Scientists have been studying the Earth’s climate for nearly 200 years and, over that time, a sophisticated and well-validated theory of our climate has emerged. In this chapter, we take the fundamental physics we learned in the last chapter and use it to explain how greenhouse gases warm the planet and why the temperature of the Earth is what it is. By the end of the chapter, you will understand why scientists have such high confidence that adding greenhouse gases to the atmosphere will warm the planet.

In Chapter 2, we detailed the overwhelming evidence that the Earth’s climate is changing – evidence so overwhelming that the IPCC describes the warming as “unequivocal.” At this point, the most heated argument is over the cause of the warming: Is it caused by human activity, or is it natural? In this chapter, we address this question.

This chapter considers types of word formation that are not found in English and languages that might be more familiar to students. We look at infixation, circumfixation and parasynthesis, internal stem change (ablaut and consonant mutation), reduplication (full and partial), templatic (root and pattern) morphology, and subtractive processes. Students are introduced to techniques for analyzing morphological data in languages that may be unfamiliar to them.

In Chapters 11 and 12, we explored our options for addressing climate change. In Chapter 14, I will pull all these together so we can explore how we can choose among these options. Before we get to that discussion, though, I describe the context of the policy debate by providing a brief history of climate change science, policy, and politics.

In this chapter we consider more closely what we mean by a word. We begin by contrasting the differences between the mental lexicon and dictionaries. We then introduce students to the methods and techniques that psycholinguists use for studying the mental lexicon. We look at reaction time experiments, brain imaging, and the ways in which we can study individuals with aphasia and genetic disorders that affect lexical knowledge. Students are introduced to how children acquire morphology. We then look at English past tense morphology in the context of the ‘storage versus rules’ debate, considering what experimentation, brain imaging, and the study of aphasia and genetic disorders tell us about this controversy. The chapter ends with a brief history of dictionaries.

This chapter begins with the basics of affixation, including the types of morphemes that are commonly found in English (prefixes, suffixes, bound bases, formatives, extenders). Students learn to formulate word formation rules, to represent the internal structure of complex words with tree structures, and to understand difficulties that arise in segmenting words. The chapter also considers the range of meanings that derivational affixes can express. It includes a section on compounding that considers the difficulties in defining what a compound is, the notion of headedness, and the types of compounds that are common in English. The chapter also briefly considers minor types of word formation such as backformation, blending, acronyms, initialisms, and coinage. Students are taught to use corpora such as the Corpus of Contemporary American English to find their own morphological data.