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Cloud brightening

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Solar geoengineering is a type of climate intervention:  deliberate actions designed to affect the climate.  There are several ways to try to reduce the amount of sunlight reaching the surface of the earth and all of them are controversial.  Perhaps the least controversial approach is cloud brightening.

The idea is based on something called the Twomey effect, which is that large numbers of small droplets in the atmosphere reflect more sunlight than small numbers of large droplets.  Spraying vast quantities of minuscule aerosols into the sky, thereby forming many small droplets, could change the reflective properties of clouds.  If clouds are more reflective, then less sunlight reaches the surface, and the temperature goes down.

This form of geoengineering is thought to be less risky because it can be performed on a localized basis and can use relatively benign materials such as sea salt. 

In early April, scientists from the University of Washington started testing a device that sprays tiny sea-salt particles into the air from the deck of a decommissioned aircraft carrier in Alameda, California.  The test was simply to see whether the machine propelled a mist of suitable size.

Within two weeks, Alameda officials ordered a stop to the experiment, citing potential health and environmental risks.  After a month-long investigation, Alameda ruled that the experiment does not generate a measurable risk to health, wildlife, or the environment.

But before more ambitious experiments take place, there are potential side effects of cloud brightening that need to be studied.  It may turn out to be a useful tool in fighting global warming, but in any case, such technology should not be viewed as a substitute for moving away from fossil fuels.

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A Test of Cloud-Brightening Machines Poses No Health Risk, Officials Say

Photo, posted September 8, 2011, courtesy of Justin Ladia via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Fusion Power And The Climate Crisis | Earth Wise

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In December, the Department of Energy announced that scientists at Lawrence Livermore National Laboratory in California had achieved a breakthrough in nuclear fusion technology.  Fusion is the process by which the sun generates energy.  If we had the means to produce nuclear fusion in a controlled fashion, it would be an almost limitless source of clean energy.

Scientists have been trying to develop controllable fusion since the advent of the hydrogen bomb in the 1950s.  H-Bombs are basically uncontrollable fusion.

There are massive experiments under development around the work seeking the means to create and control fusion.  There are multi-billion-dollar projects such as the ITER tokamak project in southern France, that have been ongoing for decades.  Colossal equipment is required to produce the temperatures of millions of degrees needed to fuse hydrogen atoms into helium atoms.

The Livermore project uses 192 powerful laser beams to vaporize a tiny pellet and provide the energy required to initiate fusion. The breakthrough is that the experiment released more energy than the lasers put in.  This was the first time a fusion experiment produced a net gain of energy.

Is fusion the solution to de-carbonizing the energy system?  Perhaps someday it might be.  However, even the most optimistic fusion researchers believe it will be at least another decade before even the experimental fusion systems around the world can reliably produce energy and the efforts will cost untold billions of dollars. 

The world cannot wait for fusion power to save the day.  The focus must remain on currently available renewable energy technologies if we are to achieve the necessary emission reductions in time to prevent the worst effects of climate change.

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Can Fusion Solve the Climate Crisis?

Photo, posted July 29, 2010, courtesy of Steve Jurvetson via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Cleaning Up Diesel With Bacteria | Earth Wise

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Mothballed military outposts with piles of rusting oil drums are not an unusual sight in Greenland.  There are about 30 abandoned military installations in Greenland and diesel that was once used to operate generators and other machinery has, in many cases, seeped into the ground.

Removing tons of contaminated soil from these sites is incredibly resource-intensive involving the use of aircraft and ships, so it has not really been practical.  As a result, Danish Defense and the engineering company NIRAS instead conducted a five-year experiment to optimize the conditions for naturally occurring soil bacteria to break down the contaminating diesel.

The experiment was performed at Station 9117 Mestersvig, an abandoned military airfield on the coast of East Greenland.  Forty tons of diesel fuel contaminated the soil there.

The remediation method using bacteria is known as landfarming and has most often been applied in warmer climates around the world.  This was the first large-scale test under Arctic conditions.

Landfarming works by distributing contaminated soil in a thin layer, which is then plowed, fertilized, and oxygenated every year to optimize conditions for bacteria to degrade hydrocarbons.

The site was monitored by scientists from the University of Copenhagen, and they found that after five years, the bacteria had bioremediated as much as 82 percent of the 5,000 tons of contaminated soil on the site. 

Based on these results, it appears to be feasible for naturally occurring bacteria to be used to remediate contamination in all of the 30 deserted military installations in Greenland as well as in other Arctic sites contaminated by diesel pollution.

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Bacteria used to clean diesel-polluted soil in Greenland

Photo, posted September 6, 2013, courtesy of Maj. Matthew J. Sala/The U.S. Air National Guard via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The Value Of Biodiversity

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It is often said that biodiversity is crucial for staving off extinctions.  Ecosystems are complex and are essentially defined by the interdependencies among the various animals and plants.  It stands to reason that removing species from an ecosystem can have significant effects up and down the food chain.  Extinctions are much more likely when biodiversity diminishes.

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