Answer:
All the human causes of global environmental change happen through a subset of proximate causes, which directly alter aspects of the environment in ways that have global effects.
Step-by-step explanation:
The important proximate human causes of global change are those with enough impact to significantly alter properties of the global environment of potential concern to humanity. The global environmental properties now of greatest concern include the radiative balance of the earth, the number of living species, and the influx of ultraviolet (UV-B) radiation to the earth's surface (see also National Research Council, 1990b).