Earth is losing albedo, reflectance. One of the reasons for the warm year is likely to be the reduction in sulfur emissions in shipping, which means the atmosphere has been less reflective and let more heat into the oceans. Those are warming up fast.
The clusterfuck shitstorm we are in is horrible and our leaders still try to keep the fire burning, simply because the collapse of our fossil dependent money system would be a global catastrophy. Humanity would quickly be cut in half, and the problem would still exist.
Geoengineering is politicized because industry doesn’t want energy to flow into it, it reeks of solutions, and the economy hates those. So the only viable solutions involve renewable energy, organic matter, or regions where nobody wants to live. Those methods are also the easiest to realize.
The oceans can reflect light if they have foam on them, and they do a lot of the time. Ice is not even that reflective, foam is way more reflective. Water itself is almost 100% translucent, so solar heat enters it, gets mixed downward and this is why the oceans warm up.
To keep the oceans and our atmosphere cooler we can cover it. For example with bamboo rafts. Maybe only bamboo weaves are enough. The question is if they will stand up against storms. Covering the ocean increases albedo by at least 30%, which is better than nothing. It provides shade and cool water for animals to rest from the heat. Yes the oceans are enormous, nope it is not a futile exercise.
As long as there are humans to take climate action, then we stand a chance against it. This means we need to give ourselves time by taking action that is effective in maintaining reasonable temperatures.
Years ago I wrote about wind turbines that could help create ice by spraying water into the cold arctic wind. Equally we can use wind turbines to create foam, even though the wind itself creates it. We could also consider adding biomass to the water that increases foaming, even though this can be dangerous to anyone on the water.
Often the “how” is secondary to the “what” question. Setting a goal is an important first step. I think we will see settlements mid ocean, in the middle of the Atlantic, in fact on regular intervals between the US and Europe at least, because I expect there to be floating airports. But with today’s technology it is not far fetched to imagine large settlements, not even of armies of floating turbines kept in place by GPS or pulsar sensors (star observation), originating from factories on some coast. Funny to realize that a floating turbine can probably navigate itself to a destination like a sailboat if designed properly.
How may foaming turbines can we build and deploy? What else is needed? Biomass? To grow seaweed to make foaming agent (which normally consists of remnants of cells which have a hydrophobic and a hydrophilic part). This sounds like science fiction, but it may be what we do, after all we need to cool our planet and its oceans.