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Comment by twright | Hacker News Reader

Or we could burn less fossil fuels, restore forests? I think of this passage every time sun-blocking solutions are discussed:

> for the fossil fuel companies and their paid champions, anything is preferable to regulating ExxonMobil, including attempting to regulate the sun. - “This Changes Everything” (Klein, 2014)

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We are past the point where stopping burning fossil fuels or planting trees is sufficient to meet the Paris goal of 1.5 degrees of warming. The IPCC scenarios now include some degree of geoengineering in the form of carbon sequestration: https://www.ipcc.ch/site/assets/uploads/sites/2/2019/09/SR15...

This technology is unproven- should it fail to be developed and scale then a sunshade might be on the table.

With the same logic, let's add the option to move to another planet.

[This report](https://energyinnovation.org/wp-content/uploads/2021/02/A-1....) talks about what's needed to stick to 1.5° of warming and it's a lot.

That said, I agree that blocking the sun should be a last resort.

Also restoring forests may have adverse effect, I've heard different researches on this topic.

Yes, there are dangers in restoring forests. I'm thinking of China's Three North Shelter Program here. While very ambitious and farsighted, the monocultures they establish are vulnerable to diseases, pests and other factors, and are a weak starting point to rebuild ecosystems. If those trees die, all the resources put into the effort will go to waste. Also, the new forests put heavy strain on the water table, which worsens the effects of desertification. The water table can only recover if the forests become strong and dense enough to retain humidity and cool down the ground. My (totally uneducated) advice would be to strengthen existing forests and ecosystems, merge them (if necessary, by reallocating agricultural use to other ares) and slowly expand them towards the affected areas.

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