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« Molecular Manufacturing vs. Nanoscale | Main | Apes Designing Humans »

May 22, 2006


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Phillip Huggan

In my Human Extinction analysis via natural processes, runaway global warming is easily the most perilous threat for this century. I'm sure there are many artificial threats (like MNT) even more ominous.


Two comments. First, without a near-term total revamping of the world economy, atmospheric CO2 levels will inevitable rise. We are at 380 ppm now, roughly double the pre-industrial level. We will shortly go through 400 and almost certainly through 500. Only with the most stringent economic controls and restrictions on growth can we hope to level off below 550 ppm.

Unfortunately, even today's 380 ppm is far too high. Looking at previous interglacial periods, this level is high enough for substantial sea level rise. Much of Florida will be gone. New York and London will flood. Coastal cities around the world will be covered.

These consequences are already built in to what has happened so far. We have passed the point of no return. At this point, conservation cannot save us. As noted, even the most stringent conservation measures will leave enough CO2 in the atmosphere to reshape human civilization.

The only solution is to remove CO2 from the atmosphere. We can't let it remain at 550 or even 380 ppm. This must be our focus. It is too late for conservation.

Fortunately there are a number of technologies that can help. Certainly if the near-magical powers of MNT come into existence we can just ask our super-intelligent slave machines to do it for us, and materialize sex goddesses out of the reclaimed carbon while they are at it.

Somewhat less science-fictional solutions are possible as well. Planting forests may be a partial solution, although it depends heavily on cheap access to fresh water.

One of the most practical mitigations is seeding the oceans with iron. In many parts of the ocean, biomass is limited by the availability of mineral nutrients, especially iron. Natural fertilization does occur due to windblown sand, leading to plankton blooms which may be short- or long-lived depending on wind patterns. Artificial supplementation with iron has been shown in a number of experiments to lead to great increases in biomass. This can substantially offset atmospheric CO2 increases.

A couple of good sites are http://www.bbm.me.uk/FeFert/index.htm and the Wikipedia, http://en.wikipedia.org/wiki/Iron_fertilization . Costs are estimated to be $1-5 per ton of CO2 sequestered. Importantly, this is 10-20 times LESS than the costs of conservation! Conservation is enormously expensive and, as noted above, has little hope of solving the problem.

Molecular nanotech is, of course, a miracle cure for global warming, just as it is a miracle cure for everything. It is important to keep in mind that even if we don't get miracles, technology will continue to advance and we will have far greater capabilities in 2050 and 2100 than we have today. Even today's technology looks adequate to sequester CO2 from the atmosphere at reasonable cost; technologies 50 and 100 years from now will be far more capable and efficient. Global warming is a solvable problem, but the solution is advanced technology for sequestration, not conservation.

Tom Craver

Umm, the first article says that the impact of all the floating ice melting will be "the equivalent of approximately 4 centimeters (1.57 inches) of sea-level rise".

Goodbye Florida!

The second article talks about a feedback loop that will warm the Arctic ocean - causing floating ice to melt even more. See above for sea level impact...

Now if all the ice on Greenland AND Antarctica melted, that would result in a 75m rise in sea level. But according to this paper:

Changes in Sea-Level associated with Modi cations
of the Mass Balance of the Greenland and Antarctic
Ice Sheets over the 21st Century

it looks like the net impact from those two will be a few centimeter DECREASE in sea level over this century.

Let's try to keep things a bit in perspective. Yes, there are issues with sea ice melting (e.g. for arctic fauna). But drowning silver haired grandmas in Florida isn't likely one of them.

Chris Phoenix

Tom, what struck me about the floating-ice article wasn't that it would cause a major rise in sea level (though I wonder about the effect of even an extra 4 cm on sea-bottom life, especially corals). It's that it took until 2005 for someone to point out that ice floating in saltwater will in fact raise the level of the water when it melts. How many other obvious effects are we missing?


Phillip Huggan

I stopped reading after pg 5 of 28 when the author asserts dynamic changes such as a West Antarctica ice sheet collapse (would raise global sea levels 40 ft during a single season) or even local glacier melting patterns (such as a glacier accelerating its rate of flow into the ocean because of melting), are ignored.

I wanted to read the whole thing because I'm lacking in understanding polar precipitation feedback mechanisms, but the whole point of global warming is to fight two specific battles: a small one to prevent melting Greenland from disrupting the Gulf Stream (does this paper even consider Ocean Currents, the most important physical system here?), and the big fight to prevent the West Antarctic ice sheet from sliding into the ocean. This paper only considers local precipitation patterns (AFAIK after 5 pgs) and for instance, ocean currents will shift and affect the precipitation assumptions of this paper.

Phillip Huggan

Hal, I noticed the idea of of seeding oceans to bloom plankton on extropy-chat a few months back. But when I tracked down the wiki links one basic conclusion was that warming temperatures will accelerate the life-cycle of plankton blooms causing them to fall into the ocean depths more quickly and sinking far less CO2 per bloom. So even to break even with present bloom rates, a massive and costly seeding campaign may be necessary.
Our agriculture is a just-in-time system that relies on predictable climate patterns. Even one growing season lost would result in widespread starvation.


please give me photos about warning global spesial in junggle disaster

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