rlacombe/ClimateX · Datasets at Hugging Face

statement_idx int64 0 8.09k	report stringclasses 3 values	page_num int64 18 2.84k	sent_num int64 0 78	statement stringlengths 13 4.29k	confidence stringclasses 4 values	score int64 0 3	split stringclasses 2 values
4,000	AR6_WGII	567	12	Direct flood damages are projected to increase by four to five times at 4°C compared to 1.5°C	medium	1	train
4,001	AR6_WGII	567	17	Projected losses include a 1.2- to 1.8-fold increase in GDP loss due to flooding between 1.5°C and 2°C warming	medium	1	train
4,002	AR6_WGII	567	19	Due to the combined effects of water and temperature changes, risks to agricultural yields could be three times higher at 3°C compared to 2°C	medium	1	train
4,003	AR6_WGII	567	22	The number of internally displaced people in sub- Saharan Africa, South Asia and Latin America increased almost five times for RCP8.5 compared to RCP2.6	low	0	train
4,004	AR6_WGII	567	26	In contrast, responses are more policy-oriented and urban-focused in developed countries	high	2	train
4,005	AR6_WGII	567	28	In addition, large- scale irrigation also affects local to regional climates, both in terms of temperature and precipitation change	high	2	train
4,006	AR6_WGII	568	1	Roughly one third and one fourth of case studies on water adaptation also documents maladaptation and co-benefits, respectively	high	2	train
4,007	AR6_WGII	568	2	A significant knowledge gap remains in knowing if observed adaptation benefits also translate to climate risk reduction, if so, by how much and under what conditions	medium	1	train
4,008	AR6_WGII	568	5	However, residual impacts remain for some options and regions at all levels of warming, and the overall effectiveness decreases at higher warming levels	high	2	train
4,009	AR6_WGII	568	9	SDGs cannot be met without adequate and safe water (high confidence), and water is fundamental to all systems transition	high	2	train
4,010	AR6_WGII	568	11	However, barriers remain for low-income countries to access funds (medium confidence), and there is insufficient evidence on benefits for marginalised groups	medium	1	train
4,011	AR6_WGII	568	13	The water intensity of mitigation must be managed in socially and politically acceptable ways to increase synergies with SDGs, improve water security and reduce trade-offs with adaptation	medium	1	train
4,012	AR6_WGII	568	16	Water adaptation policies enabled through ethical co-production between holders of Indigenous knowledge, local knowledge and technical knowledge (medium confidence), through cooperation and coordinated actions among multiple actors, including women and all marginalised groups, at various levels of governance	medium	1	train
4,013	AR6_WGII	569	7	First, approximately half the world’s population (~4 billion out of ~8 billion people) are assessed as being currently subject to severe water scarcity for at least some part fo the year	medium	1	train
4,014	AR6_WGII	569	11	Currently, many people are experiencing climate change on a day-to-day basis through water-related impacts such as the increased frequency and intensity of heavy precipitation (high confidence) (Section 4.2.1.1, Seneviratne et al., 2021); accelerated melting of glaciers (high confidence) (Section 4.2.2, Douville et al., 2021); changes in frequency, magnitude and timing of floods (high confidence) (Section 4.2.4, Seneviratne et al., 2021); more frequent and severe droughts in some places (high confidence) (Section 4.2.5, Seneviratne et al., 2021); decline in groundwater storage and reduction in recharge (medium confidence) (Section 4.2.6, Douville et al., 2021) and water quality deterioration due to extreme events	medium	1	train
4,015	AR6_WGII	569	16	Vulnerability to water-related impacts of climate change and extreme weather are already felt in all major sectors and are projected to intensify in the future, for example, in agriculture (high confidence) (Sections 4.3.1, 4.5.1); energy and industry (high confidence for observed drought impacts and projected impacts) (Sections 4.3.2, 4.5.2); water for health and sanitation (high confidence about links to precipitation extremes and disease outbreaks) (Sections 4.3.3, 4.5.3); water for urban, peri-urban and municipal sectors	medium	1	train
4,016	AR6_WGII	569	28	Third, a large majority (~60%) of all adaptation responses documented since 2014 are about adapting to water-related hazards like droughts, floods and rainfall variability (Berrang-Ford et al., 2021b)	high	2	train
4,017	AR6_WGII	569	32	Only ~20% of all documented case studies on observed water-related adaptations measure outcomes (positive or negative), but the link between positive outcomes and climate risk reduction is unclear and remains challenging to assess (Section 4.7.1)	medium	1	train
4,018	AR6_WGII	569	33	On the other hand, most of the future projected water-related adaptations are more effective at lower GWLs (1.5°C) than at higher GWLs, showing the importance of mitigation for future adaptations to remain effective	high	2	train
4,019	AR6_WGII	570	2	Therefore, minimising the risks to water security from climate change will require a full-systems view that considers the direct impacts of mitigation measures on water resources and their indirect effect via limiting climate change	high	2	train
4,020	AR6_WGII	570	11	AR5 projected an increase in meteorological, agricultural and hydrological droughts in dry regions	medium	1	train
4,021	AR6_WGII	570	12	The Special Report on Global Warming of 1.5°C (SR1.5) assessed that limiting global warming to 1.5°C is expected to substantially reduce the probability of extreme droughts, precipitation deficits and risks associated with water availability in some regions	medium	1	train
4,022	AR6_WGII	570	13	On the other hand, higher risks to natural and human systems in a 2.0°C world would mean increased vulnerability for the poor, showing that socioeconomic drivers are expected to have a more significant influence on water-related risks and vulnerabilities than changes in climate alone	medium	1	train
4,023	AR6_WGII	571	19	Climate change patterns of streamflow change include declines in western North America, northeast South America, the Mediterranean and South Asia	medium	1	train
4,024	AR6_WGII	574	3	The Special Report on Climate Change and Land (SRCCL) stated that groundwater over-extraction for irrigation is causing depletion of groundwater storage	high	2	train
4,025	AR6_WGII	574	4	The report also noted that precipitation changes, coupled with human drivers, will have a role in causing desertification, and water-driven soil erosion is projected to increase due to climate change	medium	1	train
4,026	AR6_WGII	574	6	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	high	2	train
4,027	AR6_WGII	574	7	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	high	2	train
4,028	AR6_WGII	574	21	Therefore, improving societal aspects of water management will be key in adapting to climate change-driven increases in water scarcity in the future	high	2	train
4,029	AR6_WGII	574	28	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	medium	1	train
4,030	AR6_WGII	574	29	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	high	2	train
4,031	AR6_WGII	574	30	Areas with high water availability can also be water-insecure due to increased flood risk, deteriorated water quality, and poor governance	high	2	train
4,032	AR6_WGII	574	31	Future water security will depend on the evolution of all these socioeconomic and governance factors and future regional climate change	high	2	train
4,033	AR6_WGII	574	32	The main climate change contribution to water insecurity is the potential for reduced water availability, with a secondary contribution from increased flooding risk	medium	1	train
4,034	AR6_WGII	574	33	Future socioeconomic conditions are a crucial driver of water insecurity, implying the need for further adaptation to some level of future climate change	medium	1	train
4,035	AR6_WGII	574	34	However, policy challenges are high in many regions, with uncertainty in the regional climate outcomes being a key factor	high	2	train
4,036	AR6_WGII	576	12	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	high	2	train
4,037	AR6_WGII	576	14	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	high	2	train
4,038	AR6_WGII	576	15	Direct human interventions in river systems and groundwater systems are non- climatic drivers with substantial impacts on the water cycle	high	2	train
4,039	AR6_WGII	578	9	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	medium	1	train
4,040	AR6_WGII	578	11	On the other hand, approximately 163 million people lived in unfamiliarly dry areas, mostly in low latitudes	medium	1	train
4,041	AR6_WGII	578	12	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	high	2	train
4,042	AR6_WGII	578	13	Therefore, the numbers of people seeing unfamiliar seasonal precipitation levels are expected to be higher than those quoted above for unfamiliar annual precipitation changes	medium	1	train
4,043	AR6_WGII	578	15	The intensity of heavy precipitation has increased in many regions	high	2	train
4,044	AR6_WGII	578	21	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)	medium	1	train
4,045	AR6_WGII	578	22	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	medium	1	train
4,046	AR6_WGII	578	24	Nearly half a billion people live in areas with historically unfamiliar wet conditions, and over 160 million in areas with historically unfamiliar dry conditions	medium	1	train
4,047	AR6_WGII	579	29	Changes in land cover and irrigation have also changed regional ET	medium	1	train
4,048	AR6_WGII	581	1	Global mean soil moisture has slightly decreased, but regional changes vary, with both increases and decreases of 20% or more in some regions	medium	1	test
4,049	AR6_WGII	581	2	Drying soil moisture trends are more widespread than wetting trends, not only in arid areas but also in humid and transitional areas	medium	1	train
4,050	AR6_WGII	581	3	Reduced dry-season water availability is driven mainly by increasing transpiration	medium	1	train
4,051	AR6_WGII	581	5	Tourism and recreation activities have been negatively impacted by declining snow cover, glaciers and permafrost in high mountains	medium	1	train
4,052	AR6_WGII	581	19	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	very high	3	test
4,053	AR6_WGII	582	5	Widespread cryospheric changes are affecting humans and ecosystems in mid-to-high latitudes and the high-mountain regions	high	2	train
4,054	AR6_WGII	584	26	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)	high	2	train
4,055	AR6_WGII	584	27	Climatic factors contribute to these trends in most basins	high	2	train
4,056	AR6_WGII	584	28	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	medium	1	train
4,057	AR6_WGII	584	29	Overall, anthropogenic climate change is attributed as a driver to the global pattern of change in streamflow	medium	1	train
4,058	AR6_WGII	584	37	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)	high	2	train
4,059	AR6_WGII	588	18	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)	high	2	train
4,060	AR6_WGII	588	24	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	high	2	train
4,061	AR6_WGII	588	26	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	medium	1	train
4,062	AR6_WGII	588	31	In summary, the frequency and magnitude of river floods have changed in the past several decades with high regional variations	high	2	train
4,063	AR6_WGII	588	32	Anthropogenic climate change has increased the likelihood of extreme precipitation events and the associated increase in the frequency and magnitude of river floods	high	2	train
4,064	AR6_WGII	589	4	Agricultural drought threatens food production through crop damage and yield decreases (e.g., Section 4.3.1)	high	2	train
4,065	AR6_WGII	589	7	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	medium	1	train
4,066	AR6_WGII	590	15	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	high	2	train
4,067	AR6_WGII	590	16	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	medium	1	train
4,068	AR6_WGII	590	17	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	medium	1	train
4,069	AR6_WGII	592	14	These estimates range from approximately 113 to 510 km3 yr−1 and variation in estimates is due to methods and spatio-temporal scales considered	high	2	train
4,070	AR6_WGII	592	15	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)	high	2	train
4,071	AR6_WGII	592	16	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	high	2	train
4,072	AR6_WGII	593	10	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)	medium	1	train
4,073	AR6_WGII	593	24	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	high	2	train
4,074	AR6_WGII	593	26	In higher altitudes, warmer climates have altered groundwater regimes and may have led to reduced spring recharge due to reduced duration and snowmelt discharges	medium	1	train
4,075	AR6_WGII	594	13	In summary, although climate-induced water quality degradation due to increases in water and surface temperatures or melting of the cryosphere has been observed	medium	1	train
4,076	AR6_WGII	594	17	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)	medium	1	train
4,077	AR6_WGII	594	19	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)	medium	1	train
4,078	AR6_WGII	594	26	The climate change impact on erosion and sediment load varies significantly over the world (Li et al., 2020b)	high	2	train
4,079	AR6_WGII	595	8	In summary, in the areas with high human activity, factors other than climate have a more significant impact on soil erosion and sediment flux	high	2	train
4,080	AR6_WGII	595	26	Drought has been singled out as a major driver of yield reductions globally	high	2	test
4,081	AR6_WGII	596	10	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)	medium	1	train
4,082	AR6_WGII	596	14	Moreover, extreme precipitation can lead to increased surface flooding, waterlogging, soil erosion and susceptibility to salinisation	high	2	train
4,083	AR6_WGII	596	22	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)	high	2	train
4,084	AR6_WGII	596	24	In subtropical/ tropical climates, climate-induced hazards such as floods and droughts negatively impact agricultural production	high	2	train
4,085	AR6_WGII	596	26	They often rely on rain-fed agriculture in marginal areas with high exposure and high vulnerability to water- related stress and low adaptive capacity	high	2	train
4,086	AR6_WGII	596	34	A recent global study concluded that reservoirs might emit more carbon than they bury, especially in the tropics (Keller et al., 2021)	medium	1	train
4,087	AR6_WGII	597	2	Thus, there is a growing body of evidence of negative impacts of extreme events on hydropower production	high	2	train
4,088	AR6_WGII	597	7	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	high	2	train
4,089	AR6_WGII	597	15	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)	high	2	train
4,090	AR6_WGII	597	23	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)	high	2	train
4,091	AR6_WGII	597	30	Water insecurity and inadequate WaSH have been associated with increased disease risk	high	2	train
4,092	AR6_WGII	598	11	Climate extremes have profound implications for urban and peri-urban water management, particularly in an increasingly urbanised world	high	2	train
4,093	AR6_WGII	599	1	Introduction Some extreme weather events are increasing in frequency and (or) severity as a result of climate change (Seneviratne et al., 2021)	high	2	train
4,094	AR6_WGII	599	7	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	high	2	train
4,095	AR6_WGII	602	24	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’	high	2	train
4,096	AR6_WGII	602	25	Detection and attribution studies make the climate change fingerprint of several types of disasters increasingly clear	high	2	train
4,097	AR6_WGII	602	26	Moreover, existing vulnerabilities and exposures play an important role in turning extreme events into disasters, further exacerbating existing racial, gender and social inequalities	high	2	train
4,098	AR6_WGII	603	1	Further research is necessary to determine the extent and nature of water-related climate change impacts in the urban areas of developing countries	high	2	train
4,099	AR6_WGII	603	6	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)	high	2	train

4,000

AR6_WGII

567

12

Direct flood damages are projected to increase by four to five times at 4°C compared to 1.5°C

medium

1

train

4,001

AR6_WGII

567

17

Projected losses include a 1.2- to 1.8-fold increase in GDP loss due to flooding between 1.5°C and 2°C warming

medium

1

train

4,002

AR6_WGII

567

19

Due to the combined effects of water and temperature changes, risks to agricultural yields could be three times higher at 3°C compared to 2°C

medium

1

train

4,003

AR6_WGII

567

22

The number of internally displaced people in sub- Saharan Africa, South Asia and Latin America increased almost five times for RCP8.5 compared to RCP2.6

low

0

train

4,004

AR6_WGII

567

26

In contrast, responses are more policy-oriented and urban-focused in developed countries

high

2

train

4,005

AR6_WGII

567

28

In addition, large- scale irrigation also affects local to regional climates, both in terms of temperature and precipitation change

high

2

train

4,006

AR6_WGII

568

1

Roughly one third and one fourth of case studies on water adaptation also documents maladaptation and co-benefits, respectively

high

2

train

4,007

AR6_WGII

568

2

A significant knowledge gap remains in knowing if observed adaptation benefits also translate to climate risk reduction, if so, by how much and under what conditions

medium

1

train

4,008

AR6_WGII

568

5

However, residual impacts remain for some options and regions at all levels of warming, and the overall effectiveness decreases at higher warming levels

high

2

train

4,009

AR6_WGII

568

9

SDGs cannot be met without adequate and safe water (high confidence), and water is fundamental to all systems transition

high

2

train

4,010

AR6_WGII

568

11

However, barriers remain for low-income countries to access funds (medium confidence), and there is insufficient evidence on benefits for marginalised groups

medium

1

train

4,011

AR6_WGII

568

13

The water intensity of mitigation must be managed in socially and politically acceptable ways to increase synergies with SDGs, improve water security and reduce trade-offs with adaptation

medium

1

train

4,012

AR6_WGII

568

16

Water adaptation policies enabled through ethical co-production between holders of Indigenous knowledge, local knowledge and technical knowledge (medium confidence), through cooperation and coordinated actions among multiple actors, including women and all marginalised groups, at various levels of governance

medium

1

train

4,013

AR6_WGII

569

7

First, approximately half the world’s population (~4 billion out of ~8 billion people) are assessed as being currently subject to severe water scarcity for at least some part fo the year

medium

1

train

4,014

AR6_WGII

569

11

Currently, many people are experiencing climate change on a day-to-day basis through water-related impacts such as the increased frequency and intensity of heavy precipitation (high confidence) (Section 4.2.1.1, Seneviratne et al., 2021); accelerated melting of glaciers (high confidence) (Section 4.2.2, Douville et al., 2021); changes in frequency, magnitude and timing of floods (high confidence) (Section 4.2.4, Seneviratne et al., 2021); more frequent and severe droughts in some places (high confidence) (Section 4.2.5, Seneviratne et al., 2021); decline in groundwater storage and reduction in recharge (medium confidence) (Section 4.2.6, Douville et al., 2021) and water quality deterioration due to extreme events

medium

1

train

4,015

AR6_WGII

569

16

Vulnerability to water-related impacts of climate change and extreme weather are already felt in all major sectors and are projected to intensify in the future, for example, in agriculture (high confidence) (Sections 4.3.1, 4.5.1); energy and industry (high confidence for observed drought impacts and projected impacts) (Sections 4.3.2, 4.5.2); water for health and sanitation (high confidence about links to precipitation extremes and disease outbreaks) (Sections 4.3.3, 4.5.3); water for urban, peri-urban and municipal sectors

medium

1

train

4,016

AR6_WGII

569

28

Third, a large majority (~60%) of all adaptation responses documented since 2014 are about adapting to water-related hazards like droughts, floods and rainfall variability (Berrang-Ford et al., 2021b)

high

2

train

4,017

AR6_WGII

569

32

Only ~20% of all documented case studies on observed water-related adaptations measure outcomes (positive or negative), but the link between positive outcomes and climate risk reduction is unclear and remains challenging to assess (Section 4.7.1)

medium

1

train

4,018

AR6_WGII

569

33

On the other hand, most of the future projected water-related adaptations are more effective at lower GWLs (1.5°C) than at higher GWLs, showing the importance of mitigation for future adaptations to remain effective

high

2

train

4,019

AR6_WGII

570

2

Therefore, minimising the risks to water security from climate change will require a full-systems view that considers the direct impacts of mitigation measures on water resources and their indirect effect via limiting climate change

high

2

train

4,020

AR6_WGII

570

11

AR5 projected an increase in meteorological, agricultural and hydrological droughts in dry regions

medium

1

train

4,021

AR6_WGII

570

12

The Special Report on Global Warming of 1.5°C (SR1.5) assessed that limiting global warming to 1.5°C is expected to substantially reduce the probability of extreme droughts, precipitation deficits and risks associated with water availability in some regions

medium

1

train

4,022

AR6_WGII

570

13

On the other hand, higher risks to natural and human systems in a 2.0°C world would mean increased vulnerability for the poor, showing that socioeconomic drivers are expected to have a more significant influence on water-related risks and vulnerabilities than changes in climate alone

medium

1

train

4,023

AR6_WGII

571

19

Climate change patterns of streamflow change include declines in western North America, northeast South America, the Mediterranean and South Asia

medium

1

train

4,024

AR6_WGII

574

3

The Special Report on Climate Change and Land (SRCCL) stated that groundwater over-extraction for irrigation is causing depletion of groundwater storage

high

2

train

4,025

AR6_WGII

574

4

The report also noted that precipitation changes, coupled with human drivers, will have a role in causing desertification, and water-driven soil erosion is projected to increase due to climate change

medium

1

train

4,026

AR6_WGII

574

6

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

high

2

train

4,027

AR6_WGII

574

7

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

high

2

train

4,028

AR6_WGII

574

21

Therefore, improving societal aspects of water management will be key in adapting to climate change-driven increases in water scarcity in the future

high

2

train

4,029

AR6_WGII

574

28

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

medium

1

train

4,030

AR6_WGII

574

29

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

high

2

train

4,031

AR6_WGII

574

30

Areas with high water availability can also be water-insecure due to increased flood risk, deteriorated water quality, and poor governance

high

2

train

4,032

AR6_WGII

574

31

Future water security will depend on the evolution of all these socioeconomic and governance factors and future regional climate change

high

2

train

4,033

AR6_WGII

574

32

The main climate change contribution to water insecurity is the potential for reduced water availability, with a secondary contribution from increased flooding risk

medium

1

train

4,034

AR6_WGII

574

33

Future socioeconomic conditions are a crucial driver of water insecurity, implying the need for further adaptation to some level of future climate change

medium

1

train

4,035

AR6_WGII

574

34

However, policy challenges are high in many regions, with uncertainty in the regional climate outcomes being a key factor

high

2

train

4,036

AR6_WGII

576

12

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

high

2

train

4,037

AR6_WGII

576

14

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

high

2

train

4,038

AR6_WGII

576

15

Direct human interventions in river systems and groundwater systems are non- climatic drivers with substantial impacts on the water cycle

high

2

train

4,039

AR6_WGII

578

9

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

medium

1

train

4,040

AR6_WGII

578

11

On the other hand, approximately 163 million people lived in unfamiliarly dry areas, mostly in low latitudes

medium

1

train

4,041

AR6_WGII

578

12

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

high

2

train

4,042

AR6_WGII

578

13

Therefore, the numbers of people seeing unfamiliar seasonal precipitation levels are expected to be higher than those quoted above for unfamiliar annual precipitation changes

medium

1

train

4,043

AR6_WGII

578

15

The intensity of heavy precipitation has increased in many regions

high

2

train

4,044

AR6_WGII

578

21

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)

medium

1

train

4,045

AR6_WGII

578

22

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

medium

1

train

4,046

AR6_WGII

578

24

Nearly half a billion people live in areas with historically unfamiliar wet conditions, and over 160 million in areas with historically unfamiliar dry conditions

medium

1

train

4,047

AR6_WGII

579

29

Changes in land cover and irrigation have also changed regional ET

medium

1

train

4,048

AR6_WGII

581

1

Global mean soil moisture has slightly decreased, but regional changes vary, with both increases and decreases of 20% or more in some regions

medium

1

test

4,049

AR6_WGII

581

2

Drying soil moisture trends are more widespread than wetting trends, not only in arid areas but also in humid and transitional areas

medium

1

train

4,050

AR6_WGII

581

3

Reduced dry-season water availability is driven mainly by increasing transpiration

medium

1

train

4,051

AR6_WGII

581

5

Tourism and recreation activities have been negatively impacted by declining snow cover, glaciers and permafrost in high mountains

medium

1

train

4,052

AR6_WGII

581

19

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

very high

3

test

4,053

AR6_WGII

582

5

Widespread cryospheric changes are affecting humans and ecosystems in mid-to-high latitudes and the high-mountain regions

high

2

train

4,054

AR6_WGII

584

26

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)

high

2

train

4,055

AR6_WGII

584

27

Climatic factors contribute to these trends in most basins

high

2

train

4,056

AR6_WGII

584

28

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

medium

1

train

4,057

AR6_WGII

584

29

Overall, anthropogenic climate change is attributed as a driver to the global pattern of change in streamflow

medium

1

train

4,058

AR6_WGII

584

37

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)

high

2

train

4,059

AR6_WGII

588

18

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)

high

2

train

4,060

AR6_WGII

588

24

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

high

2

train

4,061

AR6_WGII

588

26

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

medium

1

train

4,062

AR6_WGII

588

31

In summary, the frequency and magnitude of river floods have changed in the past several decades with high regional variations

high

2

train

4,063

AR6_WGII

588

32

Anthropogenic climate change has increased the likelihood of extreme precipitation events and the associated increase in the frequency and magnitude of river floods

high

2

train

4,064

AR6_WGII

589

4

Agricultural drought threatens food production through crop damage and yield decreases (e.g., Section 4.3.1)

high

2

train

4,065

AR6_WGII

589

7

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

medium

1

train

4,066

AR6_WGII

590

15

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

high

2

train

4,067

AR6_WGII

590

16

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

medium

1

train

4,068

AR6_WGII

590

17

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

medium

1

train

4,069

AR6_WGII

592

14

These estimates range from approximately 113 to 510 km3 yr−1 and variation in estimates is due to methods and spatio-temporal scales considered

high

2

train

4,070

AR6_WGII

592

15

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)

high

2

train

4,071

AR6_WGII

592

16

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

high

2

train

4,072

AR6_WGII

593

10

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)

medium

1

train

4,073

AR6_WGII

593

24

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

high

2

train

4,074

AR6_WGII

593

26

In higher altitudes, warmer climates have altered groundwater regimes and may have led to reduced spring recharge due to reduced duration and snowmelt discharges

medium

1

train

4,075

AR6_WGII

594

13

In summary, although climate-induced water quality degradation due to increases in water and surface temperatures or melting of the cryosphere has been observed

medium

1

train

4,076

AR6_WGII

594

17

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)

medium

1

train

4,077

AR6_WGII

594

19

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)

medium

1

train

4,078

AR6_WGII

594

26

The climate change impact on erosion and sediment load varies significantly over the world (Li et al., 2020b)

high

2

train

4,079

AR6_WGII

595

8

In summary, in the areas with high human activity, factors other than climate have a more significant impact on soil erosion and sediment flux

high

2

train

4,080

AR6_WGII

595

26

Drought has been singled out as a major driver of yield reductions globally

high

2

test

4,081

AR6_WGII

596

10

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)

medium

1

train

4,082

AR6_WGII

596

14

Moreover, extreme precipitation can lead to increased surface flooding, waterlogging, soil erosion and susceptibility to salinisation

high

2

train

4,083

AR6_WGII

596

22

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)

high

2

train

4,084

AR6_WGII

596

24

In subtropical/ tropical climates, climate-induced hazards such as floods and droughts negatively impact agricultural production

high

2

train

4,085

AR6_WGII

596

26

They often rely on rain-fed agriculture in marginal areas with high exposure and high vulnerability to water- related stress and low adaptive capacity

high

2

train

4,086

AR6_WGII

596

34

A recent global study concluded that reservoirs might emit more carbon than they bury, especially in the tropics (Keller et al., 2021)

medium

1

train

4,087

AR6_WGII

597

2

Thus, there is a growing body of evidence of negative impacts of extreme events on hydropower production

high

2

train

4,088

AR6_WGII

597

7

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

high

2

train

4,089

AR6_WGII

597

15

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)

high

2

train

4,090

AR6_WGII

597

23

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)

high

2

train

4,091

AR6_WGII

597

30

Water insecurity and inadequate WaSH have been associated with increased disease risk

high

2

train

4,092

AR6_WGII

598

11

Climate extremes have profound implications for urban and peri-urban water management, particularly in an increasingly urbanised world

high

2

train

4,093

AR6_WGII

599

1

Introduction Some extreme weather events are increasing in frequency and (or) severity as a result of climate change (Seneviratne et al., 2021)

high

2

train

4,094

AR6_WGII

599

7

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

high

2

train

4,095

AR6_WGII

602

24

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’

high

2

train

4,096

AR6_WGII

602

25

Detection and attribution studies make the climate change fingerprint of several types of disasters increasingly clear

high

2

train

4,097

AR6_WGII

602

26

Moreover, existing vulnerabilities and exposures play an important role in turning extreme events into disasters, further exacerbating existing racial, gender and social inequalities

high

2

train

4,098

AR6_WGII

603

1

Further research is necessary to determine the extent and nature of water-related climate change impacts in the urban areas of developing countries

high

2

train

4,099

AR6_WGII

603

6

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)

high

2

train