READ FULL ARTICLE HERE ====>>>
http://www.newscientist.com/article/mg22429974.000-geoengineering-the-planet-first-experiments-take-shape.html#.VHaavWcveSo
Geoengineering the planet: first experiments take shape
Proposals for the first trials to cool the planet include cloud brightening and spraying aerosols into the ozone layer. They might start in just two years
IF WE can't reduce emissions enough, what else can cool the planet? We need to find out if geoengineering works, and soon, say a group of atmospheric scientists.
Engineering the planet's weather and climate is a highly controversial idea. That's why we need experiments, the group say, and they want the first to start in two years' time. The frontrunners are schemes to alter the atmosphere to reflect more of the sun's rays back into space, or to change clouds so that they let more of Earth's heat out instead of trapping it
(see diagrams).
Last week, the group published a "road map" of proposals for how real-world experiments might be carried out (
Philosophical Transactions of the Royal Society A,
doi.org/xb9).
One would explore the effects of injecting aerosols of sea salt into marine clouds. The aim is to increase the water droplet content of the clouds, making them reflect more sunlight – so called marine cloud brightening.
The second, and most detailed, devised by John Dykema of Harvard University, would explore the effects of injecting sulphur-containing substances at an altitude of 20 kilometres – the lower reaches of the boundary with outer space (
Philosophical Transactions of the Royal Society A,
doi.org/xb8).
The aim of the so-called stratospheric controlled perturbation experiment, or SCoPEx, is to see if sulphate ions would undermine measures to rebuild the ozone layer. The fear is that such substances might set off chemical reactions that deplete the ozone.
The third experiment would explore the potential for making cirrus clouds in the upper atmosphere more porous to radiation bouncing back into space from Earth. Water vapour in the clouds behaves like a greenhouse gas, trapping heat almost as efficiently as carbon dioxide. By seeding them with substances like bismuth tri-iodide, which cause water to form into ice particles, the hope is to reduce the water vapour and allow more radiation to escape.
Geoengineering to cool the planet by deliberately altering Earth's atmosphere is highly controversial, with sceptics fearing it will fail and mess up the climate even more.
Altering cloud cover, for example, could change rainfall patterns and increase droughts and floods unpredictably. Opponents also fear that if we rely on geoengineering solutions, people will no longer strive towards the main goal of dramatically reducing our reliance on the fossil fuels that are inexorably heating up the planet.
in the IPCC's own values for TSI over the last century, which creates reason for pause in thought about their motives.
