Kunzig is primarily focused on the deep sea - there are no whales or dolphins or sharks or turtles as key players in the text, but if you want (mostly) hard science placed into (mostly) readable terms, Kunzig delivers. (Kunzig served as the European editor of Discover magazine when he wrote the text and the writing is on that level.)
The one issue I want to bring up here comes in Kunzig's chapter, "Greening the Oceans," which starts with the importance of phytoplankton but quickly moves to the importance of iron to that phytoplankton.
Phytoplankton are, of course, plants that convert carbon dioxide and water into oxygen and carbohydrates through photosynthesis. All life in the sea depend on phytoplankton to bring them oxygen and the plant exists wherever sunlight penetrates the ocean. There is incredible diversity in phytoplankton; no one knows for sure, according to Kunzig, exactly how wide a range that diversity actually encompasses, but there may be as many as 5,000 different species solely in the Gulf of Maine, solely in the month of August. The cataloguing of phytoplankton diversity has been a hundred-year-plus project, and in the last twenty years (the book was published in 2000, so this means the 1980s and '90s), as scientists have "zoomed in on the microworld ... they have discovered whole classes of phytoplankton they never knew existed." He points to a 1988 discovery of a new species whose size is "about 30-millionths of an inch across, that populates the ocean in concentrations as high as five million cells per ounce."
What's remarkable about the diversity of phytoplankton is that it all performs the same function; as Sallie Chisholm, a biological oceanographer at MIT, tells Kunzig, "the diversity it incredible. And yet they all essentially do the same thing; they use light and water and carbon dioxide to make organic matter."
The importance of phytoplankton to our planetary climate can't be overstated as they play a vital role in taking carbon dioxide out of the atmosphere and thus keeping the planet cooler than it would be if the carbon dioxide remained.
Kunzig explains that one of the curiosities of phytoplankton had been why certain large areas of the ocean (such as the northern Pacific off Alaska, the equatorial Pacific, the entire Southern Ocean around Antartica - Kunzig, 211) that should be the oceanic equivalent of rain forests were, instead deserts. The answer, put simply, is that those areas of the ocean suffer from a deficiency of iron.
Phytoplankton need iron to perform three primary functions: to make chlorophyll, to make nitrate reductase (an enzyme which allows the process of turning nitrates into proteins), and to make DNA. They don't need a lot of iron - perhaps, Kunzig explains, as little as "1 atom of iron for every 10,000 atoms of carbon, 1,500 atoms of nitrogen, and 100 atoms of phosphorus," yet there is a deficiency in certain parts of the ocean; much of the iron in the oceans come from atmospheric dust, putting the oeans at the mercy of "the geometry of winds and land masses." The equatorial Atlantic, then, gets peppered with Saharan dust, while the equatorial Pacific has no powerful feeder system and gets a relative trickle of dust, and thus, iron.
John Martin, former director of the Moss Landing Marine Laboratories, had the idea that to fix this natural deficiency all one had to do was dump iron into the ocean and watch the phytoplankton population explode. While Martin made outlandish statements (designed to grab attention more than pushing hard science) that all he needed was a "tanker of iron" and he could bring about "the next Ice Age," the core hypothesis that adding iron to the oceans would result in a dramatic increase in phytoplankton population was a smashing success. One scientist told the press that Martin's open-ocean tests turned the equatorial Pacific "from a desert to a jungle, from clear blue to dark green.
"It was," that scientist said, "almost biblical."
In the footsteps of Martin's success came the idea to dump iron across the oceans of the world as a solution to global warming. More phytoplankton, after all, equals more carbon dioxide taken out of the atmosphere.
The question then, as phrased by Kunzig: "Is it wise, is it moral even, for us to attempt to fix nature on so grand a scale? To tinker deliberately with the biogeochemical cycles and the climate of the entire planet?"
I immediately thought of Tom's post here at the Yawp from last week:
"As Bill McKibben pointed out in The End of Nature (and in the shorter introduction to his annotation of Walden), environmental issues are not technological problems. If they were, all we would have to do is fix the problem, like replacing the head gasket on an ailing car. The real issue is attitudinal."
Dumping iron into the oceans on a planetary scale isn't a technological fix as much as it is a biological fix, but the point, I think, is the same - instead of fixing the root cause of the issue (changing humanity's attitude) and creating less carbon dioxide, iron dumping attempts to "fix the problem" after it has become a problem. The best solution would be a combination - alter the attitude for a long-term solution and apply the band-aid for a short-term fix - but likely what would happen is that if the iron dumping lowers carbon dioxide levels governments would simply pat themselves on the back for a job well done and do nothing to lower those levels at the production end.
Unfortunately, too many people in too many positions of power see a solution as an excuse to keep making the problem.
To get at the heart of Kunzig's question, though, are such solutions a good or bad policy to adopt? Most scientists, according to Kunzig, are aghast at the idea of turning the planet into some large test tube. Martin makes an interesting point, however, when he argues:
"We're already involved in the biggest experiment ever. We're finding out what's going to happen if we dump three billion tons of carbon dioxide in the atmosphere every year. That is the biggest manipulation of the environment ever. [...] We'd better know about ways, if we have to, to bring carbon dioxide out of the atmosphere."
Martin makes clear, however, that if the cost of this is to "kill the whales and penguins" he wants no part of it. Man can "stew" in his own mess. But if there are no averse environmental impacts (and we don't know whether there would be), then Martin is for it.
I think it's dangerous to attempt to, in essence, put the Earth on a phyyoplankton growth hormone, but the point behind Martin's acceptance of that idea - that we're already experimenting on the Earth in huge and dangerous way - speaks directly to the kind of attitudinal shift McKibben is talking about.