Scientists are testing new geo-engineering technologies - the modification of the earth's climate on a large scale - that, according to them, will be able to limit the effects of global warming, or even cool the planet.

The capturing of CO2 in the atmosphere through artificial tree forests or reflecting sunlight by creating a shield in the mesosphere are some of the new technologies being tested.

What are these processes? How do they work? Is it really already possible? Tested in the laboratory, will they work on a large scale? What are the risks for the planet?

Hear the experts:
Olivier Boucher (France) Sorbonne University / CNRS
Ken Caldiera (USA) Standford University
Klaus Lackner, Shahrzad Badvipour & Allan Wright (USA) Arizona State University 
Graciela Chichilnisky (USA) Global Thermostat
Bergur Sigfusson (Iceland) Reykjavik Energy
Michael Riedjik, Farah Nour & Peter Gross (Canada) Oceaneos
Silvia Ribeiro & Jim Thomas - ETC Group
Robert Wood & Thomas Ackerman (USA) University of Washington
Simone Tilmes, Michael J. Mills & David Hosansky (USA) NCAR
Linda Schneider (Germany) Heinrich Böll Foundation
Gernot Wagner (USA) Harvard University
Leslie Field & Roman Decca - Ice 911
Tim Kruger & Steve Rayner (UK) Oxford University
Kelly Wanser – Marine Cloud Brightening Project

Also available in French: Thermostat climatique