Global Warming

Global Warming

The relationship between humans and the state of the ecosystem is not only
dependent upon how many people there are, but also upon what they do. When there
were few people, the dominant factors controlling ecosystem state were the
natural ones that have operated for millions of years. The human population has
now grown so large that there are concerns that they have become a significant
element in ecosystem dynamics. One of these concerns is the relationship between
human activities and climate, particularly the recent observations and the
predictions of global warming, beginning with the alarm sounded by W. Broecker
(1975).

The relationships among humans, their activities and global temperature can be
assessed by making the appropriate measurements and analyzing the data in a way
that shows the connections and their magnitudes. Human population can be closely
estimated and the consequences of their activities can be measured. For example,
the volume of carbon dioxide, methane and nitrous oxide emissions is an
indicator of human's energy and resource consumption. An examination of
population size, atmospheric concentrations of these gases and global
temperature relative to time and with respect to each other is presented here to
demonstrate the relations among these factors.

POPULATION GROWTH

Many of us have seen linear graphs of human population showing the enormous
growth in the last two centuries. However, significant changes in population
dynamics are lost in the exponential growth and long time scales. If the data
are replotted on a log-population by log-time scale, significant population
dynamics emerge. First, it is apparent that population growth has occurred in
three surges and second, that the time between surges has dramatically shortened
(Deevey, 1960).

Figure 1. Population (Log-population verses log-time since 1 million
years ago). Time values on x-axis, ignoring minus sign, are powers of 10 years
before and after 1975 (at... [continues]

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