Add a new one to the list of somewhat zany suggestions to counteract global warming — only this time the idea comes from the "Gaia guy."
James Lovelock, environmentalist, futurologist and creator of the Gaia hypothesis and its view of Earth as a huge organism, proposes that we help the planet "cure itself" by artificially ramping up ocean mixing, which would stimulate the growth of carbon-munching algae, thereby sinking more carbon dioxide into the ocean.
The Gaia hypothesis looks at Earth as a whole instead of at each of its systems separately — viewing it as something of a superorganism.
"I regard the Earth as a responsive, self-regulating system," Lovelock said, one which should be able to cure itself from any climactic calamities, as it has done in the past.
But human activities have knocked the system out of whack, as increasing amounts of greenhouse gases in the atmosphere raise Earth's average temperature, which in turn contributes to increased melting at the poles, sea level rise and other potentially disastrous consequences.
While some think that we still have time to stem the tide of rising carbon dioxide levels, Lovelock is less optimistic.
"I think we are almost certainly past any point of no return, and that global warming is irreversible, almost regardless of what we do in the conventional things, like following the Kyoto Protocol," he said.
Switching to cleaner energy sources and implementing strategies to mitigate global warming, such as carbon sequestration, would take too long to get into gear and would require an impossible level of global cooperation, he said.
Instead, he thinks that we need to give the Earth a way to help cure itself.
If we did nothing at all to counteract the effects of global warming, the Earth would eventually cure itself of global warming, pollution and other ills without any help from us, but that would take many hundreds of thousands of years.
"In the past there have been many hot spells when the Earth heated up as much as we think it will as a consequence of global warming — the last one was 55 million years ago. And it recovered spontaneously, but it took a long time to do it," Lovelock told LiveScience.
Recent estimates by a scientist at Texas Tech University say that the United States alone must by 2050 cut its emissions by at least 80 percent below 2000 levels to avoid a large increase in global temperatures by the end of the current century.
"So what we were trying to do here is to stimulate it to enter the recovery phase quickly," Lovelock said.
Lovelock's proposal, detailed in the Sept. 27 issue of the journal Nature, is to use free-floating or tethered pipes to increase the mixing of the ocean by moving nutrient-rich deep waters up to replace the more barren waters of the surface.
These nutrients would stimulate the growth of algae and create large blooms that would take up carbon dioxide from the atmosphere as they photosynthesize.
"And when they die, their bodies sink to the bottom of the ocean as calcium carbonate shells, and that gets rid of [the carbon] for good," Lovelock explained.
Lovelock's unusual idea joins a growing list of proposals to combat global warming that include:
— Constructing a "sun shade" by creating an artificial ring of small particles or spacecraft that would block some of the sun's rays from hitting the Earth, thereby reducing heating
— Shooting sulfur into the air to reflect incoming solar radiation back to space (volcanoes do this naturally when they erupt)
— Making airplane flights longer by requiring planes to fly at lower altitudes, which could reduce the formation of heat-trapping contrails
— Injecting carbon dioxide into wet, porous rocks deep underground to store it there for thousands of years, a process known as carbon sequestration
— Or dumping iron into the ocean, also to stimulate the growth of algae, in the hopes the blooms will act as a major carbon sink.
While some scientists doubt the feasibility of many of these proposals, Lovelock says that they would probably work, but ultimately wouldn't solve the problem because they are cases of humans curing the Earth, instead of allowing it to cure itself.
"It's not going to do a lot more than buy you time," he said, all the while allowing people to continue emitting carbon dioxide.
And though his proposal has similar results to the so-called iron fertilization experiments, Lovelock sees two key differences: "[Piping up nutrients] would be continuous. With iron fertilization, you have to keep on going out and spreading the iron," he said. "And also, this would bring all the nutrients up, not just the iron."
Will it work?
Lovelock also sees other benefits to his proposal. Because the ocean's deep water is cooler than the surface waters, the pipes could also be beneficial in regions that are at high risk for severe hurricane strikes, such as the Gulf of Mexico, Lovelock added, since hurricanes feed on warm surface waters.
Ken Caldeira, an ocean ecologist at Stanford University, says he has more confidence in the likelihood that this aspect of Lovelock's proposal could work than in its efficacy as a carbon sink.
"That will produce some cooling, at least for awhile, until you heat up that whole surface layer," he told LiveScience.
Another benefit of the proposal, as Lovelock sees it, is that it does not require a large, globally-coordinated effort, like many other proposals would.
"If it works, it's not that huge a project," Lovelock said. "Something on the order of 10 to 100,000 of these pipes would do quite a lot."
Lovelock envisions that the pipes would be about 100 to 200 meters long and about 10 meters in diameter, with a flap at the bottom that will use the motion of the waves to pump water up. (Other groups, including the private company Atmocean and Stephen Salter of the University of Edinburgh have proposed similar structures that use slightly different engineering approaches.)
Lovelock doesn't think that the proposal should be jumped on immediately, but that experiments should be done to test the scientific, economic and engineering viability of the proposal.
"I wouldn't attempt to cure the Earth tomorrow, so to speak," he said.
Instead, he advocates a small-scale project to test out the pipes on a small island in the tropics that has coral reef in danger of bleaching.
If the reef gets better over time after the pipes are put in, the project can proceed to a larger reef, such as the Great Barrier Reef in Australia, then perhaps move to the Gulf of Mexico, all the while ironing out the kinks at each stage.
Weighing pros and cons
Lovelock acknowledges that the pipes could have negative effects, such as ocean acidification — the more carbon dioxide that is added to the ocean, the more acidic it becomes, possibly endangering marine life.
Caldeira points out another possible kink in the proposal: As phytoplankton die and sink down into the ocean, the nutrients and carbon they contain tend to go back into solution in the ocean.
"And so more or less, the carbon that you're bringing up in your pipes will balance the carbon that's sinking down," he said. "I think it's unlikely to be very effective as a carbon storage approach."
Even if it does work, it is unlikely to be effective as a widespread approach, so bringing down carbon emissions is still the key to solving the global warming problem, Caldeira said.
Lovelock says these effects need to be investigated in experiments, but adds that what might be bad for one particular area or organism could be good for the planet as a whole.
He likens it to the treatments for serious human diseases that can often make a person sick, but are necessary to beat a more serious ailment (using chemotherapy to treat cancer, for example).
"If we have a treatment for something fairly serious, there'll almost certainly be side effects, and you have to balance the consequences of the benefits and the loss," he said.
Caldeira says that despite the potential problems and questions of efficacy, proposals like this should definitely be investigated, "because there's basically little risk, if you threw one of these out in the ocean."
Essentially, he says, we need to consider any ideas that might help, and weed out the bad from the good.
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