PDS AP Environmental Science 8th Period 2011-12

STOP! Before you read the rest of this blog post, sprint down a flight of stairs and run back up again as fast as you can. GO!

Okay, so how do you feel now? A little hot? Congratulations, you just got a little bit of exercise and experienced the same heating concept that is used in Geothermal Energy.

David Blackwell, SMU’s chief geological expert, recently gave a briefing to congress about the future of alternative energy sources in the United States. It was part of a series on the science and technology needed to achieve the United State’s energy goals titled, “The Road to the New Energy Economy.” Blackwell explained that geothermal is going to play a major part in our energy security in the future, and the US is in a prime position to lead the world in conventional and emerging unconventional geothermal techniques. Slowly but surely, the world is beginning to understand the importance of reducing our dependance on fossil fuels, and geothermal energy is going to play a major role in that transition.

Geothermal Energy is a way to produce energy that combines the use of a renewable resource and drilling. Geothermal energy utilizes the heat that comes from the earth’s core. Think about water that is naturally heated such as the water from “Old Faithful.” This spring is heated by convection currents bringing magma from the earth’s mantle to the earth’s crust. Heat and pressure builds up in the spring causing it spew out at temperatures up to 200∘F. Geothermal energy uses the same concept in order to heat homes or turn turbines.

How do you harvest Geothermal Energy?
Remember running up and down those stairs? Water goes through this same journey as it is pumped or circulated underground. As water comes back up, it can be piped into household radiators and has the potential to heat a home. But this heat also has the potential to produce electricity. After the water cools, the cycle repeats, constantly using the earth’s natural heat. So you may have not been as winded when you ran down the stairs, but you may have felt the heat coming back up.

Water moves through this system and can be recycled as well.

How does Geothermal Energy produce electricity?
As water is pumped into the ground, the water is heated and can be pumped, or naturally flows, into a plant where the water is converted into steam. This steam is then used to turn a turbine, used to generate electricity. It’s the same concept as a coal fired power plant but instead of burning coal, you’re heating the water with renewable energy. Some of these power plants drill up to a thousand feet underground just to generate enough energy so some of these plants are not suited for areas.

Video explanation of Geothermal energy:

Geothermal-Energy-Process.aspx

Is Geothermal Energy good for the environment?
Yes! Geothermal energy is a renewable resource so it reduces the amount of fossil fuels we use, which reduces the amount of greenhouse gases we produce. Geothermal energy also produces little to no pollution.
Geothermal energy is also economically beneficial. It not only provides jobs, but it is also 80% more cost effective than using fossil fuels. It reduces our dependence on fossil fuels.

Is Geothermal Energy bad for the environment?
Unfortunately it can be but not as much as non-renewable resources. The water that is pumped underground can be influenced by dangerous chemicals that can seep from the earth’s crust.
Geothermal energy can be more inconvenient rather than environmentally detrimental. Some areas aren’t suited to pump water underground. And although this energy is cost-effective compared to fossil fuels, the cost to design, build, and staff these plants is very expensive.

Which Countries Produce and Use Geothermal Energy?
Many countries in the world have begun producing geothermal energy, the three largest producers being the United States (3,086 MW), the Philippines, and Indonesia. The worldwide capacity of geothermal electricity production is about 10,715 MW, with about 10 countries producing the vast majority of that energy. As a percentage of total electricity use, Iceland is the largest user of geothermal electricity (almost 30% of total electricity is produced geothermally!). 100% of their total electricity is renewable; the other 70% is hydroelectric.

Source:
http://www.conserve-energy-future.com/Advantages_Disadvantages_GeothermalEnergy.php

Tags: energy, geothermal, renewables

On Thursday and Friday of last week, we began to move away from the problems of water shortage and towards the problems of water surplus. We began with Flooding- a natural phenomena that occurs when an overflow of water submerges land. Precipitation is the main catalyst for flooding, and humans have tried to control how much of an impact it has through various means of flood prevention.

Main locations of flooding-

1) Floodplain- an area of flat or nearly flat land adjacent to a stream or river that stretches from the banks of the channel to the surrounding areas. These areas are subject to natural flooding when rivers overflow their banks.

2) Reservoir- artificial lakes that are created by dams to store water. They are often used to control water flow downstream, irrigation, and provide recreation. While the dams that contain them are engineered heavily to try and minimize failures, they have still failed in the past and created catastrophic walls of floodwater that destroy property downstream.

3) Dam- a barrier that impounds water or underground streams. They are created to retain water and control its flow, while levees or floodgates attempt to prevent flow into a specific area. They can use the retained water to generate hydroelectricity while still controlling its speed and direction. When dams fail, the reservoir of water that was previously contained is now unrestricted and can cause massive destruction of civilian property downstream. In 1975, the failure of the Banqiao Dam in China killed an estimated 171,000 people!

A very famous and large dam- The Hoover Dam

Source: http://science.howstuffworks.com/engineering/structural/hoover-dam-broke.htm

4) Levee- a naturally occurring ridge or artificially constructed wall which regulates water levels. They are often used to prevent the destruction of civilian property in case of high river levels, and the largest such system in the world is along our Mississippi river. When levees are overwhelmed and fail, the water spills over and floods the adjacent land which it was originally supposed to be protecting, destroying property, as seen many times during Hurricane Katrina in 2005. Sometimes the levees are intentionally breached to protect areas further downstream or to give land back to nature.

This is how a levee/dike works-

Source: http://exploratoryblog.blogspot.com/2011/05/levee.html

5) Floodwall- a vertical wall created to protect property from rising river levels during a seasonal or unusual case of high water levels. They are mainly used where space is scarce and levees or dams aren’t viable options for containing the same waters.

Ranching, the practice of allowing livestock are allowed to graze in fields, accelerates soil erosion. After the grass is gone, winds remove the remaining fragile topsoil, rapid water runoff causes loss of silt and other erosion, and downstream this all combines to create flooding.

Natural Solutions to Flooding

1) Conserving or Reestablishing Wetlands

2) Improving water retention through the floodplains along rivers

3) Encouraging natural systems such as forests and wetlands along rivers

Not only does this decrease the strain on our infrastructure to maintain artificial control mechanisms, but it also would improve water and air quality, protect productive farmland, and allow people to live without fear of the failure of human-made systems.

Tags: floods, urban areas, water

Here are the picture of our review notes from today in class. Click on a picture to enlarge it if it appears to be crunched on your screen.

This is a good example of a parasitic relationship between organisms–

http://news.yahoo.com/zombie-fly-parasite-killing-honeybees-230200867.html

Tags: news

Before we began discussing the different factors that affect birth rates and death rates, we identified important terms that help us assess how fast a country is growing.

1) CBR (Crude Birth Rate)- Measures the approximate rate of births among a population of 1000 people. It is called crude because it does not take into account sex or age differences in a population. Countries with birth rates above 30/1000 are considered high and rates below 17 are considered low. The global average is approximately 20.3 and is predicted to shrink significantly before mid century.

2) CDR (Crude Death Rate)- Measures the approximate rate of births among a population of 1000 people. Commonly known as Mortality Rate, the world average is approximately 8.37/1000 people.

3) TFR (Total Fertility Rate)- An approximation of how many children a woman will have in her lifetime. The average in the United States is around 2.09 births/woman

4) RF (Replacement Fertility)- This is actually a type of Total Fertility Rate, and if sustained, will lead to the same population size in the  next generation. It is how many children women must have to replace themselves and their partner, yet that number is slightly higher than 2 in the United States in order to account for the small child mortality rate. In developing countries it can increase proportionately with infant and child mortality rates.

5) Life Expectancy- The expected number of years, on average, that a person will live after birth. Varies greatly by country.

6) IMR (Infant Mortality Rate)- The number of infant deaths (<1 year old) per 1000 live births per year. On average, the rate is approximately 47 for the world, yet most developed countries are close to 10 or less. The United States is 6.3 deaths/1000.

Hans Rosling discusses the dramatic change in population that has occurred since the 60′s, and will continue through the middle of the 21st century.

There are many other factors that contribute to the rate of growth in a country-

Factors Affecting CBR/TFR/RF - As these increase, births respond sensitively

1) Value of children as labor- Births increase

2) Availability of retirement/pension system- Births decrease

3) Cost of raising children- Births decrease

4) Opportunities for women- Births decrease

5) Infant Mortality Rate- Births increase

6) Average age of marriage- Births decrease

7) Availability of birth control- Births decrease

8) Legality of abortion- Births decrease

9) Urbanization- Births decrease

10) Culture, religion, and tradition have varying affects depending on country and region.

Factors Affecting CDR/LE/IMR

- Lack of sanitation, lack of healthcare, war/conflict, and starvation all contribute to an increase in deaths, regardless of the average age of the population.

Tags: demographics, population

Yesterday in class we did a simulation that was called “Gone Fishing” and was designed to simulate a situation that Garrett Hardin called “The Tragedy of the Commons.”

Each group started with a plate (lake) with a maximum of 16 fish at any time(carrying capacity)

And played the game by these rules:

1. You must “fish” by sucking up a fish with a straw and moving it to your boat (napkin)

2. You can only fish once (1 minute) each “year” (1 round)

3. The entire group gets one minute to fish, and after each round the first person to fish will change.

4. Each year (round) the fish reproduce once- (Ex. 1 –> 2, 2 –> 4)

5. Take as many fish as you would like on your turn, but if you have fewer than 2 fish after the round ends then your family starves (migrates or dies)

6. Any fish over 2 can be sold for a profit (mint)

For the first few rounds we weren’t allowed to talk, so a few groups ended up running out of fish quite early. What we found during the second attempt when we could talk was that if everyone took the minimum necessary to survive, (2 fish each) then the fish would reproduce and we would never run out. But as soon as someone took 3 or more to make a minty profit, the entire group ran out of food after two or three rounds and either starved or migrated because the fish could never recover and return to the original 16 that supported everyone.

When we went back into the classroom to discuss Garrett Hardin’s “Tragedy of the Commons” (http://en.wikipedia.org/wiki/Tragedy_of_the_commons), we came to the conclusion that public property tends to be exploited or degraded due to self interest. The general thought is “If I don’t, someone else will,” and there are examples of this everywhere. At Providence Day, the senior lounge and dining hall are among the most popular common areas.

We also reviewed how the atmosphere and the oceans are the only true commons that the globe shares, and many environmentalists agree that maintaining them is and will continue to be the world’s trickiest problem. Hardin proposed two solutions that would help in maintaining the commons- privatization of the industry or government regulation. We only touched on these issues as a class before we ran out of time, but we came to a general consensus that neither has gotten to the point where we need it to be if we are going to maintain our oceans and atmosphere.

Tags: fishing, The Tragedy

In my opinion, the biggest environmental problem of the 21st century is/will be finding alternative energy sources after we begin to run out of fossil fuels. I believe that if we don’t begin to take this issue seriously we will run out of time and end up crippling our transportation system and economy.