October 2, 2007
October 23, 2007
Geological Time Scale (handout)
Keep it with you so you can reference as it will understand where you are regarding a variety of
issues. At least for the next couple of lectures bring it with you.
Bio-fuels are what the lab is about this week. This is an extremely important area so I won’t
discuss it today. The argument is that they will replace or significantly substitute for fossil fuels.
If so how will the earth sustain that for its use? Be prepared to discuss that.
Changes in Global Climate
Precipitation & Drought
The Cryosphere – snow and ice
You will see where we have been as a benchmark and potentially where we are going.
About 10% of the earth’s land surface is permanently covered in ice. Only a tiny fraction
happens outside of Greenland and Antarctica. On an average (not including recent estimates) ice
also covers about 7% of the world’s oceans. Snow covers 49% of the lands surface in the
Northern Hemisphere in the winter. This is relevant because of Albedo which is the extent to
which an object reflects light. Incoming light is short-wave and a portion goes back into space as
short-wave, it is not converted to infrared. This is critical in the process. Albedo is a major
factor in terms of the heat load of the planet.
(Refer to graph) At the top is 100% Albedo which is reflectants and the bottom is 0% Albedo.
Old snow as it breaks down is less good so up to 90% is reflected if it is good snow and ice isn’t
quite so good. The quality of ice is variable in terms of it colouration and water isn’t good at all,
it is less than 10%. As you increase the amount of water in the oceans then you have less
Albedo. As you increase all these other components of the biosphere they have very low
BGYC58H3F.October,2, 2007 LECTURE 4 1
Albedo. This means low reflectants of short-wave radiation hence the earth converts that to
infrared and starts to heat it up.
You have these two slides but in different order. It is a composite picture by NASA. It does a
good job at showing how much snow there is in the Northern Hemisphere. Whatever shortens
the period of snow affects the amount of infrared. Many of these things are interconnected.
Snow cover effectively cools the earth and the more of it the cooler the earth.
The other thing that snow does is it acts as an insulator. Have you ever dug into the Arctic at all?
You will find permafrost if you dig and with snow cover it insulates this. In 1986/87 I was
studying Lemmings which are animals that jump off cliffs and kill themselves. They don’t
usually do that. They are between a rock and a hard place and when they have babies everything
wants to kill them. They are very small. I wanted to capture females and their young but usually
you can’t see them. I put radios around their necks and used antennas to pinpoint where they
were. You use a wand to see where they are. When she has babies she sits on them and 1 inch
from where she is the rock is solid. I would dig down really fast and catch the mom and babies
to do my research. I had to go down about 30 cm before I could catch them. While I was there a
guy from UBC was there and he was a famous permafrost researcher. They could bore down
into the permafrost and the found that it is warming and you can see the signature. If you get a
change in the insulation of snow cover in winter then many things will change. If you go to
Inuvik the houses are all on permafrost and they have big columns sunk into the ground which
they cool with Freon or whatever they use now because once it melts these guys are in the water.
The Cryosphere stores about 75% of the world’s fresh water. The critical role that fresh water
plays is for irrigation, feeding rivers, etc. A slight change in temperature will change the snow to
water and if it comes out as water it is flowing. That will change the runoff immediately and
how much runoff comes in the spring and summer and this has major implications.
The last big of data is new and it came through in September. It shows the extent of Arctic ice
depreciation. We lost approximately 1 million sq km in the summer. Remember that sea water
is 35/million parts salt so that has to be compensated as well. So now we only have 3 million sq
km up there in the summer so who knows the problems we are facing.
Glacier mass balance:
This is where we left off. Remember the slides in the Gore movie? That was dramatic but you
can look on the internet and find similar slides. This shows the cumulative change in glaciers
worldwide by area. They have been measured since the 1960’s. You can see some of the other
places are showing major losses of ice and it appears to be accelerating. Mass loss in ice is
estimated in water equivalence in a 40 year period is about ½ mm/year. You can see on the
BGYC58H3F.October,2, 2007 LECTURE 4 2
graph that in 10 years it has gone to about .77 mm/year. So the wastage that you see from a
glacier of ice is largely a response to the post 1970 warming. With respect to glaciers, have any
of you been to a glacier? Anyone seen the Columbian Ice Fields on the Banff Highway? For
any of these glaciers it is a balance of how much snow falls in winter and how much melts in
summer. If you have a large snowpack of about 10 metres, it compacts, forms ice, and the mass
balance is the amount between the amount of snowfall and compaction and the ablation (the
amount that melted at the toe of the glacier).
This shows the glacier thinning (m/yr) on the surface of the planet. If they are blue or very blue
they are gaining in mass. This is 170 glaciers that have been monitored 5 times over a 30 year
period. You can see there are some places in Alaska and Scandinavia that are increasing slightly
but many on the planet are losing mass and some are losing it enormously. New Zealand is
really experiences great losses in the South Island. The average loss of the 170 glaciers is about
1/3 metre/year. That is in thickness. You don’t have to remember this number but put it down.
There is a glacier in New Zealand called the ‘Ivory Glacier’ and it has disappeared in 1988.
Average Glacier Thickness Change:
This shows overall change in thickness over a 40-45 year period. It was increasing for several
years but they all show a negative relationship and that negative relationship intensifies since a
few years ago. This is excluding Antarctica and Greenland.
The Columbia Icefields – Jasper National Park, Alberta:
If you go from Lake Louise to Jasper you will go past here. It covers about 325 sq. kilometers.
10 metres of snowfall falls annually and these icefields are unique because from the ice sheet
water goes 3 ways:
1. Drains into the Arctic
2. Drains into the Atlantic Ocean
3. Drains into the Pacific Ocean
This is a very critical area especially for Alberta. The icefields here you can see are declining
(receding) something like 1500 metres since the late 1800’s. You don’t have to know these
numbers. You can take a vehicle onto the glacier but never walk on the glacier. Last summer I
went hiking with my son and we met a park warden. She had just taken part in a rescue of a
tourist because he jumped the fence and was killed. She also told me about a professor from U
of Calgary and his son who walked out onto the glacier. The father jumped over the crevice but
his son didn’t make it. They had to extract the little boy but he didn’t live. It is a fantastic sight
so you really should see it.
S:I have heard that water follows from North to South.
BGYC58H3F.October,2, 2007 LECTURE 4 3
Keep it with you so you can reference as it will understand where you are regarding a variety of issues. At least for the next couple of lectures bring it with you. Bio-fuels are what the lab is about this week. This is an extremely important area so i won"t discuss it today. The argument is that they will replace or significantly substitute for fossil fuels. You will see where we have been as a benchmark and potentially where we are going. About 10% of the earth"s land surface is permanently covered in ice. Only a tiny fraction happens outside of greenland and antarctica. On an average (not including recent estimates) ice also covers about 7% of the world"s oceans. Snow covers 49% of the lands surface in the. This is relevant because of albedo which is the extent to which an object reflects light.