While I agree that a majority of the geoengineering practices described in the articles we read sound like sci-fi, I am a HUGE fan of afforestation. In fact, in the IPCC video they used a reforestation effort in South America(?) as an example of an adaptation to climate change. Considering the harm we have done to carbon sinks like the world's forests in the past, replanting trees seems like the least we can do!
Re: Sustainability: The way to go