The book offers a comprehensive account of how the world evolved to its
present state in which humans now exercise a powerful, in many cases
dominant, influence for global environmental change. It outlines the
history that led to this position of dominance, in particular the role
played by our increasing reliance on fossil sources of energy, on coal,
oil and natural gas, and the problems that we are now forced to confront
as a result of this history. The concentration of carbon dioxide in the
atmosphere is greater now than at any time over at least the past
650,000 years with prospects to increase over the next few decades to
levels not seen since dinosaurs roamed the Earth 65 million years ago.
Comparable changes are evident also for methane and nitrous oxide and
for a variety of other constituents of the atmosphere including species
such as the ozone depleting chlorofluorocarbons for which there are no
natural analogues.
Increases in the concentrations of so-called
greenhouse gases in the atmosphere are responsible for important changes
in global and regional climate with consequences for the future of
global society which, though difficult to predict in detail, are
potentially catastrophic for a world poorly equipped to cope. Changes
of climate in the past were repetitively responsible for the demise of
important civilizations. These changes, however, were generally natural
in origin in contrast to the changes now underway for which humans are
directly responsible. The challenge is to transition to a new energy
economy in which fossil fuels will play a much smaller role. We need as a
matter of urgency to cut back on emissions of climate altering gases
such as carbon dioxide while at the same time reducing our dependence on
unreliable, potentially disruptive, though currently indispensable,
sources of energy such as oil, the lifeblood of the global
transportation system. The book concludes with a discussion of options
for a more sustainable energy future, highlighting the potential for
contributions from wind, sun, biomass, geothermal and nuclear,
supplanting currently unsustainable reliance on coal, oil and natural
gas.