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Name ________________________
Module 3B: Ecosystems and Climate Change
Part 1: Climate change predictions
Virtually all scientists now recognize that our climate is currently changing due at
least in part to anthropogenic (human-caused) factors. Predictions for the future can
never be certain, but a growing consensus indicates that the most of the earth will be
warmer than present in the future, and that some areas will become moister while
others dry out. Such predictions are often based on computer models of global climate,
which are rapidly becoming more sophisticated as our understanding of the Earth’s
climate improves, and as technology improves computational power.
Take some time to examine the attached figures which show model predictions
for temperature and precipitation towards the end of this century. Note that the units on
both maps represent change in average annual conditions relative to present: for
example, a value of 2 on the temperature map means that average temperature for the
entire year is expected to be 2° warmer, while a value of -10 on the precipitation map
means rainfall is expected to decrease by an average of 10 cm per year.
1. Describe the patterns you see in model predictions of temperature and
precipitation for the end of this century. Try to be specific in terms of the
magnitude (amount) and spatial pattern of the predicted changes:
a) Predicted temperature changes
Nearly all of the globe is predicted to warm by about 1–5°C. There will be
greater warming over land (~2–4°C) than over sea (~0–2°C), and more
warming over the poles (especially north pole) than at the equator.
b) Predicted precipitation changes
Precipitation predictions are more variable than temperature. Some
regions are expected to receive more rainfall on average (e.g. most of the
northern part of the Northern Hemisphere), while others will become drier
(e.g. Central America).
c) What are the major similarities and/or differences between your
responses to (a) and (b)?
As noted, the predictions for temperature are more uniform than for
precipitation. There are some similarities in the spatial patter; for instance,
both show some areas with horizontal (latitudinal) “strips” of similar
change. Overall though, the temperature shows a more obvious pattern
than precipitation, as described above.
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Name ________________________
Part 2: The effect of climate change on ecosystems
You have already learned that climate is an important state factor, meaning that it
can often have a major effect on how ecosystems function and where they occur. Thus,
you can probably see how changing climate may have a big impact on Earth’s
ecosystems, even during your lifetime.
In this part of the assignment, you will try to predict the climate of specific
locations worldwide in 2100 AD. Then, using what you learned previously about how
climate can define biomes, you will predict how the ecosystems at these locations may
be affected by the changes in climate.
2. In this part of the assignment, you will try to predict the climate of
specific locations worldwide in 2100 AD. Then, using what you learned
previously about how climate can define biomes, you will predict how the
ecosystems at these locations may be affected by the changes in climate.
a) Determine the predicted change in temperature and precipitation for
each city in Table 1. (These will be fairly rough estimates, but that’s OK.)
i) Find the city, if necessary, on the City Locations map.
ii) Find the city’s approximate location on the maps of predicted
temperature and precipitation.
iii) Using the scales provided, estimate the expected changes for each
variable.
iv) Record the predicted changes in columns 4 and 5 of Table 1
b) Based on today’s climate and the predicted changes, determine the
expected precipitation and temperature for each city in 2100 AD. Record
your answers in columns 6 and 7 or Table 1.
c) Finally, use these new climate variables to predict the expected biome
at each location in 2100 AD. Record your answers in column 8.
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Name ________________________
Part 3: Additional questions
Use your findings from Question 2 and your knowledge of the state factors and
interactive controls which govern ecosystems to answer the questions below:
3. Summarize your predictions from Question 2. Are most ecosystems
facing similar climate change scenarios, or is there a lot of variation? Give
two specific examples.
All locations face warming, but the amount of warming varies somewhat.
In many places the amount of precipitation change is fairly negligible (e.g.
Chanthaburi is already very wet, so the predicted increase of ~5 cm isn’t
much), but in drier locations (e.g. Tuscon and Fairbanks) the predicted
change is a substantial fraction of the current amount.
4. Of the locations you looked at in Question 2, which do you predict to
undergo the greatest change in ecosystem composition due to climate
change? Explain.
Toolik Lake is now tundra, but it’s 2100 AD climate will be that of a
temperate grassland. This is probably the most dramatic shift on the list,
which makes sense given that climate change is proceeding most rapidly
near the poles.
5. You should have found some locations that will no longer fit anywhere
in the Whittaker diagram if climate change occurs as predicted. Why do
you think the diagram has no predicted biome for some combinations of
temperature and precipitation? What does this mean in terms of trying to
predict the biomes for those “off the charts” locations?
There are essentially no location on Earth today has a mean temperature
of >30°C (though there are some local exceptions), so Whittaker had no
data to predict what biome would occur in such heat. Based on the
information presented here, however, Puntarenas, Costa Rica, and
Chanthaburi, Thailand will reach such temperatures within the century.
The future climates of those locations are thus “no-analog” climates,
meaning they simply aren’t observable today. Our predictive power is
reduced dramatically in no-analog situations, becuase we have no direct
evidence to support the predictions we make. It is unclear, then, whether
the ecosystems of Costa Rica and Thailand in the future will resemble just
a warmer version of some known biome, or if they will differ from any
ecosystem observed on the modern landscape.
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Name ________________________
6. If the climate in 2100 AD turns out to be exactly as predicted in this
assignment, do you expect your biome predictions will also be accurate?
Why or why not?
Probably not. The Whittaker diagram is known to work quite well at
present, and we might reasonably expect it to hold in the future. However,
ecosystems change slowly, and 100 years is probably not long enough to
make a complete transition from one biome to another. There must be
time, for example, for species to die off or migrate in or out of the region,
and then for the whole system to readjust until it resembles the new biome
it is destined to become. Thus, even if Norway has a perfect climate for
deciduous forest in 2100 A.D., there will surely be plenty of boreal species
there for a long time to come.