Storage Tanks Selection, Design, Testing, Inspection, and Maintenance: Emission Management and Environmental Protection: Emission Management and Environmental Protection

By Karan Sotoodeh

Emission prevention and environmental protection are hot topics in the oil and gas industry and many countries, especially in the United States. Among sources of pollution in the oil and gas industry, storage tanks used to store products such as oil or liquefied natural gas (LNG) are considered the second most significant source of emissions after industrial valves.

Storage Tanks Selection, Design, Testing, Inspection, and Maintenance: Emission Management and Environmental Protection provides the latest research and technological advancements in storage tank design including materials selection, welding, and techniques used order to reduce or prevent emissions. This book will detail essential information regarding inspections, testing, and maintenance that are performed to prevent the failure of storage tanks and will also explore the different types of storage tank emissions and provide recommendations for the preventive, as well as safety systems that are critical to minimize the failure of storage tanks. Researchers, engineers, industry professionals, and students in the environmental safety field will find this book to be a welcomed resource to learning about and working on storage tank emissions in the oil and gas industries.

• Provides detailed understanding of the problems and hazards of emission in the oil and gas industries
• Presents mechanical designs of storage tanks by considering various loads (e.g., axial, bending, wind, earthquake, etc.) to prevent failure
• Details studies of corrosion assessment of storage tanks
• Introduces safety systems in the oil and gas industries and the effect of tank selection on emission

• Language: English
• Publisher: Elsevier Science
• Release date: Jan 9, 2024
• ISBN: 9780443239106

Karan Sotoodeh

Karan Sotoodeh recently earned his PhD in Safety and Reliability in Mechanical Engineering from the University of Stavanger. Previously, Karan was the Senior / Lead Engineer in valves and actuators for Baker Hughes, one of the world’s largest oil field services company. He was responsible for engineering and delivering valves and actuators in subsea manifolds, working with valve suppliers, R&D activities, and maintaining the company’s valve database. He has also worked for AkerSolutions, NLI Engineering, and Nargan Engineers as a senior specialist in piping and valves, assisting with many projects around the world. He is the author of Prevention of Valve Fugitive Emissions in the Oil and Gas Industry and Subsea Valves and Actuators for the Oil and Gas Industry, both published by Elsevier. Karan earned a Master of Research in Mechanical Engineering and a Masters in Oil and Gas Engineering, both from Robert Gordon University of Aberdeen, and a Bachelors in Industrial Engineering from the Iran University of Science and Technology

Book preview

Front Cover for Storage Tanks Selection, Design, Testing, Inspection, and Maintenance - Emission Management and Environmental Protection - 1st edition - by Karan Sotoodeh

Storage Tanks Selection, Design, Testing, Inspection, and Maintenance

Emission Management and Environmental Protection

Karan Sotoodeh

Department of Valves and Actuators, Baker Hughes, Hovik, Oslo Area, Norway

Table of Contents

Cover image

Title page

Copyright

Chapter 1. An introduction to fugitive emission

Abstract

1.1 Introduction

1.2 Fugitive emission gases

1.3 Greenhouse effect

1.4 Global warming/climate change

1.5 Health, safety, and environment

1.6 Fugitive emissions organizations and regulations

1.7 Leak detection and repair

Questions and answers

Further reading

Chapter 2. Storage tank types and components

Abstract

2.1 Introduction

2.2 Types

2.3 Components

Questions and answers

Further reading

Chapter 3. Storage tank emission management

Abstract

3.1 Introduction

3.2 Storage tank release/emission types

3.3 Causes of leakage and emission

3.4 AP Chapter 7 liquid storage tanks overviews

Questions and answers

Further reading

Chapter 4. Storage tank essential design considerations

Abstract

4.1 Introduction

4.2 Codes and standards

4.3 Design considerations

Questions and answers

References

Further reading

Chapter 5. Material selection and corrosion assessment for storage tanks

Abstract

5.1 Introduction

5.2 Material choices

5.3 Types of corrosion

Questions and answers

Further reading

Chapter 6. Construction and fabrication of storage tanks

Abstract

6.1 Introduction

6.2 Tank construction

6.3 Welding

Questions and answers

Further reading

Chapter 7. Testing and examination of welding on storage tanks

Abstract

7.1 Introduction

7.2 Welding examination techniques

7.3 Other tests

Questions and answers

Further reading

Chapter 8. Inspection of storage tanks

Abstract

8.1 Introduction

8.2 Reasons for inspection

8.3 Types and intervals of inspection

8.4 Inspection history and reports

8.5 Standardization

Questions and answers

Further reading

Chapter 9. Maintenance and repair of storage tanks

Abstract

9.1 Introduction

9.2 Standardization

9.3 Maintenance types and evaluation program

9.4 General considerations for tank repair

9.5 Tank repairs and alternations

Questions and answers

Further reading

Chapter 10. Safety systems for storage tanks

Abstract

10.1 Introduction

10.2 Fire risks in storage tanks and areas

10.3 Fire water storage tank

10.4 Grounding systems

10.5 Permit to work

Questions and answers

Further reading

Index

Copyright

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Notices

Knowledge and best practice in this field are constantly changing. As new research and experience broaden our understanding, changes in research methods, professional practices, or medical treatment may become necessary.

Practitioners and researchers must always rely on their own experience and knowledge in evaluating and using any information, methods, compounds, or experiments described herein. In using such information or methods they should be mindful of their own safety and the safety of others, including parties for whom they have a professional responsibility.

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Chapter 1

An introduction to fugitive emission

Abstract

Since fugitive emissions have been negatively impacting productivity, the environment, and human health, they have become a major concern across the globe. A fugitive emission occurs when gases or vapors are released unintentionally and undesirably through equipment or facilities containing pressure, as well as components within an industrial unit or complex, such as valves, piping flanges, pumps, storage tanks, compressors, etc. This chapter provides a brief introduction to fugitive emission gases such as methane and carbon dioxide as well as the negative effects of these gases such as the greenhouse effect, global warming, and climate change. Following the introduction of fugitive emission organizations and regulations, this chapter introduces the Environmental Protection Agency, European Environment Agency, and the Kyoto Protocol. A leak detection and repair program has been proven to be one of the most effective methods of reducing and controlling emissions in industrial plants. An explanation of the different steps involved in LDAR implementation along with different leak detection methods for storage tanks is provided at the end of this chapter.

Keywords

Greenhouse gases; health; safety, and environment (HSE); intergovernmental panel on climate change (IPCC); leak detection and monitoring; leak classes; interstitial monitoring; automatic tank gauging (ATG); volatile organic compounds (VOCs); ozone layer depletion; hazard and operability analysis

1.1 Introduction

In recent years, fugitive emissions (FEs) have become a major concern across the globe due to their negative effects on productivity, the environment, and human health. The term fugitive emission refers to the unintentional and undesirable release of gases or vapors from equipment or facilities that contain pressure, as well as components of an industrial plant, such as valves, piping flanges, pumps, storage tanks, compressors, etc. A fugitive emission is also known as a leak or a leakage. FEs, however, are caused by a variety of factors and activities rather than leaks, which may be accidental (unintentional) or intentional. Fugitives are defined as emissions that are excluded from the design of equipment and components due to the fact that they are not taken into account and calculated. Moreover, these emissions are unanticipated, and as a result, typical monitoring and control equipment cannot detect them. FEs are also known as uncontrolled or unanticipated emissions since they cannot be detected by typical control equipment and facilities.

There are five primary causes of FEs: leaks from equipment and facilities, process venting, evaporation losses, disposal of waste gases through venting or flaring, and finally accidents and equipment failures. Valves and flanges in piping systems, for instance, are highly susceptible to leaks. It has been observed that oil and gas pumps are at risk of leaking on account of a number of factors, including wear and tear that can be caused by the presence of particles in the fluid. Also, the wear and tear of seals in pumps and compressors is a well-known cause of emissions or leaks from these common oil and gas facilities. The term process vent refers to a point of emission from a unit operation where a gaseous stream is discharged to the atmosphere directly or after passing through one or more combustion, recovery, or recapture devices. It is possible, for example, to burn gas in a turbine to generate electricity and in a boiler to generate heat. In addition, the gas may be burned or exhausted in order to drive machines such as pumps and compressors. During production, venting is the controlled release of gases into the atmosphere. In the processing of oil or natural gas, gases may include natural gas or other hydrocarbon vapors, as well as water vapor and other gases, such as carbon dioxide. Most process venting occurs from equipment and units such as reactors and distillation units. Pressure relief device discharges and gaseous streams routed to fuel gas systems are excluded from process vents. In the crude oil industry, evaporation loss from fixed and floating roof storage tanks is one of the major sources of product loss. A natural phenomenon that describes the transformation of a liquid into a gas is evaporation. Liquids tend to evaporate based on their vapor pressure. It is important to minimize evaporation losses in order to maximize company revenue, meet regulatory requirements, and reduce gas emissions. In the oil and gas development process, venting occurs at a number of points. For example, following the completion of a well, the wellbore and surrounding formation must be cleaned. Solids and fluids from the well are disposed of in pits, while gases are either vented into the atmosphere or burned off. A well completion is the process of preparing a well for production (or injection) following drilling operations. Various factors contribute to flaring operations at oil and gas production and processing units. Flaring is often caused by interruptions such as overpressure in the systems that produce or treat gases, which must be rerouted and disposed of in a safe and controlled manner. During the 19th century, natural gas was considered to be a hazardous and unwanted product, which resulted in disposal problems. During the early days of oil and gas production, large amounts of gas were released or burned off in flare systems as worthless compounds. Despite this, some countries use flaring operations as an alternative to constructing infrastructure for gas production and transportation for economic or logistical reasons. Fig. 1.1 illustrates the flare system on an offshore platform. Flare systems are an invaluable component of the oil and gas plant infrastructure. It should be noted that the negative impacts of releasing gas into the environment without burning it are much greater than those of burning the gas in the flare and releasing it into the atmosphere.

Figure 1.1 Burning gas in a flare system on an offshore platform. Courtesy: Shutterstock.

The most common accidents and equipment failures in the oil and gas industry are well blowouts, pipeline breaks, tanker accidents, tank explosions, gas migration to the surface around the outside of wells, and surface casing vent blows. A blowout occurs when pressure control systems fail and crude oil and/or natural gas are released uncontrollably from an oil well or gas well. The blowout preventers in modern wells are designed to prevent such an event from occurring. A pipeline break or incident can be caused by a variety of factors, including corrosion, excavation damage, incorrect operation, material or welding failures, or natural forces. Ships that are designed to transport or store liquids or gases in bulk are known as tankers (or tankships). The most common types of tankers are oil tankers, chemical tankers, and gas carriers. Among the most feared tanker incidents are fires and explosions, but other incidents can occur both at sea and in port. Additionally, tankers are susceptible to accidents involving combustible materials as well as collisions at sea, the risk of running aground on reefs or shoals, as well as foundering. The flammable vapors inside atmospheric storage tanks have caused several explosions over the last few years, resulting in catastrophic failures of storage tanks. It is shown in Fig. 1.2 that a fire occurred in gasoline storage tanks at Duque de Caxias City near Rio de Janeiro, Brazil.

Figure 1.2 There have been fires in gasoline storage tanks in Brazil. Courtesy: Shutterstock.

1.2 Fugitive emission gases

In the oil and gas industry, FEs are divided into two categories; the first category is known as the primary pollutant that is emitted directly from the process equipment or flare system. Although methane ( Equation ) is the most prevalent fugitive emission that occurs in the oil and gas industry, carbon dioxide ( Equation ) and nitrous oxide ( Equation ) can also be significant primary FEs. As a result of flaring the gas into the atmosphere, both methane and carbon dioxide are released into the atmosphere. A secondary pollutant is a gas- or a vapor-phase compound formed as a result of the reaction between primary pollutants in the atmosphere or between primary pollutants and naturally occurring compounds. The main secondary gaseous contaminants are nitrogen dioxide ( Equation ), ozone Equation ), and other petrochemical oxidants.

In general, natural gas is a colorless, highly flammable mixture of gases. In deep underground reservoirs, it is a by-product of oil production that is known as petroleum and hydrocarbons. Most natural gas consists of methane, which contributes 70%–90% of its volume. According to Fig. 1.3, it consists of one carbon atom bonded to four hydrogen atoms. The simplest alkane is methane, and an alkane, also known as paraffin, is an acyclic saturated hydrocarbon. Essentially, alkanes are composed of hydrogen and carbon atoms arranged in a tree structure with single carbon–carbon bonds. Methane is an odorless gas and appears to be colorless. The specific gravity of methane is 0.554, making it lighter than air. In the presence of water, it is only slightly soluble. Carbon dioxide and water vapor are formed when it burns in the presence of air; the flame is pale, slightly luminous, and extremely hot. There is a boiling point of methane of 162°C (259.6°F) and a melting point of 182.5°C (296.5°F) for this substance. Generally, methane is very stable, but mixtures of methane and air, with a methane content of between 5% and 14% by volume, can be explosive. In limited quantities, methane is not toxic and does not pose a hazard when inhaled; however, if large quantities of methane replace air, this can result in suffocation due to a lack of oxygen.

Figure 1.3 Methane atom structure. Courtesy: Shutterstock.

Methane ( Equation ) is a naturally occurring gas that occurs below the ground as well as beneath the seafloor, and it is formed by a combination of geological and biological processes. Due to its relative abundance on earth, methane is an economical fuel, although capturing and storing it is a technical challenge due to its gaseous state under normal conditions. In addition to natural sources, methane can also be emitted from anthropogenic sources (human influenced). The sources of anthropogenic emissions include landfills, oil and natural gas systems, agricultural activities, coal mining, stationary and mobile combustion, wastewater treatment, and certain industrial processes. In addition to the breakdown of organic material, methane can also be released into the atmosphere through natural processes. These include the decay of plant material in wetlands such as marshes and swamps, the seepage of gas from underground deposits, or the digestion of food by cattle. Human activities are responsible for a greater portion of the release of methane into the environment than natural events. Methane emissions are a major contributor to the increasing concentration of greenhouse gases (GHSs) in the earth's atmosphere and are responsible for approximately one-third of short-term global warming. The GHSs of the earth trap heat in the atmosphere and warm the planet. There are a number of gases that contribute to the greenhouse effect, including carbon dioxide, methane, nitrous oxide, and water vapor (which all occur naturally), as well as fluorinated gases (which are synthetic). Methane concentrations in the atmosphere have more than doubled since the industrial revolution. This is responsible for approximately 20% of the global warming that has occurred since then. Methane, which is the main component of natural gas, is far more effective at trapping heat than carbon dioxide, which is more abundant and lasts longer. In terms of warming the climate system, methane is 80 times more potent than carbon dioxide during the first two decades following its release.

The gas carbon dioxide ( Equation ) is colorless and odorless at atmospheric pressures and temperatures. It is relatively nontoxic and noncombustible and a substance that is heavier than air and may cause asphyxiation due to the displacement of air. The compound is soluble in water. Most animals exhale carbon dioxide as a waste product, which is a natural source of carbon dioxide. In fact, this gas is produced by burning carbon-containing materials, fermenting, and respiring animals and is utilized by plants in the photosynthesis of carbohydrates. Human activities that contribute to carbon dioxide emissions include energy production, such as the burning of coal, oil, or natural gas, as well as transportation and manufacturing. In spite of being one of the most significant GHSs contributing to global warming, it is only a minor component of the atmosphere (about 3 volumes in 10,000). A greenhouse effect occurs as a result of the presence of carbon dioxide in the atmosphere. This prevents some of the radiant energy received by the earth from being returned to space. Reducing fossil fuel consumption is the most effective means of reducing carbon dioxide emissions. In comparison with the other major heat-trapping gases emitted by humans, carbon dioxide remains in the atmosphere for a longer period of time.

In chemistry, nitrogen oxide ( Equation ) is a chemical compound composed of two atoms of nitrogen and one atom of oxygen. Nitrous oxide is also known as the laughing gas or nitrous oxide. The gas is colorless, nonflammable and has a slight sweet taste and smell at room temperature. As an anesthetic and pain-relieving agent, nitrous oxide has significant medical applications, particularly in surgery and dentistry. According to the WHO, it is an essential medicine. The term laughing gas, coined by Humphry Davy, refers to its euphoric effects following inhalation, which has led to it being utilized recreationally as a dissociative anesthetic. Additionally, nitrogen oxide is used as an oxidizer in rocket propellants and in motor racing to increase engine power. It is pertinent to note that nitrous oxide contributes significantly to global warming as it is the third most potent long-lived greenhouse gas. It is estimated that the atmospheric concentration of nitrous oxide reached 333 parts per billion (ppb) in 2020, increasing at a rate of approximately 1 ppb annually. With an impact comparable to that of chlorofluorocarbons (CFCs), it is one of the largest scavengers of stratospheric ozone. During a 100-year period, one pound of Equation warms the atmosphere about 300 times more than one pound of carbon dioxide. Due to its potency and relatively long life, Equation is one of the most dangerous contributors to climate change.

A chlorofluorocarbon (CFC) and a hydrochlorofluorocarbon (HCFC) are halogenated hydrocarbons that contain carbon (C), hydrogen (H), chlorine (Cl), and fluorine (F) and are produced as volatile derivatives of methane, ethane, and propane. The DuPont brand name Freon is also commonly used to refer to them. A CFC is a nontoxic, nonflammable chemical containing several organic elements mentioned before. In addition to their use as aerosol sprays, blowing agents, and refrigerants, they are also used in the manufacture of foams and packing materials. The CFCs were originally developed as refrigerants in the 1930s. While CFCs have a wide range of commercial and industrial applications, they have also been found to pose a significant environmental threat. When CFCs are released into the atmosphere, they accumulate in the stratosphere, where they contribute to the depletion of the ozone layer. It is the ozone that protects life on earth from the harmful effects of ultraviolet radiation from the sun. Even a relatively small decrease in the concentration of ozone can increase the incidence of skin cancer in humans and cause genetic damage to many organisms. In the late 1970s, the United States, Canada, and Scandinavian countries imposed a ban on the use of CFCs in aerosol-spray dispensers due to growing concerns about stratospheric ozone depletion and its associated dangers.

Nitrogen dioxide is a chemical compound with the formula Equation and it is in a category of nitrogen oxides. Millions of tons of nitrogen dioxide is produced each year for use in fertilizer production. It is an intermediate in the industrial synthesis of nitric acid. In the presence of rising temperatures, the gas turns reddish-brown in color and becomes a yellowish-brown liquid in the presence of lower temperatures. In addition, high levels of nitrogen dioxide are detrimental to vegetation, causing damage to foliage, decreasing growth, or reducing crop yields. The presence of nitrogen dioxide can cause furnishings and fabrics to fade and discolor, reduce visibility, and react with surfaces. High levels of nitrogen oxides can cause rapid burning, spasms, and swelling of tissues in the throat and upper respiratory tract, reduced oxygenation of body tissues, a build-up of fluid in the lungs, and even death if inhaled. A variety of natural processes contribute to the release of Equation , including the entry of Equation into the atmosphere from the stratosphere, bacterial respiration, volcanic eruptions, and lightning strikes. As a result of these sources, Equation is considered a trace gas in the atmosphere of the earth. This is because it absorbs sunlight and regulates the chemistry of the troposphere, particularly when it comes to determining the concentration of ozone.

Ozone ( Equation ) is a colorless gas at ambient temperature and pressure and has a characteristic odor even at very low concentrations. This gas has a distinctively pungent odor and a pale blue color. It is found that ozone is present on the top surface of the stratosphere, approximately 30 miles above the ground, where it protects the earth by absorbing most of the harmful ultraviolet rays from the sun. In contrast, higher in the troposphere (about 12–18 km above the troposphere), ozone is a greenhouse gas that traps heat.

1.3 Greenhouse effect

There has been a great deal of progress made by humanity over the years. It is critical to note, however, that many of these advancements have come at the expense of the exploitation of nature. The main cause of environmental pollution is human activity. The concept of global warming refers to the long-term warming of the planet’s overall temperature. This warming trend has been ongoing for a long time, but its pace has increased significantly over the last hundred years as a result of the burning of fossil fuels. In the 1980s and early 1990s, many scientists were unaware of the causes and effects of global warming. In the late 1990s, however, the scientific community reached consensus that global warming was a concern. This is because the 1990s were the warmest decade since 1861, when thermometers began to be used to measure temperature. Many people today believe that global warming is the greatest environmental threat facing the planet in the 21st century. There has been an increase in the burning of fossil fuels as the human population has increased. As a result of burning fossil fuels, the atmosphere of the earth is subjected to what is known as the greenhouse effect and consequently global warming (See Fig. 1.4). Fossil fuels include coal, oil, and natural gas.

Figure 1.4 Earth global warming. Courtesy: Shutterstock.

Generally, the greenhouse effect is defined as the warming of the earth’s surface and the lower layer of the atmosphere known as the troposphere caused by various gases known as GHGs. The most well-known GHGs are water vapor Equation , carbon dioxide ( Equation , methane Equation , nitrous oxide Equation , ozone ( Equation ), and some artificial chemicals, such as chlorofluorocarbons (CFCs). Life on earth is entirely dependent on the sun. The sun contributes to the habitability of the earth. Sunlight and energy reaching the earth are reflected back into space to a degree of approximately 30% as a result of solar radiation. The earth's surface is heated by approximately 70% of the solar energy that passes through the atmosphere, where it is absorbed by the earth's land, oceans, and atmosphere. A large amount of heat from the sun is radiated back into the atmosphere in the form of infrared light. A portion of the infrared light from the earth is reflected back into space. It should be noted, however, that GHGs have the ability to absorb sunlight radiation and trap and hold heat in the atmosphere causing the warming of the climate. As GHGs increase in concentration in the atmosphere, the amount of heat and the temperature on the earth will rise. As can be seen in Fig. 1.5, a portion of the reflected back sunrays are trapped by GHGs in the lower atmosphere as a result of the greenhouse effect.

Figure 1.5 The greenhouse effect. Courtesy: Shutterstock.

The greenhouse effect is caused in part by man-made factors such as deforestation. As a result of deforestation, the amount of carbon dioxide in the atmosphere increases. Furthermore, as a result of the disappearance of trees, photosynthesis is not possible. As a result of the development of human civilization, deforestation has become rampant. Carbon dioxide is released into the atmosphere as a result of the burning of wood. GHGs are also released into the atmosphere as a result of the burning of fossil fuels such as oil, coal, and gas. Increasingly, these materials are being used in a wide range of industries. In this regard, industries are also a major contributor to the greenhouse effect. Electrical appliances are another man-made factor contributing to the increase in the greenhouse effect due to their emission of such gases. It is critical to note that even the humble refrigerator in your home emits gases that contribute to global warming. They are known as CFCs and are used in refrigerators, aerosol cans, some foaming agents in the packaging industry, and fire extinguisher chemicals and electronic cleaning solutions. There are also some processes in the cement manufacturing industry that contribute to GHG emissions. The burning of gasoline, oil, and coal are other man-made processes that contribute to the greenhouse effect. Moreover, most factories produce a number of gases that remain in the atmosphere for a long period of time. As a result of these gases, we are experiencing global warming and the greenhouse effect. Indirectly, population growth is also a contributor to the greenhouse effect. With the growth of the population, there will be an increase in the needs and wants of people. As a result, both manufacturing processes and industry processes are enhanced. This results in an increase in the release of industrial gases that contribute to the greenhouse effect. In addition to the increase in population, there is also an increase in agricultural activities. The majority of man-made machines, such as automobiles, contribute to the greenhouse effect. The causes of the greenhouse effect as explained in this paragraph are summarized in Fig. 1.6.

Figure 1.6 Causes of the greenhouse effect.

1.4 Global warming/climate change

As a result of human expansion of the greenhouse effect, scientists attribute the observed global warming trend since the mid-20th century. As discussed in the previous section, the greenhouse effect occurs as a result of the atmosphere trapping heat emitted from the earth to space. Global warming refers to the gradual process of heating the earth's surface and the entire environment, including oceans, ice caps, etc. In recent years, it has been evident that the global atmospheric temperature has been rising. According to the Environmental Protection Agency (EPA), the earth's annual temperature has increased by approximately 0.08°C (0.14°F) per decade since 1880 and more than twice that rate (+0.18°C/+0.32°F) since 1981.

Several factors contribute to global warming, some of which are natural and some of which are man-made. As a result of some natural processes as well as human activity, GHGs are the most substantial cause of global warming. GHG levels have increased in the 20th century as a result of an increase in population, economic growth, and energy consumption. Due to the growing demand for industrialization in the modern world to meet nearly every need, a variety of GHGs are being released into the atmosphere through a variety of industrial processes. Carbon dioxide and methane are the principal GHGs that cause global warming on the earth, which results in climate change such as rising sea levels, melting ice caps, glaciers, and unexpected changes in climate that pose a serious threat to human life. In fact, the issue of global warming has given rise to another issue known as climate change. Despite the fact that these two phrases are sometimes used interchangeably, they are actually different. One of the main causes of global warming is ozone depletion, which is the decline of the ozone layer over Antarctica. Due to the increasing release of chlorofluorocarbon gases, the ozone layer is declining day by day. Many places use chlorofluorocarbon gas as aerosol propellants in industrial cleaning fluids and refrigerators, which cause a gradual loss of the ozone layer in the atmosphere due to the gradual release of the gas. As a result of the ozone layer, the earth’s surface is protected from harmful sunrays by inhibiting their propagation. In spite of this, the gradually deteriorating ozone layer is one of the most significant indicators of global warming. A city is depicted in Fig. 1.7 as a result of climate change.

Figure 1.7 The effects of climate change on a city. Courtesy: Shutterstock.

To study global warming, scientists use elaborate computer models of temperature, precipitation patterns, and atmospheric circulation. Researchers have made several predictions based on these models regarding the effects of global warming on weather, sea levels, coastlines, agriculture, wildlife, and human health.

1.4.1 Weather

During global warming, scientists predict that northern regions of the northern hemisphere will experience more heat and northern glaciers and mountain glaciers will shrink. Less ice will float in the northern oceans. It is possible that regions that currently receive light winter snowfalls may not receive any snow at all. In temperate mountains, snowlines are expected to be higher and snowpacks to melt earlier. There will be a longer growing season in some areas. Temperatures tend to rise more during winter and at night when compared with summer. Due to the increased evaporation of water from the oceans, the world will generally be more humid as a result of global warming. There is no consensus among scientists as to whether a more humid atmosphere will encourage or discourage further warming. In one sense, water vapor is a greenhouse gas, and its increased presence should contribute to the greenhouse effect and global warming. In contrast, more vapor in the atmosphere will produce more clouds, which will reflect sunlight back into the atmosphere, slowing the warming process. In the case of a temperature increase of 10°F, increased humidity will result in an increase in rainfall of approximately 1%. Rainfall has already increased by about 1% on the continents in the last century. Storms are expected to become more frequent and more intense. In the end, water evaporates from the soil more rapidly, causing it to dry out more rapidly between rains. It is possible that some regions actually become drier than before. The wind will blow harder and perhaps in a different direction. It is more likely that hurricanes will be more severe because they gain their strength from the evaporation of water. Even though the climate is warming, there will still be some periods of extreme cold. There is a likelihood that weather patterns will become less predictable and more extreme in the future. A melting glacier in Antarctica as a result of global warming can be seen in Fig. 1.8.

Figure 1.8 Global warming has resulted in a melting glacier in Antarctica. Courtesy: Shutterstock.

1.4.2 Agriculture

A variety of factors contribute to the impact of climate change on agriculture. When temperatures exceed a certain range, warming tends to decrease yields because crops speed through their development, resulting in less grain being produced. Moreover, higher temperatures interfere with the ability of plants to absorb and utilize moisture. As temperatures rise, soil evaporation speeds up and plants increase transpiration, thereby losing more moisture from their leaves. Climate change will likely result in an increase in rainfall. This will result in a race between an increase in evapotranspiration and a greater increase in precipitation as a result of higher temperatures. As a general rule, greater evapotranspiration wins the race. However, a key contributor to climate change, carbon emissions, can also help agriculture by enhancing photosynthesis in many critical crops (such as wheat, rice, and soybeans). Despite this, the science regarding the benefits of carbon fertilization is far from certain. However, we do know that this phenomenon has a minimal impact on C4 crops (such as sugarcane and maize), which represent