Chapter Overview

Our goal in this chapter is to sketch a picture of atmospheric and oceanic circulation systems at the global scale. We have some big questions to address, beginning with a very basic one: why air is so mobile and what drives its motion? Once we get a handle on why the atmosphere moves, we can examine the basic structure of the atmosphere's circulation, both at the surface and upper troposphere, and reveal how the ancient mariners used this understanding to navigate the Earth. The next step is to learn about the major wind systems such as the prevailing westerlies in the midlatitudes and the easterly tradewinds in the tropics. In the second half of the chapter we move from wind to waves to ocean currents and the big picture of oceanic circulation, noting this system's important role in shaping global climate and how it feeds into the emerging climate-change scenario.

Introduction

Perhaps none of Earth's great systems is more pivotal to understanding the geographic character of our planet than the atmosphere. Indeed, we might think of the atmosphere as the master system among the great systems: first, because it is the main engine driving other great systems, most notably the hydrologic cycle; and second, because it is the vehicle that ties together systems such as the global water and biochemical cycles. Without the atmosphere, the hydrologic cycle and biochemical cycles (such as oxygen and carbon dioxide exchanges) cannot function.

Chapter Overview

Our main objective so far in this book has centered on the systems and processes responsible for the geographic distribution of energy (mainly heat and radiation) and matter (mainly water). Accordingly, this chapter opens with a brief look at the nature of the systems that produce the main ingredients of climate and how they vary in their distributions and behavior, and goes on to examine the two big climate engines, the tropical engine and the midlatitude engine, and how they operate. This is followed by a brief description of a traditional climate classification scheme, which divides the Earth into five main climatic zones. The chapter ends on a practical note: how humans have adapted to climatic conditions through technologies of clothing and shelter.

Introduction

People everywhere brag and whimper about the woes of their early years, but nothing can compare with the Irish version: the poverty; the shiftless loquacious alcoholic father; the pious defeated mother moaning by the fire; pompous priests; bullying schoolmasters; the English and the terrible things they did to us for eight hundred long years.

Above all – we were wet.

Out in the Atlantic Ocean great sheets of rain gathered to drift slowly up the River Shannon and settle forever in Limerick. The rain dampened the city from the Feast of the Circumcision to New Year's Eve. It created a cacophony of hacking coughs, bronchial rattles, asthmatic wheezes, consumptive croaks. It turned noses into fountains, lungs into bacterial sponges.

Chapter Overview

We now examine the types of plants and animals that inhabit Earth and the factors that govern their geographic distributions. These organisms form a great system in which various, and often distant, parts are woven together into complex networks. In terms of sheer mass, the vast majority of these biota is made up of plants whereas most of the species are represented by animals, particularly insects. We will find that many factors govern the distributions of plants and animals, but at the global scale climate and the patterns of land and water, both present and past, are important. On land, smaller scale factors such as regional climate, landforms, drainage patterns, and land use are significant controls. And at an even finer scale, we will see that local factors such as variations in soil and microclimate also play a part.

Introduction

We pushed our way through the brush to the edge of the pond, a simple little basin with the uninspiring name of “Pond 20.” It was built to collect stormwater runoff from an equally uninspiring subdivision with the elegant name of Crown Isle, and we had gone there to check its summer water level. We expected little more than an overgrown mud-puddle, but were pleasantly surprised at what unfolded. Beyond the overhang of the canopy, sunlight penetrated the water, warming the surface layer and amplifying the commotion of various bugs and small fish.

Chapter Overview

The Greek playwright Euripides wrote that a bad beginning makes for a bad ending. Although humans had a tough beginning, after thousands of years better times eventually emerged as people spread over much of the world and adapted to different landscapes. But with technological advances and the pressure of growing population, adaptation changed to more and more serious forms of environmental manipulation. What began with ancient peoples as a cooperative relationship with their geographic environment has now evolved into one characterized more by a desire for control. Could the human drama on Earth have a bad ending? This chapter opens with an interesting geographic puzzle – the African origins of Homo sapiens and our early migration to Asia, Europe, Australia, and the Americas. It then goes on to consider early agriculture, the rise of population centers, the Industrial Revolution, and their effects on the geographic environment. Measured by the last few centuries, the outcome is a rapidly growing imbalance between human systems and natural systems. The chapter ends by offering a big-picture perspective on human activity on Earth in light of the fact that ours is a planet characterized more by geographic change than by stability.

Introduction

Life has profoundly influenced Earth's geographic character. Of that there is absolutely no doubt among geographers. During its evolution life has directly or indirectly caused many big changes in Earth systems, which have in turn led to major transformations in the biophysical and geographic character of the planet.

Chapter Overview

This chapter is about the grandest of all the great systems. It opens with a brief examination of the Sun's nuclear power plant and the nature of the energy it broadcasts into space and to Earth. Is the flow of energy from the Sun a perfectly steady stream, what form does it take, and what happens to that fraction captured by Earth? How does the motion of Earth in space influence the receipt of solar radiation and is this motion important to Earth's geographic character? We will find that, among other things, it governs the huge north–south swings in energy that give us the seasons. We will try to convince you that in order to understand the geographic character of Earth, we need to see it as an energy system, where solar radiation is converted into heat and heat is stored, transferred, and redistributed over Earth. The chapter concludes with a look at Earth's major heat-storage reservoirs, the oceans, landmasses, and atmosphere, and how planet Earth compares with two sister planets, Mercury and Mars, as a thermal body.

Introduction

At three miles above sea level in the remote mountains of the Hindu Kush of Asia, we made camp on a magnificent glacier. It lay in a narrow valley, partly visible in Figure 3.1, framed by great mountain walls on the east and west.

Chapter Overview

We open this chapter where we left off in Chapter 12, on the nature of the relationship between soil and the geographic environment. The idea here is to provide a simple set-up for classifying soil, beginning at the most elementary level with a two-part scheme and then moving on to classification systems widely used by scientists to describe and map soil. Though sometimes a little challenging to understand, these systems are important learning tools because they enable us build coherent discussions about the character of common soils and what traits make them noteworthy. In addition, without a means of classifying soils, there is no way we can build soil maps and examine the distribution of soils in relationship to other geographic phenomena like climate. The second part of the chapter is concerned with human use and abuse of soil, both past and present. The role of soil and its depletion in the destiny of early civilization is examined, and this is followed by a look at the pressing issue of soil management and food production in the modern world.

Introduction

Besides its foundational role in the terrestrial life system, soil is a tablet upon which are recorded Earth's environmental conditions, that is, the nature of all those things that interact to shape the geographic character of a place on the Earth's surface. Etched into soil, in its composition, its chemistry, its horizons, is an accounting of the systems that have operated there over time.

Chapter Overview

Few things on Earth are as central to physical geography as water or, to put another way, without water Earth's physical geography would be a much simpler matter than it is. So we start this section of the book with an overview of this magnificent system, a glimpse into the big picture of water. The discussion is driven by some compelling questions including how Earth got its water, how much water is held where on the planet, how the water-exchange system, the hydrologic cycle, works, and how on land the system is organized into subsystems. We are led to a model called the water budget that helps us understand how the subsystems like watersheds, glaciers, and soils function. We then give some thought to hydrologic landscapes and what makes humid and arid landscapes different in terms of where water is stored and accessed by plants. Finally, and consistent with one of the book's main themes, Earth is a planet of changing systems, and so it is with the hydrologic system, for no matter where we are this great system is constantly changing around us.

Introduction

Of the many things that make Earth unique as a planet, one of the most striking is its water system. It is not merely the presence of a large water supply that is striking – Mars also has abundant water – but rather the makeup, distribution, and dynamics of Earth's water system.

Chapter Overview

“The man on the farm over there says he pumps water directly from the ground and the supply is endless … he thinks there must a huge lake down there, at least that's what the old timers tell him.” This is a common notion about groundwater, one held by people around the world and one that we hope to dispel in this chapter. There is little doubt indeed that the ground holds immense amounts of water, but how does it get there and how and where is it stored? We will make a case for groundwater as a subsystem in the hydrologic cycle, an open system with inputs from and outputs to the surface water system that we discussed in the previous chapter. We also explore the geographic significance of groundwater and this leads us to the influences it has on the landscape, in particular on streams, lakes, wetlands, and land use. As we will discover, in a world that will see 3 billion additional people in the next 40 years, more than half of whom will be living in dry lands subject to the desiccating effects of global warming, groundwater's role in supplying water to cities, farms, and industry will reach levels of acuity unmatched in history.

Introduction

Groundwater is Earth's single largest supply of fresh, liquid water. Humans have known about it and used it for thousands of years.The fi rst of ancient Rome’s aqueducts was fed by groundwater discharged from springs in the hills outside the city. The ancient qanats of the Middle East tapped into groundwater aquifers on mountain slopes, and tens of thousands of public wells have dotted the landscapes of China, India, and Europe since prehistoric times.

Chapter Overview

Earth is a diverse and colorful planet and there is lot to be learned about it by merely looking down on it from space. Accordingly, we open this chapter with some simple visual impressions of our planet. The first is based on the colors Earth exhibits to the space observer and the second considers the meaning of the patterns we see, particularly the distribution of life and the largescale motion represented by the great whirls and swirls of the atmosphere and oceans. We then discuss Earth's physical dimensions and how we use a system of north–south and east–west lines, called meridians and parallels, to reference and document locations and other geographic phenomena on the planet's surface. This leads to mapping, the basic properties of maps, and the sorts of maps most commonly employed in geography. And finally, any examination of Earth in physical geography must include time, for the planet's calendar is long, more than four billion years, and filled with events that help explain where we are today geographically.

Introduction

Earth's first great navigators were the Phoenicians, who determined the location of their ships in terms of the length and width of the Mediterranean Sea. The Phoenicians' navigational methods were taught to the Greeks and eventually to the Romans. When translated into Latin, the perpendicular directions of length and width became the longitude (longus, or long) and latitude (latus, or wide).

Ancient Greek philosophy was divided into three sciences: physics, ethics, and logic. This division is perfectly suitable to the nature of the matter, and there is no need to amend it, except perhaps just to add its principle, partly so as to assure oneself in this way of its completeness, partly to be able to determine correctly the necessary subdivisions.

All rational cognition is either material and considers some object, or formal and occupied merely with the form of the understanding and of reason itself, and with the universal rules of thinking as such, regardless of differences among its objects. Formal philosophy is called logic, whereas material philosophy, which has to do with determinate objects and the laws to which they are subject, is once again twofold. For these laws are either laws of nature, or of freedom. The science of the first is called physics, that of the other is ethics; the former is also called doctrine of nature, the latter doctrine of morals.

If so far we have drawn our concept of duty from the common use of our practical reason, it is by no means to be inferred from this that we have treated it as an experiential concept. Rather, if we attend to our experience of the behavior of human beings we meet frequent and, as we ourselves concede, just complaints that no reliable example can be cited of the disposition to act from pure duty; that, though much may be done that conforms with what duty commands, still it is always doubtful whether it is actually done from duty and thus has a moral worth. That is why there have been philosophers in every age who have absolutely denied the actuality of this disposition in human actions, and attributed everything to a more or less refined self-love, without however calling into doubt the correctness of the concept of morality because of this; rather, with intimate regret they made mention of the frailty and impurity of a human nature that is indeed noble enough to take an idea so worthy of respect as its prescription, but at the same time too weak to follow it, and that uses reason, which should serve it for legislation, only to take care of the interest of inclinations, whether singly or, at most, in their greatest compatibility with one another.

In fact, it is absolutely impossible by means of experience to make out with complete certainty a single case in which the maxim of an action that otherwise conforms with duty did rest solely on moral grounds and on the representation of one’s duty. For at times it is indeed the case that with the acutest self-examination we find nothing whatsoever that – besides the moral ground of duty – could have been powerful enough to move us to this or that good action and so great a sacrifice; but from this it cannot be inferred with certainty that the real determining cause of the will was not actually a covert impulse of self-love under the mere pretense of that idea; for which we then gladly flatter ourselves with the false presumption of a nobler motive, whereas in fact we can never, even by the most strenuous examination, get entirely behind our covert incentives, because when moral worth is at issue what counts is not the actions, which one sees, but their inner principles, which one does not see.