53
to adapt to this rapid climate change or to move fast enough to
more suitable areas as their current areas become less suitable
for them.”
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An Unnaturally Warming World
Environmental groups such as the National Wildlife Federation,
along with most of the world’s scientists, say that the unnatural
warming is a result of human actions. Not everyone agrees with
this—but the number of doubters has been shrinking over the
years as evidence of climate change becomes more difficult to
refute. According to the National Aeronautics and Space Admin-
istration (NASA), 97 percent of climate scientists now agree that
climate-warming trends over the past hundred years “are very
likely due to human activities, and most of the leading scientific
organizations worldwide have issued public statements endors-
ing this position.”
54
Whatever the cause, no one can deny that
the earth is heating up, and this is creating serious problems for
wildlife habitats throughout the world.
The human activity that is widely believed to be the culprit
of the fast-warming climate is the burning of fossil fuels: coal,
oil, and natural gas. These fuels all have a high concentration of
carbon. When they are burned, the combustion produces mas-
sive amounts of a colorless, odorless gas called carbon dioxide
(CO
2
), and this gas is emitted into the atmosphere. This occurs
in a number of different ways. For instance, CO
2
is created when
coal is burned in power plants to generate electricity. According
to the US Energy Information Administration, 35 percent of the
total CO
2
emissions in the United States during 2016 were from
coal-fired power plants. CO
2
is also produced when people burn
gasoline or diesel fuel in their vehicles; when rain forests are cut
down and burned for agriculture; and when factories manufac-
ture metals, chemicals, plastics, and minerals, generating CO
2
as
a by-product.
CO
2
is a powerful heat-trapping gas, so named because when
it is in the atmosphere, it traps and holds heat from the sun. It is
also called a greenhouse gas since its heat-trapping capability
