In this chapter you will:

• Learn about the ways in which the natural environment functions and sustains life;

• Look at the first and second laws of thermodynamics;

• Learn about energy and nutrient flows in ecosystems;

• See how the fossil fuels came into existence;

• Study population dynamics;

• Consider the concept of ecosystem resilience;

• Learn about global nutrient cycles;

• Look at evolutionary processes.

In the previous chapter we introduced the idea that the economy and the natural environment are interdependent systems, with the economy located within the environment. That idea is to be developed in the following chapters of Part I. This chapter looks at the functioning of the natural environment itself, largely ignoring the role of humanity. It is a simple, and brief, overview of the material from environmental science that is necessary for an understanding of ecological economics. Readers who are familiar with environmental science will find that they can get through the chapter quickly, though they probably should not skip it completely. For other readers, the Further Reading section at the end of the chapter offers some guidance on how to go further into the environmental science topics introduced here.

This chapter is organised as follows. First, in section 2.1, we look at the planet in terms of four interacting systems. Section 2.2 is about thermodynamics, the science of energy. Some appreciation of the essentials of thermodynamics is essential for understanding the way that the planet works, and particularly the nature of life on earth, which is dependent on energy.