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From nuclear fission to cloud seeding to carpooling, New Mexico Tech students offered a variety of ways to combat carbon dioxide emissions and global warming at a public seminar April 30.
The seminar was part of an environmental chemistry class.
Carbon Sequestration
In speaking about carbon sequestration, senior chemistry major Katrina Burleigh said people are looking for ways to handle carbon dioxide emissions.
Forests and soils, empty gas and oil wells, geologic features, oceans and possibilities no one has thought of yet could provide places to store carbon dioxide. Some organisms also eat carbon dioxide.
For this sequestration, people would have to collect emissions from "point sources" like power plants.
On geologic carbon sequestration, senior environmental science major Sofia Sigstedt said that option is the largest reservoir for carbon. When people take fossil fuels out of the ground and burn them, she said, the resulting carbon dioxide might be able to go back into the ground, sometimes even the same formation, permanently.
Possible storage formations could include deep saline aquifers, sandstone, basalt or deep unmineable coal seams, Sigstedt said. Also, carbon dioxide could be used to displace and recover normally hard-to-get oil or gas in wells or methane in coal beds.
Before injecting the carbon dioxide, people would have to evaluate the site to ensure they had an impermeable layer to hold in the gas and that the area didn't have earthquakes or faults that would break the formation and release the gas. After injection, the sites would require monitoring to be sure there were no problems.
In the United States, Sigstedt said, the location of point sources corresponds to the location of potential storage formations, and the storage potential is greater than the yearly emissions. However, worldwide the reverse is true.
Also, Sigstedt said the gains of carbon sequestration don't always outweigh the expenses, so governments would need to pass laws and incentives to encourage it.
On terrestrial storage, master's student majoring in chemistry Giovanni Luchetti said the method involves plants and microorganisms taking up carbon dioxide from non-point sources. Techniques include no-till farming, reforestation and producing biofuel and hydrogen from some algae.
The algae in question use carbon dioxide as an energy source.
"And in the process, they end up producing side products we're interested in," Luchetti said.
Terrestrial storage has pluses and minuses, he said.
Global Environmental Manipulation
Next, doctoral chemistry student Asitha Cooray and junior majoring in chemistry Jesse Mora presented ideas for global environmental manipulation to stop global warming, but didn't seem enthusiastic about the possibilities.
Cooray said it has become obvious that reduction of greenhouse gases isn't enough to stop global warming.
One proposal he explained was iron fertilization of oceans to induce a boom in the growth of marine photosynthetic microorganisms to take up carbon dioxide. Certain areas of the ocean far from land have high nutrient contents but few such microorganisms, also called phytoplankton, due to lack of iron.
"Basically, the main source of iron for the ocean is dust fall," Cooray said.
Adding iron to the desolate areas would encourage the growth of phytoplankton, which would take up carbon dioxide and then get eaten or sink to the ocean floor still holding the gas.
"This is not really a perfect plan," Cooray said.
First, he said the iron wouldn't remain dissolved in the water for long, so people would have to keep fertilizing the oceans. Also, the phytoplankton produce gases that could cause problems and the boom of the microorganisms' population would affect the ocean food web.
Cooray also explained the idea of controlling climate through sulfate aerosols, which would reflect solar radiation.
However, Cooray said the aerosols could cause acid rain, accelerated ozone depletion, uneven cooling and decreased global precipitation.
On cloud seeding, Mora said people might use clouds to reflect the sunlight.
"Well, obviously these clouds won't be natural since we're using manmade sources," he said.
If using this method, humans would shoot tiny particles into the air so water vapor would condense on them and form clouds.
For benefits, Mora said cloud seeding could decrease temperatures, bring more rainfall to dry areas and provide research opportunities for better understanding hurricanes.
Still, Mora the method could take water from places that needed it. Also, polluted areas couldn't form clouds as easily, and it's uncertain if ecosystems would adjust for the better.
Furthermore, Mora said if dry ice, solid carbon dioxide, used to form clouds didn't get condensation on it and fall, the atmosphere would have more carbon dioxide.
People have also thought of putting reflective debris or spacecraft in orbit above the equator. This idea would take a significant amount of such objects as well as constant monitoring, Mora said.
On the plus side, the objects could decrease temperature, extend twilight to allow less energy use and, in the case of satellites, double as a source of solar energy. On the down side, the longer twilight could hurt plants and animals that thrive at night, and the reflective items might endanger low-earth satellites as well as taking a lot of time and money to remove.
Mora said people must address global warming.
"But going about it in a reckless way to drastically change our ecosystem wouldn't be foolproof, obviously," he said.
Alternatives to Fossil Fuel
Chemistry seniors Michael Butkus and David Taylor along with master's chemistry student Kimberly Samuels spoke on alternatives to fossil fuels.
Samuels named the renewable energy sources of solar, wind, geothermal and hydroelectric power. Solar panels operate on an energy source that doesn't run out and have no emissions, but they are expensive and their manufacture releases toxic chemicals.
Butkus talked about biofuels.
"There's an endless supply as long as we keep growing it," he said.
Biofuels create no net carbon dioxide increase from their burning.
"What we emit is what we absorb," Butkus said.
However, refining the materials produces emissions.
Cellulose bioethanol, compared to the starchy kind made from such things as corn, is more efficient but harder to produce. It uses waste plant material instead of foodstuffs.
On biodiesel, Taylor said people use energy in waste oils and fats mixed with methanol to produce biodiesel and glycerin, a component of soap, at low to no cost, he said.
Biodiesel would require few modifications to cars.
For hydrogen fuel cells, Taylor said they don't emit carbon and do waste less energy.
"The major, major problem with hydrogen from an environmental standpoint is the production of it," he said.
The process creates carbon monoxide, and is less efficient or more costly than other alternatives.
Butkus spoke about nuclear fission, which produces "a massive amount of energy" when atoms split. People would need to mine and refine a rare form of uranium.
"There is a finite amount of it in the earth's crust," he said.
However, the uranium produces more energy per volume than coal and releases carbon dioxide only in mining and manufacture.
Nuclear fission produces cheap energy with small amounts of dangerous radioactive waste. New technologies to improve the fission are on the horizon, Butkus said, but using that method risks nuclear meltdown and proliferation.
With meltdowns, he said, the right procedures can prevent them or mitigate 100 percent of the damage.
Ways to Help
At the end of the presentations, geology master's student Josh Feldman gave a number of suggestions on how individuals can combat global warming.
People can use halogen light bulbs and turn down thermostats. Feldman advised cutting power to electronics not in use to avoid LED lights continuing to use power.
Concerned individuals can buy local food, which has needed less energy to transport, and grow plants with low-water-use techniques. Watering with drip irrigation, collected rainwater or gray water, which comes from laundry machines, bathroom sinks, bathtubs and showers.
People can dry laundry on clotheslines, get reusable grocery bags and buy water purification devices instead of bottled water, Feldman said. Walking, riding bikes or carpooling also saves energy.
For homeowners interested in improvement, double-pane windows, which provide better insulation and stop some light, and radiant heating are available. Radiant heating systems run hot water, which solar panels can heat, through the house and are more efficient.
Feldman recommended the Web site www.carbonrally.com for more information, including how much different actions make a difference.
