When geoengineering goes wrong

Paul Raven @ 26-03-2009

Barcelona sunsetWhile it’s probably a bit too soon to go rushing into geoengineering projects in an attempt to readjust the earth’s runaway climate, discussing the ideas thoroughly is of great benefit – principally because it gives people a chance to pick holes in the plans and think of potential downsides before we do something irreversible.

Exhibit A: seeding the atmosphere with dust to increase the amount of sunlight reflected away into space might actually be shooting ourselves in our renewable foot, so to speak:

While such atmospheric modifications would only be expected to deflect about 3 percent of the sunlight incident on the earth, Murphy has found that solar energy collectors would face a reduction of up to one-fifth of the usable energy that they collect presently. Even though 97 percent of the sun’s light will make it through the Earth’s modified stratosphere, much of it will be scattered, making the light diffuse. Diffuse light cannot be focused in the same manner that direct light can be, which lessens its usability in most optical systems. Almost all projects that harness solar energy require a large portion direct sunlight that can be focused and concentrated on a cell of some kind.

So: reduce the bad effects of sunlight, and you’ll reduce the useful ones as well. Best relegate that plan to the back-burner… at least until someone finally develops a usable fusion system.

On a similar note, it looks like iron-dumping in the ocean is off the menu at least for us. For a certain type of shrimp, however, it’s very much on the menu:

The iron triggered a bloom of phytoplankton, which doubled their biomass within two weeks by taking in carbon dioxide from the seawater. Dead bloom particles were then expected to sink to the ocean bed, dragging carbon along with them.

Instead, the bloom attracted a swarm of hungry copepods. The tiny crustaceans graze on phytoplankton, which keeps the carbon in the food chain and prevents it from being stored in the ocean sink.

Back to the drawing board. Thank goodness for thinking ahead, eh? [image by papalars]

Solar eclipse ‘diamond ring’ as seen from the moon

Paul Raven @ 19-02-2009

A little snippet of space-pr0n for ya; last week, the Japanese SELENE/Kaguya lunar orbiter probe shot some video footage of the Earth passing between the Moon and the Sun.

The ‘diamond ring’ effect is only ever seen on Earth on the rare occasion that we witness a total solar eclipse; this is probably the easiest way to see something otherwise incredibly rare (and mind-expandingly awesome, as far as I’m concerned). [via PinkTentacle]

Space elevators and orbital solar power

Tom James @ 05-01-2009

neonA nice confluence of Clarkian techno-positivism and 21st century orbital solar power in this post on Short Sharp Science:

There’s another slight problem: the elevator doesn’t exist.

And neither do the supermaterials that could make it a reality. The elevator community’s oft-quoted carbon nanotube fibres languish in labs unable to stretch more than a few tens of centimetres without breaking.

All the more reason, says Swan, to get serious research into elevator technology underway. “We should initiate the space elevator project now and have the space solar power people buy into the concept that we’ll have one by 2030 and start planning for it. Instead of a 50-year horizon, let’s have a 20-year one.”

Stirring stuff. The space elevator is in the class of things I definitely hope to see within my lifetime.

[from Short Sharp Science][image from tanakawho on flickr]

Spain’s solar graveyard

Tom Marcinko @ 25-11-2008

When they perfect that spinach-based solar power, maybe they’ll use it to landscape cemetaries:

Santa Coloma de Gramenet, a gritty, working-class town outside Barcelona, has placed a sea of solar panels atop mausoleums at its cemetery, transforming a place of perpetual rest into one buzzing with renewable energy.

The town doesn’t have a lot of room for solar, so the cemetary was the only place for 462 panels that can light up 60 homes. The panels are arranged above mausoleum niches, and the town’s residents seem to appreciate the respect for the dead shown by the placement.

[Image: Wikimedia Commons]

Solar power turns over a new leaf

Paul Raven @ 25-11-2008

autumn leafWhat do you get when you combine thin sheets of gold leaf and a protein found in spinach? You get an artificial leaf that can photosynthesise energy from sunlight. It’s not a highly efficient conversion rate yet – way behind the top-of-the-range silicon photovoltaics – but the simplicity of the design means it could become a much cheaper alternative. [image by angelrays]

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