The major challenges posed by climate change globally include increasing temperatures and altered precipitation patterns [33]. Approximately 4 billion people globally face water scarcity, with regions such as China experiencing reduced water flow, declining water tables, and wetland shrinkage [34]-[36]. Key river basins, including the Yellow River Basin in China, the Murray-Darling Basin in Australia, and the Mekong River Basin in Southeast Asia, are under severe water exploitation, impeding sustainable development [37][38]. In Africa, countries such as Kenya, Somalia, South Sudan, Tanzania, Burundi, and Uganda experienced severe drought conditions during the periods 2008-2009, 2010-2011, and 2016-2017 [39][40].

There can be profound impacts of climate change on the water cycle, influencing water and energy balances, hydrothermal coupling, and river discharge across varying temporal and spatial scales. But there is an absence of interactions between water and energy fluxes across scales in the existing hydrological models. Among the key indicators of climate change on water resources are the rising sea levels, glacier melting, freshwater scarcity, and ecological disruptions, which have been extensively documented [41][42]. The current changes in precipitation intensity and frequency further underscore the changing climate’s role in maintaining the current global water-balance [25]. Substantial unpredictability for future precipitation extremes exists especially in areas with limited data.

Changing precipitation patterns are a critical factor considered in this review, as they greatly affect agriculture, which consumes about 70% of global freshwater for irrigation. This makes agriculture highly vulnerable to the ongoing decline in water availability. Furthermore, drought has played a key role in reducing river water levels, leading to the extinction of aquatic, floodplain, and human ecosystems. The disruption of the ecosystem primarily causes the destruction of habitats, including wetlands, rivers and lakes. A study of River Naoli Basin in China focused on assessment of runoff and drought patterns. The authors revealed a significant increase in drought frequency during summer, leading to reduced runoff in waterways. The decline in River Naoli’s water levels caused the extinction of some aquatic ecosystems through habitat destruction, leading to biodiversity loss, vegetation stress, and reduced water quality [43]. Such situations require urgent attention to prevent a severe water crisis in the vulnerable regions of the world in the near future.

In the past and current centuries, human activities, especially industrialization and burning of fossil fuel, have significantly increased GHG and aerosol emissions [44]-[46]. This has resulted in changing climate patterns that are affecting water resources [2][47][48]. However, there is uncertainty in the relative contributions of sources of emissions to the variations in regional hydrology.

Increased Earth’s surface temperatures and energy imbalance resulting from amplified GHG effect has strongly contributed to the alteration of the water cycle through thermodynamic and plant physiological processes. In particular, the temperature difference caused by elevated CO₂ levels enhances the rate at which water vapor is trapped in the atmosphere by approximately 7% per ˚C of warming [49]. Rising CO₂ levels induce physiological processes that reduce stomatal conductance and enhance water-use efficiency, thereby decreasing transpiration rates. The suppression of moisture movement can disrupt terrestrial moisture recycling, thereby inhibiting precipitation. Typically, vegetation emits water vapor that condenses to form clouds, which subsequently contribute to local and regional rainfall [49]. On the other hand, the intensity and frequency of precipitation increase due to elevated evapotranspiration rates, particularly in areas with high humidity.

Numerous studies indicate that ongoing anthropogenic activities are expected to exacerbate the impact of climate change on water resources for future generations [12]-[50]. Rising temperatures have reduced water levels and disrupted water distribution and circulation between the Earth’s surface, atmosphere, and subsurface, leading to water resource degradation [51]-[53]. Extreme weather conditions like drought events reduce the extent of groundwater recharge in the aquifers. Additionally, rising temperatures accelerate evapotranspiration, reducing groundwater recharge, depleting soil moisture, and decreasing water runoff in rivers and streams. But the extent to which these alterations become irrevocable is yet to be clearly understood. The Colorado River Basin serves as an example of a region significantly impacted by evapotranspiration driven by rising temperatures. Studies indicate that the streamflow of the Colorado River decreases by approximately 9.3% per ˚C of warming [54]. This moisture loss has contributed substantially to the depletion of water resources, posing challenges to water management for the communities in the surrounding areas [55].

Several regions, including those in the tropics, have experienced significant impacts from rising temperatures. The tropics face an increased frequency of extreme rainfall leading to floods and erosion. Subtropical zones are also experiencing heightened heat stress and aridity, which contribute to water conflicts [56]. Temperate regions, on the other hand, are encountering seasonal climatic contrasts characterized by wetter winters and more intense summer heatwaves and droughts [57]. The Intergovernmental Panel on Climate Change (IPCC) has documented global warming effects, with thermometer data from various regions showing average temperatures 1.1˚C to 1.5˚C above pre-industrial levels, surpassing the 1.5˚C threshold in 2024.

The spatial and temporal distribution of rainfall has been significantly altered by climate change, leading to variations in water levels across different water bodies [2][24][58][59]. The primary factor that influences water quantity in surface water bodies and groundwater is precipitation. Precipitation intensity and frequency determine the occurrence of major events in some areas, such as excessive rainfall that causes floods or long-term dry periods which indicate drought.

3.1.1. Drought

Drought in this review refers to the reduced frequency of precipitation coupled with increased temperatures for a prolonged period [60]. Most tropical and subtropical regions in the world are facing frequent droughts resulting in decreased streamflow [61]. Changes in precipitation patterns, marked by longer dry periods and shorter wet ones, lead to reduced water discharges. The reduction of water quantity in water reservoirs occurs when rainfall and inflows from snowmelt and groundwater cause depletion of water bodies. Furthermore, reduced groundwater recharge, and continued human water withdrawals for industrial and domestic use during dry spells lead to shrinkage of both surface and subsurface water. This decline in water availability impacts irrigation, agriculture and hydropower generation [62]. Evidence reveals that River Mekong Basin received a record-breaking drought in 2019 with low precipitation from May to October amounting to 71.9% of the climatological mean which contributed to low stream flows [63][64]. Literature also indicates that since 2000, River Colorado’s water flow in the US has reduced by 19% as influenced by the decrease of spring season precipitation (drier springs) that contributed over 80% of the river discharge [65][66]. Furthermore, there is increased frequency of dry spells in the horn of Africa particularly in River Nile which has experienced a meteorological drought especially in Ethiopia, Sudan and Egypt leading to reduced river flow [67]. Uganda, a country in East Africa, is also facing climate variability with an increase in drought periods correlated to high temperatures affecting the availability of water [68]. Similarly, the Mediterranean basin has undergone periods of reduced winter precipitation caused by the movement of storm tracks towards the poles since 1970. These long dry periods reduce soil moisture, hinder evapotranspiration from land and surface water, lower humidity, and trigger repeated low rainfall events, which decrease water levels in rivers, lakes and wetlands (Figure 1). These effects are particularly significant in countries such as Egypt, Morocco, and Sudan, which rely heavily on irrigated agriculture [69]. Several regions, including subtropical areas and districts in Northern Uganda such as Gulu, Kotido and Kitgum, are also experiencing reduced precipitation due to seasonal changes characterized by extended dry periods compared to wet periods [69][70]. The above literature confirms how increased length of climate-driven droughts play a vital role in the reduction of water quantity in water reservoirs.

3.1.2. Flooding

Flooding, caused by extreme precipitation patterns, is another critical event analyzed in terms of its frequency, intensity and distribution [71]. Occurrence of floods in urban areas usually happens after rains of short duration and high intensity which submerge the drainage systems causing heavy runoff [72]. This event not only damages the infrastructure but also destroys the municipal water supply treatment plant and deteriorates the water quality through the deposition of nutrients in water resources [73] (Figure 2). In a study on Hu-Xi watershed on the upper stretch of Lake Taihu China, over 90% of annual runoff of water resources was stimulated by extreme precipitation periods [74]. These changes in precipitation trends affect water levels. Lake Victoria, the second-largest lake in the world, experienced fluctuations in water levels due to high precipitation. The lake’s water level rose by 1.21 metres between late 2019 to 2020, impacting over 29,000 people living within 50 kilometers. These floods caused infrastructure destruction and the displacement of residents [75]. The changing climate in some areas is characterized by more intense rainfall, leading to peak river and stream discharges. This results in fluvial, pluvial, coastal, and dam-burst events, causing water overflow on plains and reducing the rate of water infiltration [76][77].

A rise in temperatures leads to increased evaporation rates, significantly reducing surface water levels in oceans, rivers, lakes and reservoirs. This not only affects water bodies but also soil moisture levels, which in turn impairs water infiltration and percolation, thereby reducing groundwater recharge. A study in Ukraine demonstrated that surface water evaporation substantially decreases the availability of water in rivers and other water resources [78]. Another recent study modeled the evaporation of Lake Turkana using climate change projections and an artificial neural network model, forecasting average evaporation rates of 23.76, 25.68, 18.89, and 18.57 billion m³ for HADGEM, MPI 4.5, and 8.5 scenarios, respectively. Lake Turkana in Kenya, an endorheic water resource was reported to lose most of its water by evaporation with an evaporation rate approximated at 92 inches (2335 millimeters) annually [79]. These reduced water levels result in alteration of thermal balance in water resources which may lead to the growth of algae and death of aquatic life reducing biodiversity. The increased evaporation rates also minimize the availability of water supply for irrigation, hydropower and industrial use, hence affecting human well-being. The Zambezi River Basin at Kariba Dam highlights the potential impact of climate change on hydropower energy. Rising temperatures in the region have increased evaporation and reduced Zambezi River flows, significantly affecting hydropower production. Projections suggested a 9% decline by 2020, 18% by 2050, and 28% by 2080 of water quantity [80][81].

Groundwater recharge occurs when water from precipitation and surface water sources, such as wetlands, rivers, and streams, infiltrates into the soil which replenishes both confined and unconfined aquifers. The presence of cracks facilitates rapid water infiltration to the aquifer compared to the slower percolation through the soil. Assessing groundwater recharge rates is crucial for ensuring sustainable water resource availability [82][83]. Climate variability directly and indirectly affects groundwater recharge, leading to reductions in the water table, recharge rates, and base flow supporting rivers, streams, and other water bodies [82]. A study in Kiryandongo, Uganda, demonstrated that changes in rainfall and temperature significantly influence groundwater recharge [84]. High-intensity rainfall diminishes infiltration effectiveness due to increased surface runoff in lowland areas. Another study in the Usangu catchment, Tanzania, projects shorter rainy periods and a temperature rise of 6 - 2˚C, potentially causing a 7% reduction in water yield and a 26% decline in recharge [85]. Additionally, high temperatures and evaporation degrade soil by reducing porosity and aggregate stability, which decreases infiltration rates, raises runoff coefficients, and ultimately lowers groundwater recharge. There is a recent trend in Africa, which involves constructing groundwater supply systems to address the growing demand for water. These systems aim to support irrigation and supplement insufficient water for crops, leading to increased groundwater extraction and subsequent depletion of groundwater supplies [86][87].

The increase of CO₂ levels in the atmosphere is considered as the main driver of anthropogenic climate change with 2.29 W m⁻² or 66% of the global-radiative forcing from 1750 through 2023 [88][89]. This increase in CO₂ levels has caused a global temperature rise of 1.11˚C, resulting in the melting of glaciers and a rise in sea levels. In temperate regions like Himalayas, Tibetan plateau and tropical regions of Rwenzori Mountain in Africa, elevated temperatures have caused glaciers and snowpacks to melt, leading to a temporary increase in river flow from frozen water stores. Consequently, glacial water stores are being depleted at an exponential rate as the ice continues to diminish [90][91]. In summary, high temperatures lead to snowmelt, which causes rapid runoff, reducing the detention time necessary for water infiltration. This process diminishes groundwater recharge, ultimately decreasing water availability in reservoirs during dry seasons (Figure 2). Today, the Chhota Shigri region in the Indian Himalayas faces a long-term water security threat due to rising temperatures which have altered glacier lengths. Despite this, the region’s water resources remain heavily reliant on glacial meltwater [92]. Mount Rwenzori of East Africa is facing a spatial uniform loss of its glacier due to the elevated air temperatures. Mount Rwenzori glacier’s area decreased from approximately 6.5 square kilometers in 1900s to approximately 1 square kilometer in 2003 [93][94]. In the Rwenzori region, particularly in areas like Kasese, annual flooding events have caused deaths and displacement of people [95].

Figure 2. Schematic diagram showing the impacts of climate change on water resources and the ecosystem.

Increasing atmospheric temperatures increase water temperatures which greatly affects water quality in several water resources and aquatic biodiversity [97][98]. Elevated water temperatures reduce dissolved oxygen levels, leading to a phenomenon known as hypoxia. This condition creates a hostile and stressful environment for aquatic organisms, often resulting in their mortality [99]. Rising temperatures contribute to oxygen depletion through increased microbial decomposition of organic matter, particularly by anaerobic bacteria [100]. This process is exacerbated by higher nutrient loads, which, in combination with elevated temperatures, accelerate eutrophication. Eutrophication promotes the growth of algae and cyanobacteria, leading to harmful algal blooms and further oxygen depletion. Warm temperatures enhance these conditions, fostering the proliferation of algae and cyanobacteria. A study conducted in Lake Balaton, Hungary, revealed that increased temperatures stimulated the growth and reproduction of algae and cyanobacteria. This proliferation degraded the water’s clarity, taste, and odor [101][102]. Another study conducted at Dianchi Lake further demonstrated that the temperature of lake surface water significantly influences the occurrence of cyanobacteria blooms [97]. Additionally, warm water may stimulate the release of harmful substances such as NH₃, Hg and other volatile compounds. A study in Lake Kasumigaura, Japan, documented a significant rise in NH₃ and PO 4 3 − fluxes as water temperatures increased from 1.8˚C to 3.2˚C [103].

Extreme weather conditions such as floods and droughts can influence water quality deterioration [10]. Increased runoff and flooding occur when floodplains are inundated by water from heavier rainfall and more intense storms. In such cases, water sources are often contaminated by sewage, agricultural runoff, and other pollutants, altering the water’s physicochemical and biological state and making it unsafe for domestic use. Areas along Odaw River in Ghana have experienced increased precipitation and flooding. These floods resulted in destruction of sewage systems, mixing sewage with surface and groundwater, and caused microbial contamination [104].

The low levels of water flow caused by drought in waterways usually result in stagnation, accumulation of pollutants from agricultural areas, industries and urban areas. Low precipitation also causes salinization which usually affects the taste of water, loss of aquatic habitats, increased turbidity, and increased concentration of heavy metals like iron and manganese [105].

Rising sea levels increases the total volume of ocean water and is considered as one of the most catastrophic outcomes of climate change. These sea levels usually result from melting glaciers and expansion of water caused by increased temperatures. Evidence from satellite data suggested a significant ice melt in Greenland and Antarctica since 1993 with about 270 billion tons melting per year hence causing a substantial contribution to the rising sea level [106]. Research identified that about five sea level rise scenarios are likely to take place in relation to the increasing GHG emissions detected [107]. Scientists also projected that the global sea level rise will increase to 0.28 m by 2050 and more than 1 meter by 2100 [108]. Currently, Mexico is facing a rapid sea level rise with an expected increase ranging from 0.49 to 0.69 m in the next 30 years [109].

During periods of sea level rise, water quality is mainly altered by the flow of salt (sodium chloride, NaCl) water into fresh water sources like rivers, wetlands, and aquifers. This has been reported to affect the coastal ecosystems in major cities like Miami, and Shanghai [110][111]. When salty water mixes with freshwater due to the rise of sea level, the water chemical composition is altered significantly, rendering it unsuitable for drinking and other domestic uses. Salinization also results in substantial biodiversity loss, including fisheries and river dolphins [112]. Coastal erosion, driven by rising sea levels have been reported to cause sedimentation in waterways, leading to property losses exceeding $500 million in the United States [113]. Rising sea levels displace thousands of people annually, particularly in Pacific Island nations, where over 50,000 individuals migrate yearly. Additionally, the movement of pollutants caused by sea level rise has triggered outbreaks of waterborne diseases where over 70% of the respondents confirmed to be suffering from hypertension, diarrhea, and gastrointestinal issues [114]. The altered water parameters increase the costs of treatment to meet acceptable levels for their intended purposes.

Increased temperatures stimulate the melting of glaciers and snowpack which leads to runoff of meltwater to rivers, lakes and increased groundwater recharge [115]. A study of 77 Himalayan glaciers in India revealed shrinkage, snout retreat, thickness changes (−1.27 + 0.37) and mass loss (−1.08 + 0.31) with a reduction of average velocity from 21.3.3 m a⁻¹ to 16.68 m a⁻¹ by 2020 which showed that glaciers will disappear entirely, having an impact in regional water supply [116]-[118]. During glacial melting, there is a noticed variation in water levels, change in water temperatures, high sedimentation, increased levels of dissolved organic C and release of harmful pollutants in the water. The stored pollutants commonly include mercury, lead and persistent organic compounds which deteriorate water quality. Global history shows that viral diseases such as malaria and Spanish flu have a relationship with glacial melting since viruses are preserved in ice across the Artic and high-altitude tundra [118]. Antarctica and Greenland are known to have ice of 60 m and 7 m respectively which today, is said to melt, resulting in increase in sea levels by 20 cm by the last century [119][120]. A study in Greenland and Antarctica showed an interrelation between global warming and sea level rise, revealing a 50 m rise for each 2.5˚C [121].

Aquatic ecosystems like wetlands act as C sinks through the photosynthesis of vegetation such as mangroves, salt marshes, peatlands, and others. These ecosystems play a vital role in GHG uptake and emission, making them one of the most important ecosystems [131][132]. Carbon dioxide is commonly stored in anaerobic and water-logged sediments. Wetlands occupy about 2 - 6% of the Earth’s surface area and store approximately 20% of the global organic C qualifying them as one of the most efficient C stores [133][134]. However, extreme weather conditions have significantly disrupted the rate of CS in wetlands. Increased precipitation, prolonged droughts, heavy floods, and tropical storms are altering wetland hydrology, vegetation, and structure, thereby impairing C storage. Intense precipitation and floods, for instance, reduce a wetland’s ability to store C by causing erosion and disturbing C-rich soils, which releases C into the water and atmosphere. A notable example of coastal marshes in Louisiana is the historical loss of the wetland CS capacity by 1.0 Tg C yr⁻¹ which projected a 50% reduction in C storage in the next 50 years if restoration is not done [135]. Conversely, long-term droughts convert wetlands into C sources by exposing organic matter to oxygen, which accelerates its decomposition and CO₂ and CH₄ release. This was observed in the Okavango Delta, where severe droughts caused a decline in C accumulation due to organic matter oxidation. Rising temperatures further exacerbate these effects by destroying vegetation and biodiversity, leaving only heat-resistant species that disrupt the C cycle. For instance, in Indonesian tropical peatlands, vegetation destruction and decomposition have led to significant C losses [136]. Similarly, wildfires, such as those in Australian bushfires, release GHG emissions and destroy vegetation that would otherwise aid in C uptake. In summary, climate change contributes to the degradation of wetlands by altering the hydrology, increasing evaporation, and causing extreme droughts and floods. This ultimately reduces the wetlands’ ability to sequester C and filter water, worsening water quality and increasing GHG emissions.

The ocean is considered as a primary C sink which stores substantial amounts of CO₂ [136]. The ocean is usually one of those water resources majorly affected by changes in climate and is also considered as one of the main contributors to mitigation of climate change. Carbon dioxide is absorbed by the ocean annually, accounting for about 25% of emissions [137]. This process involves a flux that moves in two directions: positive when CO₂ is released into the atmosphere and negative when it is absorbed by the ocean. Absorption is more significant in colder, nutrient-rich waters compared to warmer regions. Literature indicates that by 2100, ocean chemistry is expected to change, which might lead to lower pH levels and increased acidity [138].

The capacity of the ocean’s CS is deteriorating due to the extreme weather events such as increased precipitation, temperature, storms and intense floods. Some parts of the ocean have reduced light penetration and disrupted phytoplankton photosynthesis which lessens the biological C uptake. This majorly results from heavy precipitation and coastal flooding which aids high runoff containing sediments and nutrients. On the other hand, high sea surface temperatures usually reduce the rate of solubility of CO₂ and escalate ocean stratification which reduces C drawdown. The rising temperatures also lead to loss of marine biodiversity and bleaching of coral reefs which release stored C to the atmosphere. In summary, extreme weather events disrupt both the physical and biological processes regulating C cycling in the ocean by reducing CO₂ absorption, enhancing C release, and diminishing the ocean’s capacity to store C, thereby compromising its role in maintaining the C cycle.

The major consequences of increased CO₂in the atmosphere are global temperatures and frequent heat waves which result in melting glaciers, rise of sea levels and variations in precipitation trends. Accumulation of CO₂ at the ecosystem level contributes to the acidification of water bodies. When CO₂ dissolves in water, it forms carbonic acid, which dissociates to release hydrogen ions, thereby lowering water pH. This process has significant biological implications such as accelerating the dissolution of skeletons in aquatic species such as corals and mollusks. Additionally, oxygen transport is impaired, and metabolic processes are reduced, potentially leading to the death and sometimes extinction of aquatic life. These changes ultimately result in the deterioration of water characteristics [138]. Elevated temperatures accelerate the desiccation of vegetation, creating conditions conducive to wildfires. These fires disrupt flora dispersal, reduce evapotranspiration rates critical for rainfall formation, lower water levels in rivers and lakes, and degrade water quality through increased sedimentation and impaired natural filtration systems.

Globally, climate change can qualitatively and quantitatively deteriorate water resources. Adaptation measures are crucial for reducing the impact of disasters like droughts and floods on water ecosystems [139][140]. The main objective of adapting to climate change is to improve resilience, enable sustainable water availability and quality under altering conditions (Figure 3). One impactful approach to address the challenges of unsustainable water resources is the use of climate smart technologies which involve innovative tools and practices which help to ensure water sustainability, food security, adaptation to climate change and minimized GHG emissions. These strategies include rainwater harvesting, desalination, wastewater recycling, nature-based systems, and controlled aquifer recharge can help mitigate resource depletion by replenishing groundwater and providing alternative water sources [141][142] (Figure 3). For instance, a study in arid and semi-arid areas showed enhancement of groundwater availability through climate smart rainwater harvesting and managed aquifer recharge in Egypt. This study revealed an aquifer recharge of 24.3, 28.8, 36.7 and 49.7 mcm with groundwater storage of 11.8%, 32.1%, 69%, 127.4% respectively for return periods of 10, 25, 50 and 100 years indicating a sustainable support of freshwater [143].

Another approach is improving water use efficiency, which is defined as the ratio of productivity per unit use of water. This commonly applies in agricultural systems that use most of global water. Farmers can opt to adopt techniques such as drip irrigation which can help moderate the amount of water being used for irrigation. Such systems have been implemented by Israel national irrigation committee to help control the rate of water misuse in their region [144]. Implementing community awareness and innovative water-saving technologies in urban areas can reduce leakages and promote the adoption of water-efficient devices, such as low-flow fixtures and recycling systems, in households and industries.

Figure 3. Schematic diagram summarizing the proposed mitigations and adaptation of climate change effects on water resources.

Advanced wastewater treatment technologies, including nutrient removal processes for N and P, along with effective disinfection methods, are essential for safeguarding water quality by reducing pollutant levels in water resources. Establishing buffer zones around wetlands and water sources can mitigate direct contamination from agricultural runoffs, thereby minimizing eutrophication. In China, natural infiltration systems have been employed to reduce urban flooding and control aquifer recharge, achieving a 75% annual runoff reduction through bioretention (34.5%) and sunken green spaces (46%) [145]. Rise of sea levels often leads to the salinization of freshwater bodies. Climate-smart adaptation strategies to address water salinization include controlled aquifer recharge and pumping, cultivating salt-tolerant crops such as rice, wheat, and vegetables, restoring mangroves and wetlands as natural barriers, and employing renewable energy-driven desalination techniques. In Israel, the National Water Management has incorporated desalination and recycling to help suppress the decreasing scarcity of freshwater resources with more than 87% of wastewater being used for agriculture and the five desalination plants providing about 80% of urban water used [146][147].

Lastly, focus can be put on preparedness and capacity building. For flooding, there should be implementation of flood adaptation techniques such as restoring flood plains, levees and flood walls, flood warning systems, providing flood hazard maps and flood forecasting systems (Figure 3). Communities can accommodate drought through integration of climate resilient infrastructures like micro scale irrigation systems depending on groundwater pumping, and growing drought resistant crop varieties like sorghum, cassava and millet.

Climate change mitigation involves addressing its root causes, primarily by reducing GHG emissions that significantly impact water sustainability. Water resources act as both sources and sinks of GHGs. Mitigation strategies include conserving ecosystems such as wetlands, which serve as critical C sinks, support CS, regulate floods, and naturally filter contaminants from rivers, lakes, and oceans [136]. Increased and enhanced CS activity plays a crucial role in addressing global climate change through the reduction of levels of CO₂ which trap heat in the atmosphere [148]. Coastal ecosystems, including mangroves, seagrasses, and salt marshes, are crucial for shoreline protection. They mitigate the impacts of storm surges and help prevent salinity intrusion, highlighting their importance in maintaining coastal resilience.

Table 1. Possible outcomes from implementation of different adaptation and mitigation measures.

Sustainable agricultural practices and proper land use management are key measures for mitigating climate change impacts on water resources (Figure 3). For instance, optimization of fertilizer use especially nitrogenous fertilizers using the 4R (right rate, source, timing and placement) strategy, and irrigation can be practiced to minimize the release of N₂O and nutrient pollution from agricultural lands. Additionally, reliance on synthetic fertilizer production can be minimized through the recycling of N and P in agricultural systems (Table 1).

Lastly, climate change-driven water degradation can be mitigated by integrating the circular water-energy nexus which includes the recovery of nutrients from wastewater such as the extraction of biogas from sludge treatment. This can facilitate the transition to renewable energy systems, thereby reducing GHG emissions. Awareness campaigns play a critical role in educating vulnerable communities about the conservation of aquatic ecosystems and the prevention of their degradation. These efforts ensure the preservation of essential ecological functions within these ecosystems [148].