Download Indicators and Effects of Climate Change File

Indicators and Effects of Climate
Change
Indicators of Climate Change
There are several indicators that help us to perceive changes in global
climates.
•global warming
•changes in polar and glacial ice
•rising sea levels and increasing
Indicators
ocean acidity
of Climate
•changing wind and precipitation
patterns
Change
•changing storm intensity and
frequency
Effects – All of the above lead to changes in biomes
1. Global Warming
The average global temperature is rising
Not convinced? Click on the above picture to link to some
“scientific” evidence.
2. Changes in Polar and Glacial Ice
Generally, rising global temperatures have been associated
with a decrease in the extent of coverage of the earth’s oceans
by sea ice.
Changes in Polar and Glacial Ice
Satellite images taken at the same time of year clearly indicate a
decline in the arctic polar ice cap in recent decades.
Changes in Polar and Glacial Ice
Sea ice thickness has
likewise shown
substantial decline in
recent decades. Using
data from submarine
cruises, scientists have
determined that the mean
ice draft at the end of the
melt season in the Arctic
has decreased by about
1.3 meters between the
1950s and the 1990s.
Changes in Polar and Glacial Ice
Canadian glaciers have been melting
rapidly since the end of the Little Ice
Age about 150 years ago. Continuing
climate changes, which are predicted
to result from increasing
concentrations of greenhouse gases
in the atmosphere, are likely to have
a further and significant impact on the
glaciers in Canada. Continued
glacier shrinkage would contribute
to global sea level rise, and increased
inputs of fresh water to high latitude
oceans might modify ocean currents
in the North Atlantic. Some glaciers
will ultimately disappear.
3. Rising Sea Levels
In the past 100 years, sea levels on earth have risen 10-15 cm.
This effect has been attributed to a combination of melting ice
and thermal expansion as the temperature of the sea-water has
increased as well.
Coastal areas become much
more vulnerable to storms and
flooding when sea levels are
increased.
4. Ocean Acidity
As the result of increased levels of carbon dioxide gas in the
atmosphere, there has been a drop in the surface ocean pH due
to increasing acidity levels in the sea water. More CO2(g) leads
to a lower pH by driving the following chemical reaction
forward.
CO2(g) + H2O  H2CO3(aq) carbonic acid
Rising acidity affects coral
reefs which exhibit great
amounts of biodiversity.
The coral becomes
“bleached” in the more
acidic environment. The
fishing industry may also be
affected in the long run.
5. Changing Storm Intensity and
Frequency
There is already some evidence for increasing storm intensity.
Worldwide, the proportion of hurricanes reaching categories 4 or 5
has risen from 20% in the 1970s to 35% in the 1990s. This trend is
predicted to continue, as shown in figure 3. Precipitation hitting the
US from hurricanes also increased by 7% during the 20th century.
6. Changing Wind and Precipitation Patterns
The speed, frequency, and direction of winds have fluctuated
unpredictably for several years. Increased temperature can also
influence precipitation patterns.
According to the above model, where will it get drier over the
next several decades? Where will it get wetter?
Effects of Climate Change
As earth’s climate changes, there will be changes in the
distribution of energy over the earth’s surface.
This will lead to changes in wind speed, wind direction, and
patterns of precipitation.
Climate changes can lead to changing biomes which in turn
could lead to widespread extinction of various species through:
•desertification
•shrinking wetlands
•deforestation
Changing Biomes
While many species could become extinct due to rapid
climate shifts, other species may flourish and could
move into regions where they were otherwise unknown.
These invasive species could put even more pressure on
native species and may also introduce diseases that
affect humans.
Eg. West Nile virus, and waterborne diseases such as
Yellow Fever.
See Figure 7.27 p.297 ON Science 10, McGraw-Hill Ryerson
Review Questions
p.299 #1 to 8