Sonntag, 29. März 2009
Article Summary: 'Out of the mouths of babes'
Date: March 26th 2009
Publisher: The Economist
URL: http://www.economist.com/world/unitedstates/displaystory.cfm?story_id=13376113
The incidents of the past still play a big role in today’s society… more than we’d like in some cases. A research project that was conducted in the late 1950’s to early 1960’s tested thousands of baby teeth, collected in the St. Louis area, for the effects of radioactive fallout. Now, another project aims to, with the help of these baby teeth, study the link between radioactive exposure during childhood and health problems in later life.
The radioactive fallout that was being tested for in the 1950’s to 60’s came from the above ground nuclear tests that had been conducted in America and throughout the world. The experiment discovered that Strontium-90, a byproduct of these tests, was found in children’s teeth. The isotope had been ingested by cows, since it fell onto the land after the tests, therefore ‘contaminating’ the milk supply. The undisputable results were a major contributing factor to the creation of the 1963 Test Ban Treaty, which banned above ground nuclear testing.
Researchers today at the Radiation and Public Health Project, after having rediscovered 85,000 baby teeth (a quarter of the total amount of teeth collected), are trying to find more than 6,000 donors in order to monitor their health problems or premature deaths. Results could support already existing evidence that 1950’s children from the St. Louis area grew up to have a higher than average cancer rate.
Article Summary: 'Who ate all the algae?'
Article: Who ate all the algae?
Date: March 26th 2009
Publisher: The Economist
URL: http://www.economist.com/science/displaystory.cfm?story_id=13361464
It seems that scientists are willing to try most anything these days in order to reduce carbon dioxide (CO2) in the atmosphere. One of these attempts at reducing CO2 is a joint project, the largest geo-engineering experiment ever, being conducted by India’s National Institute of Oceanography and the Alfred Wegner Institute for Polar and Marine Research in Germany. It is an expedition that consists of pouring 6 tons of iron sulphate into the Southern Ocean, an area surrounding Antarctica, to create a bloom of phytoplankton.
Phytoplankton is a type of algae that depends on certain conditions, such as sunlight (for photosynthesis) and iron (a crucial nutrient). Increases and decreases in iron levels in the Southern Ocean, that normally occur naturally, therefore play a role in determining the size of the phytoplankton population. Tests have shown that adding iron artificially creates algal blooms. One advantage of creating these blooms is that phytoplankton absorbs CO2 as it grows and locks up small amounts of the gas when it dies and sinks to the ocean floor. Therefore, in theory, creating large blooms of phytoplankton would lead to more CO2 being sent to the bottom of the ocean.
However, first results of this experiment have shown that there are certain factors that hinder its success. Though the iron sulphate that was poured into the water, covering an area of 300 km2, did lead to the creation of a phytoplankton bloom that grew to double its size within 2 weeks, the bloom eventually stopped growing since it was being eaten by copepods (small crustaceans). The problem was the type of phytoplankton; the bloom consisted of a group of algae called Phaeocystis, which are heavily grazed by copepods. Diatoms, another group of algae, are protected from this by shells made of silica and therefore are more likely to die and sink to the ocean floor than get eaten. Had this type of algae been present, the results regarding CO2 absorption would have been better.
The results suggest that the experiment won’t be as successful in removing CO2 from the atmosphere as had been expected; however, this has given researchers a lot of material to work with. So maybe it wasn’t all for nothing after all.
Samstag, 14. März 2009
Article Summary: 'Fire in the hole'
Article: Fire in the Hole
Date: March 12th 2009
Publisher: The Economist
Some fires just burn and burn. In Pennsylvania alone, 36 fires are blazing in abandoned coal mines, covering a total area of 180,000 acres. The oldest of these fires is in the Red Ash mines, located in the hillsides of Wilkes-Barre; it has been burning since 1915 because, according to the legend, a coal miner forgot his lantern down in the mines. The most famous of these fires is beneath Centralia, started by residents burning rubbish on top of an exposed coal seam in 1962. Many of these fires have enough fuel to burn on for several decades to come.
Putting these fires out has not been an attractive solution to the problem because the process would be both expensive and possibly unsuccessful, since the mines consist of subterranean tunnel networks that cover a significant area. Therefore, the solution has been to evacuate towns located near these mines.
A possible solution to the problem has been presented by GAI consultants: a concrete like substance derived from the waste of coal powered power plants has been pumped into a mine and extinguished a fire. The mixture contained the fire and starved it of oxygen; however, the substance hardens quickly and could not cover an area as vast as Centralia. For now all one can hope is that the fire doesn’t spread to cover 5,000 acres; that would make it hard to extinguish.
Sonntag, 8. März 2009
Article Summary: 'Party Time!'
Article: Party time!
Publisher: The Economist
Date: March 5th 2009
Technology today is all about efficiency, because efficient technology is cheaper. This is true, for example, for solar cells. Since they are very expensive, it is desirable for them to work at the maximum capacity. Therefore, to make them more efficient, sunlight is concentrated on smaller areas of a cell to convert the same amount of light a larger area of the cell would normally convert. Normally, the concentrating of light is done by mirrors that are steered by motors so that they focus sunlight directly onto the cell. Now, however, a company called Cool Earth Solar (based in California) has come up with a cheaper alternative to these mirrors: balloons coated with metal on one side (the other is transparent).
The balloons, approximately 2.5 meters in diameter, are the equivalent of the mirrors; the inner surface of the coated side of the balloons acts as a concave mirror that focuses sunlight directly onto the solar cells. Since a balloon concentrates sunlight up to 400 times, the solar panels have to be immersed in water. Different methods of steering the balloons are being tested currently; the curve of ‘concave mirror’ can be adjusted by changes in air pressure in the balloon. Though the balloons only have a working life of about a year, they are much, much cheaper than actual mirrors. The kilogram of plastic from which the balloons are made costs about $2. The balloons cost $1 per watt of generating capacity to install. The result would be that the electricity generated by the solar cells could then be sold to California’s power grid for 11 cents a kilowatt-hour. Cool Earth plans to open a 1-megawatt facility to put this hypothesis to test. If it works, solar power plants will soon be looking a lot more festive.
Article Summary: ' Scrubbing the Skies'
Article: Scrubbing the Skies
Publisher: The Economist
Date: March 5th 2009
Environmentally oriented technology today is designed to emit as little carbon dioxide as possible in order to reduce the level of man-made CO2 in the atmosphere. Countries have made ambitious pledges to reduce emissions by 80, 90 or even 100% in the years to come. However, a new technology, still in the experimental phase, is potentially a much simpler way of reducing the CO2 in the atmosphere: air capture machines that remove CO2 from the air.
Several designs of these air machines are being developed that all follow the same basic principle. The idea behind these machines is that air is to come in contact with a sorbent material which binds chemically to carbon dioxide. One version of air capturing machinery, designed by a team led by Dr. David Keith (University of Calgary) is towers, several meters tall, in which a liquid sorbent is sprayed to make a fine mist. This increases the sorbents efficiency, since it increases its surface area. Air is wafted through these towers, the CO2 is absorbed and the sorbent drains out of the tower as a liquid. The CO2 would be removed, either by a series of chemical reactions or by applying an electric current, and then it would be compressed to liquid form. The sorbent would be recycled. In another version of this technology, designed by Dr. Lackner (professor of geophysics at Columbia University), a solid sorbent is used; thin sheets of material coated with proprietary chemicals would be used. Carbon dioxide in the air is trapped by the sheets and is then absorbed by liquid chemicals. The CO2 is removed from the chemicals by heat.
However, certain technical, financial and political objections have to be overcome in order for the technology to go anywhere. Powering these machines requires electricity, which in turn produces carbon dioxide emissions. If the machinery emits more carbon dioxide than it processes, the technology would be obsolete. Tests revealed that Dr. Keith’s prototype needed 100 kilowatt-hours of electricity, which was generated by a coal-fired power station, to capture one ton of CO2; overall, 3.5% of the amount of carbon dioxide removed by the machine was added to the atmosphere. If a cleaner power source was used, this percentage could be lessened further. Therefore, the technology effectively carries out its purpose. Another issue is the cost of these machines relative to other options for carbon reduction that are currently available. Selling the technology to companies that require CO2 would make it profitable. In addition, the CO2 itself could be sold, since many businesses need it. However, the price of ‘pollution permits’ (allow for emission of 1 ton of CO2) is currently at below $10, while the price of the CO2 produced by this technology is at $200. Only when this new technology becomes more economically attractive will it be preferable to just buying the right to pollute. Finally, this new technology could eliminate the incentive to invest time and money into other environmentally friendly technologies. However, they two technologies could be combined. For example, excess energy from wind farms could be used to power the air capture plants. Overall, this technology, though still in the stages of experimentation, could be the solution to the world’s carbon emission problems.
Sonntag, 1. März 2009
Article Summary: ' Accounting from Above'
Article: Accounting from Above
Publishing Date: February 12th 2009
From: The Economist
Understanding the earth’s carbon cycle would answer many questions regarding the cause and effect of global climate change. Thus far, researchers have only been able to analyze specific areas of the earth with regards to greenhouse gases. However, the launching of two satellites that are designed to monitor greenhouse gases from space will provide concentration maps of areas around the entire globe.
The satellites Ibuki, launched by JAXA (Japanese space agency), and OCO (Orbiting Carbon Observatory), launched by NASA (American space agency), will be providing the information that will help the understanding of where carbon enters and leaves the atmosphere. Ibuki orbits the earth approximately every 100 minutes and it has two detectors that gather information from 56,000 places on the earth. It does this by measuring, with a spectrometer, the amount of sunlight that is reflected from the earth’s surface, therefore detecting the carbon and methane concentration (they both reflect sunlight, each in a unique way). OCO, which will be part of a larger group of satellites, orbits the earth every 99 minutes and studies the carbon dioxide and oxygen levels in the earth, again through reflected sunlight.
Currently, it is estimated that the carbon cycle turns over approximately 330 tons of carbon dioxide every year and oceans absorb approximately half of this. The satellites will provide information on this topic. In addition they can resolve debates over, for example, where the large surface ‘sink’ of atmospheric carbon dioxide is located, since they provide information on areas that are inaccessible to humans. Though the information they provide will be less precise, they will cover a much larger area and provide a lot of data.