Geo-engineering is a collection of ideas for reducing the temperature through engineering. It can be divided into two:

1) removing CO2 from the air - see pages on CCS
2) limiting the sunlight reaching the planet - this page. 

"Large-scale geo-engineering may be needed to avoid the worst effects of climate change. However geo-engineering may not be realistic. Many see it as an excuse to keep polluting by doing business as usual."

Royal Society report: Geoengineering the climate: science, governance and uncertainty

This wouldn't solve the CO2 problem, nor will it tackle ocean acidity. But the plan could create a window of opportunity in which the global economy could be decarbonised without the earth being pushed over the threshold of runaway global warming.

The need to look more closely at geo-engineering has been recognised in the work of NASA, the Royal Society, the UK House of Commons Science and Technology Committee and the US Climate Institute.

The American Geophysical Union and the American Meteorological Society have prepared formal position statements on the issue.

The Intergovernmental Panel on Climate Change has also commenced its own assessment of the topic."  from The 26 Sept 2011 - full article


Making the planet more reflective

The surface of the planet can be made more reflective by::

  • Increasing cloud cover to reflect sunlight back into space.  so they are more reflective
  • introducing masses of tiny bubbles into ocean waters
  • growing crops/vegetation of high-reflectance, Different varieties of wheat and other crops reflect sunlight differently.
  • reflective covering of human-built structures and areas,

Painting roofs white 

Painting roofs white is as green as taking cars off the roads for 50 years, says study

In hot sunny conditions a building can use 10 or 15 per cent less electricity for air conditioning if the roof is a light colour.

A city or town where the roofs and the pavements and roads have light-coloured surfaces can increase their albedo by about 10 per cent, which globally would provide a CO2 offset of between 130 billion and 150 billion tonnes – the same as taking every car in the world off the road for 50 years.  Ref

The independent

If the earth's surface is lightened, there is a long-term global cooling effect of 3 x 10-15  oK for each 1 m2 of a surface with an albedo increase of 1%

This temperature reduction corresponds to an equivalent CO2 emission reduction of about 7 kg over 10 years, 


Cloud making ships

Whitening clouds over the ocean could be accomplished by reducing the size of the water droplets making up the clouds. “Rain clouds, which have big droplets, tend to be grey and absorb sunlight, whereas clouds with smaller droplets tend to be white and fluffy and reflect more sunlight to space,” says co-authorKen Caldeira of the Carnegie Institution’s Department of Global Ecology. “In practice this could be done by shooting a fine spray of seawater high into the air, where the tiny salt particles would create condensation nucleii to form small cloud droplets. More.

Prof Stephen Salter of the University of Edinburgh has a plan to expand the size and whiteness of these clouds using a fleet of remote-controlled,energy-self-sufficient ships. The ships use energy from the wind to propel themselves around and spray minuscule droplets of sea water into the air. These droplets become the nuclei, or "seeds", around which reflexive stratocumulus clouds can form.

Salter believes that if fifty of these ships were built each year the fleet would be capable of increasing the reflexivity of the planet sufficiently to cancel out the temperature rise caused by man-made climate change. 








Engineer Stephen Salter's design for an unmanned ship designed to generate clouds and reflect sunlight away from the earth

Injecting sulphate aerosols into the stratosphere

The global temperature rise has been 0.9oC. If it had not been for the shielding effect of sulphur or sulphate aerosol emissions it would b.e 2oC. These aerosols come from coal fired power plants. So when we finally do replace coal with renewables, we will actually increase temperature for a while due to the cleaning of our atmosphere.

But do we want to maintain this pollution forever?

One idea is to float a balloon the size of a large football stadium 20 KM high and release sulphate particles. This is a diagram of a smaller test using only water. The water pressure in a 20 KM hose will be enormous!  Is there a rope and pipe strong enough?

(I have helped build, and flown a hot air balloon, and know the problems tethering a baloon in high wind. I can't see this scheme as possible. John Davis)

They're dreaming!


Space reflectors

Placing reflectors into space to divert sunlight from the earth is being researched, but most people are deeply uneasy about this idea.