rlacombe/ClimateX huggingface dataset:
Moreover, the high natural variability of EBUS and their insufficient representation by global ESMs [Earth system models] gives low confidence that these observed changes can be attributed to anthropogenic causes.’‘Anthropogenic changes in EBUS will emerge primarily in the second half of the 21st century (IPCC AR6_WGII, confidence: medium)
EBUS will be impacted by climate change in different ways, with strong regional variability with consequences for fisheries, recreation and climate regulation (IPCC AR6_WGII, confidence: medium)
The Pacific EBUS are projected to have calcium carbonate undersaturation in surface waters within a few decades RCP8.5 (high confidence); combined with warming and decreasing oxygen levels, this will increase the impacts on shellfish larvae, benthic invertebrates, and demersal fishes (high confidence) and related fisheries and aquaculture (medium confidence).’ ‘The inherent natural variability of EBUS, together with uncertainties in present and future trends in the intensity and seasonality of upwelling, coastal warming and stratification, primary production and biogeochemistry of source waters poses large challenges in projecting the response of EBUS to climate change and to the adaptation of governance of biodiversity conservation and living marine resources in EBUS (high confidence).’ ‘Given the high sensitivity of the coupled human–natural EBUS to oceanographic changes, the future sustainable delivery of key ecosystem services from EBUS is at risk under climate change; those that are most at risk in the 21st century include fisheries (high confidence), aquaculture (medium confidence), coastal tourism (low confidence) and climate regulation (low confidence).’ ‘For vulnerable human communities with a strong dependence on EBUS services and low adaptive capacity, such as those along the Canary Current system, unmitigated climate-change effects on EBUS (complicated by other non-climatic stresses such as social unrest) have a high risk of altering their development pathways (IPCC AR6_WGII, confidence: high)
Notwithstanding these trends, EBUS remain vulnerable both to MHWs (high confidence) (Sen Gupta et al., 2020) and to their long-lasting impacts (IPCC AR6_WGII, confidence: high)
Despite low confidence in detailed projections for ecological changes in EBUS, the WGI assessment (WGI AR6 Chapter 9; Fox-Kemper et al., 2021) that upwelling-favourable winds will weaken (or be present for shorter durations) at low latitude but intensify at high latitude (high confidence), albeit by no more than 20% in either case (IPCC AR6_WGII, confidence: medium)
Over the past two decades, Arctic Ocean surface temperature has increased in line with the global average, while there has been no uniform warming across the Antarctic (IPCC AR6_WGII, confidence: high)
Thus, the rate of change due to warming, and associated sea ice loss, is greater in the Arctic than in the Antarctic (IPCC AR6_WGII, confidence: high)
Previous assessments of polar seas (Table 3.14) concluded that climate change has already profoundly influenced polar ecosystems, through changing species distributions and abundances from primary producers to top predators, including both ecologically and economically important species (high confidence), and that it will continue to do so (Table 3.14).Since SROCC, evidence demonstrates that warmer oceans, less sea ice and increased advection results in increasing primary production in the Arctic, albeit with regional variation (high confidence), while trends remain spatially heterogeneous and less clear in the Antarctic (IPCC AR6_WGII, confidence: medium)
Major community shifts, both gradual and abrupt, are observed in polar oceans in response to warming trends and MHWs (Arctic only) (IPCC AR6_WGII, confidence: high)
In general, abundances and ranges of Arctic fish species are declining and contracting, while ranges of boreal fish species are expanding, both geographically and in terms of feeding interactions and ecological roles (IPCC AR6_WGII, confidence: high)
Phenological, behavioural, physiological and distributional changes are observed in marine mammals and birds in response to altered ecological interactions and habitat degradation, especially to loss of sea ice (IPCC AR6_WGII, confidence: high)
Reproductive failures and declining abundances attributed to warmer polar oceans and less sea ice cover are observed in populations of polar bears, Ursus maritimus, seals, whales and marine birds (IPCC AR6_WGII, confidence: high)
Calcareous polar organisms are among the groups most sensitive to ocean acidification (IPCC AR6_WGII, confidence: high)
Impacts of shifts in ocean conditions affect fish and shellfish abundances in the Arctic (IPCC AR6_WGII, confidence: high)
Changes in sea ice and the physical environment to the west of the Antarctic Peninsula are altering phytoplankton stocks and productivity, and krill (high confidence).Some marine species will shift their ranges in response to changing ocean and sea ice conditions in the polar regions (IPCC AR6_WGII, confidence: medium)
Loss of sea ice in summer and increased ocean temperatures are expected to impact secondary pelagic production in some regions of the Arctic Ocean, with associated changes in the energy pathways within the marine ecosystem (IPCC AR6_WGII, confidence: medium)
Ocean acidification has the potential to inhibit embryo development and shell formation of some zooplankton and krill in the polar regions, with potentially far-reaching consequences to food webs in these regions (IPCC AR6_WGII, confidence: medium)
Shifts in the timing and magnitude of seasonal biomass production could disrupt coupled phenologies in the food webs, leading to decreased survival of dependent species (IPCC AR6_WGII, confidence: medium)
SR15 (Hoegh-Guldberg et al., 2018a) ‘A fundamental transformation is occurring in polar organisms and ecosystems, driven by climate change (IPCC AR6_WGII, confidence: high)
There is high agreement and robust evidence that phytoplankton species will change because of sea ice retreat and related changes in temperature and radiation, and this is very likely to benefit fisheries productivity [in the Arctic spring bloom system].’ ‘‘Unique and threatened systems’ (RFC1), [including Arctic and coral reefs], display a transition from high to very high risk of transition at temperatures between 1.5°C and 2°C of global warming, as opposed to at 2.6°C of global warming in AR5 (high confidence).’ SROCC (Bindoff et al., 2019a) Climate-induced changes in seasonal sea ice extent and thickness as well as ocean stratification are altering marine primary production (high confidence), with impacts on ecosystems (IPCC AR6_WGII, confidence: medium)
Changes in the timing, duration and magnitude of primary production have occurred in both polar oceans, with marked regional or local variability (IPCC AR6_WGII, confidence: high)
In both polar regions, climate-induced changes in ocean and sea ice conditions have expanded the range of temperate species and contracted the range of polar fish and ice-associated species (IPCC AR6_WGII, confidence: high)
Ocean acidification will affect several key Arctic species (medium confidence).Future climate-induced changes in the polar oceans, sea ice, snow and permafrost will drive habitat and biome shifts, with associated changes in the ranges and abundance of ecologically important species (IPCC AR6_WGII, confidence: medium)
Projected range expansion of sub-Arctic marine species will increase pressure for high-Arctic species (IPCC AR6_WGII, confidence: medium)
Both polar oceans will be increasingly affected by CO 2 uptake, causing corrosive conditions for calcium carbonate shell-producing organisms (high confidence), with associated impacts on marine organisms and ecosystems (IPCC AR6_WGII, confidence: medium)
The projected effects of climate-induced stressors on polar marine ecosystems present risks for commercial and subsistence fisheries, with implications for regional economies, cultures and the global supply of fish, shellfish, and Antarctic krill (IPCC AR6_WGII, confidence: high)
While levels of pollutants in biota (e.g., persistent organic pollutants, mercury) have generally declined over the past decades, recent increasing levels are associated with release from reservoirs in ice, snow and permafrost, and through changing food webs and pathways for trophic amplification (IPCC AR6_WGII, confidence: medium)
Also, a warmer climate, altered ocean currents and increased human activities elevate the risk of invasive species in the Arctic (medium confidence), potentially changing ecosystems in this region (IPCC AR6_WGII, confidence: high)
Fisheries are largely sustainably managed yet are expanding polewards following sea ice melt in the Arctic (IPCC AR6_WGII, confidence: high)
Tourism is increasing and expanding in both polar regions, while shipping and hydrocarbon exploration are growing in the Arctic, increasing the risks of compound effects on vulnerable and already stressed populations and ecosystems (IPCC AR6_WGII, confidence: high)
Nevertheless, increasing evidence supports that sustainable and adaptive ecosystem-based fisheries practices can reduce detrimental impacts of climate change on harvested populations (IPCC AR6_WGII, confidence: medium)
On average, species’ distributions have shifted poleward by 72.0 ± 0.35 km per decade (high confidence).Spatial shifts of marine species due to projected warming will cause high-latitude invasions and high local-extinction rates in the tropics and semi-enclosed seas (IPCC AR6_WGII, confidence: medium)
SROCC (Bindoff et al., 2019a) ‘Ocean warming has contributed to observed changes in biogeography of organisms ranging from phytoplankton to marine mammals (high confidence).’ ‘The direction of the majority of the shifts of epipelagic organisms are consistent with a response to warming (high confidence)’ but are also shaped by oxygen concentrations and ocean currents across depth, latitudinal and longitudinal gradients (IPCC AR6_WGII, confidence: high)
Geographic ranges have shifted since the 1950s by 51.5 ± 33.3 km per decade (mean and very likely range) and 29.0 ± 15.5 km per decade for organisms in the epipelagic and seafloor ecosystems, respectively.‘Recent model projections since AR5 and SR15 continue to support global-scale range shifts of marine fishes at rates of tens to hundreds of km per decade in the 21st century, with rate of shifts being substantially higher under RCP8.5 than RCP2.6.’ range shifts consistent with climate change) estimates that marine species are moving poleward at a rate of 59.2 km per decade (very likely range: 43.7–74.7 km per decade), closely matching the local climate velocity (IPCC AR6_WGII, confidence: high)
Biogeographic shifts lead to novel communities and biotic interactions (high confidence) (Zarco-Perello et al., 2017; Pecuchet et al., 2020b), with concomitant changes in ecosystem functioning and servicing (IPCC AR6_WGII, confidence: high)
These changes subsequently affect biogenic carbon cycling through alteration of microbial remineralisation and carbon sequestration in deep water (IPCC AR6_WGII, confidence: medium)
Although vertical redistribution of thermal niches is three to four orders of magnitude slower than horizontal displacement, maximum depth limits imposed by the seafloor and photic layer (both of which are projected to be reached in this century) will likely vertically compress suitable habitat for most marine organisms (IPCC AR6_WGII, confidence: medium)
The volume of OMZs have been expanding at many locations (high confidence), and the oxygen content of the subsurface ocean is projected to decline to historically unprecedented conditions over the 21st century (IPCC AR6_WGII, confidence: medium)
Projections also suggest that warming-related increases in trophic efficiency lead to a 17% increase in the biomass of the deep-scattering layer (zooplankton and fish in the mesopelagic) by 2100 (IPCC AR6_WGII, confidence: low)
Observational studies appear to show that mesopelagic fishes adapted to warm water increased in abundance and distribution in the California Current associated with warming and the expansion of OMZ (Koslow et al., 2019), suggesting that some mesopelagic fish stocks might be resilient to a changing climate (IPCC AR6_WGII, confidence: medium)
Moreover, different trophic levels within epipelagic food webs are responding at different rates (IPCC AR6_WGII, confidence: very high)
There is high agreement in model projections that the start of the phytoplankton Table 3.18 | Summary of previous IPCC assessments of phenological shifts and trophic mismatches Observations Projections AR5 WGII (Hoegh-Guldberg et al., 2014; Larsen et al., 2014) ‘Changes to sea temperature have altered the phenology, or timing of key life-history events such as plankton blooms, and migratory patterns, and spawning in fish and invertebrates, over recent decades (IPCC AR6_WGII, confidence: medium)
There is medium to high agreement that these changes pose significant uncertainties and risks to fisheries, aquaculture and other coastal activities.’ The highly productive high-latitude spring bloom systems in the northeast Atlantic are responding to warming (medium evidence, high agreement), with the greatest changes being observed since the late 1970s in the phenology, distribution and abundance of plankton assemblages, and the reorganisation of fish assemblages, with a range of consequences for fisheries (IPCC AR6_WGII, confidence: high)
This impact would be exacerbated if shifts in timing occur rapidly (IPCC AR6_WGII, confidence: medium)
SROCC (Bindoff et al., 2019a) ‘Phenology of marine ectotherms in the epipelagic systems related to ocean warming (high confidence) and the timing of biological events has shifted earlier (IPCC AR6_WGII, confidence: high)
WGI AR6 Chapter 2 (Gulev et al., 2021) ‘Phenological metrics for many species of marine organisms have changed in the last half century (IPCC AR6_WGII, confidence: high)
The changes vary with location and with species (IPCC AR6_WGII, confidence: high)
There is a strong dependence of survival in higher trophic-level organisms (fish, exploited invertebrates, birds) on the availability of food at various stages in their life cycle, which in turn depends on the phenologies of both (IPCC AR6_WGII, confidence: high)
Overall, the regional patterns are qualitatively similar under SSP1-2.6 and SSP5-8.5 but with greater magnitude and larger areas under SSP5-8.5 (IPCC AR6_WGII, confidence: low)
Furthermore, under RCP8.5, trophic mismatch events exceeding ±30 days (Asch et al., 2019) leading to fish-recruitment failure are expected to increase tenfold for geographic spawners across much of the North Atlantic, North Pacific and Arctic Ocean basins (IPCC AR6_WGII, confidence: low)
Temperatures during the last Interglacial (~125 ka), which were warmer than today, led to poleward range shifts of reef corals (IPCC AR6_WGII, confidence: medium)
Temperature has also driven marine range shifts over multi-million-year time scales (IPCC AR6_WGII, confidence: medium)
Warming climates, even with low ocean- warming rates, inevitably decreased tropical marine biodiversity compared with middle latitudes (IPCC AR6_WGII, confidence: high)
The paleorecord confirms that marine biodiversity has been vulnerable to climate warming both globally and regionally (IPCC AR6_WGII, confidence: very high)
In extreme cases of warming (e.g., >5.2°C), marine mass extinctions occurred in the geological past, and there may be a relationship between warming magnitude and extinction toll (IPCC AR6_WGII, confidence: medium)
A combination of warming and spreading anoxia caused marine extinctions in ancient episodes of rapid climate warming (IPCC AR6_WGII, confidence: high)
The role of ocean acidification in ancient extinctions is yet to be resolved (IPCC AR6_WGII, confidence: low)
At the community level, the magnitude and shape of projected future biodiversity changes differ depending on which groups are considered (IPCC AR6_WGII, confidence: medium)
On longer time scales, alteration of energy flow through marine food webs may lead to ecological tipping points (Wernberg et al., 2016; Harley et al., 2017) after which the food web collapses into shorter, bottom-heavy trophic pyramids (IPCC AR6_WGII, confidence: medium)
Table 3.20 | Summary of previous IPCC assessments of community composition and biodiversity Observations Projections AR5 (Hoegh-Guldberg et al., 2014; Pörtner et al., 2014) The paleoecological record shows that global climate changes comparable in magnitudes to those projected for the 21st century under all scenarios resulted in large-scale biome shifts and changes in community composition, and that for rates projected under RCP6 and 8.5 those changes were associated with species extinctions in some groups (IPCC AR6_WGII, confidence: high)
Loss of corals due to bleaching has a potentially critical influence on the maintenance of marine biodiversity in the tropics (high confidence).Spatial shifts of marine species due to projected warming will cause high-latitude invasions and high local-extinction rates in the tropics and semi-enclosed seas (IPCC AR6_WGII, confidence: medium)
Species richness and fisheries catch potential are projected to increase, on average, at mid and high latitudes (high confidence) and decrease at tropical latitudes (IPCC AR6_WGII, confidence: medium)
Thereby, climate change will reassemble communities and affect biodiversity, with differences over time and between biomes and latitudes (IPCC AR6_WGII, confidence: high)
However, specific quantitative projections by these models remain imprecise (low confidence).’ SROCC (Bindoff et al., 2019a) ‘Ocean warming has contributed to observed changes in biogeography of organisms ranging from phytoplankton to marine mammals (high confidence), consequently changing community composition (high confidence), and in some cases altering interactions between organisms and ecosystem function (IPCC AR6_WGII, confidence: medium)
In addition, geographic barriers, such as land, [bounding the] poleward species range edge in semi-enclosed seas or low-oxygen water in deeper waters are projected to limit range shifts, resulting in a larger relative decrease in species richness (medium confidence).’ ‘The large variation in sensitivity between different zooplankton taxa to future conditions of warming and ocean acidification suggests elevated risk on community structure and inter-specific interactions of zooplankton in the 21st century (IPCC AR6_WGII, confidence: medium)
Under continuing climate change, the projected loss of biodiversity may ultimately threaten marine ecosystem stability (medium confidence) (Albouy et al., 2020; Nagelkerken et al., 2020; Henson et al., 2021), altering both the functioning and structure of marine ecosystems and thus affecting service provisioning (IPCC AR6_WGII, confidence: medium)
Abrupt ecosystem shifts have been observed in both large open-ocean ecosystems and coastal ecosystems (Section 3.4.2), with dramatic social consequences through significant loss of diverse ecosystem services (IPCC AR6_WGII, confidence: high)
Abrupt ecosystem shifts are associated with large-scale patterns of climate variability (Alheit et al., 2019; Beaugrand et al., 2019; Lehodey et al., 2020), some of which are projected to intensify with climate change (IPCC AR6_WGII, confidence: medium)
Over the past 60 years, abrupt ecosystem shifts have generally followed El Niño/ Southern Oscillation events of any strength, but some periods had geographically limited ecological shifts (~0.25% of the global ocean in 1984–1987) and others more extensive shifts (14% of the global ocean in 2012–2015) (IPCC AR6_WGII, confidence: medium)
Typically, interacting drivers, such as eutrophication and overharvest, reduce ecosystem resilience to climate extremes (e.g., MHWs, cyclones) or gradual warming, and hence promote ecosystem shifts (IPCC AR6_WGII, confidence: high)
Shifts in different ecosystems may be connected through common drivers or through cascading effects (IPCC AR6_WGII, confidence: medium)
Recent MHWs (Section 3.2.2.1) have caused major ecosystem shifts and mass mortality in oceanic and coastal ecosystems, including corals, kelp forests and seagrass meadows (Sections 3.4.2.1, 3.4.2.3, 3.4.2.5, 3.4.2.6, 3.4.2.10; Cross-Chapter Box MOVING SPECIES in Chapter 5; Cross-Chapter Box EXTREMES in Chapter 2), with dramatic declines in species foundational for habitat formation or trophic flow, biodiversity declines, and biogeographic shifts in fish stocks (IPCC AR6_WGII, confidence: very high)
Marine birds and mammals are vulnerable to climate-induced loss of breeding and foraging habitats such as sea ice (Section 3.4.2.12), sandy beaches (Section 3.4.2.6), salt marshes (Section 3.4.2.5) and seagrass beds (IPCC AR6_WGII, confidence: high)
Marine mammals dependent on sea ice habitat are particularly vulnerable to warming (IPCC AR6_WGII, confidence: medium)
Nevertheless, even under an intermediate emission scenario RCP4.5, increasing ice-free periods will likely reduce both recruitment and adult survival across most polar bear populations over the next four decades, threatening their existence (IPCC AR6_WGII, confidence: medium)
Climate change is affecting marine food-web dynamics (IPCC AR6_WGII, confidence: high)
Higher-vulnerability species include central-place foragers (confined to, for example, breeding colonies fixed in space), diet and habitat specialists, and species with restricted distributions such as marine mammal populations in SES (IPCC AR6_WGII, confidence: medium)
Surface-feeding and piscivorous marine birds appear to be more vulnerable to food-web changes than diving seabirds and planktivorous seabirds (IPCC AR6_WGII, confidence: medium)
Marine birds are vulnerable to phenological shifts in food-web dynamics, as they have limited phenotypic plasticity of reproductive timing, with potentially little scope for evolutionary adaptation (IPCC AR6_WGII, confidence: medium)
Also, climate-change driven distributional shifts have strengthened interactions with other anthropogenic impacts, through, for example, increasing risks of ship strikes and bycatch (medium confidence) (e.g., Hauser et al., 2018; Krüger et al., 2018; Record et al., 2019; Santora et al., 2020).Box 3.2 (continued) the risk of abrupt ecosystem shifts (IPCC AR6_WGII, confidence: high)
However, where climate change is a dominant driver, ecosystem collapses increasingly cause permanent transitions (IPCC AR6_WGII, confidence: high)
Over the coming decades, MHWs are projected to very likely become more frequent under all emission scenarios (Section 3.2; WGI AR6 Chapter 9; Fox-Kemper et al., 2021), with intensities and rates too high for recovery of degraded foundational species, habitats or biodiversity (IPCC AR6_WGII, confidence: medium)
In contrast, the anthropogenic signal in phytoplankton community structure, which has a lower natural variability, will emerge under RCP8.5 across 63% of the ocean by 2100 when two standard deviations are used (limited evidence) (Dutkiewicz et al., 2019).Table 3.21 | Summary of previous IPCC assessments of observed and projected abrupt ecosystem shifts and extreme events Observations Projections AR5 (Wong et al., 2014) Observations of abrupt ecosystem shifts and extreme events were not assessed in this report.‘Warming and acidification will lead to coral bleaching, mortality, and decreased constructional ability (IPCC AR6_WGII, confidence: high)
Temperate seagrass and kelp ecosystems will decline with the increased frequency of heatwaves and sea temperature extremes as well as through the impact of invasive subtropical species (high confidence).’ SROCC (Collins et al., 2019a) ‘Marine heatwaves (MHWs), periods of extremely high ocean temperatures, have negatively impacted marine organisms and ecosystems in all ocean basins over the last two decades, including critical foundation species such as corals, seagrasses and kelps (very high confidence).’‘Marine heatwaves are projected to further increase in frequency, duration, spatial extent and intensity (maximum temperature) (IPCC AR6_WGII, confidence: very high)