6.2.1 Marine and Coastal Ecosystems CCP6.2.1.1 Warming and sea ice retreat cause shifts in distribution ranges of species In Arctic seas, warming and other climate impact drivers, primarily sea ice retreat, have led to range contractions of Arctic marine and ice-associated species and poleward expansions of boreal species

very high

3

train

6,525

AR6_WGII

2,336

21

Altered conditions allow more microorganisms to move poleward and provide opportunities for invasive species (Cavicchioli et al., 2019; Nielsen et al., 2020; Driver Region Observed changes Projected changes Permafrost ArcticRising permafrost temperatures over past three to four decades (high confidence, WG1-9); decreases in permafrost active layer thickness

very high

3

train

6,526

AR6_WGII

2,336

22

Submarine permafrost warming (medium confidence, WG1-9)Increases in temperature and active layer thickness (WG1-9); near-surface terrestrial permafrost extent will reduce under all scenarios by 2100 (virtually certain, WG1-9) AntarcticRising permafrost temperatures over past three to four decades (high confidence, WG1-9) Lake, river ice ArcticDeclines in seasonal lake ice cover thickness and duration over most Arctic lakes; declines in cold-season river ice extent (high confidence, WG1-12)Many lakes will lose >1 month lake ice cover by 2050

medium

1

train

6,527

AR6_WGII

2,338

1

Affected systemHazard *Cascading effectObserved impacts, future risks and natural adaptations identified in SROCC (confidence level) Arctic marine ecosystems Primary producers (PP-1)Sea ice loss * Freshening * StratificationImpact: timing (earlier and later blooms), distribution and magnitude (>30% increase in annual net primary production since 1998) (high confidence) Acidification Adaptation: phytoplankton may compensate for decrease in pH Zooplankton * PP-1 Impact: changing production and community composition (medium confidence) Benthos * PP-1 Impact: changing production and biodiversity

medium

1

train

6,528

AR6_WGII

2,339

4

Numerous mammals and sea birds respond to changes in the distribution of their preferred habitats and prey by shifting their range, altering the timing or pathways for migration or switching prey

very high

3

train

6,529

AR6_WGII

2,339

5

Ice-breeding seals (e.g., harp seals – Pagophilus groenlandicus) often have little scope to shift distribution, leading to increases in strandings and pup mortality in years with little ice cover

medium

1

train

6,530

AR6_WGII

2,339

6

Recent studies confirm that polar bears (Ursus maritimus) are negatively affected by changing ice and snow conditions with decreases in denning, foraging, reproduction, genetic diversity and survival rates

very high

3

train

6,531

AR6_WGII

2,339

8

Such shifts have so far only been detected for Antarctic krill (Euphausia superba), with a poleward contraction of the highest densities of krill in the Atlantic sector

medium

1

train

6,532

AR6_WGII

2,339

9

Ocean warming is expected to put pressure on Antarctic phytoplankton (Pinkerton et al., 2021) and fish species unable to move further south in shelf areas, including waters off sub-Antarctic islands

low

0

train

6,533

AR6_WGII

2,339

10

Off the Antarctic Peninsula and sub-Antarctic islands, invasive benthic invertebrates and macroalgae have already been detected

medium

1

train

6,534

AR6_WGII

2,339

11

On a local to regional scale, the benthic recolonisation of the newly exposed seabed after the disintegration of ice shelves shows typical succession patterns, with mass occurrences of few pioneer species followed by gradual shifts to a more diverse typical shelf community, driven by increasing pelagic primary production upon ice-shelf collapse and strengthening of the pelagic–benthic coupling

high

2

train

6,535

AR6_WGII

2,339

12

Range changes of Antarctic birds and marine mammals have been observed, which vary among sub- regions and are mostly attributable to changes in sea ice extent and food availability

high

2

train

6,536

AR6_WGII

2,339

13

With projected sea ice retreat and associated change in prey distribution (Henley et al., 2020), foraging areas of sub-Antarctic sea birds and marine mammals will shift southwards, leading to elevated pressure on populations due to higher foraging costs during the breeding season

medium

1

train

6,537

AR6_WGII

2,339

14

These changes are particularly impacting emperor penguins (Aptenodytes forsteri) (Table CCP6.2), with the projected population declining close to extinction by 2100 under Business-As-Usual climate scenarios (medium confidence) (Jenouvrier et al., 2020; Trathan et al., 2020; Jenouvrier et al., 2021), whereas population decline is halted by 2060 under the 1.5°C climate scenario

low

0

train

6,538

AR6_WGII

2,339

15

CCP6.2.1.2 Ocean warming and sea ice changes affect marine primary productivity In the central Arctic Ocean, primary productivity remains low

medium

1

train

6,539

AR6_WGII

2,339

16

In inflowing (Barents and Chukchi Sea) and interior shelf regions (Laptev, Kara, and Siberian Sea), changes in sea ice extent, thickness and seasonal timing have altered light and mixing regimes, causing increasing overall productivity in open-water and under-ice habitats, and in leads

high

2

train

6,540

AR6_WGII

2,339

17

Productivity changes are associated with the earlier- onset phytoplankton spring blooms and the increasing occurrence of autumn blooms, particularly at lower latitudes of the Arctic

high

2

train

6,541

AR6_WGII

2,339

18

Ice algal communities are expected to change in productivity and species composition in response to the transition from a predominantly multi-year to a seasonal sea ice pack

high

2

train

6,542

AR6_WGII

2,340

0

CCP6 2329Polar Regions Cross-Chapter Paper 6 in Greenland

medium

1

train

6,543

AR6_WGII

2,340

1

Macroalgae and seagrass are generally expanding in the Arctic

medium

1

test

6,544

AR6_WGII

2,340

2

In the future Arctic Ocean, higher light availability in response to further sea ice decline and reduced deep mixing is projected to generally increase primary productivity

medium

1

train

6,545

AR6_WGII

2,340

3

However, productivity may increase less than predicted and eventually even decrease once nutrient limitation outweighs the benefits of higher light availability

low

0

train

6,546

AR6_WGII

2,340

4

Despite large-scale environmental changes in the Southern Ocean, such as the deepening of the summer mixed layer (medium confidence) (Panassa et al., 2018; Sallée et al., 2021), and the expected impacts via altered nutrient entrainment, light availability and grazer encounter rates (Chapter 3) (Behrenfeld and Boss, 2014; Llort et al., 2019), assessments indicated no consistent changes in primary production at the circumpolar scale, as sectors and regions show different trends

medium

1

test

6,547

AR6_WGII

2,340

6

Primary productivity has increased in the Pacific sector and decreased in the Atlantic sector and the Ross Sea

low

0

test

6,548

AR6_WGII

2,340

7

Higher productivity has also been observed in regions where rapid environmental changes occurred, such as in the vicinity of retreating IS and declining sea ice cover off the Antarctic Peninsula

medium

1

train

6,549

AR6_WGII

2,340

10

Such an increase in Southern Ocean productivity will lead to a decline in global ocean productivity

medium

1

train

6,550

AR6_WGII

2,340

11

CCP6.2.1.3 Impacts of ocean acidification vary spatially and among biotas In Arctic seas, areas with acidification levels corrosive to organisms forming CaCO 3 shells or skeletons expanded between the 1990s and 2010

high

2

train

6,551

AR6_WGII

2,340

12

Key species of diatom and picoeukaryote phytoplankton species yet appear relatively resilient to decreasing pH levels over a range of temperature and light conditions

medium

1

train

6,552

AR6_WGII

2,340

13

In contrast, there is evidence for species- and stage-specific sensitivities of zooplankton, pteropods and fishes

high

2

train

6,553

AR6_WGII

2,340

14

Warming, rising river-sediment discharge and coastal erosion in Arctic shelf regions are expected to increase the input of labile, often permafrost-derived organic carbon, the remineralisation of which further increases acidification rates

medium

1

train

6,554

AR6_WGII

2,340

16

In the Southern Ocean, calcifying organisms are also most vulnerable to ocean acidification

high

2

train

6,555

AR6_WGII

2,340

17

Calcifying species with low- magnesium calcite or mechanisms to protect their skeletons are less vulnerable to the corrosive effects of acidification than those using aragonite or high-magnesium calcite

high

2

train

6,556

AR6_WGII

2,340

18

In diatom-dominated communities, silicification diminishes with reduced pH levels, albeit with rates differing among taxa

low

0

train

6,557

AR6_WGII

2,340

19

Species-specific responses exist regarding growth and primary production, which are further strongly modulated by iron and light availability

high

2

train

6,558

AR6_WGII

2,340

23

CCP6.2.1.4 Climate change alters food web dynamics Climate change has transformed Arctic marine ecosystems from sea ice- associated to open-water production regimes, with profound impacts on trophic energy transfer efficiencies and pathways (high confidence) (Behrenfeld et al., 2017; Meredith et al., 2019; Huntington et al., 2020) as well as benthic–pelagic coupling

medium

1

train

6,559

AR6_WGII

2,340

24

Shifts in bloom phenology favour small phytoplankton and smaller zooplankton over large lipid-rich macro-zooplankton, leading to longer, less efficient food chains

medium

1

train

6,560

AR6_WGII

2,341

1

Species range shifts have restructured higher trophic levels in Arctic food webs

high

2

train

6,561

AR6_WGII

2,341

5

Climate impacts on Arctic marine food webs will be profound and intensify with GWL

high

2

train

6,562

AR6_WGII

2,341

6

However, the exact nature of these impacts remains unclear due to attenuating and amplifying dynamics of both top-down and bottom-up processes in polar food webs and the management of fisheries

high

2

train

6,563

AR6_WGII

2,341

8

Warming is expected to reduce the quantity and quality of lipid-rich copepod prey (high confidence) (Aarflot et al., 2018; Kimmel et al., 2018; Bouchard and Fortier, 2020; Møller and Nielsen, 2020; Mueter et al., 2020), leading to declines in survival and growth of multiple upper-trophic level fish species; these impacts are amplified over time under low mitigation scenarios (RCP8.5)

high

2

train

6,564

AR6_WGII

2,341

9

Marine mammals and sea birds will continue to attenuate climate change impacts by shifting their diets and behaviour

medium

1

train

6,565

AR6_WGII

2,341

10

However, sea birds generally have low temperature-mediated plasticity of reproductive timing, making them vulnerable to mismatches with their prey and limiting long-term adaptation

medium

1

train

6,566

AR6_WGII

2,341

15

The optimum habitat for Antarctic krill is expected to decline with a shortening of suitable season for krill growth and reproduction, particularly in the northern Scotia and Bellingshausen Seas

medium

1

train

6,567

AR6_WGII

2,341

18

Although salps have long been considered to be competitors of Antarctic krill (Suprenand and Ainsworth, 2017; Rogers et al., 2020), they provide a third energy pathway in pelagic food webs and, given the changing ocean conditions and their preference for smaller phytoplankton, may increase in importance for copepods

low

0

train

6,568

AR6_WGII

2,341

20

CCP6.2.2 Terrestrial and Freshwater Ecosystems Since the publication of AR5 (IPCC, 2014) and SROCC (IPCC, 2019) and their findings (Table CCP6.2), more studies confirm rapid changes in Arctic terrestrial and freshwater systems including increased permafrost thaw, changes to tundra hydrology and vegetation (overall greening of the tundra, regional browning of tundra and boreal forests), coastal and riverbank erosion

high

2

train

6,569

AR6_WGII

2,341

23

Further evidence shows that warming and changes to the Arctic hydrologic cycle increase the risk of wildfire

medium

1

train

6,570

AR6_WGII

2,341

24

Both the frequency of and the area burned by wildfires during recent years are unprecedented compared with the last 10,000 years

high

2

train

6,571

AR6_WGII

2,342

0

CCP6 2331Polar Regions Cross-Chapter Paper 6 most tundra and boreal regions, and interactions between climate and shifting vegetation (Song et al., 2018) will influence future fire intensity and frequency

medium

1

train

6,572

AR6_WGII

2,342

2

Even though the overall regional water cycle will intensify, including increased precipitation, evapotranspiration and river discharge to the Arctic Ocean (Table CCP6.1), snow and permafrost decline may lead to further soil drying

medium

1

train

6,573

AR6_WGII

2,342

5

Soil temperatures along the Antarctic Peninsula are now sufficient for germination of non-native plants; invasions by non- endemic species are expected to increase with rising temperatures (high confidence) (Bokhorst et al., 2021), posing a risk to endemic polar species

medium

1

train

6,574

AR6_WGII

2,342

6

Vegetation responses to warming are contingent on water availability and local temperature

medium

1

train

6,575

AR6_WGII

2,342

8

West Antarctica is showing evidence of greening in the dominant cryptogrammic vegetation, with greater growth in mosses

high

2

train

6,576

AR6_WGII

2,342

9

Peatland ecosystems may increase on the west Antarctic Peninsula with future warming

low

0

train

6,577

AR6_WGII

2,342

10

In contrast, some parts of East Antarctica and the subantarctic islands to the north have been experiencing a drying climate, with declining health of mosses and other vegetation

high

2

train

6,578

AR6_WGII

2,342

15

However, this trend is not as great in southern colder locations (medium confidence) (e.g., Kim et al., 2018; Newsham et al., 2019), as the microbial community structure is affected by vegetation cover and water availability

high

2

train

6,579

AR6_WGII

2,342

16

Antarctic terrestrial invertebrate communities on the West Antarctic Peninsula may be controlled more by vegetation and water availability than by air temperature

medium

1

train

6,580

AR6_WGII

2,342

17

Evidence from laboratory studies, field programmes and sedimentary records indicate that Antarctic freshwater ecosystems may become more productive under climate warming scenarios

medium

1

train

6,581

AR6_WGII

2,342

19

Since SROCC, there is further evidence that climate change alterations of polar ecosystems increasingly challenge production of, and access to, sufficient, healthy and nutritious food, posing risks to future food and nutritional security within and beyond polar regions

high

2

train

6,582

AR6_WGII

2,342

21

Climate change has impacted Indigenous subsistence resources across the Arctic (very high confidence) (SMCCP6.2), and future food systems and ecological connections are at risk from future climate change hazards interacting with non-climate pressures, some of which are mediated or amplified by novel conditions and opportunities in Arctic regions

high

2

train

6,583

AR6_WGII

2,342

22

Increasing heatwaves, wildfires, extreme precipitation, permafrost loss and rapid seasonal snow and ice thaw events will further threaten terrestrial subsistence food resources across the Arctic

high

2

train

6,584

AR6_WGII

2,344

3

Shifting spatial distributions of fish stocks have led to transboundary management challenges in the Atlantic, Bering Sea and Arctic areas previously inaccessible due to sea ice (Table CCP6.6) (Gullestad et al., 2020).Cascading and interacting effects of climate change impacts in polar regions (Table CCP6.1) will reduce access to, and productivity of, future fisheries, and pose significant risks to regional and global food and nutritional security that increase with atmospheric carbon levels and declines in sea ice

high

2

train

6,585

AR6_WGII

2,344

5

Some global- scale models project increases in potential fishery yields in Arctic Canada (Cheung, 2018; Bindoff et al., 2019; Tai et al., 2019), whereas many observational studies and high-resolution regional projections suggest overall declines in biomass, productivity and yield associated with warming and loss of sea ice in multiple regions such as the Bering Sea

medium

1

test

6,586

AR6_WGII

2,344

6

Reduced production of macronutrients and protein by polar marine sources will disproportionately impact people already experiencing food and nutritional scarcity (Myers et al., 2017), marine-dependent communities within and beyond polar regions, and women and children who require higher quantities of macronutrients

high

2

train

6,587

AR6_WGII

2,345

0

CCP6 2334Cross-Chapter Paper 6 Polar Regions Large-scale commercial fisheries are expected to continue to operate in polar regions (high confidence) (Barange et al., 2018; Cavanagh et al., 2021; Grant et al., 2021), and will shift poleward (high confidence) toward geopolitical and management boundaries

high

2

train

6,588

AR6_WGII

2,345

2

Increased distances from ports to redistributed fishing grounds as well as increased frequency of storms and other extreme events are expected to increase risks and costs for fishery operations

medium

1

train

6,589

AR6_WGII

2,345

4

There will be increased demand for new port infrastructure across the Arctic

high

2

train

6,590

AR6_WGII

2,346

2

Coupling adaptation measures with global carbon mitigation strategies substantially decreases climate change risks to polar fisheries

very high

3

train

6,591

AR6_WGII

2,346

3

CCP6.2.4 Economic Activities Climate change presents significant risks to economic activities in the polar regions (very high confidence) and simultaneously enables development possibilities for fisheries (CCP6.2.3.3), agriculture (CCP6.2.3.2), the sharing and subsistence economy (CCP6.2.3.1) (SMCCP6.2) (high confidence), maritime trade (Box CCP6.1), natural resource development (CCP6.2.4.1)

medium

1

train

6,592

AR6_WGII

2,346

5

CCP6.2.4.1 Changing access to natural resources with consequences for safety, economic development and climate mitigation Climate change is improving access to natural resources in the Arctic with consequences for human safety (high confidence), economic development (very high confidence) and global mitigation efforts

medium

1

train

6,593

AR6_WGII

2,346

13

Climate change has increased risks to, and demand for, polar tourism experiences with the development of a ‘last chance tourism market’

medium

1

test

6,594

AR6_WGII

2,346

21

Climate hazards create risks to transportation sectors with consequences for economic development

high

2

test

6,595

AR6_WGII

2,347

2

Fog (low confidence) and an increase in precipitation falling as ice pellets or hail

high

2

train

6,596

AR6_WGII

2,347

4

Polar settlements are at significant risk from climate change through shoreline erosion, permafrost thaw and flooding

high

2

train

6,597

AR6_WGII

2,347

6

Degradation of ice-rich permafrost can threaten the structural stability and functional capacities of community-based infrastructure (i.e., airports and roads; CCP6.2.5) and can have implications for local economies with coupled impacts for local livelihoods, health and well- being (CCP6.2.5, CCP6.2.6)

high

2

train

6,598

AR6_WGII

2,350

9

Permafrost thaw, sea-level rise and reduced sea ice protection also presents the potential for the introduction and propagation of invasive species (Chan et al., 2019; Rosenhaim et al., 2019), and sovereignty tensions with implications for global geopolitics (Drewniak et al., 2018)

medium

1

test

6,599

AR6_WGII

2,351

4

CCP6.2.6 Human Health and Wellness in the Arctic Climate change continues to have wide-ranging physical human health risks in the Arctic, particularly for Indigenous Peoples

high

2

train