rlacombe/ClimateX huggingface dataset:
With 1.5 and 2°C global warming, approximately 15 and 20% of the current global population, respectively, would experience both an increase in high streamflows and a decrease in low streamflows (IPCC AR6_WGII, confidence: medium)
Both AR5 (Jiménez Cisneros et al., 2014) and SROCC (Hock et al., 2019b) concluded that spring snowmelt floods would be earlier (high confidence), and hazards from floods involving meltwater will gradually diminish, particularly at low elevation (IPCC AR6_WGII, confidence: medium)
In all climate scenarios projected, earlier snowmelt leads to earlier spring floods (IPCC AR6_WGII, confidence: high)
Projected increases in flooding pose increasing risks, with a 1.2–1.8 and 4–5 times increase in global GDP loss at 2°C and 4°C compared to 1.5°C warming, respectively (IPCC AR6_WGII, confidence: medium)
Without adaptation, projected increases in flooding are 1.4 to 2.5 and 2.5 to 3.9 times in global GDP loss at 2°C and 3°C compared to 1.5°C warming, respectively (IPCC AR6_WGII, confidence: medium)
However, the snowmelt floods are projected to decrease (medium confidence) and occur 25–30 d earlier in the year by the end of the 21st century with RCP8.5 (IPCC AR6_WGII, confidence: high)
Many studies focus on precipitation-based drought indices (Carrão et al., 2018), but higher evaporative demands and changes in snow cover are additional drivers of hydrological, agricultural and ecological drought (IPCC AR6_WGII, confidence: medium)
In summary, the likelihood of drought is projected to increase in many regions over the 21st century (IPCC AR6_WGII, confidence: high)
Different forms of drought broadly show similar patterns of projected change in many regions (high confidence), but the frequency of agricultural drought is projected to increase over wider areas than for meteorological drought (IPCC AR6_WGII, confidence: medium)
Overall, several recent studies of climate change impacts on groundwater in different parts of the world have concluded that projected groundwater recharge could either increase or decrease, and results are often uncertain (IPCC AR6_WGII, confidence: high)
An emerging body of studies have projected amplification of episodic recharge in the tropics and semiarid regions due to extreme precipitation under global warming (IPCC AR6_WGII, confidence: medium)
Climate change is also projected to impact groundwater-dependent ecosystems and groundwater quality negatively (IPCC AR6_WGII, confidence: medium)
In the tropics and semiarid regions, growing precipitation intensification under global warming may enhance the resilience of groundwater through increased episodic recharge (IPCC AR6_WGII, confidence: medium)
In addition, SROCC reported water quality degradation due to the release of legacy contaminants in glaciers and permafrost (IPCC AR6_WGII, confidence: medium)
Water insecurity due to water quality degradation is projected to increase under climate change due to warming, enhanced floods and sea level rise (Arnell and Lloyd-Hughes, 2014; Dyer et al., 2014; Whitehead et al., 2015) (IPCC AR6_WGII, confidence: medium)
In summary, climate change is projected to increase water pollution incidences, salinisation and eutrophication due to increasing drought and flood events, sea level rise and water temperature rise, respectively, in some local rivers and lakes, but there is a dearth of exact quantification at a global scale (IPCC AR6_WGII, confidence: medium)
Herewith, recent studies demonstrate increasing impact of the projected climate change (increase of precipitation, thawing permafrost) on soil erosion (IPCC AR6_WGII, confidence: medium)
SR1.5 further reinforced AR5 conclusions in terms of projected crop yield reductions, especially for wheat and rice (high confidence), loss of livestock and increased risks for small-scale fisheries and aquaculture (IPCC AR6_WGII, confidence: medium)
In summary, agricultural water use is projected to increase globally due to cropland expansion and intensification and climate change- induced changes in water requirements (IPCC AR6_WGII, confidence: high)
Parts of temperate drylands may experience increases in suitability for rain- fed production based on mean climate conditions; however, risks to rain-fed agriculture increase globally because of increasing variability in precipitation regimes and changes in water availability (IPCC AR6_WGII, confidence: high)
Regions reliant on snowmelt for irrigation purposes will be affected by substantial reductions in water availability (IPCC AR6_WGII, confidence: high)
For example, regions like central Africa, India, central Asia and northern high-latitude areas are projected to see more than 20% increases in gross hydropower potential (IPCC AR6_WGII, confidence: high)
The Mediterranean region is projected to see almost a 40% reduction in hydropower production (IPCC AR6_WGII, confidence: high)
On the other hand, northern Europe and India are projected to add to their hydropower production capacity due to climate change by mid-century (IPCC AR6_WGII, confidence: high)
Apart from climate impacts on hydropower production, climate- induced flood loads and reservoir water level change may lead to dam failure under RCP2.6 and RCP4.5 scenarios (Fluixá-Sanmartín et al., 2018; Fluixá-Sanmartín et al., 2019) (IPCC AR6_WGII, confidence: medium)
A systematic review showed consistent decreases in mid to end of the century in thermal power production capacity due to insufficiency of cooling water in southern, western and eastern Europe (high confidence); North America and Oceania (high confidence), central, southern and western Asia (high confidence) and western and southern Africa (IPCC AR6_WGII, confidence: medium)
Overall, apart from emissions benefits, moving away from thermal power generation to other renewable energy will also lower the chances of climate-induced curtailment of energy production (IPCC AR6_WGII, confidence: high)
While not WaSH-specific, AR5 showed that more people would experience water scarcity and floods (high confidence) and identified WaSH failure due to climate change as an emergent risk (IPCC AR6_WGII, confidence: medium)
In addition, both SR1.5 (IPCC, 2018a) and SRCCL (IPCC, 2019b) projected the risk from droughts, heavy precipitation, water scarcity, wildfire damage and permafrost degradation to be higher at 2°C warming than 1.5°C (IPCC AR6_WGII, confidence: medium)
Waterborne diseases result from complex causal relationships between climatic, environmental and socioeconomic factors that are not fully understood or modelled (Boholm and Prutzer, 2017) (IPCC AR6_WGII, confidence: high)
In addition, changes in thermotolerance and chlorine resistance of certain viruses have been observed in laboratory experiments simulating different temperatures and sunlight conditions (Carratalà et al., 2020), increasing potential health risks even where traditional water treatment exists (Jiménez Cisneros et al., 2014) (IPCC AR6_WGII, confidence: low)
These challenges include population growth, the rapid pace of urbanisation and inadequate investment, particularly in less developed economies with limited governance capacity (IPCC AR6_WGII, confidence: high)
Modified streamflow is projected to affect the amount and variability of inflow to urban storage reservoirs (IPCC AR6_WGII, confidence: high)
In summary, rapid population growth, urbanisation, ageing infrastructure and changes in water use are responsible for increasing the vulnerability of urban and peri-urban areas to extreme rainfall and drought, particularly in less developed economies with limited governance capacity (IPCC AR6_WGII, confidence: high)
In addition, modified stream flows due to climate change (Section 4.4.3) are projected to affect the amount and variability of inflows to storage reservoirs that serve urban areas and may exacerbate challenges to reservoir capacity, such as sedimentation and poor water quality (IPCC AR6_WGII, confidence: high)
Rising water temperatures are also projected to cause shifts in freshwater species distribution and worsen water quality problems (IPCC AR6_WGII, confidence: high)
Furthermore, according to IPCC SR1.5 (Hoegh-Guldberg et al., 2018), if the world warms by 2°C–4°C by 2050, rates of human conflict could increase, but again, the role of hydrological change in this was not explicit (IPCC AR6_WGII, confidence: medium)
Yet, since both conflictive and cooperative events are possible under conditions of climatic variability, whether conflict arises or increases depends on several contextual socioeconomic and political factors, including the adaptive capacity of the riparian states (Koubi, 2019), the existence of power asymmetries (Dinar et al., 2019) and pre-existing social tensions (IPCC AR6_WGII, confidence: medium)
However, to date, other factors are considered more influential drivers of conflict, including lack of natural resource use regulations (Linke et al., 2018b), societal exclusion (von Uexkull et al., 2016; van Weezel, 2019), poor infrastructures and a history of violent conflict (Detges, 2016) (IPCC AR6_WGII, confidence: high)
On the other side, intergroup cohesion (De Juan and Hänze, 2020) and policies that improve societal development and good governance reduce the risk of conflict associated with the challenges to adaptation to climate change (Hegre et al., 2016; Witmer et al., 2017) (IPCC AR6_WGII, confidence: medium)
In addition, recent scenario analysis in global transboundary basins supports the finding that there is more potential for conflict in areas already under water stress, such as central Asia and the northern parts of Africa (Munia et al., 2020) (IPCC AR6_WGII, confidence: medium)
Evidence exists that climate change imposes additional pressures on regions already under water stress or fragile and conflict-prone (IPCC AR6_WGII, confidence: medium)
In synthesis, fundamental changes in observed climate are already visible in water-related outcomes (IPCC AR6_WGII, confidence: high)
Projected increases in hydrological extremes pose increasing risks to societal systems globally (IPCC AR6_WGII, confidence: high)
Similarly, a near doubling of drought duration (Naumann et al., 2018) and an increasing share of the population affected by various types, durations and severity levels of drought are projected (IPCC AR6_WGII, confidence: high)
While there are increasing potentials of ~2–6% for hydropower production by 2080 (medium confidence), risks to thermoelectric power production increase for most regions (IPCC AR6_WGII, confidence: high)
Increasing hydrological extremes also have consequences for the maintenance and further improvement of the provision of WaSH services (IPCC AR6_WGII, confidence: medium)
Globally, climate change will exacerbate existing challenges for urban water services, driven by further population growth, the rapid pace of urbanisation and inadequate investment, particularly in less developed economies with limited governance capacity (IPCC AR6_WGII, confidence: high)
However, water-specific conflicts between sectors and users may be exacerbated for some regions of the world (IPCC AR6_WGII, confidence: high)
Hydrological change, especially increasing extreme events, pose risks to the cultural uses of water of Indigenous Peoples, local communities and traditional peoples (high confidence), with implications for the physical well-being of these groups (IPCC AR6_WGII, confidence: high)
Small islands are already regularly experiencing droughts and freshwater shortages (IPCC AR6_WGII, confidence: high)
In addition, FWLs are threatened by climate change due to changes in rainfall patterns, extended droughts and wash-over events caused by storm surges and sea level rise (IPCC AR6_WGII, confidence: high)
In sum, small islands are already regularly experiencing droughts and freshwater shortages (IPCC AR6_WGII, confidence: high)
For atoll islands, freshwater availability may be severely limited as early as 2030 (IPCC AR6_WGII, confidence: low)
The effects of temperature increase, changing rainfall patterns, sea level rise and population pressure combined with limited options available for water-related adaptation leave small islands partially water-insecure currently, with increasing risks in the near-term and at warming above 1.5°C (IPCC AR6_WGII, confidence: high)
There is high confidence that water-related adaptation is occurring in the agricultural sector (Acevedo et al., 2020; Ricciardi et al., 2020), and water-related adaptation in the agricultural sector makes up the majority of documented local, regional and global evidence of implemented adaptation (IPCC AR6_WGII, confidence: high)
However, while there is increasing evidence of adaptation and its benefits across multiple dimensions, the link between adaptation benefits and climate risk reduction is unclear due to methodological challenges (IPCC AR6_WGII, confidence: medium)
On the other hand, while it is methodologically possible to measure the effectiveness of future adaptation in reducing climate risks, the main limitation here is that not all possible ranges of future adaptations can be modelled given the limitations of climate and impact models (IPCC AR6_WGII, confidence: high)
This measure is deemed to have economic benefits and benefits for vulnerable communities who adopt this measure (high confidence) and benefits in terms of water saving and positive ecological and sociocultural benefits (IPCC AR6_WGII, confidence: medium)
In addition, this measure is shown to have positive economic benefits (high confidence) and also benefits on other parameters (IPCC AR6_WGII, confidence: medium)
In sum, water-related adaptation in the agricultural sector is widely documented, with irrigation, agricultural water management, crop diversification and improved agronomic practices among the most common adaptation measures adopted (IPCC AR6_WGII, confidence: high)
Overall, freshwater withdrawals for adapted cooling systems under all scenarios are projected to decline by −3% to −63% by 2100 compared to the base year of 2000 (Fricko et al., 2016) (IPCC AR6_WGII, confidence: medium)
Furthermore, reducing the share of thermoelectric power with solar and wind energy (Tobin et al., 2018; Arango-Aramburo et al., 2019; Emodi et al., 2019) can be synergistic from both climate and water perspectives, as solar and wind energy have lower water footprints (IPCC AR6_WGII, confidence: high)
For instance, sharing of hydropower revenues and profits to fund local infrastructure and pay dividends to local people has been practiced in Nepal and in some countries of the Mekong basin to enhance the social acceptability of hydropower projects (Balasubramanya et al., 2014; Shrestha et al., 2016) (IPCC AR6_WGII, confidence: low)
Further, while irrigation expansion is one of the most commonly proposed adaptation responses, there are limitations to further increases in water use, as many regions are already facing water limitations under current climatic conditions (IPCC AR6_WGII, confidence: high)
However, residual risks will remain, especially at higher levels of warming (IPCC AR6_WGII, confidence: medium)
WaSH interventions have been demonstrated to reduce diarrhoea risk by 25–75% depending on the specific intervention (Wolf et al., 2018) (IPCC AR6_WGII, confidence: high)
Conversely, inadequate WaSH is associated with an estimated annual loss of 50 million daily adjusted life years (Prüss-Ustün et al., 2019), of which 89% of deaths are due to diarrhoea, and 8% of deaths from acute respiratory infections (Chapter 7 WGII 7.3.2), making universal access to WaSH (i.e., achievement of SDG 6.1, 6.2) a critical adaptation strategy (IPCC AR6_WGII, confidence: high)
Improved integrated (urban) water resources management (Kirshen et al., 2018; Tosun and Leopold, 2019) and governance (Chu, 2017; Miller et al., 2020) and enhanced ecosystem management (Adhikari et al., 2018b) lead to policies and regulations that reduce water insecurity and, when developed appropriately, reduce inequities (IPCC AR6_WGII, confidence: medium)
Supply (source) augmentation, including dams, storage and rainwater/fog harvesting, can increase the supply or reliability of water for drinking, sanitation and hygiene (DeNicola et al., 2015; Pearson et al., 2015; Majuru et al., 2016; Poudel and Duex, 2017; Lucier and Qadir, 2018; Goodrich et al., 2019) (IPCC AR6_WGII, confidence: high)
Demand for water can be decreased through reductions in water loss from the system (e.g., pipe leakage) (Orlove et al., 2019) and water conservation measures (Duran-Encalada et al., 2017) (IPCC AR6_WGII, confidence: medium)
Further analyses of co-benefits, particularly employing a gender lens, are required to improve adaptation strategies (McIver et al., 2016).In summary, ensuring access to climate-resilient WaSH infrastructure and practices represents a key adaptation strategy that can protect beneficiaries against water-related diseases induced by climate change (IPCC AR6_WGII, confidence: high)
Better management of water resources, supply augmentation and demand management are important adaptation strategies (IPCC AR6_WGII, confidence: high)
In summary, although water-related adaptation is underway in the urban, peri-urban and municipal sectors of some nations, governance, technical and economic barriers remain in implementing locally informed strategies, particularly in developing countries (high confidence).4.6.6 Adaptation for Communities Dependent on Freshwater Ecosystems AR5 concluded that some adaptation responses in the urban and agricultural sectors could negatively impact freshwater ecosystems (IPCC AR6_WGII, confidence: medium)
These have been implemented in many locations around the world, yet, challenges remain, including improving the evidence base of their effectiveness, scaling up of these interventions, mainstreaming across sectors and receiving more adaptation finance (IPCC AR6_WGII, confidence: medium)
These measures also require further financial support, mainstreaming across sectors and the scaling up of individual measures (IPCC AR6_WGII, confidence: medium)
However, challenges remain, including improving the evidence base of their effectiveness, scaling up these interventions, mainstreaming across sectors and receiving more adaptation finance (IPCC AR6_WGII, confidence: medium)
At the urban and peri-urban scale, the use and effectiveness of NbS is a crucial feature to build resilience in cities for urban stormwater management and heat mitigation (Depietri and McPhearson, 2017; Carter et al., 2018; Huang et al., 2020; Babí Almenar et al., 2021) (IPCC AR6_WGII, confidence: high)
Moreover, several NbS– —for example, natural (blue and green) and grey infrastructure—can help address water-related hazards such as coastal hazards, heavy precipitation, drought, erosion and low water quality (IPCC AR6_WGII, confidence: high)
Vulnerable populations exposed to hydrological changes may become trapped due to a lack of economic and social capital required for migration (Adams, 2016; Zickgraf, 2018) (IPCC AR6_WGII, confidence: medium)
Migration has increased vulnerability among women and female-headed households (Patel and Giri, 2019), but has also triggered gender-positive processes such as increased female school enrolment (Gioli et al., 2014) (IPCC AR6_WGII, confidence: medium)
Remittances, that is, transfers of money from migrants to beneficiaries in sending areas, may reduce vulnerability and increase adaptive capacity to climate-induced hydrological changes (Ng’ang’a et al., 2016; Jha et al., 2018b) (IPCC AR6_WGII, confidence: medium)
However, they often fail to include affected populations in the process and may lead to greater impoverishment and increased vulnerability (Wilmsen and Webber, 2015) (IPCC AR6_WGII, confidence: medium)
In summary, measures that facilitate successful migration and inclusive resettlement may facilitate adaptation to climate-induced hydrological changes (IPCC AR6_WGII, confidence: medium)
However, relocation can be culturally, socially, financially, politically and geographically constrained due to the importance of cultural relationships with traditional, customary or ancestral lands (IPCC AR6_WGII, confidence: high)
In sum, although some Indigenous Peoples, local communities and traditional peoples can adapt, and are adapting to climate-driven hydrological changes, and their impacts on and risks to culturally significant practices and beliefs (medium confidence), these strategies are constrained by structural barriers and adaptation limits (IPCC AR6_WGII, confidence: high)
Most of these adaptation case studies are from Asia and Africa, and agriculture is the predominant sector where most of these adaptation responses are being implemented (IPCC AR6_WGII, confidence: high)
Agriculture is the most important sector in all continents, except Europe and Australasia, where most adaptation occurs in the urban sector (IPCC AR6_WGII, confidence: high)
These top four responses provide several benefits such as higher incomes and yields, better water use efficiencies and related outcomes (IPCC AR6_WGII, confidence: high)
Responses such as migration, including spontaneous and planned relocation, are also relatively well documented (medium confidence), as are responses such as collective action, training and capacity building and economic and financial measures for increasing adaptive capacities (IPCC AR6_WGII, confidence: medium)
In developing countries, most adaptation measures improve economic outcomes (IPCC AR6_WGII, confidence: high)
Adaptation responses also have benefits in terms of water outcomes and environmental and ecological parameters, and these benefits are more commonly manifested in developed countries (IPCC AR6_WGII, confidence: high)
Of the papers assessed for water-related adaptation, roughly one fourth reported adaptation co-benefits (IPCC AR6_WGII, confidence: high)
In contrast, one third of studies reported maladaptive outcomes, now or in the future (IPCC AR6_WGII, confidence: high)
Despite many adaptation case studies, there is a knowledge gap in understanding if the benefits of adaptation also translate into a reduction of climate impacts, and if so, to what extent, and under what conditions (IPCC AR6_WGII, confidence: high)
Results show a range of effectiveness levels across regions and warming levels and vary depending on the tested response options (Qin et al., 2018) (Figure 4.29), with moderate to small effectiveness, large residual impacts or potential maladaptive outcomes, as well as decreasing effectiveness with increasing warming (Figure 4.28) (IPCC AR6_WGII, confidence: high)
For all regions, a reduction in effectiveness is apparent from 1.5°C to higher levels of warming, leading to increased residual risk with increasing warming (IPCC AR6_WGII, confidence: high)
Irrigation can increase yield relative to present day, showing co-benefits for some regions, though the share of co-benefits decreases with higher warming (IPCC AR6_WGII, confidence: high)
Adaptation generally performs more effectively at 1.5°C, though residual damages are projected at this warming level across sectors and regions (IPCC AR6_WGII, confidence: high)
Reduction in the effectiveness of future adaptation at higher global warming levels emphasises the need for limiting warming to 1.5°C, as space for adaptation solution starts to shrink beyond that for most options for which future projections exists (IPCC AR6_WGII, confidence: high)
First, the nature of literature on current adaptation makes it challenging to infer their effectiveness in reducing climate risks, even though the benefits of adaptation are clear (IPCC AR6_WGII, confidence: high)
SR1.5 also shows that water-related risks can be reduced substantially by limiting warming to 1.5°C (IPCC AR6_WGII, confidence: high)
The SRCCL further highlighted the critical importance of water-related climate change adaptation and potential limits to adaptation in the land sector when extreme forms of desertification lead to a complete loss of land productivity (IPCC AR6_WGII, confidence: high)
Institutional constraints, including path dependency and lengthy decision- making processes, remain major limitations to successful adaptation globally (IPCC AR6_WGII, confidence: high)
Water-related impacts that occurred despite implemented adaptation have been documented across all world regions (IPCC AR6_WGII, confidence: high)