xxviii The Environmental Debate
rain, which causes widespread damage to forests and life in lakes and rivers. Activated by sunlight, the
nitrogen oxides also react photochemically with the hydrocarbons produced by vehicle emissions, power
plants and factories, and fumes from volatile solvents to cause smog, which is responsible for impaired
respiratory function, especially in the very young and the very old. Early efforts, beginning in the 1970s,
to control the emission of polluting gases into the atmosphere were relatively successful, and the smog
problem in places like Los Angeles was reduced significantly but by no means eliminated.
According to the National Climate Data Center, there is unequivocal scientific evidence that the con-
centration in the atmosphere of greenhouse gases, primarily carbon dioxide (CO2), has been increasing
as a result of the burning of coal, oil, and gas. Prior to the beginning of the Industrial Revolution, CO2
levels were about 280 parts per million by volume (ppmv); current levels are about 400 ppmv and increas-
ing at a rate of 2.0 ppmv per year since 2006. The global concentration of CO2 in our atmosphere
CO2today far exceeds the natural range over the last 650,000 years of 180 to 300 ppmv,8 and climatolo-
gists would like to see CO2 levels reduced to 360 ppmv before mid-century.
Since the late-nineteenth century, there has also been an increase in global surface temperatures of
about 0.74°C (plus or minus 0.18°C). This warming trend has not been uniform across the planet how-
ever. In fact, some parts of the southeastern United States and some areas of the North Atlantic have
cooled slightly during the last century. It should also be noted, though, that 15 of the 16 warmest years
on record have all been in the twenty-first century.
Despite the data, some people believe the warming trend that has been recorded in recent decades
is merely the result of normal temperature variations. No matter what the cause, the global rise in tem-
perature and the accompanying change in the distribution of rain will have a major effect on agriculture
and the way we live. As the amount of CO2 in the atmosphere increases and the earth warms, glaciers
are melting, sea levels are rising, and the oceans are acidifying. Although many of us find it hard to worry
about tides a few more inches above sea level, people in coastal communities recognize the devastating
potential of this seemingly minor change. Indeed, island nations as well as countries with large areas of
lowlands, such as Bangladesh, stand to lose substantial portions of their national territory, a loss that
will destroy natural resources and displace human populations. Extreme climate events such as abnor-
mally severe storms, heat waves, droughts, and flooding are having devastating effects around the world,
from Louisiana to Pakistan. Environmentalists think that it would be unconscionable for nations to fail
to control carbon emissions even if the causal relation between CO2 emissions and global warming were
unproved and only a strong probability.
While some industrialists have concluded that the threat of global warming is real and have responded
with efforts to reduce their carbon footprints, others consider it is foolish to expend vast sums of money
and possibly undermine economic prosperity in order to address the possibility of environmental dan-
ger. In the international arena, more and more countries are questioning the right of other countries to
pursue policies that could have a deleterious effect on the environment of their nation.
WASTE PRODUCTION AND DISPOSAL
As the nation’s population has grown, and as cities and towns have expanded, the need to find safe and
adequate ways to dispose of everincreasing amounts of both organic and inorganic wastes has become
an increasingly formidable challenge.
Since organic wastes are routinely digested by microorganisms both on land and in water, waste
from the life processes of various organisms, including humans, are generally recycled in the environ-
ment without event. However, because bodily wastes have an environmental impact in addition to being