Just a few years ago, technologies like these, that attempt to re-engineer the natural environment, were on the scientific fringe.
But with the dangers from climate change worsening, and the world failing to meet its goals of slashing greenhouse gas emissions, they are quickly moving to the mainstream among both scientists and investors, despite questions about their effectiveness and safety.
First in a series on the risky ways humans are starting to manipulate nature to fight climate change.
They are testing whether adding iron to the ocean could carry carbon dioxide to the sea floor.
And with massive facilities like the one in Iceland, they are seeking to reduce the concentration of carbon dioxide in the air.
Locations:
Iceland