rlacombe/ClimateX huggingface dataset:
SRCCL stated that improved irrigation techniques (e.g., drip irrigation) and moisture conservation (e.g., rainwater harvesting using indigenous and local practices) could increase farmers’ adaptive capacity (IPCC AR6_WGII, confidence: high)
The Sixth Assessment Report (AR6) Working Group I (WGI) (Douville et al., 2021) concluded that anthropogenic climate change has increased atmospheric moisture and precipitation intensity (very likely by 2–3% per 1°C) (high confidence), increased terrestrial ET (medium confidence) and contributed to drying in dry summer climates including in the Mediterranean, southwestern Australia, southwestern South America, South Africa and western North America (medium to high confidence), and has caused earlier onset of snowmelt and increased melting of glaciers (IPCC AR6_WGII, confidence: high)
Therefore, improving societal aspects of water management will be key in adapting to climate change-driven increases in water scarcity in the future (IPCC AR6_WGII, confidence: high)
In summary, roughly half of the world’s population are assessed as currently subject to severe water scarcity for at least some part of the year due to climatic and non-climatic factors, and this is projected to be exacerbated at higher levels of warming (IPCC AR6_WGII, confidence: medium)
General water insecurity issues are seen worldwide, particularly in South Asia, North China, Africa and the Middle East, due to high population densities often coupled with low water availability, accessibility, quality and governance (IPCC AR6_WGII, confidence: high)
Areas with high water availability can also be water-insecure due to increased flood risk, deteriorated water quality, and poor governance (IPCC AR6_WGII, confidence: high)
Future water security will depend on the evolution of all these socioeconomic and governance factors and future regional climate change (IPCC AR6_WGII, confidence: high)
The main climate change contribution to water insecurity is the potential for reduced water availability, with a secondary contribution from increased flooding risk (IPCC AR6_WGII, confidence: medium)
Future socioeconomic conditions are a crucial driver of water insecurity, implying the need for further adaptation to some level of future climate change (IPCC AR6_WGII, confidence: medium)
However, policy challenges are high in many regions, with uncertainty in the regional climate outcomes being a key factor (IPCC AR6_WGII, confidence: high)
In summary, radiative forcing by GHG and aerosols drives changes in ET and precipitation at global and regional scales, and the associated warming shifts the balance between frozen and liquid water (IPCC AR6_WGII, confidence: high)
Land cover changes and urbanisation affect both the climate and land hydrology by altering the exchanges of energy and moisture between the atmosphere and surface (IPCC AR6_WGII, confidence: high)
Direct human interventions in river systems and groundwater systems are non- climatic drivers with substantial impacts on the water cycle (IPCC AR6_WGII, confidence: high)
In 2020, approximately 498 million people lived in unfamiliarly wet areas, where the long-term average precipitation is as high as previously seen in only about one in 6 years (IPCC AR6_WGII, confidence: medium)
On the other hand, approximately 163 million people lived in unfamiliarly dry areas, mostly in low latitudes (IPCC AR6_WGII, confidence: medium)
Due to high variability over time, the signal of long-term change in annual mean precipitation is not distinguishable from the noise of variability in many areas (Hawkins et al., 2020), implying that the local annual precipitation cannot yet be defined ‘unfamiliar’ by the above definition.Notably, many regions have seen increased precipitation for part of the year and decreased precipitation at other times (IPCC AR6_WGII, confidence: high)
Therefore, the numbers of people seeing unfamiliar seasonal precipitation levels are expected to be higher than those quoted above for unfamiliar annual precipitation changes (IPCC AR6_WGII, confidence: medium)
The intensity of heavy precipitation has increased in many regions (IPCC AR6_WGII, confidence: high)
Substantially more people (~709 million) live in regions where annual maximum one-day precipitation has increased than in regions where it has decreased (~86 million) (IPCC AR6_WGII, confidence: medium)
However, more people are experiencing longer dry spells than shorter dry spells: approximately 711 million people live in places where annual mean CDD is longer than in the 1950s, and ~404 million in places with shorter CDD (IPCC AR6_WGII, confidence: medium)
Nearly half a billion people live in areas with historically unfamiliar wet conditions, and over 160 million in areas with historically unfamiliar dry conditions (IPCC AR6_WGII, confidence: medium)
Changes in land cover and irrigation have also changed regional ET (IPCC AR6_WGII, confidence: medium)
Global mean soil moisture has slightly decreased, but regional changes vary, with both increases and decreases of 20% or more in some regions (IPCC AR6_WGII, confidence: medium)
Drying soil moisture trends are more widespread than wetting trends, not only in arid areas but also in humid and transitional areas (IPCC AR6_WGII, confidence: medium)
Reduced dry-season water availability is driven mainly by increasing transpiration (IPCC AR6_WGII, confidence: medium)
Tourism and recreation activities have been negatively impacted by declining snow cover, glaciers and permafrost in high mountains (IPCC AR6_WGII, confidence: medium)
During the last two decades, the global glacier mass loss rate exceeded 0.5-meter water equivalent (m w.e.) per year compared to an average of 0.33 m w.e. yr–1 in 1950–2000. This volume of mass loss is the highest since the start of the entire observation period (IPCC AR6_WGII, confidence: very high)
Widespread cryospheric changes are affecting humans and ecosystems in mid-to-high latitudes and the high-mountain regions (IPCC AR6_WGII, confidence: high)
However, trends emerge on a regional level (a general increasing trend in the northern higher latitude region and mixed trend in the rest of the word) (IPCC AR6_WGII, confidence: high)
Climatic factors contribute to these trends in most basins (IPCC AR6_WGII, confidence: high)
They are more important than direct human influence in a larger share of major global basins (medium confidence), although direct human influence dominates in some (IPCC AR6_WGII, confidence: medium)
Overall, anthropogenic climate change is attributed as a driver to the global pattern of change in streamflow (IPCC AR6_WGII, confidence: medium)
Warming in the last 40–60 years has led to a 1–10-d earlier per decade spring flood occurrence depending on the location (the most frequent being 2–4 d per decade) (IPCC AR6_WGII, confidence: high)
Nevertheless, anthropogenic climate change increased the likelihood of a number of major heavy precipitation events and floods that resulted in disastrous impacts in southern and eastern Asia, Europe, North America and South America (Table 4.3) (IPCC AR6_WGII, confidence: high)
Although there is growing evidence on the effects of anthropogenic climate change on each event, given the relatively poor regional coverage and high model uncertainty, there is low confidence in the attribution of human- induced climate change to flood change on the global scale.In snow-dominated regions, 1~10 d earlier spring floods per decade due to warmer temperature are reported for the last decades (IPCC AR6_WGII, confidence: high)
Despite the increase in the number of glacial lake studies (Wang and Zhou, 2017; Harrison et al., 2018; Begam and Sen, 2019; Bolch et al., 2019), changes in the frequency of occurrence of glacier-related floods associated with climate change remain unclear (IPCC AR6_WGII, confidence: medium)
In summary, the frequency and magnitude of river floods have changed in the past several decades with high regional variations (IPCC AR6_WGII, confidence: high)
Anthropogenic climate change has increased the likelihood of extreme precipitation events and the associated increase in the frequency and magnitude of river floods (IPCC AR6_WGII, confidence: high)
Agricultural drought threatens food production through crop damage and yield decreases (e.g., Section 4.3.1) (IPCC AR6_WGII, confidence: high)
Cascading effects of droughts can include health issues triggered by a lack of sanitation (Section 4.3.3); can cause human displacements and loss of social ties, sense of place and cultural identity; and migration to unsafe settlements (IPCC AR6_WGII, confidence: medium)
In summary, droughts can have substantial societal impacts (virtually certain), and agricultural and ecological drought conditions in particular have become more frequent and severe in many parts of the world but less frequent and severe in some others (IPCC AR6_WGII, confidence: high)
Drought- induced economic losses relative to GDP are approximately twice as high in lower-income countries compared to higher-income countries, although the gap has narrowed since the 1980s, and at the global scale there is a decreasing trend of economic vulnerability to drought (IPCC AR6_WGII, confidence: medium)
Nevertheless, anthropogenic climate change has contributed to the increased likelihood or severity of drought events in many parts of the world, causing reduced agricultural yields, drinking water shortages for millions of people, increased wildfire risk, loss of lives of humans and other species and loss of billions of dollars of economic damages (IPCC AR6_WGII, confidence: medium)
These estimates range from approximately 113 to 510 km3 yr−1 and variation in estimates is due to methods and spatio-temporal scales considered (IPCC AR6_WGII, confidence: high)
Global hydrological models (Herbert and Döll, 2019) show that human-induced groundwater depletion at rates exceeding 20 mm yr–1 (2001–2010) is occurring in the major aquifers systems such as the High Plains and California Central Valley aquifers (USA), Arabian aquifer (Middle East), North-Western Sahara Aquifer System (North Africa), Indo-Gangetic Basin (India) and North China Plain (China) (IPCC AR6_WGII, confidence: high)
Groundwater depletion at lower rates (<10 mm yr–1) is taking place in the Amazon Basin (Brazil) and Mekong River Basin (South East Asia), primarily due to climate variability and change (IPCC AR6_WGII, confidence: high)
In Finland, a sustained reduction (almost 100 mm in 100 years) of long- term snow accumulation combined with early snowmelt has reduced spring recharge (Irannezhad et al., 2016) (IPCC AR6_WGII, confidence: medium)
In summary, groundwater storage has declined in many parts of the world, most notably since the beginning of the 21st century, due to the intensification of groundwater-fed irrigation (IPCC AR6_WGII, confidence: high)
In higher altitudes, warmer climates have altered groundwater regimes and may have led to reduced spring recharge due to reduced duration and snowmelt discharges (IPCC AR6_WGII, confidence: medium)
In summary, although climate-induced water quality degradation due to increases in water and surface temperatures or melting of the cryosphere has been observed (IPCC AR6_WGII, confidence: medium)
In addition, accelerated soil erosion and sedimentation have severe societal impacts through land degradation, reduced soil productivity and water quality (Section 4.2.7), increased eutrophication and disturbance to aquatic ecosystems (Section 4.3.5), sedimentation of waterways and damage to infrastructure (Graves et al., 2015; Issaka and Ashraf, 2017; Schellenberg et al., 2017; Hewett et al., 2018; Panagos et al., 2018; Sartori et al., 2019) (IPCC AR6_WGII, confidence: medium)
Sedimentation increases due to soil erosion in mountainous regions burned by wildfires, as a result of warming and altered precipitation, is documented with high confidence in the USA (Gould et al., 2016; DeLong et al., 2018), Australia (Nyman et al., 2015; Langhans et al., 2016), China (Cui et al., 2014) and Greece (Karamesouti et al., 2016) and can potentially damage downstream aquatic ecosystems (Section 4.3.5) and water quality (Section 4.2.7) (Cui et al., 2014; Murphy et al., 2015; Langhans et al., 2016) (IPCC AR6_WGII, confidence: medium)
The climate change impact on erosion and sediment load varies significantly over the world (Li et al., 2020b) (IPCC AR6_WGII, confidence: high)
In summary, in the areas with high human activity, factors other than climate have a more significant impact on soil erosion and sediment flux (IPCC AR6_WGII, confidence: high)
Drought has been singled out as a major driver of yield reductions globally (IPCC AR6_WGII, confidence: high)
Livestock production has also been affected by changing seasonality, increasing frequency of drought, rising temperatures and vector-borne diseases and parasites through changes in the overall availability, as well as reduced nutritional value, of forage and feed crops (Varadan and Kumar, 2014; Naqvi et al., 2015; Zougmoré et al., 2016; Henry et al., 2018; Godde et al., 2019) (IPCC AR6_WGII, confidence: medium)
Moreover, extreme precipitation can lead to increased surface flooding, waterlogging, soil erosion and susceptibility to salinisation (IPCC AR6_WGII, confidence: high)
These are important because they shape farmers’ perceptions, which in turn shape the adaptation measures farmers will undertake (Caretta and Börjeson, 2015; Savo et al., 2016; Sujakhu et al., 2016; Su et al., 2017) (Section 4.8.4) (IPCC AR6_WGII, confidence: high)
In subtropical/ tropical climates, climate-induced hazards such as floods and droughts negatively impact agricultural production (IPCC AR6_WGII, confidence: high)
They often rely on rain-fed agriculture in marginal areas with high exposure and high vulnerability to water- related stress and low adaptive capacity (IPCC AR6_WGII, confidence: high)
A recent global study concluded that reservoirs might emit more carbon than they bury, especially in the tropics (Keller et al., 2021) (IPCC AR6_WGII, confidence: medium)
Thus, there is a growing body of evidence of negative impacts of extreme events on hydropower production (IPCC AR6_WGII, confidence: high)
Globally, for the period 1981–2010, the utilisation rate of thermoelectric power was reduced by 3.8% during drought years compared to long-term average values (van Vliet et al., 2016a), and none of the studies reported increases in thermoelectric power production as a consequence of climate change (IPCC AR6_WGII, confidence: high)
In addition, melting and thawing of snow, ice and permafrost (Section 4.2.2) have also adversely impacted water quality, security and health (high confidence) (IPCC, 2019a) (Section 4.2.7).Literature since AR5 confirms that temperature, precipitation and extreme weather events are linked to increased incidence and outbreaks of water-related and neglected tropical diseases (Colón- González et al., 2016; Levy et al., 2016; Azage et al., 2017; Harp et al., 2021) (IPCC AR6_WGII, confidence: high)
Drinking water treatment can be compromised by degraded source water quality and extreme weather events, including droughts, storms, ice storms and wildfires that overwhelm or cause infrastructure damage (Sherpa et al., 2014; Khan et al., 2015; Howard et al., 2016; White et al., 2017) (IPCC AR6_WGII, confidence: high)
Water insecurity and inadequate WaSH have been associated with increased disease risk (IPCC AR6_WGII, confidence: high)
Climate extremes have profound implications for urban and peri-urban water management, particularly in an increasingly urbanised world (IPCC AR6_WGII, confidence: high)
Introduction Some extreme weather events are increasing in frequency and (or) severity as a result of climate change (Seneviratne et al., 2021) (IPCC AR6_WGII, confidence: high)
These disasters reflect immediate societal and political implications of rising risks (high confidence), but also provide windows of opportunity to raise awareness about climate change and to implement disaster-reduction policies and strategies (IPCC AR6_WGII, confidence: high)
With the frequency, severity and (or) likelihood of several types of extreme weather increasing, disasters can increasingly be regarded as ‘the public face of climate change’ (IPCC AR6_WGII, confidence: high)
Detection and attribution studies make the climate change fingerprint of several types of disasters increasingly clear (IPCC AR6_WGII, confidence: high)
Moreover, existing vulnerabilities and exposures play an important role in turning extreme events into disasters, further exacerbating existing racial, gender and social inequalities (IPCC AR6_WGII, confidence: high)
Further research is necessary to determine the extent and nature of water-related climate change impacts in the urban areas of developing countries (IPCC AR6_WGII, confidence: high)
Under extreme heat, often associated with minimal rainfall or water flows, the drying of shallower areas and the migration or death of individual organisms can occur (Dell et al., 2014; Miller et al., 2014; Scheffers et al., 2016; Szekeres et al., 2016; Myers et al., 2017; FAO, 2018a) (IPCC AR6_WGII, confidence: high)
Many wetland-dependent species have seen a long-term decline, with the Living Planet Index showing that 81% of populations of freshwater species are in decline and others being threatened by extinction (Davidson and Finlayson, 2018; Darrah et al., 2019; Diaz et al., 2019) (IPCC AR6_WGII, confidence: high)
Freshwater ecosystems are also under extreme pressure from changes in land use and water pollution, with climate change exacerbating these, such as the further decline of snow cover (DeBeer et al., 2016) and increased consumptive use of fresh water, and leading to the decline, and possibly extinction, of many freshwater-dependent populations (IPCC AR6_WGII, confidence: high)
The predominant key drivers are changes in land use and water pollution (IPCC AR6_WGII, confidence: high)
However, the large majority acknowledges reduction of water availability due to climate change as having the potential to exacerbate tensions (de Stefano et al., 2017; Waha et al., 2017), especially in regions and within groups dependent on agriculture for food production (von Uexkull et al., 2016; Koubi, 2019) (IPCC AR6_WGII, confidence: high)
However, evidence suggests that changes in rainfall patterns amplify existing tensions (Abel et al., 2019); examples include Syria, Iraq (Abbas et al., 2016; von Lossow, 2016) and Yemen (Mohamed et al., 2017) (IPCC AR6_WGII, confidence: medium)
There is also medium evidence that in some regions of Africa (e.g., Kenya, Democratic Republic of the Congo), there are links between observed water stress and individual attitude for participating in violence, particularly for the least resilient individuals (von Uexkull et al., 2020) (IPCC AR6_WGII, confidence: medium)
Climate change concerns also play a role in stimulating cooperative efforts, as in the case of the Ganges- Brahmaputra-Meghna River Basin (Mirumachi, 2015; Link et al., 2016) (IPCC AR6_WGII, confidence: medium)
Furthermore, household water insecurity has also been singled out as a driver of migration, given its physical, mental health and socioeconomic effects (Stoler et al., 2021) (IPCC AR6_WGII, confidence: medium)
The outcome is determined mainly by the socioeconomic, political and environmental context (IPCC AR6_WGII, confidence: medium)
Climate-driven hydrological changes are affecting culturally significant terrestrial and freshwater species and ecosystems, particularly for Indigenous Peoples, local communities and traditional peoples in the Arctic, high mountain areas, and small islands (IPCC AR6_WGII, confidence: high)
In summary, the cultural water uses of Indigenous Peoples, local communities and traditional peoples are being impacted by climate change (IPCC AR6_WGII, confidence: high)
Continuation of projected warming and other physical mechanisms will further accelerate the melting of snow cover and glaciers and thawing of permafrost (IPCC AR6_WGII, confidence: high)
Water cycle variability and extremes are projected to increase faster than average changes in most regions of the world and under all emission scenarios (IPCC AR6_WGII, confidence: high)
Importantly, in most land regions, the future changes are subject to high uncertainty even in the sign of the projected change (IPCC AR6_WGII, confidence: high)
For any given location, the range of projected changes generally increases with global warming (IPCC AR6_WGII, confidence: high)
The geographical patterns of local agreement/disagreement in projected precipitation change remain broadly similar with increased global warming, but the range of uncertainty generally increases (IPCC AR6_WGII, confidence: high)
Taken together, these projections of more intense precipitation and changes in the length of dry spells give a clear picture of increasingly volatile precipitation regimes, with many regions seeing both longer dry spells and heavier events when precipitation does occur (IPCC AR6_WGII, confidence: high)
The ranges of projected precipitation changes are smaller at lower levels of global warming (IPCC AR6_WGII, confidence: high)
Either an increase or decrease is possible in most regions, but there is an agreement among models on the increase in the far north (IPCC AR6_WGII, confidence: high)
There is a stronger model consensus on heavy precipitation increasing with global warming over most land areas (IPCC AR6_WGII, confidence: high)
There are widely varying projections of change in dry spell length (high confidence), but in regions with increasing projected dry spells, the potential increase is larger at higher levels of global warming (IPCC AR6_WGII, confidence: high)
In addition, the impacts of rising CO 2 concentrations on plant stomata and leaf area play a role in model projections of ET change (IPCC AR6_WGII, confidence: high)
In summary, projected soil moisture changes increase with levels of global warming (IPCC AR6_WGII, confidence: high)
In the CMIP6 multi- model ensemble at 4°C global warming, decreased soil moisture of up to 40% is projected in Amazonia, southern Africa and western Europe in all models (IPCC AR6_WGII, confidence: high)
Constraining warming to 1.5°C would prevent the thawing of a permafrost area of 1.5 to 2.5 million km2 compared to thawing under 2°C (IPCC AR6_WGII, confidence: medium)
Projections of snow cover metrics [IPCC AR6 WGI, 2021 (Section 9.5.3.3)] suggest a further decrease in snow water equivalent (SWE) and snow cover extent (SCE), though the inter-model spread is considerable (Lute et al., 2015; Thackeray et al., 2016; Kong and Wang, 2017; Henderson et al., 2018) (IPCC AR6_WGII, confidence: high)
In summary, in most basins fed by glaciers, runoff is projected to increase initially in the 21st century and then decline (IPCC AR6_WGII, confidence: medium)
Projections suggest a further decrease in seasonal snow cover extent and mass in mid to high latitudes and high mountains (IPCC AR6_WGII, confidence: high)
Permafrost will continue to thaw throughout the 21st century (IPCC AR6_WGII, confidence: high)
Changes in streamflow could increase the number of people facing water scarcity or insecurity (IPCC AR6_WGII, confidence: high)
Nevertheless, since projected changes typically increase with global warming, limiting warming to 1.5°C or 2°C substantially reduces the potential for either large increases or decreases in mean streamflow compared to 3°C or 4°C (Warszawski et al., 2014; Falkner, 2016; Gosling et al., 2017; Figure 4.16) (IPCC AR6_WGII, confidence: high)
In summary, mean and extreme streamflow changes are projected over most of the ice-free land surface (IPCC AR6_WGII, confidence: high)
The magnitude of streamflow change is projected to increase with global warming in most regions (IPCC AR6_WGII, confidence: high)
Annual mean runoff in one third of assessed glacierised catchments is projected to decline by at least 10% by 2100 under RCP4.5, with the most significant reductions in central Asia and the Andes (IPCC AR6_WGII, confidence: medium)
Substantial fractions of ensemble projections disagree with the multi-model mean (IPCC AR6_WGII, confidence: high)