Truth be told, climate scientists talk a pretty good line, but often we're a little short on explanations. For example, we can regale you about how atmospheric carbon dioxide (CO₂) is increasing, but we can't explain why its concentration is so low.

We do actually have a pretty good idea how much fossil fuel is burnt every year, and how much CO₂ that puts in the air. But every time we try to figure out how much of that gas should remain in the atmosphere, we come up with way too much. The problem is known as the "missing sink"—we know it's going somewhere but we don't know where.

Figure 1. Although global carbon dioxide emissions continue to increase steadily (top), the atmospheric growth rate of carbon dioxide has leveled off at about 1.5 parts per million per year (bottom). This is one of the great mysteries of climate "science."

The big debate is whether it's into the forests or into the seas. Forests are indeed growing better as a result of that CO₂, but no one has successfully made a proper global measurement of the total amount to determine if they're a big enough "sink." Others argue that the CO₂ must be going into the ocean, but until recently, it seemed there weren't enough nutrients available in the sea to stimulate the amount of algae required to eat all that "missing" CO₂.

Oceanic algae, like land plants, require nitrogen for their proteins. But up until now, no one could find enough microorganisms in the ocean that could "fix" normally inert nitrogen into the form required by plants.

Recently, though, Jonathan Zehr and seven co-workers discovered that there are a large numbers of nitrogen-fixing cyanobacteria in the open ocean—so many that they may explain the difference between predicted and observed amounts of atmospheric carbon dioxide.

Zehr's findings are of potentially enormous value. Many years ago, scientists proposed "seeding" oceans with minute amounts of iron. Iron is currently in such short supply that is it thought to be the "limiting nutrient" for oceanic algae—which therefore limits the ocean's ability to take up atmospheric carbon dioxide.

Naysayers argued that nitrogen was just about as limiting as iron, so adding the latter would ultimately do no good. If Zehr and colleagues are right, however, there may in fact be plenty of nitrogen fertilizer around, so adding iron would indeed make the ocean "bloom" with algae, deep-sixing even more atmospheric carbon dioxide.

Those who think a lot about global warming, such as President Bush, have increasingly realized that any "solution" (the need for which remains questionable) is going to result from technology and investment rather than taxation-forced conservation (as proposed by our European friends, who aren't thinking very much).

The notion of enhancing the oceanic capture of carbon dioxide with iron is precisely one of those solutions. Now that it's been established that there's enough usable nitrogen in the sea thanks to those cyanobacteria, we may actually be able to accelerate the removal of atmospheric carbon dioxide after all. But we can't say for sure, because, until we run this experiment, we're still long on talk and short on facts.

Reference:

Zehr, J.P., et al., 2001. Unicellular cyanobacteria fix N₂ in the subtropical Pacific Ocean. Nature, 412, 635–638.

Putting a Barker to Sleep

One sleepless night in early 1998, Vice President Gore had an idea. Wouldn't it be great if NASA launched a brand new satellite that constantly took pictures of the sunlit earth and beamed them back to a dedicated cable television channel, which could then carry little crawlers of ecological propaganda at the same time? Gore's take was that the channel "will have inspirational value that's hard to describe."

As critics wagged that the television channel amounted to little more than "baying at the earth," Gore, after what he called "20 minutes worth of research" (and proud of it!), called up the head of NASA with the proposal. Administrator Dan Goldin said he hoped to keep the cost "definitely below $50 million."

Nevermind that there's already a fleet of weather satellites that view the full earth disc with tremendous resolution. If you want to stay in daylight, just flip from GOES East to GOES West and then over to the Pacific satellite, or the one over the Indian Ocean, and so forth, a task that will take you about 30 seconds on the internet.

The weather satellites, at 22,500 miles, are in the "geostationary" position, falling around the earth at exactly the same rate at which the earth rotates. Gore's bird would be out at 1 million miles, where the gravity of the sun and the earth equilibrate, resulting in a fall around the planet that constantly looks at the sunlit disc. So much for a high-resolution image. That baby would be four times farther away than the moon.

Well, guess what? We've already spent $120 million on development, the International Space Station is looking to be about $4 billion over budget, and right now we just can't afford to send this thing into space. It has to be launched on the Space Shuttle, which itself costs $470 million a pop. Already, two flights per year of the expensive hydrazine-burner have been cancelled, and Gore's satellite—called Triana—has been bumped to cold storage in Greenbelt, Md.

Triana's cost ballooned when it was loaded down with a few scientific instruments besides a television camera, in order to camouflage the guffaws. But, alas, those may also be as redundant as another cable TV channel, if what its developers say is true. The project's engineers and scientists, reports the August 8 Washington Post, "say their instruments can measure changes in the earth's climate that now have to be pieced together with large margins of error."

Really? The margin of error on the MSU satellite measurements is ±0.01°C. The problem is that those satellites simply don't find much warming. Which is why we needed a satellite-propaganda channel for people to bay at to begin with. That's "inspirational value" for you!