rlacombe/ClimateX huggingface dataset:
Climate models project increases in the frequency of marine heatwaves by 2081–2100, relative to 1850–1900, by approximately 50 times under RCP8.5 and 20 times under RCP2.6 (IPCC AR6_WGII, confidence: medium)
Extreme El Niño events are projected to occur about twice as often under both RCP2.6 and RCP8.5 in the 21st century when compared to the 20th century (medium confidence).’ ‘Limiting global warming would reduce the risk of impacts of MHWs, but critical thresholds for some ecosystems (e.g., kelp forests, coral reefs) will be reached at relatively low levels of future global warming (IPCC AR6_WGII, confidence: high)
Better accounting for multiple interacting factors in ESMs (see Box 3.1) will provide insight into how marine ecosystems will respond to future climate (IPCC AR6_WGII, confidence: high)
Using an ensemble of global-scale marine ecosystem and fisheries models (Fish-MIP) (Tittensor et al., 2018) with the CMIP5 ESM ensemble, SROCC concludes that projected ocean warming and decreased phytoplankton production and biomass will reduce global marine animal biomass during the 21st century (IPCC AR6_WGII, confidence: medium)
These declines result from combined warming and decreased primary production (with low confidence in future changes in primary production; Section 3.4.3.5) and are amplified at each trophic level within all ESM and marine ecosystem model projections across all scenarios (IPCC AR6_WGII, confidence: medium)
Owing to contradictory observations there is currently uncertainty about the future trends of major upwelling systems and how their drivers (enhanced productivity, acidification and hypoxia) will shape ecosystem characteristics (IPCC AR6_WGII, confidence: low)
Animal biomass Observed changes in animal biomass were not assessed in this report.‘The climate-change-induced intensification of ocean upwelling in some eastern boundary systems, as observed in the last decades, may lead to regional cooling, rather than warming, of surface waters and cause enhanced productivity (IPCC AR6_WGII, confidence: medium)
The strong dependence of the projected declines on phytoplankton production (IPCC AR6_WGII, confidence: low)
Some increases are projected in the polar regions, due to enhanced stratification in the surface ocean, reduced primary production and shifts towards small phytoplankton (IPCC AR6_WGII, confidence: medium)
Overall, ocean warming and decreased phytoplankton production and biomass will drive a global decline in biomass for zooplankton (low confidence), marine animals (medium confidence) and seafloor benthos (low confidence), with regional differences in the direction and magnitude of changes (IPCC AR6_WGII, confidence: high)
There is increasing evidence that responses will amplify throughout the food web and at ocean depths, with relatively modest changes in surface primary producers translating into substantial changes at higher trophic levels and for deep-water benthic communities (IPCC AR6_WGII, confidence: medium)
This is consistent with previous assessments that identified ocean warming and increased stratification as the main drivers (IPCC AR6_WGII, confidence: high)
Furthermore, accurate simulation of many of the biogeochemical tracers upon which NPP depends (e.g., the distribution of iron; Tagliabue et al., 2016; Bindoff et al., 2019a) remains a significant and ongoing challenge to ESMs (IPCC AR6_WGII, confidence: high)
Increasing model complexity with more widespread representation of ocean biogeochemical processes between CMIP5 and CMIP6, and inclusion of more than one or two classes of phyto- and zooplankton, will provide opportunities to improve assessments of how climate-induced drivers affect different components of biological carbon pump in the epipelagic ocean, as well as changes in the efficiency and magnitude of carbon export in the deep ocean (IPCC AR6_WGII, confidence: high)
Model results indicate that sea surface temperatures (high confidence), Arctic sea ice (high confidence), surface ocean acidification (very high confidence) and surface ocean deoxygenation (IPCC AR6_WGII, confidence: very high)
In an overshoot scenario in which CO 2 returns to 2040 levels by 2100 (SSP5-3.4-OS; O’Neill et al., 2016), SST and Arctic sea ice do not fully return by 2100 to levels prior to the CO 2 peak (IPCC AR6_WGII, confidence: medium)
Models also indicate that global sea level rise, as well as warming, ocean acidification and deoxygenation at depth, are irreversible for centuries or longer (IPCC AR6_WGII, confidence: very high)
A small decrease in productivity is evident globally for the period 1998–2015, but regional changes are larger and of opposing signs (IPCC AR6_WGII, confidence: low)
The deep sea covers >63% of Earth’s surface (Costello and Cheung, 2010) and is exposed to climate-driven changes in abyssal, intermediate and surface waters that influence sinking fluxes of particulate organic matter (IPCC AR6_WGII, confidence: high)
Acute mortality of some reef-forming cold-water corals to laboratory-simulated warming (Lunden et al., 2014) suggests that both long-term warming and the increase of MHWs in intermediate and deep waters (Elzahaby and Schaeffer, 2019) could pose significant risk to associated ecosystems (IPCC AR6_WGII, confidence: high)
The extension and intensification of deep-water acidification (Section 3.2.3.1) has been identified as a further key risk to deep-water coral ecosystems (IPCC AR6_WGII, confidence: medium)
Desmophyllum pertusum7and Madrepora oculata maintain calcification in moderately low pH (7.75) and near-saturation of aragonite (Hennige et al., 2014; Maier et al., 2016; Büscher et al., 2017), but lower pH (7.6) and corrosive conditions lead to net dissolution of D. pertusum skeletons (IPCC AR6_WGII, confidence: high)
In OMZ regions (Section 3.2.3.2), benthic species distributions (Sperling et al., 2016; Levin, 2018; Gallo et al., 2020), abundance and composition of demersal fishes in canyons (De Leo et al., 2012) and deep-pelagic zooplankton (Wishner et al., 2018) follow oxygen gradients, indicating that deep-sea biodiversity and ecosystem structure will be impacted by extension of hypoxic areas (IPCC AR6_WGII, confidence: medium)
Despite mortality and functional impacts from low oxygen concentrations observed in aquaria (Lunden et al., 2014), recent observations of the deep-water coral D. pertusum suggest adaptive capacity to hypoxia among specimens from OMZ regions that are highly productive (IPCC AR6_WGII, confidence: low)
Climate-driven impacts further limit the resilience of deep-sea ecosystems to impacts from human activities (IPCC AR6_WGII, confidence: high)
The spatial resolution of CMIP5 models is too coarse to robustly project changes in mesoscale circulation at the seafloor (Sulpis et al., 2019), on which deep-sea ecosystems depend for organic material supplies and dispersal of planktonic and planktotrophic larvae (IPCC AR6_WGII, confidence: high)
Biodiversity has changed in association with ocean warming and loss of sea ice, sea level rise, coral bleaching, marine heat waves and upwelling changes (IPCC AR6_WGII, confidence: high)
Overlapping non-climate drivers (Section 3.1) also decrease ocean and coastal ecosystem biodiversity (IPCC AR6_WGII, confidence: very high)
Projected changes in biodiversity due to climate change (Section 3.4.3.3.3) are expected to alter the flow and array of ocean and coastal ecosystem services (IPCC AR6_WGII, confidence: high)
Non-indigenous marine species are major agents of ocean and coastal biodiversity change, and climate and non-climate drivers interact to support their movement and success (IPCC AR6_WGII, confidence: high)
At times, non-indigenous species act invasively and outcompete indigenous species, causing regional biodiversity shifts and altering ecosystem function, as seen in the Mediterranean region (IPCC AR6_WGII, confidence: high)
Non-climate drivers, especially marine shipping in newly ice-free locations (Chan et al., 2019), fishing pressure (Last et al., 2011), aquaculture of non-indigenous species (Mach et al., 2017; Ruby and Ahilan, 2018) and marine pollution and debris (Gall and Thompson, 2015; Carlton et al., 2018; Carlton and Fowler, 2018; Lasut et al., 2018; Miralles et al., 2018; Rech et al., 2018; Therriault et al., 2018), promote range shifts and movement of non-indigenous species (IPCC AR6_WGII, confidence: high)
Invasive marine species can alter species behaviour, reduce indigenous species abundance, reduce water clarity, bioaccumulate more heavy metals than indigenous species and inhibit ecosystem resilience in the face of extreme events (IPCC AR6_WGII, confidence: medium)
Catch composition is changing in many locations fished by smaller-scale, less-mobile commercial, artisanal and recreational fisheries (IPCC AR6_WGII, confidence: high)
Where possible, fishers are maintaining harvests by broadening catch diversity, traveling poleward and changing gear and strategies (IPCC AR6_WGII, confidence: high)
Both positive and negative impacts result for food security through fisheries (medium confidence), local cultures and livelihoods (medium confidence), and tourism and recreation (IPCC AR6_WGII, confidence: medium)
The impacts on ecosystem services have negative consequences for health and well-being (medium confidence), and for Indigenous Peoples and local communities dependent on fisheries (high confidence) (1.1, 1.5, 3.2.1, 5.4.1, 5.4.2, Figure SPM.2)’ (SROCC SPM A.8; IPCC, 2019c).‘Long-term loss and degradation of marine ecosystems compromises the ocean’s role in cultural, recreational, and intrinsic values important for human identity and well-being (IPCC AR6_WGII, confidence: medium)
Biodiversity (Section 3.5.2)‘[Climate] Impacts are already observed on [coastal ecosystem] habitat area and biodiversity, as well as ecosystem functioning and services (IPCC AR6_WGII, confidence: high)
Food provision (Section 3.5.3)‘Warming-induced changes in the spatial distribution and abundance of some fish and shellfish stocks have had positive and negative impacts on catches, economic benefits, livelihoods, and local culture (IPCC AR6_WGII, confidence: high)
There are negative consequences for Indigenous Peoples and local communities that are dependent on fisheries (IPCC AR6_WGII, confidence: high)
Shifts in species distributions and abundance has challenged international and national ocean and fisheries governance, including in the Arctic, North Atlantic and Pacific, in terms of regulating fishing to secure ecosystem integrity and sharing of resources between fishing entities (high confidence) (3.2.4, 3.5.3, 5.4.2, 5.5.2, Figure SPM.2)’ (SROCC SPM A.8.1; IPCC, 2019c).‘Future shifts in fish distribution and decreases in their abundance and fisheries catch potential due to climate change are projected to affect income, livelihoods, and food security of marine resource-dependent communities (IPCC AR6_WGII, confidence: medium)
Long-term loss and degradation of marine ecosystems compromises the ocean’s role in cultural, recreational, and intrinsic values important for human identity and well-being (IPCC AR6_WGII, confidence: medium)
The emerging demand for alternative energy sources is expected to generate economic opportunities for the ocean renewable energy sector (high confidence), although their potential may also be affected by climate change (IPCC AR6_WGII, confidence: low)
Habitat creation and maintenance (Section 3.5.5.1)‘[Climate] Impacts are already observed on [coastal ecosystem] habitat area and biodiversity, as well as ecosystem functioning and services (IPCC AR6_WGII, confidence: high)
Climate regulation and air quality (Section 3.5.5.2)‘Global ocean heat content continued to increase throughout [the 1951 to present] period, indicating continuous warming of the entire climate system (IPCC AR6_WGII, confidence: very high)
This is projected to result in a higher proportion of emitted CO 2 remaining in the atmosphere (IPCC AR6_WGII, confidence: high)
Technology-based adaptations (Section 3.6.3) have minimised aquaculture losses from ocean acidification, including early-warning systems to guide hatchery operations and culturing resilient shellfish Ecosystem service and chapter subsectionObserved impacts Projected impacts Observed impacts on marine organisms’ contribution to climate regulation not previously assessed.‘The effect of climate change on marine biota will alter their contribution to climate regulation, that is, the maintenance of the chemical composition and physical processes in the atmosphere and oceans (IPCC AR6_WGII, confidence: high)
Provision of freshwater, maintenance of water quality, regulation of pathogens (Section 3.5.5.3)Observed climate impacts on salinisation of coastal soil and groundwater not previously assessed.‘In the absence of more ambitious adaptation efforts compared to today, and under current trends of increasing exposure and vulnerability of coastal communities, risks, such as erosion and land loss, flooding, salinisation, and cascading impacts due to mean sea level rise and extreme events are projected to significantly increase throughout this century under all greenhouse gas emissions scenarios (IPCC AR6_WGII, confidence: very high)
Regulation of physical hazards (Section 3.5.5.4)‘Coastal ecosystems are already impacted by the combination of sea level rise, other climate-related ocean changes, and adverse effects from human activities on ocean and land (high confidence)... Coastal and near-shore ecosystems including saltmarshes, mangroves, and vegetated dunes in sandy beaches,...provide important services including coastal protection...(high confidence)’ (SROCC Chapter 4 Executive Summary; Oppenheimer et al., 2019).‘The decline in warm water coral reefs is projected to greatly compromise the services they provide to society, such as...coastal protection (IPCC AR6_WGII, confidence: high)
However, the effect of these changes is not yet reflected in a weakening trend of the contemporary (1960–2019) ocean sink (IPCC AR6_WGII, confidence: high)
Cultural services (Section 3.5.6)‘Climate change impacts on marine ecosystems and their services put key cultural dimensions of lives and livelihoods at risk (IPCC AR6_WGII, confidence: medium)
This includes potentially rapid and irreversible loss of culture and local knowledge and Indigenous knowledge, and negative impacts on traditional diets and food security, aesthetic aspects, and marine recreational activities (medium confidence)’ (SROCC SPM B.8.4; IPCC, 2019c).‘Future shifts in fish distribution and decreases in their abundance and fisheries catch potential due to climate change are projected to affect income, livelihoods, and food security of marine resource-dependent communities (IPCC AR6_WGII, confidence: medium)
Laboratory studies show that ocean acidification decreases the fitness, growth or survival of many economically and culturally important larval or juvenile shelled mollusks (IPCC AR6_WGII, confidence: high)
Ocean acidification alters larval settlement and metamorphosis of fish in laboratory studies (IPCC AR6_WGII, confidence: high)
Ocean and coastal organisms will continue moving poleward under RCP8.5 (high confidence) (Section 3.4.3.1.3; Figure 3.18), and this is expected to decrease fisheries harvests in low latitudes and alter species composition and abundance in higher latitudes (IPCC AR6_WGII, confidence: high)
Temperature will continue to be a major driver of fisheries changes globally, but other non-climate factors like organism physiology and ecosystem response (Section 3.3) and fishing pressure (Chapter 5), as well as other climate-induced drivers like acidification, deoxygenation and sea ice loss (Section 3.2), will play critical roles in future global and local fisheries changes (IPCC AR6_WGII, confidence: high)
Warming, acidification and business-as-usual fishing policy under RCP8.5 are projected to place around 60% of global fisheries at very high risk (IPCC AR6_WGII, confidence: medium)
Model intercomparison showed that ocean acidification and protection affect ecosystems more than fishing pressure, and ecological adaptation will significantly determine impacts on fishery biomass, catch and value until approximately 2050 (IPCC AR6_WGII, confidence: medium)
Declining stocks of forage fish are expected to have detrimental effects on seabirds, pelagic fish and marine mammals (medium confidence) (Lindegren et al., 2018; Steiner et al., 2019), which may harm dependent human communities, including Arctic Indigenous Peoples (IPCC AR6_WGII, confidence: low)
Modelled fishery futures and revenue depend on environmental scenario, fishing- fleet composition and management, and ocean acidification and temperature responses of harvested species (IPCC AR6_WGII, confidence: high)
At the same time, projected hypoxic conditions of ~2 mg l–1 of oxygen will be consistently detrimental across taxonomic groups, developmental stages and climate regions (IPCC AR6_WGII, confidence: high)
Because ooligan spawning relies on the timing of the spring freshet, and because the species has declined in the past 25 years due to fishing pressure and predation, the species may be at risk from combined climate-induced and non-climate drivers (IPCC AR6_WGII, confidence: medium)
Decreasing the vulnerability of renewable-energy installations, particularly wind turbines, to climate risks (Table 3.26; Bindoff et al., 2019a) could include technological adaptations (Section 3.6.2.2) such as storm ‘survival mode’ settings (Penalba et al., 2018); preparation for hazards such as icing, SLR, drifting sea ice and wave activity (Neill et al., 2018; Goodale and Milman, 2019; Solaun and Cerdá, 2019); and biofouling (medium confidence) (Want and Porter, 2018; Joyce et al., 2019; Vinagre et al., 2020), which is expected to increase in response to warming and acidification (IPCC AR6_WGII, confidence: medium)
Over the 21st century, ocean heat and CO 2 uptake will continue (WGI AR6 SPMB4.1, B5.1; IPCC, 2021b) and sea ice loss from warming will allow some additional CO 2 uptake (Armstrong et al., 2019), but the ocean will take up a smaller fraction of CO 2 emissions as atmospheric CO 2 concentrations rise (IPCC AR6_WGII, confidence: high)
Coastal salinisation is attributed to regionally varying combinations of climate-induced drivers, like SLR and storm-related flooding by seawater, and non- climate drivers, like water withdrawal and land-use changes (IPCC AR6_WGII, confidence: very high)
Salinisation will continue to endanger coastal water and soil quality in the future (high confidence) (Islam et al., 2019; Paldor and Michael, 2021), but the evidence assessed above shows that subsequent impacts to human health and agriculture will depend heavily on regional variations in environment and human behaviour (IPCC AR6_WGII, confidence: medium)
Together, climate-induced and non-climate drivers can mobilise toxins and contaminants in ways that harm human and marine species health (very high confidence) (see Box 3.2), and climate change is altering these relationships (IPCC AR6_WGII, confidence: high)
Projected increases in temperature, extreme and variable rainfall conditions, coastal flooding and SLR (Section 3.2; Cross-Chapter Box SLR in Chapter 3) strongly increase the risk of frequent and severe aquatic human pathogen outbreaks in ocean and coastal areas that will continue to harm human health and cause economic losses (IPCC AR6_WGII, confidence: high)
Climate-driven changes in temperature, salinity (from ice melt and precipitation changes), deoxygenation and ocean acidification can alter dynamics of infectious diseases that target ocean and coastal species by increasing hosts’ susceptibility or pathogens’ abundance or virulence (IPCC AR6_WGII, confidence: high)
Coral and urchin diseases have increased over time driven by warming-related declines in organism recovery and survival or immunity (IPCC AR6_WGII, confidence: medium)
Climate change, especially episodic extreme rains and RSLR (Romero-Lankao et al., 2014), is challenging management and design of wastewater and stormwater systems (IPCC AR6_WGII, confidence: high)
Without substantial adaptation that addresses projected wastewater management challenges and community needs (Section 4.2.6.1; Kirshen et al., 2018; Kirchhoff and Watson, 2019; Kool et al., 2020; Nazarnia et al., 2020; Hughes et al., 2021), coastal water quality in many areas will decrease because of more frequent or severe releases of untreated wastes (high confidence) (Flood and Cahoon, 2011; Hummel et al., 2018; Hughes et al., 2021; McKenzie et al., 2021b), and this will have harmful consequences for human and coastal ecosystem health (IPCC AR6_WGII, confidence: high)
Non-climate drivers [e.g., invasive species (James et al., 2020), sediment-supply changes (Ganju, 2019; Ladd et al., 2019; Ilia, 2020), erosion and storm damage (Mehvar et al., 2019; Bacopoulos and Clark, 2021)], acting together with climate-induced drivers and associated impacts [e.g., SLR (Cross-Chapter Box SLR in Chapter 3), changes in plant biodiversity (Section 3.5.2; Lee Smee, 2019; Silliman et al., 2019; Schoutens et al., 2020), MHWs (Section 3.4.3.7) and acidification (Section 3.4.2.1)], compromise physical protection by coastal ecosystems (IPCC AR6_WGII, confidence: very high)
Coastal vegetated ecosystems are vulnerable to harm from multiple climate-induced and non-climate drivers, and together these have reduced wetland area globally (high confidence) (Section 3.4.2.5) and endangered the services provided by these ecosystems (IPCC AR6_WGII, confidence: high)
These changes also strongly determine the quantity and longevity of blue carbon storage (IPCC AR6_WGII, confidence: high)
Specific site characteristics and ecosystem responses to climate change will determine future local blue carbon storage or loss (IPCC AR6_WGII, confidence: high)
But recovery of coastal vegetated ecosystems is expected to bring back the full suite of ecosystem services they provide, not just carbon storage (IPCC AR6_WGII, confidence: medium)
Successful restoration requires using appropriate plant species in suitable environmental settings (Wodehouse and Rayment, 2019; Friess et al., 2020a) with favourable geomorphology and biophysical conditions (Cameron et al., 2019; Ochoa- Gómez et al., 2019) and considering social, economic, policy and operational constraints (Section 3.6.3.2.2; Cross-Chapter Box NATURAL in Chapter 2), now and in the future (IPCC AR6_WGII, confidence: high)
Sea level rise and storm-driven coastal erosion endanger coastal archaeological and heritage sites around the world (IPCC AR6_WGII, confidence: very high)
Observed disruption of ocean and coastal cultural services by climate impacts, plus increasingly severe and widespread projected climate- change impacts on ocean and coastal ecosystems, imply that the risk to cultural ecosystem services will remain constant or even increase (IPCC AR6_WGII, confidence: medium)
Recent studies assert that cultural ecosystem services are at risk from climate change (IPCC AR6_WGII, confidence: high)
AR5 concluded that local adaptation measures would not alone be enough to offset global effects of increased climate change on marine and coastal ecosystems, and that mitigation of emissions would also be necessary (IPCC AR6_WGII, confidence: high)
SROCC assessed that ecosystem-based adaptation, including MPAs (high confidence) (Bindoff et al., 2019a) and adaptive management, are effective to reduce climate-change impacts (IPCC, 2018; IPCC, 2019b), but that existing marine governance is insufficient to provide an effective adaptation response in the marine ecosystem (IPCC AR6_WGII, confidence: high)
Future social responses depend on warming levels and on the institutional, socioeconomic and cultural constructs that allow or limit livelihood changes (IPCC AR6_WGII, confidence: medium)