I guess the strategy for megascale geoengineering projects should be to think really, really hard about them before you do them.
For the olivine and iron proposals above, potentially you could run a proof of concept on a lake for a few years first?
For the olivine and iron proposals above, potentially you could run a proof of concept on a lake for a few years first?
There is also fertilization from natural sources of iron and other minerals that we can observe - the sands of Sahara that fly to the Atlantic and the Amazon basin, some vulcanic eruptions had high iron content, etc.
I suppose slowly increasing the scale of iron fertilization experiments could be a good direction.
1) we will make some things worse (just like returning to pre-industrial climate would). From roads in France, life in Eastern Europe/Russia, destruction of trade through the "Northwest passage", ... Some 100's of people will freeze to death in Brussels, London and Paris and most of Western Europe every winter once again if climate return to pre-industrial levels.
I wonder if the few thousand I-needed-heat-so-got-a-fire-I-fucked-it-up-and-got-carbon-monoxide-poisoning deaths will return too. On the one hand we don't use coal anymore. On the other hand with enough stupidity (and leaving something bad on top of it) you can still get even an electric heater to give you carbon monoxide poisoning.
2) it's a project done by someone. So someone will have responsibility. Whoever actually acts will be vilified endlessly for the inevitable negative consequences. Such as those people freezing to death.
3) it will have unforeseen consequences. In other words: despite climate "proof" implying models are complete ... they aren't. There will be big surprises.
4) Nature is good and great and Gaia will save us! We are killing people's belief in nature and/or God by fixing problems by interfering in Nature on a large scale. They will fight any and all attempts to interfere at all just for that reason.
5) it won't stop most of the changes underway. We are in an interglacial. Temperature is rising, just way too fast. But it should be rising. Getting CO2 to pre-industrial levels leaves most or all of the changes we've already seen intact. In a practical example, that means every cubic meter a glacier loses is gone until the next ice age. Ice sheets will grow back more, but not to the levels 100 years ago. Pre-industrial climate generally won't make them grow back.
6) what's to stop some countries from using Climate change as a weapon if they control climate change infrastructure?
So it doesn't really matter that we know of many ways to influence and take control of the climate, and that it's becoming ever clearer we want to do so. The problems are political, even psychological, not scientific (although more research into it would help with more options)
The original steam engines standing in as a pilot project didn‘t do much to the atmosphere. Billions of combustion engines did.
The great insect apocalypse went almost unnoticed until two decades in and an order of magnitude of change.
* All the potential wars where nations had a disagreement, but did nothing.
* All the chemical and biological weapons nations might have built, but didn't.
* ...
And I'm sure glad we built universal surveillance systems.
* All the fossil fuel that might have been burned, but wasn't.
So sure, do a pilot project. Let's make sure that even the first-order stuff works the way we expect. But also think hard about second-order effects. And even after that, continually watch for un-thought-of second-order effects emerging as (and after) you roll it out.