Should we envisage shale gas exploitation?

Two points of view about shale gas exploitation are presented. The first one is proposed by an American scientist who outlines that the consequences of shale gas exploitation in the USA are already disastrous, notably in terms of water consumption by hydraulic fracturing (50 to 100 times more water for shale gas than for oil or natural gas), of greenhouse gas emissions (a lot a methane is leaking during this exploitation, and methane has a much stronger greenhouse effect than CO2), of environmental risks (shale gas wells are significantly susceptible to pollute underground waters, and radon is present in shale gas and would be released in housing). The second point of view outlines the lack of knowledge of the French underground, and that it is therefore impossible to assess shale gas reserves and exploitation possibilities