Water and climate mitigation (4).pdf

1. Our water environment 1.1 The water budget and hydrological cycle The water budget is a hydrological tool to quan9fy the ﬂow of water in and out of system. The rate of change of water stored in a given area is balanced by the quan9ty and rate of water ﬂowing and out of that area. We can express this as: P + Qin = ET + ∆S + Qout P = precipita9on (rain, snow, etc.) Qin = water ﬂow (discharge) into the watershed ET = quan9ty of evapotranspira9on from soils, surfacewater, plants, etc. ∆S = Change in water storage Qout = sum of water ﬂowing out of the watershed Simplified schematic of the water budget Inﬂuence on river ﬂow - > soil moisture -> runoﬀ conversion Water is less likely to be converted into runoff -> rivers dry up Runoﬀ and groundwater are recharged Field capacity may be reached -> percolation of precipitation into watertable and groundwater. 1.2 Deﬁning water supply and water resource resilience Water supply resilience Resilient water supplies ensure both quantity and quality support all aspects of socioeconomic sectors. Water resource resilience 2013 Defra and the Welsh Government defined as: The ability of a system to withstand shocks and continue to function i.e. an healthy aquatic environment will likely support healthy aquatic ecosystems in recovering from periods of low flow and drought. These shocks include: Drought – water shortage Flooding – risk to water supply Heat waves – increased demand h"ps://researchbrieﬁngs.ﬁles.parliament.uk/documents/POST-PB-0040/POST-PB-0040.pdf - Water supply depends on the availability and quality of the water. - In the UK we have precipita9on all year round but the majority occurs in the winter and demand is highest in the summer. - The ground geology and porosity and permeability of soil are the main drivers for the storage of water in a catchment. - If we understand these mechanisms we can think about how to mi9gate climate change impacts on water. - There is a balance between permeability (inﬁltra9on) and porosity (storage reten9on) for aquifers to form –which form natural groundwater reserves. https://researchbriefings.files.parliament.uk/documents/POST-PB-0040/POST-PB-0040.pdf Porosity - the percentage of open space within an unconsolidated sediment or rock. What do we need for a good aquifer ? Groundwater exists where there is porosity i.e. gaps However, how well our groundwater can flow is dependent on permeability i.e. flow ability There must be sufficient permeability for water to flow through the rock. Specific yield must be higher and specific retention. Gravel, sand and silt make good aquifers - specific yield is high and specific retention is low. Clay makes a good aquitard – specific yield is low and specific retention is high. Speciﬁc yield – the amount of water available for groundwater extracCon. - The geology of South and East of England is primarily comprised of chalk which makes it useful for holding large reserves of water (but hard to replenish). - Here, chalk streams form and are an example of a rare ecosystem supported by groundwater, there are only 200 known chalk streams worldwide with 85% located in South and East England. - Groundwater provides over 75% of public water supply in some areas of England (see map). - Groundwater contributes to river flow and supports abstraction. - But sufficient precipitation is needed to replenish surface water and ground water sources. h"ps://researchbrieﬁngs.ﬁles.parliament.uk/documents/POST-PB-0040/POST-PB-0040.pdf 2. The role of water in climate change The interacAon between water and the major socio-economic sectors impacted by climate change Many people will experience climate change through its effects on water Source: UNESCO, UN-Water, 2020: United Nations World Water Development Report 2020: Water and Climate Change, Paris, UNESCO. When we think about climate change, we tend to think about CO2 and CH4 but water (vapor) is the most dominant GHG We oMen do not consider its eﬀects as: 60% - It spreads out a lot in the atmosphere (unlike carbon). - It can take many forms (cloud, haze, liquid) with diﬀerent eﬀects ….. - This makes it hard to model. - water vapor roughly accounts for about 60% of the Earth's greenhouse warming eﬀect. Haze Has a warming effect – solar radiation reaching the ground decreases and the surface heat flux is reduced. Cooling eﬀect – providing a reﬂecAve surface and increasing surface albedo. Solar radiaAon is reﬂected back out (except at night when it has the opposite eﬀect – acts as storage). Clouds When we think about climate change we often think about warm and cold rather than wet and dry. We also associate droughts and floods as causes of climate change but they are climate change. Temperature is a cause of floods and droughts but really these are caused by disruptions to the hydrological cycle and the water budget. Simplified: Precipitation – evaporation – condensation (clouds) Complex: Healthy permeable soil – infiltration (supports vegetation) –percolation aquifer formation – feeds rivers and streams - more saturated land (more water) - increases evaporation – increases condensation – more rain Maintaining healthy ecosystems are essenCal to support a funcConing hydrological balance and climate. Changes to the water budget Hydrological imbalance drought: Reduced vegetation Lower evapotranspiration Less humidity Reduction in cloud cover & less rain Less evaporation Less evaporative surface cooling – greater sensible heat flux Less evapora9on Less humidity Warming Warming Hydrological imbalance Flood: Bare-ground exposure Compaction of ground Reduced infiltration Increased surface runoff Creation of floods Reduced water storage Depletion of ground water Hydrological imbalance Flood: Impermeable surface Reduced inﬁltra9on Increased surface runoﬀ Creation of floods Reduced water storage Depletion of ground water Summary: Changes to hydrology across the watershed 3. Response of water resources to climate change Changes in both precipitation and temperature directly impact the water budget -> increased precipitation in N latitudes. Changes in evaporation and precipitation will determine future soil moisture and groundwater levels. Example: Polar regions are predicted to experience accelerated melting of glaciers – locally and temporality increasing water availability – increased stream flow. Change in annual Q with a 2℃ temperature increase However, the reduction in glacier cover is likely to lead to more variable river flows and a reduction in water storage and baseflow. This is because there is more chance of increased flooding -> reducing water availability overall. Water stress impacts every con0nent Water use is growing at twice the rate of populaCon increase. This combined with more erraCc and uncertain water supplies is exacerbaCng already water-stressed regions. These include: Semi-arid regions Coastal hinterlands Unless action is taken soon, water will become scarce in regions where it is currently abundant - such as Central Africa and East Asia - and scarcity will greatly worsen in regions where water is already in short supply - such as the Middle East and the Sahel in Africa. These regions could see their growth rates decline by as much as 6% of GDP by 2050 due to water-related impacts on agriculture, health, and incomes. World Bank. 2016. “High and Dry: Climate Change, Water, and the Economy.” World Bank, Washington, DC. License: Creative Commons Attribution CC BY 3.0 IGO Spatial and uneven distribution of runoff Our hydrological system is a closed dynamic system so runoﬀ volume will remain relaCvely stable. However, the spaCal distribuCon will change. Regions already experiencing water stress will experience more scarcity. Decline ins runoﬀ will be buﬀered in areas were there is high baseline runoﬀ and water availability. i.e. 100 mm reducCon in runoﬀ is of less consequence when average rainfall is 3,000 mm a year, as in Colombia, than when it is about 300 mm a year, as in Chad. World Bank. 2016. “High and Dry: Climate Change, Water, and the Economy.” World Bank, Washington, DC. License: CreaKve Commons ALribuKon CC BY 3.0 IGO Risk sensitive areas: Semi-arid PrecipitaCon < 25 -50 cm per year P/PET raCo < 0.65 (Huang et al. 2017) Will experience increased aridity and increased warming, combined with a growing populaCon –signiﬁcant landuse change and deserCﬁcaCon. ReducCon in the reliability, quanCty and quality of water ﬂows. Source: UNESCO, UN-Water, 2020: United Nations World Water Development Report 2020: Water and Climate Change, Paris, UNESCO. Huang, J., Li, Y., Fu, C., Chen, F., Fu, Q., Dai, A., Shinoda, M., Ma, Z., Guo, W., Li, Z., Zhang, L., Liu, Y., Yu, H., He, Y., Xie, Y., Guan, X., Ji, M., Lin, L., Wang, S., Yan, H. and Wang, G. 2017. Dryland climate change: Recent progress and challenges. Reviews of Geophysics, Vol. 55, No. 3, pp. 719–778. doi.org/10.1002/2016RG000550. Risk sensitive areas: Coastal hinterlands Land that extends towards the coastline. 10% of the worlds populaCon live in coastal regions less than 10 m above sea level – these areas are becoming increasingly urbanized. Sea level rise (from climate change) threatens these regions as well as major deltas including the Nile and Mekong. Saline intrusion – threatening water supply alongside sanitaCon infrastructure. Source: UNESCO, UN-Water, 2020: United Nations World Water Development Report 2020: Water and Climate Change, Paris, UNESCO. https://www.visitsunshinecoast.com/place/the-hinterland McGranahan, G., Balk, D. and Anderson, B. 2007. The rising tide: Assessing the risks of climate change and human settlements in low elevation coastal zones. Environment and Urbanization, Vol. 19, No. 1. doi.org/10.1177/0956247807076960. Risk sensiAve areas: Mountainous regions Evidence suggests that high-mountain areas warm at faster rates than lower elevaCons (Pepin et al., 2015). PosiCve feedback loops: - Cold surface temperatures + Increased snow + Increased albedo - Less solar radiaCon absorbed + Higher surface temperatures +increased temperatures + increased atmospheric water vapor +increases downward longwave radiaCon + increased temepratures Source: UNESCO, UN-Water, 2020: United Nations World Water Development Report 2020: Water and Climate Change, Paris, UNESCO. https://epthinktank.eu/2018/07/15/people-living-in-mountainous-regions-what-europe-does-for-you/ Pepin, N., Bradley, R. S., Diaz, H. F., Baraer, M., Caceres, E. B., Forsythe, N., Fowler, H., Greenwood, G., Hashmi, M. Z., Liu, X. D., Miller, J. R., Ning, L., Ohmura, A., Palazzi, E., Rangwala, I., Schöner, W., Severskiy, I., Shahgedanova, M., Wang, M. B., Williamson, S. N. and Yang, D. Q. 2015. Eleva]on-dependent warming in mountain regions of the world. Nature Climate Change, Vol. 5, No. 5, pp. 424–430. doi.org/10.1038/ nclimate2563. This warming makes mountainous regions particularly vulnerable to climate change including melting of glaciers and snowcaps. The way in which melt water contributes to downstream water availability is complex: • It can increase water security – this is particularly important in semiarid regions • However, the amount and seasonality in river-runoff is variable which can damage ecohydrology. • Reduced snowcaps will also lead to changes in vegetation, soil and non-hydrological processes. These changes could impact a large range of ecosystem services including biodiversity and carbon sequestration. Risk sensiAve ecosystems: wetlands Water-related ecosystems i.e. wetlands are highly vulnerable to changes in water ﬂows. These ecosystems providing valuable ecosystem services including ﬁltering, buﬀering and carbon sequestra9on. Wetlands are huge pools of carbon. Peatlands store twice as much carbon as the world’s forests. Degraded peatlands are signiﬁcant sources of greenhouse gas emissions. Over the past 100 years we have lost half our natural wetlands. Hydrology underpins the life span of peatland Hydrology and carbon loss … Low watertable High watertable Acrotelm Watertable Catotelm Easily degradable organic carbon More stored carbon • Anoxic conditions (lack of oxygen) • Less microbial activity • Organic matter is not degraded • Carbon is stored • Oxic condi9ons • Ac9vates microbes • Organic mager is degraded • Released into water and atmosphere Watertable More easily degradable organic carbon Water quality will also be impacted: Greater runoff results in greater river loads of: salts faecal coliforms Pathogens heavy metals Organic matter – drinking water implications Increasing temperature Þ increase in algal bloomsÞ toxins in water Increasing temperature and increased evaporaCon Þ increase in suspended soils Þ less water in lakes and rivers Rising temperatures and sea level rise Þ greater saline intrusion Reduced risk of eutrophication when nutrients are flushed away by storms etc. Case Study: UK – Climate change and UK water resources What is happening… ````````` ``````````` ``` https://www.ukri.org/wp-content/uploads/2021/12/091221-NERC-LWEC-WaterClimateChangeImpacts-ReportCard2016.pdf 4. Climate change mitigation and water resources Within the next 30 years demand for water from agriculture could increase by 50 percent, and for urban uses by between 50 percent and 70 percent. By 2035, the energy sector is projected to consume 85 percent more water. These increased strains will create unprecedented conﬂicts between diﬀerent water uses, and interconnected risks between them. We will be faced with having to divide the same amount of water across more components. We need to reconcile the mismatch between escalaAng water demands and the ﬁnite/ variable supply of water in ways that do not further degrade the natural resource. Keyways to miAgate the impacts of climate change on freshwater resources 1. Water conservation: Implementing water conservation measures such as efficient irrigation systems, reducing water loss in distribution systems, and promoting water-efficient appliances and practices can help reduce water consumption and increase the availability of freshwater resources. 2. Enhancing water storage and management: InvesAng in water storage infrastructure such as dams and reservoirs can help manage water availability during Ames of drought or low rainfall. Keyways to miAgate the impacts of climate change on freshwater resources 4. Improving water quality: Addressing pollution sources and improving wastewater treatment can help ensure that freshwater resources remain clean and safe for human consumption and the environment. 5. Promoting sustainable land use practices: Encouraging sustainable land use practices such as reducing deforestation, promoting agroforestry, and promoting sustainable agriculture practices can help maintain healthy ecosystems and ensure the availability of freshwater resources. The way forward: not a new concept -> Water conservaAon Conserving water is not a new concept: • Bermuda has no fresh-water springs, lakes or rivers. • So how can humans se=le here? Buildings have white roofs with steps which are designed to harvest rain water. The steps slow down heavy rainfall helping the gu=ers to collect the water and store in under the house in tank. Each home is self suﬃcient. There is no mains water and no water rates. The roofs are made from limestone. The white paint reflects UV lights from the sun and helps to purify the water. PromoAng sustainable land pracAces Sustainable land prac7ces can help reduce the impacts of climate change on freshwater by: • Reducing erosion and sedimentation • Promoting natural water filtration • Protecting and restoring wetlands • Promoting sustainable agriculture practices • Promoting forest conservation and restoration Reducing erosion and sedimentation Sustainable land pracAces such as agroforestry, conservaAon Allage, and cover cropping can help reduce erosion and sedimentaAon in waterways, improving water quality and reducing the negaAve impacts of ﬂooding and drought on freshwater systems. h"ps://www.holganix.com/blog/how-do-you-build-soil-health Promo1ng natural water ﬁltra1on Sustainable land practices such as riparian buffer zones, wetland restoration, and conservation of natural vegetation can help promote natural water filtration, improving water quality and reducing the need for expensive water treatment infrastructure. Eutrophication The enrichment of waters by inorganic plant nutrients, especially nitrogen and phosphorus which results in an increase in primary production. Artificial eutrophication – increase in nutrients from human activities. Algal blooms Freshwater algal blooms are the result of an excess of nutrients, par7cularly some phosphates. Bright green blooms in freshwater systems are frequently a result of cyanobacteria known as "bluegreen algae" Eﬀects of eutrophicaAon Eﬀects 1. Species diversity ohen decreases and the dominant biota change 1. Plant and animal biomass increases 2. Turbidity increases 3. Rate of sedimenta9on increases, shortening the lifespan of the lake. 4. Anoxic condi9ons develop Mg/L ad e ld l A 6.5 12 9.5 Al liv l ca e n 4 On su ly sm ppo all rt ﬁs h 0 Ve su r y rv few ive Problems 1. The water maybe injurious to health 2. The amenity value of the water may decline 3. Increased vegeta9on may impede water ﬂow and naviga9on 4. Commercially important species of ﬁsh may disappear 5. Treatment of drinking water may be diﬃcult Our natural environment is an asset Resilient water supplies must ensure both quantity and quality are protected which is needed to underpin all aspects of society and the economy. Viewing the natural environment as an asset that can provide long-term resilience, and not just as a resource to be exploited. What knowledge do we need? • A beLer understanding of the variability of river ecosystems to low ﬂow condi7ons would help catchment speciﬁc rick assessments to be undertaken and appropriate restric7ons to be implemented. • This could help inform op7mal water abstrac7on at low ﬂow whilst s7ll protec7ng the natural environment. Nature Based SoluAons (NBS) Nature Based Solu.ons - introduced towards the end of the 2000s by the World Bank (MacKinnon et al.2008). Interna.onal Union for Conserva.on of Nature (IUCN) recognises that human well being does not need to come at the expense of nature – biodiversity can itself generate human well-being and economic beneﬁts. Conserving nature is fundamental in delivery ecologically sustainable development. NBS embody this concept. In the context of climate change nego.a.ons in Paris NBS were put forward as: “as a way to mi+gate and adapt to climate change, secure water, food and energy supplies, reduce poverty and drive economic growth.” (IUCN 2014). MacKinnon K, Sobrevila C, Hickey V et al (2008) Biodiversity, climate change and adaptaPon: nature-based soluPons from the Word Bank porRolio. World Bank, Washington, DC IUCN (2014) Nature-based solutions. Available via http://www.iucn.org/about/union/secretariat/offices/europe/european_union/key_issues/nature_based_solutions. Features of NBS 1. Broad in scope and definition. Designed to target climate change but also/can address biodiversity conservation, disaster risk reduction, green economy promotion, and further economic growth. 2. “Nature”. The term nature is broad – European Commission lists 310 actions as examples of NBS ranging from: expansion and protection of forests , planting green roofs, carbon storage and storm water retention. Can be distinguished from conventional engineering techniques as being – multifunctional, conserving and adding to the stock of natural capital and being adaptable in order to contribute resilience to a landscape. Paileit et al., 2017 hGps://link.springer.com/chapter/10.1007/978-3-319-56091-5_3 Features of NBS 3. Bo?om up. Governance-based approaches to both the crea7on and management are embraced. Par7cipatory approaches to co-design, co-crea7on and co-management are advocated. 4. Action orientated. Policy must be linked to action on the ground. This requires regulatory frameworks, planning systems and economic instrumentation is strong. Under Horizon 2020/ Horizon Europe (European Research and Innovation funding) NBS research must include large scale pilot and demonstration projects to serve as a reference point for upscaling NBS. Paileit et al., 2017 hGps://link.springer.com/chapter/10.1007/978-3-319-56091-5_3 The IUCN es.mates that NBS can contribute up to 37% of the mi.ga.on required to meet the Paris climate goal of keeping warming to 1.5°C above pre-industrial 7mes. Limi7ng temperature rise to 1.5°C requires global CO2 emissions to decline by 45% from 2010 levels by 2030, and reach net zero by 2050. IUCN ambition that by 2030 biodiversity is stabilised across intact, productions and urban landscapes. Global greenhouse gas emissions and warming scenarios NBS: Constructed Wetlands Wetlands which are used to treat polluted eﬄuent (e.g. sewage or runoﬀ from roads). Can be seminatural created by excava7ng a basin or engineered wetlands where the eﬄuent is piped through a bed of sand or gravel. Case studies: London UK Mexico City It is designed to replicate the natural processes of a wetland, but is constructed specifically for the purpose of wastewater treatment. Beneﬁts - Filter out pollutants -> increase water reten7on 7mes. - Allow water to soak into groundwater -> groundwater recharge. - Promote biodiversity - Accumulate and store organic maLer in soil - Wetland plants grow at a faster rate than them decompose -> carbon capture. - Depending on water levels -> bacterial oxidation can convert DOC into inorganic matter which can be stored by mineralization. Case Study: Misconnections Constructed wetlands, Salmons Brook, Enfield North London Misconnected plumbing was causing pollu7on (speciﬁcally phosphate and total coliforms) to enter the Salmons Brook, in Enﬁeld North London. Misconnec7ons: gaps in the drainage so non-treated water was escaping into the Brook before reaching to water treatment works. Salmons Brook Healthy River Challenge: The start-up performance of three constructed wetlands at improving water quality. Gilbert, 2016. h"p://www.thames21.org.uk/wp-content/uploads/2013/11/Salmons-Brook-constructed-wetlands-impact-assessment-FINAL.pdf Case Study: Mexico City Mexico city is one of the world’s largest cities (6,000 people/km2) -> 20% of Mexico’s city live there. Population is expanding (city migration) -> 21 million projected to grow to 30 million by 2030. Crumbling infrastructure -> burst sewage -> blocked drains with rubbish. Aquifer the city sits on is being depleted rapidly and supplies 70% of the area with water. Monsoon rains but 40% of the water is lost due to poor infrastructure. Only 43% of waste water is treated. Climate change: - Intense water drawdown -> aquifer draw down is causing the city to sink Change in rainfall -> hydrological extremes Inequity in water resource access Socio-hydrological resilience is key Engineered constructed wetlands: a solu8on to developing socio-hydrological resilience Using constructed wetlands to treat wastewater, reducing disease and low maintenance infrastructure -> decentralised sanitation. Reduce water stress and increase the capacity of society to adopt to times of flooding and drought. Creating green infrastructure . Engineered constructed wetlands: a solution to developing socio-hydrological resilience Scalable tool that highlights areas of Mexico city that have the lowest resilience and enables to assessment of diﬀerent constructed wetland schemes to op7mise resilience. The tool analyses the social-hydrological resilience across Mexico City both now and in the future, based on forecast climate, land-use and popula7on change in 2050. It then analyses the resilience amer the implementa7on of a system of Constructed Wetlands across the whole city, for both the current and future scenario. Tool: h&ps://app.mexicoshr.com Lets explore it Engineered constructed wetlands: a solution to developing socio-hydrological resilience Outcomes: Implementation of constructed wetlands across the city has the potential to decrease the number of vulnerable people by 32% (6 million). Wetlands also have the ability to decrease the number of highly vulnerable people by 0.5 million. By 2050 and with no improvements to water sustainability, our findings show that 4 million people will move from lowest vulnerability. In addition to this, around 70% of the population would be expected to be classified as highly vulnerable. Tool: h&ps://app.mexicoshr.com Protecting and restoring freshwater environments -> wetlands Wetlands act as natural carbon sinks, absorbing and storing carbon dioxide, and reducing the amount of greenhouse gases in the atmosphere. ProtecAng and restoring wetlands can help reduce the impacts of climate change on freshwater systems. Restora7on: In England wetlands (e.g. fens) have been lost from lowland ﬂoodplains with 64% converted to arable farming and 85% of rivers in 555 catchments having no associated wetlands. Restoring these areas could help moderate ﬂood risk. The Dasgupta review outlined how economic prosperity has been achieved at the expense of nature and the demands for goods and services provided by natural systems. Key measures to improve freshwater quality include: • Restoring environmental ﬂows • Improving water quality • Protec7ng and restoring cri7cal habitats e.g. wetlands • Restoring freshwater connec7vity • Managing exploita7on of freshwater species • Controlling non-na7ve species invasion What restora8on targets do we need to achieve for freshwater systems? W A T E R Problem: 83% decline in freshwater biodiversity. Wetlands are disappearing 3 times faster than forests. Water-use and management is driving ecosystem degradation and fragmentation. Ambi.on: by 2030 freshwater systems must support and sustain biodiversity and human needs -> NBS are key to achieving this. Targets: - Loss of freshwater species and decline of freshwater ecosystem health is halted and restoration is initiated. - Ensure equitable access to water resources and all associated ecosystem services are secured. - Promote water governance, law and investment decisions to promote the multiple value of nature and incorporate biodiversity knowledge. https://portals.iucn.org/library/sites/library/files/documents/WCC-7th-001-En.pdf NBS targets in the context of climate change C L I M A T E Problem: Greenhouse gas (GHG) emissions have risen progressively. Global temperatures are 1°C higher than preindustrial levels and rising. These need to be halted at 1.5 °C to ensure impacts are not severe. Ambition: temperature rises are limited to 1.5°C reaching a net zero target by 2050. Targets: - NBS are scaled up across countries to help adapt to the impacts of climate change. - NBS are scaled up to reach climate mi.ga.on targets. -> NBS will contribute to at least 30% of overall climate mi.ga.on required by 2030. - Reponses to climate change and its impacts are informed by scien.ﬁc assessment and knowledge. h>ps://portals.iucn.org/library/sites/library/ﬁles/documents/WCC-7th-001-En.pdf Expand water availability and supply We need to expand the range of water sources available. If we keep relying on one major sources of water (e.g. surface water) when this becomes depleted it will be unable to meet demand. What are our op7ons? • The types of water source available to a water company are largely dependent on the environmental characteris7cs of the region. • Reservoirs can provide large-scale water storage. Thames Water rely on surface water more than any other water company – their priority is to increase storage capacity. • Demand in the London Water Resource Zone was exceeded 2020 and the deﬁcit is projected to increase by tenfold in 2044 - from 35 to 362 megalitres per day! • • • • • Large areas ﬂooded People relocated Property damage Reduc7on in diversity around the reservoir Eroded material is deposited in the reservoir and not along the rivers natural course so farmland downstream can be less fer7le. Building more dams and reservoirs may provide short-term solu7ons to water shortages, but may also have nega7ve impacts on ecosystems and water quality. Improving water efficiency is a key part of managing water demand. Water companies have committed to a 50% reduction in leakage rates from 2017–18 levels by 2050. There is not currently a national target for reducing household or nonhousehold consumption. A reduction in water consumption will reduce the demand for water supply, reducing abstractions and pressure on the environment. Novel InnovaAon According to the IPCC we need to remove 10 gigatonnes (10 billion tonnes !) of carbon per year to reduce our impacts on climate change. Could algae be key to this? Algae can remove as much carbon as all the trees, plants and land combined. A UK company called Brilliant Planet are unlocking the potential of algae The technology developed by this company has the poten7al to sequester 2 billion tonnes of carbon dioxide a year! hGps://www.brilliantplanet.com The process involves pumping sea water which is rich in carbon and nutrients from the ocean in algae aquacultures, located in coastal desert loca7ons -> Morocco Carbon and nutrients in the sea water support the growth of local strains of algae, through a specially developed accelerated growth process. What makes algae really efficient is that it doesn’t need to grow huge support systems e.g. trunks and roots to take in C via photosynthesis. The algae can double in biomass in less than a day. hGps://www.youtube.com/watch?v=zr6CYS9ie5E Shade balls During times of drought reservoirs act as water stores for many communities. Reservoirs are suspectable to large amounts of evaporation -> problematic Amid California’s latest drought (2011-2017) 96 million ‘shade balls’ were deployed on the LA reservoir. These are black plastic balls that cover the surface preventing evaporation. The LA officials estimate that up to 300 million gallons (1.15 million m3) per year have been conserved by the shade balls through evaporation suppression The shade balls are made of a kind of plas7c that requires oil, natural gas and electricity to produce, all of which require large quan77es of water. Producing 96 million balls of standard 5mm thickness would use up to an es7mated 2.9 million cubic metres of water. During their 7me on the reservoir, the balls are es7mated to have saved 1.7 million cubic metres of water. Summary Water and climate change are closely linked as changes in climate have signiﬁcant impacts on the availability, quality, and distribu7on of water resources. Addressing climate change is therefore crucial to ensuring sustainable water management and ensuring access to clean water for all. Mi7ga7ng the impacts of climate change on freshwater resources demands: Water conserva7on Enhancing water storage and management Improving water quality Promo7ng sustainable land prac7ces

Water and climate mitigation (4).pdf

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