Reversing Climate Change Ideas

By far the biggest and most important decision facing the Planet is how to deal with Climate Change and the recent announcement by the authority on all things Global Warming, the Intergovernmental Panel on Climate Change (IPCC) that we have as little as 12 years to save the planet have sent scientists taking a second look at some of the schemes they previously placed in the file marked 'barnpot ideas'.
The idea of deliberately fiddling with the Earth's climate to reduce global warming, Geoengineering, has long been seen as a preposterous notion due to the unintended consequences of blotting out sunlight to cool the planet but where we once dismissed it as an act of desperation, well, things are now getting desperate.
The idea is to put reflective particles in the atmosphere to block or reflect sunlight and plans considered include spraying sulfate particles into the stratosphere much like what volcanic eruptions do or surrounding the Earth with tiny mirrors or increasing the reflectivity of clouds by spraying seawater into the atmosphere to make clouds whiter and thicker.
These plans are considered too risky as the consequences are too poorly understood but other option up for serious consideration are pulling carbon dioxide out of the atmosphere which would involve planting many, many more trees or inventing a machine that scoops carbon-dioxide directly out of the air and burying it underground.
With only 12 years and counting and any invention still at the blueprint stage it may not be quick enough but there is always the idea of piling iron dust into the oceans to promote the growth of plankton that absorb carbon-dioxide. 
We could always go back and have another look at painting all roofs of buildings white or
covering the Arctic ocean with white plastic to reflect sunlight back into space and let's not forget the idea of slowing the melting of glaciers by constructing a giant wall on the sea floor to prevent warmer water from coming into contact with them. 
My personal favourite and most window shakingly mad, is to block the Atlantic Ocean from entering the Mediterranean by damming the Strait of Gibraltar which would drain the Mediterranean therefore give us more than 1.5 million m² of reclaimed land to used for farming.
Desperate times call for desperate measures and at least these people are having a go and it’s better to do something right? I mean, if you fire trillions of tiny mirrors into deep space or fill the ocean with iron filings and it somehow doesn’t work out, we could always…erm.. we can...umm.
Well, i'm sure we’ll think of something.