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Lecture

EESA01 UTSC Lecture 2- Population and Environmental Consequences

8 Pages
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Department
Environmental Science
Course Code
EESA01H3
Professor
Carl Mitchell

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Description
Environment lecture 2 Tutorial 1  Search for peer reviewed scientific info, summarize and cite properly.  Annotated bibliography  To link with scientific method  Scientific method, how to come up with the questions etc What is environmental science?  Interdisciplinary, does not have its own foundation on anything, it takes from multiple disiplines. Answers questions across boundaries o Eg hydrology, geochemistry, toxicology, biology, social sciences o Science for people who are a jack of all trades  Ask how do things in environment affect us and how do the things we do to the environment affect everything else Environmental scientists vs environmentalist  Most environmentalists are activist types. Hugely biased  Environmental scientists are held to be unbiased in what they are doing, cannot going into an experiment hoping for something to occur o Need to be objective  That does not mean that Environmental scientists can’t be environmentalists, just that they are not necessarily so Tragedy of the commons  How unregulated resource use occurs in environment and what consequences it can have  Concept proposed by Hardin  Theory that unregulated exploitation of any resource leads to its depletion o Relatively rapid  Resource users are tempted to increase use/extract in relation to the technology they have to do so until resource is gone o Regardless that all resources are taken away, they still want to get all of it  Can we do anything about it, is it still the basis o Any public trade company goal is to make as much money as they can, not as much money as they can with least damage to earth o Eg oil sands, unregulated resource, no quota. The speed at which oil is being taken out of the ground is almost entirely a function of the technology, how quickly it can be extracted, processed etc. o Not a lot of government regulations. Government deals by putting regulation on the exploitation. Theory goes that without an intervention like government or a co-op there will be depletion Rapa Nui  Story: European exploration on Easter island and found these statues. The people were living in caves, no resources. No way for them to have been able to create the statues o Landscape wasn’t always like that o Paleoecology, looked at lake sediments. Sediments create a record over time, can look and examine what’s in there.  Did pollen analysis o Saw vegetation that used to be on the island o There was a thriving civilisation of maybe tens of thousands of people with massive trees and resources o But without regulation of the resources especially the palm trees, didn’t realise it took hundreds of years to grow the trees o On small island and saw the trees were disappearing but still using them. Nothing left to build things with o Ecology of island changed, downfall of a civilisation Base cause of environmental degradation  Population growth, massive amount of consumption ( in form of non-renewable energy), too stupid to realise it  We realise it but also paralyzed to do much about it Contextualization of impact: the ecological footprint  How to numerate on how much we are overusing resources o Ecological footprint- taking all of a person’s needs on average (how much they eat, how they use their house) how they use resources and assigning an area on earth it would take to garner the lifestyle that the person is leading o Eg driving more, means more land it takes to get the gas etc o Average Canadian leaves a huge ecological footprint,  Dependant on lifestyle and access to resources  Developing nations tend to have smaller footprints o If take footprint of every person in the world and added it together it has surpassed where the footprint was smaller than the land area of earth  Amount of resources we need to continue the lifestyle we live is beyond the area that we have on the earth  We are using resources that aren’t meant for us at this time  Depleting the area that will be useful for the future generations. o We are on an increasingly unsustainable path Our future: cornucopian vs Cassandras. Views on the future  Cornucopia: horn of plenty. o It’s fine, we are going to come up with new technologies to better use our resources o Regardless of the challenge we have ahead, we’ll figure it out o Human ingenuity will see us through a our environmental problems via new tech  Cassandra: mythical princess of troy who prophesised about dire future scenarios o We’re screwed. o All is lost because of our impact on our environment o Very little is also done because it is a depressive way to think about things Population and Environmental Consequences IPAT(S) Model  Conceptual model to bring together all the things that impact the environment  P-population, A-affluence (how much money you have), T-technology, S- sensitivity (added on)  Population o Increasing population is a + number  Affluence o More money, more impact on the environment  Technology o Decrease impact or increase impact o Tech increase impact by producing machines eg. that are better at extracting oil o Decrease impact by eg. Help clean the air  If multiplying it all, if have something with impact, then will be greater than one  If decrease impact, it is less than one. NOT NEGATIVE  Eg population 10. Technology .5 The first humans  World been around for 4.5 billion years  Humans for 20-30 thousand, homo sapiens sapiens  Human type beings have been around for a few million years. Dated back to 4-7 million years ago  Since these first human beings and learned to reproduce they have produced more and more people  Amount of time to increase a population, to double can be relatively accurately modeled o Understand the what the equation means.  Ln2 x constant is always 70. So it is 70/ growth rate o Eg growth rate of 2% per year. Therefore 35 years  In our current situation, in 58 years could be 14 million people on the earth  Canada’s population if taking away immigration and emigration is negative rate  Are places on earth with a declining population o China population growth rate used to be very high. Now it’s down to 2.8% year but already have a lot of people  this equation assumes that the growth rate stays the same, stable over long periods of time.  2 ways to express growth rate. Unit is years.  With doubling rate, we have had a stable and small population until industrial revolution o We did not hit 1 billion until early 1800 o In last 200 years we have gone to over 7 billion o Doubling rate is exponential growth, what happens is that as populations get bigger, the doubling is even bigger Carrying capacity  Theoretically there is a limit to how far a population can increase- carrying capacity  When you have a new population, or old one that hasn’t reached cc  It will eventually reach cc and reach a point where it levels off over time o Maximum number that the ecosystem can sustain o Births equal deaths and is stable  Limiting factors o Water, space , food, predators, disease o People live too close together, spread disease o Starvation, disease, fight to resources will limit the population  Estimation of world’s population at present varies widely o 10 million people on earth can live like bill gates, carrying capacity o On the far end, carrying capacity is 33 billion, lead to chages to everyday life  Can’t carry that cc with same lifestyle like now, it will be survival  Carrying capacity is very uncertain to whether that leveling off will occur or there is some feedback that causes something more surprising, deadly  Simple organisms. o Top left is normal cc curve, simple organisms. Exponential growth then population levels off  Others are feast or famine cycles instead of steady curve, based on feed back o Back and forth relationship. Not straight line. Tight along the curve  Bottom right, population goes down drastically. Almost to 0 in short amount of time. abnormal  Top right and bottom left are more normal. Show some steady state but problem is rather than being tight around the line, it’s extremely erratic o Have flip flow + and – feedback o – feedback is good, things stay stable. Good for environment and people
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