Disco-ball Earth

Too bad we can’t convert the infrared getting trapped by the greenhouse effect back into ultraviolet that can escape. Or… can we?

[This is another in my occasional series of half-baked ideas for saving the world. If you can actually make this idea work, it is all yours, and a grateful planet will thank you.]

As you probably know, the climate crisis is due to the greenhouse effect, in which the Earth absorbs more energy from the sun than it is able to shed back into space, causing the planet gradually to grow warmer and warmer. This is a change from the past, when the Earth’s “energy budget” — the amounts of arriving and departing energy — was more or less in balance.

The problem is that a lot of solar radiation reaching the Earth is in the form of ultraviolet light, which is easily able to pass through the atmosphere and reach the surface, where it heats things up. Hot things emit infrared light, and if enough of that can escape back into space to offset the incoming ultraviolet, all is well.

But carbon in the atmosphere blocks infrared from escaping — while doing nothing to reduce the amount of ultraviolet getting in. All substances absorb some wavelengths of light and not others; that’s simply “color.” (Ultraviolet and infrared are just colors our eyes can’t perceive.) When it comes to the gases in the atmosphere, the color hand we’ve been dealt is: let in UV, trap IR. It seems unfair, but chemistry doesn’t care about your feelings.

The politics of our age make it doubtful we can rebalance the energy budget by meaningfully reducing the amount of carbon in the air in a useful timeframe. Too bad we can’t convert the infrared getting trapped back into ultraviolet that can escape, as an alternative.

Or… can we?

Much of what the sun heats up is ocean — naturally, since that’s most of the Earth’s surface. The warming of the oceans is associated with more-intense storms, acidification and coral bleaching, imperiling the Gulf Stream, and a host of other ills.

Most of the warming of the oceans is confined to the upper few hundred feet of depth. Below that in most places is a thermocline — an abrupt temperature drop, with much cooler water below, mostly isolated from the warming effects above.

The thermoelectric effect is a physical phenomenon that can convert a difference in temperature into an electric current.

Putting all of the above together, here’s the idea: build a buoy that floats on the ocean. Beneath the buoy, a long wire extends down past the thermocline. The difference between the surface temperature and the temperature at depth creates a current in the wire — small, but continuous. The current is used to power an ultraviolet laser in the buoy, aimed at the sky. It shines weakly, but continuously, steadily drawing heat from the ocean and beaming it into space.

With enough of these simple, inexpensive units built and deployed, we should be able to offset the greenhouse effect. Doing the math on how many that would be is left as an exercise for the reader. Undoubtedly it would take thousands, perhaps millions, of UV-laser buoys floating in oceans all around the world.

One thing is for sure, though: if this solution works, saving the world wouldn’t be the only cool thing about it. An alien looking at the Earth from space, with eyes that can perceive ultraviolet rays, would see a spinning celestial disco ball.

The Sigma Tax

Pronounced income disparity is the root of many of our country’s problems. Economists have been talking about it for years, and last week President Obama made an attempt to bring the issue front-and-center in a speech at Knox College.

Another thing that economists have long said is, “When you tax something, you get less of it.” So here’s an idea: let’s tax income disparity!

How would this work? Easy. For companies of a given size, we decide what the ideal distribution is of wages and other compensation. We might decide, for instance, that the 90th percentile should be earning no more than 50x what the 10th percentile earns. Whatever numbers we choose, the result is a curve; presumably a less-pronounced one than this:

Once we decide on the shape of our curve, companies are free to obey it or not, distributing their compensation however they see fit. But if their curves deviate too far from the ideal, they pay a proportional income-disparity tax. Maybe they can even be eligible for an income-disparity credit if the curves deviate in the other direction.

Properly tuned, and phased in slowly, this “Sigma Tax” (for the Greek letter that designates standard deviation in statistics) should result in gentle but inexorable pressure that reduces the wage gap, improving things for the bottom 99% without breaking the 1%, while paring some of their shameful excess.


In a recent e-mail exchange with my friend Kurt, we were discussing the problem of orbital space junk and the difficulty of cleaning it up. It’s a subject we’ve batted around on and off for many years, wondering about a workable and economical solution but never managing to find one. It’s been in the news more lately, as the crisis has grown more acute and inventors have trotted out different proposals, each more outlandish than the last.

In the middle of this exchange, after years of coming up with nothing, I suddenly invented my own solution, an idea I now offer publicly as the second in my occasional save-the-world series. It’s called SIEVE: Scanning, Illuminating, Even Vaporizing Engines.

It involves deploying into low earth orbit thousands of semi-autonomous robots. Each SIEVE unit is small and light and costs no more than a few hundred dollars of off-the-shelf components. Specifically, these components:

  • A solar panel for power;
  • Gyros for orientation;
  • A radio for coordination with other SIEVE units;
  • A camera;
  • A simple computer;
  • A Mylar mirror; and
  • A small rocket engine.

Each unit, when in sunlight, is in one of three modes: Scanning, Illuminating, and Vaporizing.

In Illuminating mode, the unit orients itself so that the mirror reflects sunlight through a given volume of space.

In Scanning mode, the unit trains its camera on a region of space that other nearby units are Illuminating and searches for debris.

In Vaporizing mode, numerous units all aim their mirrors to shine sunlight on a piece of debris, one previously identified by Scanning and Illuminating units and whose orbital trajectory has been plotted. Focusing enough sunlight on the debris for a long enough time should heat it to the point of vaporizing. If the debris can be fully vaporized, great; it should be harmless in that form. If it can’t, it might still expel enough vapor to slow its orbit (a la the laser broom idea) to the point where it falls back into the atmosphere.

The rocket engine is only needed twice: once to insert the unit into a distinct orbit when initially deployed, and once to deorbit the unit at the end of its service life.

Care will have to be taken that the SIEVE robots do not themselves become hazards to space navigation. And that they don’t go into Michael Crichton mode, become sentient, and decide the Earth is a gigantic ball of debris.

Save the world with Admiral Bob

Recently I read a NewScientist article about changes in rainfall patterns due to global warming, and it predicted the usual depressing outcomes in the medium to long term: famine, disease, war, immense human suffering.

Then three thoughts occurred to me: 1) a very large amount of the world’s freshwater is lost in the form of rain that falls at sea; 2) meanwhile, enormous petroleum supertankers ply those very same seas; 3) in some places, people pay more per liter for bottled water than they do for gasoline.

These thoughts were synthesized into a pretty freakin’ awesome idea: deploy a fleet of supertankers harvesting rainwater. They would use weather radar to hunt the heaviest precipitation (and the stormiest seas, like as not — only the hardiest sailors need apply). Any rain falling on their decks could be funneled straight into the holding tanks. I’m not sure how you’d keep seawater out of the tanks, as waves would frequently break over the deck of the ship in stormy seas, but that seems like a surmountable engineering detail.

Does it make economic sense to harvest rainwater this way? Let’s start by assuming it’s economical to transport petroleum by supertanker. (A safe assumption.) The retail price of a gallon of gasoline here in Northern California is presently right around three dollars. I don’t know how much crude oil goes into a gallon of gasoline, but for our very rough calculations it’s simplest and safe to say a gallon of gasoline equals a gallon of crude.

That three dollars per gallon we pay at the pump has to cover a lot of oil-industry expenses that a freshwater industry would not have: refineries, research, exploration, and drilling, not to mention giant slush funds for dealing with corrupt foreign regimes. And oil-industry tankers must be double-hulled to protect against spills. Freshwater tankers can be single-hulled.

On the other hand, whereas the oil industry can use their supertankers simply to transport millions of barrels of oil from one place directly to another, a freshwater fleet would have to roam at sea for a while until it contained enough water to make a delivery. This is an operational expense the oil industry does not have. How long must a freshwater supertanker follow rainstorms around until it is full? According to Wikipedia, a supertanker named the TI Asia has a depth (height) of 112 feet. Let’s guess that the tanks it contains are 60 feet high. For simplicity, let’s further assume these tanks have a uniform width — they don’t taper at the bottom or anything like that. This means that the ship must collect 60 feet of rain to fill its tanks — possibly less if a catch area much wider than the tanks themselves can be funneled into them. How long would it take to collect that much rain, if you’re always steering into the heaviest rainfall? Let’s guess that a good freshwater supertanker captain can expect an average of four inches of rain per day. That’s six months at sea to fill the freshwater tanks.

How much does it cost to have a supertanker crisscrossing the bounding main for six months? I have no idea, but let’s keep guessing and say that that cost roughly offsets the petroleum-industry-only costs I listed above (drilling, bribes, etc). This means that the fleet could deliver freshwater for about three dollars per gallon, which is about 79 cents per liter, which is very reasonable compared to the prices paid per liter of bottled water in many places threatened by future global-warming droughts.

The TI Asia can carry half a billion gallons of oil. If a comparable freshwater supertanker can carry an equal volume of water (which is not certain, since water is heavier than oil), then it can deliver a year’s worth of drinking water for a million people. Half a billion gallons is also equal to 1,534 acre-feet, enough water to irrigate 736 acres of crops for a year, but that sounds much less impressive, and at a cost of almost a million dollars per acre-foot, it’s nowhere near competitive.

Would I like to be the admiral of a fleet of freshwater supertankers saving the world? Hell yeah. For many weeks after this idea came to me, I kept it to myself. But then I looked at my pile of ideas-to-implement-someday, and the large subset of those that are in the category no-idea-how-to-get-started (which includes this one), and decided the world needs this idea more than I do. So, one of you reading this: get started. Just do me a favor and christen the first ship the gee bobg.