Global Climate Change Demystified

James G. Speight

• Verlag: Wiley
• Jahr: 2019
• ISBN:
  9781119653882
• Auflage: 1
• Thema: Politica e relazioni internazionali
• Thema: Politica ambientale ed energetica

Tackling one of the most controversial subjects of our time, one of the world's foremost environmental and petroleum engineers explores the potential causes and ramifications of global climate change.

For too many years climate change (also referred to as global warming) has been assigned predominantly to the emissions of carbon dioxide through the combustion of fossil fuels. It must never be forgotten or ignored, however, that the Earth has been constantly changing since its formation and has gone through different eras like glaciations, among others. These changes need thousands of years to be made visible, and are likely still continuing, given the increase in the average temperature of the Earth since the pre-industrial period (provided that the measurements of past climatic temperatures are accurate and beyond reproach). It follows that the warming trend that has occurred over the past 100 years is very likely to have some origins in natural events as well as in human activity. The precise contributions of natural effects and anthropogenic effects on the climate are not known, but it is accurate to conclude that many factors continue to influence climate. Whether or not human activities have become a dominant force in the changing climate and are responsible for most of the warming observed is still open to question.

When studying the climate system of the Earth, an area of common confusion is whether climate scientists agree or disagree as to whether or not climate change is happening, or if it is happening, whether or not humans are the primary cause. There are a variety of reasons for this, but a majority of scientists who study climate and publish in peer-reviewed journals agree that human activity is causing the warming of the Earth.

The purpose of this book is to weigh all of these various data points and, in a scientific and unemotional way, arrive at likely conclusions regarding global climate change. Whether human activity is the main driver behind our current changes in climate, one thing is certain: Climate change is happening, and we all need to make informed, rather than emotional, decisions.

Chapter 1
The Climate of the Earth

1.1 Introduction

Typically, climate is frequently defined as a description of the climate system which includes the analysis of the behavior of the major components that influence the climate of the Earth: (i) the atmosphere, which is the gaseous envelope surrounding the Earth, (ii) the hydrosphere, which is the liquid water such as the oceans, lakes, underground water and, for the purposes of this text, (iii) the cryosphere, which are those portions of the surface of the Earth where the water is in solid form, including sea ice, lake ice, ice sheets, and glaciers, (iv) the lithosphere, which refers to the crust and upper mantle of the Earth, and (v) the biosphere, which refers to living organisms and the interactions between them [1, 2]. These components interact with one another and with aspects of the biosphere of the Earth to determine not only the day-to-day weather, but also the long-term averages that are referred to as climate.

On the other hand, the most general definition of climate change is a change in the statistical properties of the climate system when considered over long periods of time, regardless of the cause(s). By this definitions, fluctuations over periods shorter than several decades, such as El Niño, do not represent climate change. A key difference between climate change and climate variability is in persistence of anomalous conditions that used to be rare but occur more frequently (summertime maximum air temperatures increasingly break records each year), or vice versa (duration and thickness of seasonal lake ice decreasing with time). In statistical terminology, the curve of the frequency distribution representing the probability of specific meteorological events occurring is changed. The curve may be modified either in amplitude, or shifted about a new mean, or both [3].

However, care must be taken not to confuse climate change and climate variability. For the most part, climate variability (that is, variable climate caused by non-anthropogenic sources) relates to the natural processes that affect the atmosphere, such as the North Atlantic oscillation (NAO) that refers to anomalous changes in atmospheric pressure at sea level that occur near Iceland. The North Atlantic oscillation phases are often associated with above-average storm counts over parts of Europe and the United States. In addition, there is also the El Niño Southern Oscillation (ENSO) phenomenon near the equatorial Pacific Ocean, where fluctuations of the temperatures of the surface of the sea typically alternate every few years between a warming phase (El Niño) and cooling periods (La Niña), with a neutral phase in between.

By way of clarification, the term above average as used above or, for that matter, in any example of climatic conditions, is often difficult to define precisely because it is based on a minimum and a maximum that may be close or far apart. In other words, the limits of the data can give misleading information about the actual conditions that fall into the range of the data limits.

Many regions of the world experience greater variability, climatologically speaking, than do others. In some parts of the world, or in any region for certain time periods or parts of the year, the variability can be weak (i.e., there is not much difference in the conditions within that time period). In other places or time periods, the conditions can swing across a large range, from freezing to very warm, or from very wet to very dry and exhibit strong variability. A certain amount of this is understood and accepted, instinctively, by the people in a region. What are typical normal climatic conditions for Denver (Colorado) in terms of the frequency of precipitation (high variability) would be abnormal for Rome (Italy) (low variability). Thus, any single event, such as a severe tropical cyclone, cannot be attributed to human-induced climate change, given the current status of scientific understanding [3] but it can contribute to the so-called average climate.

Within scientific journals, global warming refers to an increase in the surface temperature of the Earth. Global warming is a long-term rise in the average temperature of the climate system of the Earth, which is an aspect of climate change, as manifested by temperature measurement and by multiple effects of the warming. On the other hand, climate change is a more all-inclusive term that includes global climate systems on a worldwide basis.

Climate change occurs when changes in the climate system of the Earth result in new weather patterns that last for at least decades, if not millennia [4]. The term climate change is often used arbitrarily to refer to climate change caused by human activity as the predominant cause without giving consideration to changes in the climate that may have resulted from the natural processes of the Earth. As a result, especially in the context of modern environmental policy and environmental science, the term climate change has unfortunately (and incorrectly) been associated with anthropogenic (human) activities as the causative factor.

The issue of global climate change is often associated with the use of fossil fuels as sources of energy. Of most concern is the increase in emissions of carbon dioxide (CO₂) due to emissions from fossil fuel combustion:

Other factors, including land use, ozone depletion, animal agriculture, and deforestation, are also of concern in the roles they play – both separately and collectively – in affecting climate, microclimate, and the climatic variables (Chapter 2). This focus is operative even though emissions from other sources such as agriculture, waste management, and biomass burning occur on a regular basis [5].

Chemical compounds released at the surface by natural processes and by anthropogenic processes are oxidized in the atmosphere before being removed by wet or dry deposition. Key chemical species of the troposphere include organic compounds such as methane and non-methane hydrocarbon derivatives as well as oxygenated organic species and carbon monoxide, nitrogen oxides (which are also produced by lightning discharges in thunderstorms) as well as nitric acid. Other chemical species include hydrogen compounds (and specifically the hydroxy radical (OH•), and the hydroperoxy radical (HO₂•) as well as hydrogen peroxide (H₂O₂), ozone (O₃), and sulfur compounds such as dimethyl sulfide (CH₃SCH₃), sulfur dioxide (SO₂), and sulfuric acid (H₂SO₄). The hydroxyl radical (OH•) deserves additional consideration since it has the capability of reacting with and efficiently destroying a large number of organic chemical compounds and, hence, making a direct contribution to the oxidation capacity (reactivity) of the atmosphere [6].

Finally, the release of sulfur compounds at the surface of the Earth surface and the subsequent oxidation of the sulfur compounds in the atmosphere leads to the formation of small liquid or solid particles that remain in suspension in the atmosphere. These aerosol particles affect the radiative balance of the atmosphere directly, by reflecting and absorbing solar radiation, and indirectly, by influencing cloud microphysics. The release to the atmosphere of sulfur compounds has increased dramatically, particularly in regions of Asia, Europe, and North America as a result of human activities, specifically coal combustion [7, 8].

When studying the climate system of the Earth, an area of common confusion that relates to whether climate scientists agree or disagree as to whether or not climate change is happening, or if it is happening, whether or not humans are the primary cause [9]. There are a variety of reasons for this, but (supposedly) a majority of scientists who study climate and publish in peer-reviewed journals agree that human activity is causing the warming of the Earth. But when anthropogenic activities are cited as the main cause the cause of the warming there is serious concern because of the other factors that are often ignored.

However, before progressing any further into the changeability of the Earth and the various subsystems, it is also necessary to introduce the terminology applied to the various subsystems to aid in an understanding of the Earth. The climate system itself is often considered as part of the broader Earth system, which includes all the parts of the Earth and not only the elements that are directly or indirectly related to the temperature or precipitation [10].

The following sections of this chapter provide some general information about the components of the Earth system that play an important role in determining climate change. These components are: (i) the atmosphere, (ii) the hydrosphere, (iii) the cryosphere and geosphere, (iv) the lithosphere, and (v) the biosphere.

1.2 The Atmosphere

Physically, the atmosphere is the envelope of air surrounding the Earth that is held in place around the Earth by gravitational attraction and which has a substantial effect on the environment. It is the layer or a set of layers of gases surrounding the Earth that is held in place by gravity. Chemically, dry air contains nitrogen (78.09% v/v), oxygen (20.95% v/v), argon (0.93% v/v), carbon dioxide (0.04% v/v), and small amounts of other gases [11].

The atmosphere contains oxygen used by most organisms for respiration and carbon dioxide used by plants, algae, and cyanobacteria for photosynthesis. Also, the atmosphere helps protect living organisms from genetic damage by solar ultraviolet radiation, solar wind, and cosmic rays. The current composition of the atmosphere is the product of billions of years of biochemical modification of the paleoatmosphere by living organisms [12]. The atmosphere can be divided (atmospheric stratificatio...