Let’s look at the projections with respect to vegetation changes. This shows the global
vegetation in the year 1990. In Canada you see the Boreal forest and the open Boreal forest and
then the Tundra. You can see the Great Planes and the Grasslands. The tropical rain forests are
large. Now we will see what happens on the next slide. This is what it will be with the doubling
of CO2. Basically certain forest regions will increase markedly. You can see the forests in
Canada moving north and the Eastern Deciduous forests are moving to the west. Grasslands are
also moving and then we will be in trouble as that is where the ‘breadbasket’ is. They produce
the food we eat. Notice in Australia you have the dry inland areas and with global warming (in
this model) they will decline and you get the Grassland instead. Remember there is uncertainty.
If you look for potential for changes you will see the red squares and they indicate the areas that
would have changed as a function of doubling of C02 over 100 year span. I won’t ask you for
this number but the expectation of change in vegetation with this model is 34%. This chart is the
proportion of changes that will occur. Grey is not analyzed (Greenland) but the darker you get
represents a greater degree of change. Most changes will be in the northern hemisphere so you
can see they grayed from deep beige to brown. The changes are going to occur in northern
Europe and northern Russia. Some changes in the Amazon forest area as well. Australia also
changes especially as you get further away from the equator. If you look at the Canadian scene
you see the Boreal forest and eastern deciduous forests. You can see the Boreal forest increases
under this scenario (Potential Vegetation 2100). What aren’t uncertain are the Canadian forests
which will change very drastically.
You get the picture. It is rapid and major for Canada and much of the world at high latitudes.
Let’s take a look now as an example of change and the factors that will occur in causing that
change. Last week we looked at a wonderful American Beech tree that is about 100 years old.
What do we expect to happen with trees like that? What types of changes are likely to occur?
What will the future look like for these trees? I am giving the broad spectrum change and that is
hard to understand but if I talk about specific trees it is more understandable.
People have been making predictions for the last 20 to 30 years. The EPA (Environment
Protection Association of the U.S.) is a separate arm from the government, or at least it is
supposed to be. Once legislation is passed in the U.S. they have to do it unlike Canada. Our
Prime Minister can decide to do or not do things in Canada but it isn’t so in the U.S. The EPA
has been forward in thinking and in the 80’s they decided to protect the environment so they
wanted to predict where vegetation will go under the doubling of C02 so they can be proactive in
the future. They contacted a Paleo-ecologist (Margaret Davis, Katharine Zabinski) and they
modeled the Eastern deciduous trees i.e. Sugar Maple, American Beech, Yellow Birch, and
Eastern Hemlock. All these we know about. What they did is asked what is important about the
tolerance limits of the trees. They decided what was important was January temperature, July
temperature, and annual precipitation. If we can project where those conditions will be and
BGYC58H3F.November,6,, 2007 LECTURE 8 3