What is geoengineering?  Geoengineering aims to tackle climate
change by removing CO2 from the air or limiting the sunlight
reaching the planet  See all questions and answers Read about
the project Geoengineering or climate engineering solution to
climate change: marine cloud whitening Engineer Stephen Salter's
design for an unmanned ship designed to generate clouds and
reflect sunlight away from the earth.  Geoengineering schemes
are projects designed to tackle the effects of climate change
directly, usually by removing CO2 from the air or limiting the
amount of sunlight reaching the planet's surface. Although
large-scale geoengineering is still at the concept stage,
advocates claim that it may eventually become essential if the
world wants to avoid the worst effects of climate change.
Critics, by contrast, claim that geoengineering isn't realistic
– and may be a distraction from reducing emissions.  The first
category of scheme – those designed to remove CO2 from the air
– include machines (sometimes called