CLIMATE CHANGE AND OCEAN ACIDIFICATION - Marine Pollution: What Everyone Needs to Know - page 162

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CLIMATE CHANGE AND OCEAN
ACIDIFICATION
What causes global warming or climate change?
The burning of fossil fuels emits carbon dioxide into the atmo-
sphere, which results in the greenhouse effect—less heat can
be re-radiated away from the earth, thus raising the tempera-
ture of the atmosphere and ocean. In the past century the
oceans have warmed by about 1 degree F to a depth of 200 feet,
and the overwhelming scientific consensus is that increasing
levels of human-caused greenhouse gases in the atmosphere
are the principal cause.
What problems are happening or expected to happen in the
marine environment because of climate change?
Climate change is the biggest single threat to our oceans'
health. The warming of the oceans will have numerous effects
on all organisms, most basically elevating their metabolic rates,
which ultimately affects life history, population growth, and
ecosystem processes. Elevated metabolic rates create increased
demand for oxygen at the same time that the warmer water
can hold less oxygen. The uptake of toxic contaminants is also
accelerated by elevated metabolic rates.
Variation in temperature can also affect the abundance
and distribution of plankton. As the ocean's surface warms, it
becomes more stratified—with greater temperature differences