ABSTRACT
With the exception of humans and some chemosynthetic ecosystems powered by geothermal energy, all other known ecosystems on earth are powered either directly or indirectly by the sun, mostly via photosynthesis, which usually converts about 1% to 2% of incident solar energy into “plant energy.” If we include geothermal with solar energy, then humans stand alone in trying to use sources of energy other than these. In this chapter I will, among other things, outline an argument for the fol-
lowing claim: The most economical (as in “cheapest”), fastest, and most reliable way to provide non-carbon based energy for human societies is to make use of solar energy in its various forms. About half the solar energy that reaches the ground drives the hydrologic, i.e., water, cycle. This is truly an immense amount of energy. Wind, solar thermal, solar photovoltaic, ocean thermal, ocean wave, ocean (moon caused) tides, and “cool” geothermal (available at shallow depths nearly everywhere) are all sources of energy. “Hot” geothermal, that issues from the earth due to radioactive processes (“nuclear energy”) within the earth, is plentiful in select locations. The good news is that it is technologically possible to power our societies using these energy sources. It is also possible to make the transition to these sources in measured steps over the next twenty years. This incremental process would give us and the rest of the earth and its ecosystems time to adjust to whatever unintended or unforeseen consequences this process might entail. It is also possible that “subunits” of society can start this process without waiting for national leadership, although the most efficient transition could be effected by enlightened leaders. Biofuels may have a role to play, but there are some major difficulties we will discuss. Nuclear power, which is the favorite of some, is not competitive with or as reliable as a well designed, sustainable, solar-driven system; and we will examine this assertion as well.
