framework of causes, consequences, and responses used in human dimensions research (see Table 7.5). Others cut across several of these themes, develop understanding of fundamental social processes that affect human-environment interactions, or suggest broadening of the overall USGCRP agenda.

Previous research has identified changes in the use of land, energy, and materials as priority subjects in understanding the causes of global change. Although the driving forces for the use of these resources include population growth and technological change, in many regions the most important determinant of environmental impacts is the per capita consumption of energy and materials. Debates over the relative roles of "northern" consumption and "southern" population growth, and over the responsibility of different social groups within countries, have confounded international environmental negotiations and domestic policy development. A recent report¹⁵¹ identifies the study of environmentally significant consumption as an important area for research, a point that is echoed by the recent joint statement on consumption of the National Academy of Sciences and the Royal Society of London, as well as by new research initiatives of the Organization for Economic Cooperation and Development and the European Community.

Consumption, that is, the human transformation of energy and materials, is environmentally significant "to the extent that it makes materials or energy less available for future use, moves a biophysical system toward a different state, or,