California's Water Crisis in the Context of Global Warming: Water

Resources Future Trends, and Countermeasures

Yang Zheng

Material Science and Engineering School, Beijing University of Technology, Beijing, 100029, China

Keywords: California, Water Resources, Climate Change, Global Warming.

Abstract: Since the advent of the Second Industrial Revolution, the accelerated development of science, technology,

and industry has precipitated an unprecedented rate of resource consumption, particularly of Earth's natural

reserves. This industrial activity has significantly contributed to greenhouse gas emissions, predominantly

carbon dioxide, thereby exacerbating global warming. The repercussions of these environmental changes are

profound, affecting ecosystems and various natural resources, with water resources being notably impacted.

This study focuses on the water crisis in California, highlighting the dual challenges of pollution and excessive

water resource consumption. By examining the past two decades, this paper analyzed the interplay between

groundwater depletion, climate change, and the increasing aridity of California's landscapes. This analysis is

crucial for the long-term management of water resources, offering data and insights to address current water

challenges, ensure future water sustainability, and inform the development of effective policies and strategies.

1 INTRODUCTION

Global warming is a major issue in the world in the

21st century. Since the mid-20th century, the Earth's

land and ocean surface temperatures have continued

to rise, and this phenomenon is mainly due to the

emission of large amounts of greenhouse gases,

including carbon dioxide, methane and nitrogen

oxides. Greenhouse gases accumulate near the

atmosphere and allow the sun's short-wave radiation

to pass through, but the long-wave radiation emitted

by the earth is blocked and absorbed, causing the

earth's surface and atmosphere to increase in

temperature, forming the greenhouse effect. Since the

Industrial Revolution, industry has developed rapidly

and the use of fossil fuels has been increasing,

resulting in rising anthropogenic greenhouse gas

emissions. According to a report published by the

IPCC in 2023, global greenhouse gas emissions

increased by an average of 1.5% per year from 2009

to 2018

(Yang et al., 2023). In 2022, global CO

emissions reached 36.1±0.3 Gt, an increase of 1.5%

compared to 2021 (Liu et al., 2023). From 1850 to

2020, the global surface temperature has risen by

about 1.1℃, which will lead to sea level rise and

increase the frequency of extreme weather events

such as heat waves, heavy precipitation, and

droughts, which will affect millions of human

habitats in the future.

As the third largest state in the United States in

terms of area and the largest state in terms of total

production in the United States, California has

diverse characteristics in terms of geography,

landform, products, and population composition.

California's economy is dominated by agriculture,

which is more than twice the size of its second-largest

industry, along with aviation, entertainment, and light

industry (Helbling and Meierrieks, 2023 & Pedersen

et al., 2022). However, California's industrial

development makes it more susceptible to climate

change due to its climatic diversity and rich landform

features (coastal, inland, and alpine regions). During

the 2007–2009 and 2012–2016 periods, California

experienced two periods of extreme drought, with the

Central Valley, for example, losing groundwater

reserves by 19 and 28 cubic kilometers, respectively.

In the two post-drought recovery periods of 2010–

2011 and 2017–2019, the recovery rate of

groundwater was very low, with only 34% and 19%

restored (Alam et al., 2021). Nearly two decades of

successive droughts have also led to significant

impacts on California's water resources and

ecosystems, including years of below-average

precipitation, high temperatures, and extreme

droughts that have led to significant reductions in

Zheng, Y.

California’s Water Crisis in the Context of Global Warming: Water Resources Future Trends, and Countermeasures.

DOI: 10.5220/0013844800004914

Paper published under CC license (CC BY-NC-ND 4.0)

In Proceedings of the 2nd International Conference on Renewable Energy and Ecosystem (ICREE 2024), pages 52-57

ISBN: 978-989-758-776-4

river flows and groundwater reserves (which have

also led to a decline in soil moisture and the effects of

drought on a large number of plants, including wild

plants and agricultural crops, especially in inland

forest areas, with increased vegetation mortality). In

a recent study climate change in California has led to

an increase in the frequency and intensity of droughts,

especially in the interior, which will lead to the early

depletion of soil moisture resources, and the

vegetation of grassland ecosystems will remain in a

state of drought for a long time and die rapidly,

increasing the risk of wildfires and even leading to

desertification in parts of California (Warter et al.,

2021).

The purpose of this paper is to study the water

resources situation in California in the context of

climate change in the past two decades, identify the

problems of the water crisis, analyses and predict the

future global greenhouse gas emissions and water use

management trends in California, and put forward

suggestions for policy-making, industrial, urban and

agricultural water use, etc., in order to alleviate the

water crisis in California in the next decade.

2 CURRENT STATUS AND

FUTURE TRENDS OF

CALIFORNIA'S WATER

RESOURCES UNDER GLOBAL

WA RMING

2.1 California Water Resources Status

Over the past two decades, average annual

temperatures in California have risen by more than 1

℉ (about 0.56 ℃), with some areas experiencing

increases of more than 2 ℉ (about 1.1℃). According

to forecasts, average daily maximum temperatures

will rise by 4.4–5.8℉(about 2.4–3.2℃) by the middle

of this century, and by the end of the century, this

increase may reach 5.6℉ to 8.8 ℉(about 3.1– 4.9℃).

California has been grappling with increasing water

demands and emerging water conflicts brought about

by population growth, agricultural demands, and

increasingly severe climate change. Previous studies

have shown that California mainly relies on surface

water and groundwater to supply urban and

agricultural water, but the supply of surface water is

decreasing due to drought and climate variability

(Dahlke et al., 2018 & Moyers et al., 2024). At the

same time, over-exploitation of groundwater has led

to problems such as well depletion and land

subsidence, and water stress continues to increase

despite water conservation measures. To this end,

California enacted the Sustainable Groundwater

Management Act in 2014 to ensure the long-term

availability of groundwater. In addition, water

resources projects, including the State Water Project

and the Central Valley Project, facilitate the

replenishment of surface water from water-rich

Northern California to arid areas such as Southern

California and the Central Valley.

Despite the above significant progress in water

management, California continues to attempt to adopt

multifaceted strategies to comprehensively address

the water crisis (Table 1). These initiatives cover

water resources planning, conservation, development

of alternative water sources (such as desalination and

recycled water use), sustainable groundwater

management, and measures to combat climate

change. In addition, the state is actively responding to

the impacts of climate change by strengthening

infrastructure and promoting green infrastructure

solutions.

Table 1: California Water Management Plans

Purpose

Corresponding

olicies

Policy content

Water

resources

planning and

utilization

California

Water Plan

California’ s long-term water management strategy, updated every five years, is

designed to ensure sustainable use of water resources across the state. The plan

includes improving water use efficiency, developing alternative water sources,

rovin

water su

infrastructure, etc.

Integrated

Regional Water

Management

(IRWM)

Through regional collaboration, the IRWM program promotes water management

across sectors and regions to increase efficiency and flexibility

Urban Water

Management

Plans

Require city water suppliers to submit detailed water use plans every five years,

including water conservation measures and contingency plans

California’s Water Crisis in the Context of Global Warming: Water Resources Future Trends, and Countermeasures

Alternative

Water

Resources

Development

Desalination

Project

Promote the construction and operation of desalination plants to increase drinking

water supplies, such as the Carlsbad Desalination Plant

Reclaimed

Water

Utilization

Water

Recycling and

Reuse

Promote wastewater treatment and reuse technologies to use recycled water for

purposes such as agricultural irrigation, industrial cooling and landscape irrigation

Sustainable

Groundwater

Management

Sustainable

Groundwater

Management

Act

(

SGMA

)

Require local governments and water management agencies to develop and

implement sustainable groundwater management plans to prevent over-exploitation

of groundwater and land subsidence

Tackling

Climate

Change

California

Climate

Adaptation

Strateg

Includes improving water infrastructure, increasing reservoir reserve capacity and

advancing green infrastructure to increase resilience to droughts and extreme

weather events caused by climate change

2.2 Future Trends of California’s

Water Resources Under Different

RCP Backgrounds

Through extensive reading of literature and annual

reports of major organizations, different RCP

scenarios were considered in the analysis of global

greenhouse gas emissions and California water

resources trends in the next ten years (IPPC adopted

it in the fifth assessment report released in 2014).

Under three different RCP scenarios, global

greenhouse gas emissions have the following

development trends:

(1) Under the RCP 2.6 scenario (ideal case), by

developing renewable energy and clean technologies

and reducing non-carbon dioxide emissions, global

carbon emissions will peak in 2040 and decline

rapidly, and global warming will be controlled within

2℃.

(2) RCP 4.5 and 6.0 scenario (moderate): Under

this scenario, a more moderate emission reduction

plan will be adopted in the future; that is, according

to the United Nations Environment Program (UNEP),

the current climate change under the Paris Agreement

will be fully implemented. It is promised that the

global surface temperature will rise by 2.1–2.6℃ by

the end of this century.

(3) Under the RCP 8.5 scenario (high dependence

on fossil fuels and no control), greenhouse gas

emissions continue to grow and if more radical

measures are not taken, global emissions will increase

sharply and global surface temperatures will rise by

4.3℃ by the end of this century. or even higher,

leading to severe climate change impacts.

These scenarios will impact California's water

resources, potentially leading to more extreme

precipitation patterns, including droughts and

flooding events, and increasing the frequency of

"climate whiplash" events.by 50–100% (Dahlke et

al., 2018 & Ghasemizade et al., 2019). In the next ten

years, as the population increases, the demand for

water in cities and agriculture will inevitably

increase, and competition for water resources will

become more intense. But according to the latest

California Water Resources Plan, urban water use

will be controlled through water management and

water conservation measures to keep urban water

demand relatively stable until 2035 (Liu et al., 2022).

Based on the California Water Plan, this paper

predicts and maps the water resources in California in

the next ten years (based on the Climate Model and

Historical Data) as follows (shown in Figure1),

agricultural water is still the main consumer of water

resources in California, with slight fluctuations with

the proportion of crops planted each year (Dahlke et

al., 2018 & Ghasemizade et al., 2019); The average

annual precipitation decreases significantly during

the dry period, and gradually rises during the wet

period, and so on. Urban water use is increasing year

by year due to the rise of California's population, but

due to better water-saving measures, annual urban

water use will only increase slightly year by year; The

efficiency of groundwater restoration is low, but the

amount of groundwater used has been reduced, and

there are a large number of water-using projects and

construction, and groundwater is restored year by

year with a stable amount.

ICREE 2024 - International Conference on Renewable Energy and Ecosystem

Figure 1: Forecast chart based on California Water Resources Plan.

3 CARBON EMISSIONS AND

WATER MANAGEMENT

RECOMMENDATIONS TO

ADDRESS WATER SCARCITY

IN CALIFORNIA

California has made some progress in reducing

greenhouse gas emissions, but it still faces some

inherent problems, such as industrial emissions,

agricultural emissions and water use, and urban living

emissions and water conservation. These issues are

analyzed in Table 2 and recommendations are made.

Table 2: Countermeasures and suggestions for California emissions

Types Existing Issues Plans Suggested measures

Industrial

Emissions

Industry and manufacturing

are accounting for about

24% of total emissions.

Carbon Capture and Storage,

(CCS)

Invest in carbon capture

technologies and promote related

demonstration projects

Industrial terminals emit

many emissions

End-of-line treatment

technology for treatment at

the first time of waste

generation

Timely treatment of pollution

incidents or wastes that have

occurred can significantly

improve environmental quality

and citizens' health

Emissions from

Urban Life and

Water Waste

Transportation accounting

for about 40% of the state's

emissions.

Zero Emission Vehicle

Program, (ZEV)

Subsidies for purchases,

construction of charging and

refuelin

infrastructure

Natural gas power

generation accounting for

about 15% of total emissions

Utilities are required with

50% of electricity coming

from renewable sources by

2030

Promoting renewable energy

sources to reduce dependence on

fossil fuels (Gov-tech)

California’s Water Crisis in the Context of Global Warming: Water Resources Future Trends, and Countermeasures

Energy use in buildings,

including heating, cooling,

and electricity consumption

accounting for 12% of total

emissions

Enforce the California Title

24 Building Energy

Efficiency Standard, which

requires high energy

efficiency in building design

and construction

Replace high-efficiency

windows, add insulation, upgrade

HVAC systems, install solar

panels and geothermal energy

systems to provide clean energy

for buildin

s, etc

Methane and other

greenhouse gases from

landfills and wastewater

treatment facilities account

for about 2% of total

emissions

California Integrated Waste

Management Act

Promote waste sorting and

resource recycling, carry out

waste reduction publicity and

education, and support

composting projects and

recycling technologies

Emissions from

agricultural

activities and

water use

Water conservation in

agriculture

Promote drip irrigation and

micro-sprinkler irrigation

techniques

Delivers water directly to plant

roots, reducing water evaporation

and soil moisture loss

Agricultural activities,

including livestock farming

and the use of chemical

fertilizers accounting for

about 8% of total emissions

Reduce greenhouse gas

emissions by accurately

monitoring and managing

farmland and optimizing

fertilizer and water use.

Use sensors and drone technology

to monitor soil moisture, nutrient

content, and crop health for

precise fertilization and irrigation.

4 CONCLUSION

The California water crisis underscores the critical

need for effective water management amidst global

warming. Historically, California has struggled with

a disparity between water supply and demand, a

situation aggravated by climate change. The

increasing global greenhouse gas emissions have led

to rising temperatures, exacerbating the state's water

issues, including declining surface water reserves,

over exploitation of groundwater, and land

subsidence. As a major agricultural hub in the United

States, California's water resources are vital to

produce fruits, vegetables, and nuts. Prolonged

droughts necessitate the study of water resources to

optimize agricultural irrigation, enhance water use

efficiency, and ensure sustainable agricultural

development.

Moreover, population growth, urbanization, and

economic expansion have intensified the demand for

water, complicating its management. The future

presents even greater challenges due to the

unpredictability induced by climate change,

complicating forecasts of water supply and demand.

Recognizing the urgency, the California government

and private sector have undertaken initiatives to

address these issues. Efforts include promoting water-

saving technologies, improving agricultural irrigation

systems, and enhancing water infrastructure. There is

a growing societal focus on water resource protection

and management, with increased public participation

in relevant initiatives.

California must develop a long-term water

management strategy and collaborate with

neighbouring states and countries to tackle water

challenges collectively. This involves sharing

expertise and technology and co-developing and

implementing water management strategies.

Strengthening water resource policies and

regulations, raising public awareness of water

conservation, and encouraging public participation in

water management are crucial. Education and

publicity efforts can enhance residents' understanding

of water conservation and environmental protection,

promoting the rational use of water resources.

Future water management will heavily rely on

technological innovations, such as precision

agriculture, intelligent irrigation systems, advanced

sewage treatment technologies, and comprehensive

water monitoring systems. These innovations will

significantly improve water efficiency and reduce

waste. Despite the challenges, California can mitigate

some of the adverse effects of global warming

through comprehensive policy measures, innovative

technological applications, and active public

engagement. Achieving the sustainable use of water

resources and minimizing the impacts of the water

crisis in California will require a multifaceted

approach that integrates policy, technology, and

public involvement.

ICREE 2024 - International Conference on Renewable Energy and Ecosystem

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California’s Water Crisis in the Context of Global Warming: Water Resources Future Trends, and Countermeasures