Earlier quoted context omitted.
Why would you think we have tricks up our sleeves? What’s that mean “geo-engineering will be done when…” The whole problem is we aren’t capable of doing what we know needs to be done.
When we can burn fossil fuels to impact the atmosphere that cause climate change then we can also pump other gasses that will have a cooling effect. We aren’t doing much at the moment because there aren’t economic incentives to do so, but that can change if we have policy changes.
So does the CO2 itself. The oceans are getting more acidic already, killing shellfish and throwing off food webs.
Throwing additional geoengineering on top of the geoengineering we're already doing will almost certainly cause as many problems as it solves. It would be so much simpler, cheaper, and more effective to just stop digging carbon out of the ground and putting it in the sky.