Scientists have been trying to devise ways of slowing down or stopping global warming. This concept is called geoengineering. The ideas range from great to idiotic, according to Simon Worden, head of NASA’s Ames Research Center. They are all last chance efforts to deal with global warming.

One private company has already begun its plan. Planktos Inc. of California has begun dumping 50 tons of iron dust into the Pacific Ocean to trigger plankton and algae blooms, or growths that helps use up carbon dioxide (CO2) in the atmosphere. They hope to remove 3 billion tons of CO2 from the atmosphere, half of what is needed to stop global warming. It’s called the “Geritol Solution” and is an attempt to restore the ocean to a more ecologically normal, balanced state. It could change the temperature of the ocean affecting other species.

Another idea is the “manmade volcano”. Scientists think they can use jet engines, cannons, or balloons to get sulfates into the air, blocking solar heat. It would mimic the effects of a volcano. It would increase sulfur pollution by a very small percentage. It would take tens of thousands of tons of sulfates shot into the air every month. Scientist Caspar Anman of the National Center for Atrmospheric Research calls it “ridiculous”. It could dry out the Mediterranean Sea and has no effect on CO2.

The “artificial tree” or “air capture” method is a device designed to mimic trees by creating large filters that would absorb CO2 from the air. A chemical reaction would take the carbon from it and change it into another form to eliminate it. It would take a lot of wind and energy to power the devices, transportation, and a recycling facility. Filters the size of a television could remove about 25 tons of CO2 a year. A 200-foot tree could filter 6.6 pounds per second, the same amount one American produces annually. The costs are high and there is a slight chance of leakage.

A “solar umbrella” or “sun shade” is an idea of Roger Angel from the University of Arizona. His idea is to launch a small cloud of Frisbee-like spaceships, weighing an ounce and measuring about a yard wide, to orbit Earth blocking the solar heat. It would take 16 trillion pieces to make the solar umbrella with at least 20 million launches to place them in orbit. The cost would be over $4 trillion over a time span of 30 years. The cost is enormous, less than 2% of the sun’s heat would be blocked, and there is no effect on CO2 levels in the atmosphere.