I strongly support efforts to limit the rise in CO2 levels by more familiar means, to reduce both predicable harms and the risk of triggering unexpected feedback processes or climatic transitions.

There are many partially-effective ways to reduce harm and risk. Some are ready to apply, others are in early research. None of them can substitute for the rest. Among the purely conventional scenarios, though, even those the most optimistic look bad.

Regarding plausible timelines for developing advanced capabilities, this deserves an extended discussion. Here, I’ll just say that times short compared to those routinely discussed in the context of climate change seem entirely feasible. A rate-limiting step will be the development of a discipline centered on integrating, advancing, and applying existing technologies for atomically precise fabrication. This isn’t a matter of new technologies per se, but of suitable objectives and organization.

Regarding charcoal and soil, have you read 1491, a book that describes the thriving societies of the Americas in the centuries before the waves of Old-World plague that struck them down? It changed my view of history. Among other topics, the book discusses discoveries about Amazonian civilization and agriculture, and a soil-building technology employing charcoal is part of the story.

Although there doesn’t seem to be a whole lot of legitimate scientific dissent that the rise in CO2 levels around to be directly caused by humans, whether the acidification problem or the warming problem will turn into the sensationalist end of the world environmental disaster scenario that the most extreme environmentalists claim they will does not seem to be as clear. From my understanding, scientists believe that there have been as many as five mass extinctions throughout the history of life on Earth where 90% of species disappear. I think that life will adapt to this sudden change as it has in the past. Of course it would be better for the human race if we could avoid this presumably extremely unpleasant scenario.

I am not convinced that pursuing nanotechnology as you originally conceived of it, Dr. Drexler, or even the modernized concept of molecular manufacturing as a primary strategy for reversing or at least halting environmental damage due to CO2 levels is the best solution. It seems like there are still a great number of rungs on the “ladder of technologies” separating us from true MNT. Wouldn’t you agree that even optimistic predictions of a time frame for development and implementation of the level of MNT required for it to be a real solution is beyond the predicted time frame of the major effects of elevated CO2 levels?

In my opinion, to ameliorate the global CO2 problem in a reasonable time frame, we need to pursue intermediate technological solutions. Research efforts across the board should be increased many fold. What we need is a “moonshot” with the focused goal of achieving true MNT. Just as with sending humans to the moon in the 60′s, a great number of auxiliary developments would be achieved along the way and those developments would help keep the CO2 levels at bay. The rapidly falling price of solar energy, for example, is promising. Once MNT is commonplace, a problem such as CO2 levels will be trivial.

Biochar sequestration could in theory remove about 1 PPM of atmospheric CO2 per year, while significantly improving farmland worldwide. Of course, it will take some time to ramp up to that scale. And the total carbon that can be sequestered in productive land may be limited to about 35 PPM equivalent – not quite enough to get us back to the “safe” 350 PPM, even if all CO2 emissions stopped today. But it still seems very much worth looking at.

If carbon credits can be handled properly, biochar sequestration might provide an economically sound “money pump” from developed to developing nations, on the order of $100 billion per year.

James Lovelock says this is a great idea, but it probably won’t be done. Who will prove him wrong?

Also, the anthropogenic global warming deniers say solar cycles and long term climatology have not been explored. But from all I’ve read, solar flares and orbits and huge spans of time have been studied.

The P. R. campaign against science has got to be more specific. Guess that’s why it’s not.