Long - term sustainability of humans on Earth requires a balance between global population and consumption of renewable resources — not consumption of nonrenewable resources as we are currently doing. (dotearth.blogs.nytimes.com)
With the rising cost of nonrenewable energy sources and the declining costs of producing energy from renewable sources, demand for highly skilled professionals in the solar energy field is increasing both in the United States and in emerging markets in Asia, Latin America and the Middle East. (affordablecollegesonline.org)
I refer to the large spectrum of challenges that we now associate with ecology — world population, food supply, pollution, dwindling supplies of nonrenewable natural resources, and so on. (religion-online.org)