lec2 - ECONOMICS 175 Professor Ronald D. Lee 1/22/09...

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ECONOMICS 175 Professor Ronald D. Lee 1/22/09 Lecture 2 ASUC Lecture Notes Online is the only authorized note-taking service at UC Berkeley. Do not share, copy or illegally distribute (electronically or otherwise) these notes. Our student-run program depends on your individual subscription for its continued existence. These notes are copyrighted by the University of California and are for your personal use only. D O N O T C O P Y Sharing or copying these notes is illegal and could end note taking for this course. ANNOUNCEMENTS Professor Lee is not here today so I am taking his place. My name is Professor Wilmoth. Please see the lecture notes on bSpace for the readings due for next Tuesday. The GSIs will not hold office hours next week. Please go to the computer sections if you need help with the problem set. Next week all sections will meet in 64 Barrows (see bSpace for times). Again, please send a confirmation email if you are enrolled or if you are on the waitlist. LECTURE Population Balance Equation The idea is things have to add up over time. If you take the population at time 1 and 2, the difference has to be explained by births, deaths and immigrations. For example, during 2006, the population was 6.555 billion. In 2007 the population was 6.625 billion. The difference between the two is .070 billion (70 million). To compute a growth rate, you take this increment over the average population size during the year. So take .07/6.590 which gives you .011. This means that the population has grown 1.1% a year. Make sure the decimal places are the same in the numerator and denominator. There is another way to look at it. The 70 million population increase represents .129 births minus .059 deaths in 2006. Pop(2007)- Pop(2006) = Birth(2006) – Death(2006) If you divide both sides by the average population you will get the rate of growth. If you take the right hand side of the equation by the average population size and this gives you the crude birth rate and the crude death rate. r = cbr – cdr [rate of growth = crude birth rate – crude death rate] This tells you how many births were added to the population per individual already living and how many people died per people already living in the population. The difference between the two gives you the rate of growth (r). If this were not the world population, you would need to figure in numbers for migration. Since we are looking at the world, we do not have migration to and from the world so we do not need to take this into account. Historical Population Growth Rates (Graph: world population growth rates from 1500- 2150.) What is interesting is for hundreds and thousands of years, the population barely grew. You look at this graph that starts in 1515 and the growth rate is already up to .3% which is much higher than historical values. Already in this era population growth had started to take off compared to previous periods. But this rate of increase is still small compared to what has happened since 1950. After
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lec2 - ECONOMICS 175 Professor Ronald D. Lee 1/22/09...

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