1 Ecosystems and Climate

When viewed from space, Earth is seen as a blue marble. The dominant features of the planet are the blue of the oceans and the white of the clouds traversing the atmosphere. It is an image of fluids – water and air – in motion. Indeed, the study of Earth’s climate is dominated by the geophysical principles of fluid dynamics. With closer inspection, however, one can discern land masses – the continents – and the plants that grow on the land. The blue of the oceans gives way to the emerald green of vegetation. Weather, climate, and atmospheric composition have long been known to determine the floristic composition of these plants, their arrangement into communities, and their functioning as ecosystems. Earth system scientists now recognize that the patterns and processes of plant communities and ecosystems not only respond to weather, climate, and atmospheric composition, but also feedback through a variety of physical, chemical, and biological processes to influence the atmosphere. The geoscientific understanding of planet Earth has given way to a new paradigm of biogeosciences. Ecological climatology is an interdisciplinary framework to study the functioning of terrestrial ecosystems in the Earth system through their cycling of energy, water, chemical elements, and trace gases. Changes in terrestrial ecosystems through natural vegetation dynamics and through human uses of land are a key determinate of Earth’s climate.