Download The Earth`s climate is different from what it was only 20,000 years

Global Warming Explained and Acidification of Oceans
Global Warming
The Earth's climate is different from what it was only 20,000 years ago when ice
sheets covered much of the Northern Hemisphere. Since the industrial revolution
humans have been dumping exhaust from burning fossil fuels into the
atmosphere, thereby significantly increasing the amount of carbon dioxide (CO 2)
in the atmosphere. This “extra” CO2 increases the natural capacity of the
atmosphere to trap radiant heat near the Earth's surface. This trapping is called
the greenhouse effect that works in the following manner. Solar energy reaching
the Earth's surface warms the lower atmosphere. Gases such as water vapor
and CO2 trap a large fraction of this heat near the Earth's surface. The natural
greenhouse effect, not aided by human emissions, is responsible for keeping our
planet at a livable temperature—around 33C on average at the surface. The
concentration of greenhouse gases in the atmosphere determines how much
heat is trapped. Even seemingly small human-induced addition of greenhouse
gases have already resulted in the average global temperature increasing around
0.8oC in the last 100 years. Without technology that allows us to switch off our
fossil-fuel lifestyle yet maintain or improve our typical life style that we have
today, within the next century the global average temperature could continue to
warm by 1C if we are quite lucky, 6C if we are unlucky or up to 12oC or more if
we are very unlucky. This could result in ecologically significant changes, which
are why climatic considerations are fundamental in the discussion of possible
ecological consequences of wildlife.
Acidification of Oceans
Besides increasing the average global temperature, the added CO2 in the
atmosphere is discernibly changing the pH balance of the oceans. The CO 2
concentration is greater in the atmosphere than in the oceans, meaning that at
the air-water boundary CO2 is diffusing into the water. The carbonic acid that
forms in the water has already discernibly changed the oceans pH from 8.0 - 8.3
(before the industrial revolution) to 7.9 – 8.2. If we do not change away from how
we currently use fossil fuels, The Royal Society of the United Kingdom has
estimated by 2100 the pH range could be 7.5 – 7.8. Coral reefs and other
structure built by animals using calcium carbonate (e.g., shells) will not only be
difficult to build, but those that are built will dissolve. Obviously this will be
detrimental to marine organisms, but we will also be affected because ocean
fisheries will most likely be negatively affected and reefs that protect the shores
during large storms could be so weaken or eroded to be of little use. Scientist in
The Royal Society warn that even if we curtailed our CO2 emissions in 2010, the
pH change already evident in the oceans will take tens of thousands of years to
return to pre-industrial levels. What we are doing today will truly impact the lives
of people over 500 generations from now.
Further Resources
Intergovernmental Panel on Climate Change (IPCC). 2001. Climate Change
2001: Impacts, Adaptations, and Vulnerability. Cambridge University Press, NY.
The Royal Society. 2005. Ocean acidification due to increased atmospheric
carbon dioxide. Policy document 12/05.
Terry L. Root