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Lecture

Lecture 2


Department
Biological Sciences
Course Code
BIOC58H3
Professor
Rudy Boonstra

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LECTURE 2
September 18, 2007
The lecture from last week is not on the intranet but the PowerPoint presentation
is. It was a good idea to get the PP lecture onto the intranet so I did that but today
I changed the order. I will try to have it on Monday evenings or Tuesday mornings.
Tutorial
Thursdays -> Brenda Dalahante
There will be a film and I would like for you to go if possible. There is a News Week
article on Is Climate Change a Hoax that I want you to read so we can discuss it.
Tutorial information will be on the exam so I encourage you to go.
LECTURE #2 BACKGROUND OF GLOBAL CHANGE
You will get an in-depth grounding in terms of the state of the planet at the present
time. There are many details in here and I expect you to know much of it. Some
numbers will be important and some are just to add to your knowledge.
You should know:
Concentration of the atmosphere -> CO2, methane, nitrous oxide, etc.
I try to ask the big questions.
(Quotes Harold Wilson know crap from non-crap)
AS I indicated I am not an environment biologist, I am an ecologist. But
environmental biology concerns us all. Unlike issues dealing with the environment
the issue with respect to climate change and global change involves the entire
earths system.
The science is complex and there is uncertainty that still remains. We know a lot of
how it works but not everything. The challenge of what happens now and in the
future is the collaboration of many scientists from many disciplines. I indicated my
modest contribution to the destruction of the forests.
Whats happening, and what can we expect?
BGYC58H3F.September ,18, 2007 LECTURE 2 1
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(Quote by Walter Lippmann in notes) This is a truism as far a climate change and
what we do affect everywhere on earth. The quote was done in 1913 so he wasnt
referring to global change; he referred to the start of WW1. He was an American.
What is climate?
There is some confusion between weather and climate.
Weather is the day to day changes in climate. They are the long term conditions
including seasonal changes. These include the extremes and the variation for a
specific location/region on earth. Environment Canada will ask what the climate on
the Prairies is. They will then average over the last 30 years for example. Roughly
it is 30 years that they average so the way you can distinguish between the two is
climate is what we expect to get and weather is what we actually get.
Weather is naturally variable and that is a problem. You can probably look today at
the forecast and there is a good chance they could be wrong. It can change over
weeks, months, and years. Weather is a result/consequence of an inter-play of a
number of factors; rapid shifts in air circulation, slower variations in ocean
conditions, and seasonal changes in sunshine.
If we look at climate it can also vary from average conditions. It is variable. One
year is colder or warmer than the next so if you have it change over time what has
to be distinguished is the variation caused by short-term variability from long-term
trends. You have to have a baseline. The baseline here with respect to climate is
important to have. It has to be consistent. One extreme year in
temperature/precipitation isnt enough but if it goes on for 10 or 20 years or more
then you can be confident that maybe you have a problem.
Now the size of the change. If the change is very small over time it is difficult to
distinguish that from natural variation. If the change is large you have a better
handle of what is going on.
From a global perspective we are not interested so much what happens in Toronto
but on the entire face of the planet.
What is climate change?
BGYC58H3F.September ,18, 2007 LECTURE 2 2
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Climate change is a shift in climate relative to a given reference time
period.
A long time shift or alteration in a region or the entire planet. You measure
in a variety of parameters (precipitation etc.). Change occurs between two
specific points in time and at least from our perspective and now it usually
occurs when something alters the total amount of the suns energy that is
absorbed by our atmosphere and the earths surface.
It could be the suns energy that changes (less sunlight over time). It could be
from forcing.
It could also be changes in how much light we are retaining.
So changes in average weather and how much weather varies about those averages.
Other forces could be:
Volcanic eruptions they can cause short-term changes depending on size. It
could last years and have tremendous effects. The changes in the last 50
years have been relatively small.
Ocean circulation these are a major player in what we get in terms of
climate.
Greenhouse gases/aerosols which are the function of humans are changing
land surface temperatures.
So there are natural factors that cause variation and there are human factors. We
will focus on both but our major focus. We will also look at the past to get a
benchmark of where things have been i.e. geologic history of the planet.
S: you can distinguish change by direction and size so how would climate vs.
weather changes? In size?
T:Weather can change one day to the next. Overnight we could have 6 degrees
and tomorrow we could have 30 degrees. So that is the type of scale but it could be
larger for immediate weather but climate you can look at over a year. In 1995 it
has the warmest temperatures than ever before. So you look at an entire year. In
2003 there were major heat waves in Europe that killed many of the elderly. This
summer in Hungary they estimated that this summer was hot for a small period
and up to 500 people died. They were all old so they didnt matter! Just kidding!
That is the long term change/shift in climates. You have a bouncing around but
BGYC58H3F.September ,18, 2007 LECTURE 2 3
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