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Comment by danparsonson | Hacker News Reader

Attempting to exercise control over such a chaotic system with simplistic solutions like giant space mirrors strikes me as a very bad idea indeed. Until we have a complete understanding of how the climate is regulated naturally I really don't see how we can do any good at all.

Not to mention that, as you say, the politics are beyond us at the moment anyway (global consensus? yeah, right...)

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The nice thing about space mirrors is that of all the climate mitigation methods I've heard, they are by far the most controllable. Solutions like "let's stuff the oceans full of iron to grow plankton to absorb CO2", even assuming they work as intended, have the problem that they are irreversible. Space mirrors can put heat where we want it, and remove it from where we want it, and can do so on hours of notice. It's actually the least simplistic solution. It also actually allows some reasonable engineering experimentation with commensurate levels of commitment.

Unfortunately, it is also the easiest to turn into one hell of a weapon.

Then, following that logic, climate control in general is one hell of a weapon. If anybody actually can control the climate, can we allow them that power? Things like "turn it over to the UN" aren't a magical answer to that problem because "the UN" is ultimately just another group of people, not particularly imbued with magical resistance to the temptations of power. (Arguably, quite the opposite.)

But assuming the massive political problems can be solved, problems which all climate control schemes have equally, space mirrors are actually the one I favor most. Too many of the other ones have a failure case of "triggering an ice age", and for all the words spent on explaining how bad global warming is, ice ages are several orders of magnitude worse than the worst global warming story I've heard. A true ice age is the end of civilization.

What makes it simplistic for me is really the idea that we can make the climate better by tinkering with a single variable (temperature in this case) - I'm not convinced we even know what 'better' is, let alone have enough understanding to predict what the side effects would be. What if we cause some imbalance that doesn't immediately manifest any problems but has a detrimental longer term effect?

I do take your point about space mirrors and the ability to experiment, though - certainly more appealing than man-made plankton blooms shudder - and I think you hit the nail on the head with respect to the political issues!

IIRC, plankton blooms were debunked. They tried it and the number of predators just a level removed from the plankton increased to offset the bloom.

They were; I just picked that as a convenient example of a non-reversible idea. Once you dump the iron in, you're committed. It turns out that in a dynamic system (ahem) that just smashing one of the inputs doesn't guarantee a linear response, but regardless, you're committed once you've done it.

(It turns out that in this case the system tends towards stability. There are good reasons to believe that most changes we can make will also be neutralized. But there's no a priori reason that the same experiment couldn't have experienced a wildly disproportionally large response instead.)

Temperature as a single variable doesn't deal with /known/ problems.

Besides the well-known effect on temperature, CO2 also causes ocean acidification, which among other things kills coral. In its own way, ocean acidification is far scarier than global warming, because there is absolutely no question that it is taking place. While you need a PhD to analyze climate data, you only need high school chemistry to demonstrate ocean acidification. Moreover, you have to deal with the carbon dioxide directly to solve this problem; you can't just try changing the albedo of the Earth, through mirrors or surface reflectors or particulates in the upper atmosphere. And worse: simply stopping where we are may not an option. The current levels may already be long-term undesirable.

Honestly, by analyzing fossil records of CO2 in past times, like the Jurassic period, I believe that somewhere in the ocean there are creatures with genomes adapted or rapidly adaptable to an increased acidic ocean.

The geological average of CO2 in the atmosphere seems to be about 20 times the current amount.

Not necessarily corals are the optimum staple life form of the oceans.

I do not claim to know anything about what would the optimum staple life form in the ocean, I'm simply open to the possibility that an increase in CO2 could lead to a improvement in photosynthesis ability for algae and therefore an increase in ocean life.

Ah, but with space mirrors we don't get "temperature", we get temperature in locations. You don't just point the mirrors "at Earth", you point them "at Utah" or, well, engineering-wise there's nothing really stopping us from getting it down to a few hundred square meters or even tighter, which is why this can be such a weapon. But it's also why they really are the best solution, they have fine-grained control over many things and can even be used to do things like significantly increase evaporation in oceans or something, not just control temperature directly.

You're not following Lean Climate Control practices.

Failing Fast seems suboptimal, here.

The morning weather forecast will promise that "some weather" will be delivered but they don't know what form it will take or how much of it there will be. They will go on to say that if you're not happy with the weather that is delivered then you shouldn't worry because they can guarantee that some more weather will be delivered the following day.

That's assuming that there is any kind of natural 'regulation' of the earth's climate. It appears to veer erratically from mini-ice age to heatwave. However it's true we do need to vary carefully consider the downsides of any potential interventions and be flexible about it. There's far too much dogma and polarisation of debate in climate science at the moment.

That is indeed an assumption on my part, although there is evidence of such regulation that I, at least, find compelling; for example:

http://en.wikipedia.org/wiki/File:Vostok_420ky_4curves_insol...

and it's worth pointing out that long term regulation and the shorter term variations that you mentioned aren't necessarily incompatible.

IANA Climate Scientist though!

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