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4 The Climate Change Debate The Climatic Record The first question one might ask in this “climate change debate” is what we know about the topic from Earth’s history. Is the changing climate observed today a new phenomenon? Or is it an integral part of Earth’s history? If the latter, how do scien- tists explain the changes that have taken place in climate? How do they collect information about climatic patterns a hundred years ago a thousand years ago a million years ago (if at all)? Weather and Climate The topic of climate change is intimately related to the subject of global warming. Although climate is the product of many factors, Earth’s annual average temperature is certainly one of the most important. If the planet’s temperature increases by one degree Celsius over a 100-year period, that change will have an observable effect on seasons, weather patterns, sea level, biological diversity, and a host of other factors. So, in the simplest possible terms: climate change = global temperature + other stuff A brief aside: Temperature measurements appear frequently in this book. Just for the record: A change of 1°C = a change of 1.8°F (one degree Celsius) (one degree Fahrenheit) A change of 1°F = a change of 0.56°C The first issue in this review requires a discussion of the dis- tinction between weather and climate. One finds in many de- bates over climate change comments such as, “Well, this was the coldest winter in a hundred years in Smithville. So how can global warming be taking place?” “The coldest winter in a hun- dred years” refers to atmospheric conditions that take place in a single year: the weather for that year. Weather measurements usually cover a period of a few weeks, a few months, or a few years. Scientists know a great deal as to the factors that cause