209
Atmospheric Chemistry
Some questions with answers that are not known at the present time with certainty are
What is the timing and severity of the warming?
What are the regional distributions of the impacts?
What are the magnitudes of the feedback processes?
It is useful to briefly review the state of our understanding of these issues. As discussed,
the increase of CO 2 in the atmosphere is largely related to the burning of fossil fuels. The
increase of greenhouse gases in the atmosphere and the resultant increase in the temperature of the earth can cause some global changes. Some of those include
Sea- level rise: The increase in the temperature can cause an increase in the volume
of seawater and a subsequent increase of sea level. The increased temperature can
also melt ice on land, which would increase the sea level. For example, if the ice on
Antarctica melts, the sea level may rise by 70 m.
Extreme weather events: These can result from the higher temperature of the surface waters in the oceans. Hurricanes, for example, can become more frequent and
stronger in warmer waters. Some have speculated that if the temperatures of North
Atlantic surface waters become too warm, they will not be able to sink to form
North Atlantic deep water. This could have large- scale climate effects on the earth.
Spread of tropical diseases: The warmer waters in tropical regions may result in an
increase in tropical diseases such as malaria and typhoid fever.
Species extinctions: The increase in the temperature of ocean waters may cause
coral bleaching of reefs.
There is some evidence that the ice cover in the Arctic Ocean is thinning because of
global warming. These results come from submarine measurements from 1957 to 1997. The
ice has decreased by as much as 3 m over the past 40 years. Some predict that the ice will
completely disappear in the Arctic in the summer in 50 years. There is also some evidence
that surface ocean waters have increased over the past 20 years. For example, the heat content of the waters has increased over the past 50 years. This means that part of the increase
in the temperature of the atmosphere has been used to heat up the surface waters of the
oceans. Although current measurements indicate that the sea level is rising, we cannot
accurately predict what it will be in the future. We can, however, estimate the level based
on the possible increases in the temperature. If the temperature increases by 3°C over the
next 50 years, the sea level could rise by 80 cm, or 32 inches. Recently, some have predicted
that if the ice on Antarctica melts, the ocean will rise by as much as 70 m (~200 ft). This
increase in sea level can cause an inundation of water in some coastal areas and result in
more serious coastal flooding from hurricanes and typhoons. Some Web sites for more
information on global warming are www.ipcc.ch, www.ucsusa.org, and www.iclei.org.
5.4.1 effects of global Warming on the Oceans
The increase in CO 2 in the atmosphere causes a number of stresses on the surface waters of
the oceans. Gruber (2011) has recently discussed the following stresses:
Atmospheric Chemistry
Some questions with answers that are not known at the present time with certainty are
What is the timing and severity of the warming?
What are the regional distributions of the impacts?
What are the magnitudes of the feedback processes?
It is useful to briefly review the state of our understanding of these issues. As discussed,
the increase of CO 2 in the atmosphere is largely related to the burning of fossil fuels. The
increase of greenhouse gases in the atmosphere and the resultant increase in the temperature of the earth can cause some global changes. Some of those include
Sea- level rise: The increase in the temperature can cause an increase in the volume
of seawater and a subsequent increase of sea level. The increased temperature can
also melt ice on land, which would increase the sea level. For example, if the ice on
Antarctica melts, the sea level may rise by 70 m.
Extreme weather events: These can result from the higher temperature of the surface waters in the oceans. Hurricanes, for example, can become more frequent and
stronger in warmer waters. Some have speculated that if the temperatures of North
Atlantic surface waters become too warm, they will not be able to sink to form
North Atlantic deep water. This could have large- scale climate effects on the earth.
Spread of tropical diseases: The warmer waters in tropical regions may result in an
increase in tropical diseases such as malaria and typhoid fever.
Species extinctions: The increase in the temperature of ocean waters may cause
coral bleaching of reefs.
There is some evidence that the ice cover in the Arctic Ocean is thinning because of
global warming. These results come from submarine measurements from 1957 to 1997. The
ice has decreased by as much as 3 m over the past 40 years. Some predict that the ice will
completely disappear in the Arctic in the summer in 50 years. There is also some evidence
that surface ocean waters have increased over the past 20 years. For example, the heat content of the waters has increased over the past 50 years. This means that part of the increase
in the temperature of the atmosphere has been used to heat up the surface waters of the
oceans. Although current measurements indicate that the sea level is rising, we cannot
accurately predict what it will be in the future. We can, however, estimate the level based
on the possible increases in the temperature. If the temperature increases by 3°C over the
next 50 years, the sea level could rise by 80 cm, or 32 inches. Recently, some have predicted
that if the ice on Antarctica melts, the ocean will rise by as much as 70 m (~200 ft). This
increase in sea level can cause an inundation of water in some coastal areas and result in
more serious coastal flooding from hurricanes and typhoons. Some Web sites for more
information on global warming are www.ipcc.ch, www.ucsusa.org, and www.iclei.org.
5.4.1 effects of global Warming on the Oceans
The increase in CO 2 in the atmosphere causes a number of stresses on the surface waters of
the oceans. Gruber (2011) has recently discussed the following stresses: