In Oregon, within a few hundred miles you can see snowy volcanoes, parched deserts, semiarid grasslands, alpine meadows, and coastal temperate rain forests. On any given day, the weather across the state can range from freezing cold to baking hot, from bone dry to soaking wet, from tranquil to tempestuous. Oregon regularly experiences the extremes of average precipitation, temperature, humidity, and wind characteristic of the North American West. Some places in the Coast Range, for example, receive as many as 200 inches of rain in some years, while the rain shadow of Steens Mountain in eastern Oregon sometimes receives as little as five inches. But even highly variable weather creates patterns over time, and scientists use the word climate to describe those patterns over decades, or even centuries.

Oregon’s climate is not only diverse, it is also changing. In geological time—the intervals of time that geologists use to chart changes and sequences of events in the rock record—Oregon’s climate has vacillated between tropical and arctic. Since the Industrial Revolution, however, human activity has contributed to changes in the Earth’s climate, causing geological change on shorter, human timescales. Scientists refer to the changes that humans make to climate as anthropogenic Climate Change, which have occurred largely as a result of changes in the composition of the atmosphere, particularly through the emission of greenhouse gases like CO2 that increase the overall temperature of the Earth. Because anthropogenic climate change, on balance, increases the overall temperature of the planet, it is also often referred to as anthropogenic warming or, more commonly, global warming. The terms are not perfectly interchangeable, but both have been used to describe the causes of the climate crisis, a term scientists and concerned citizens often use to refer to the related negative effects of an increase in average global temperatures on animal and human populations, as well as the ecosystems and infrastructure on which they rely.

Read more in Howe’s Essay: Climate Change in Oregon