The climate impact of shale gas has to be evaluated in terms of the greenhouse gas emissions that occur during the production of shale gas, as well as emissions released during energy conversion (burning natural gas for power generation). While the latter may be readily compared to other energy sources, CO₂ and CH₄ emission data from shale gas production are scarce. 

Most recent studies indicate that overall shale gas-related greenhouse gas emissions are only slightly higher than those from conventional natural gas, but the lack of production-related emission data is still a shortcoming of all currently available studies on the climate impact of shale gas. 

The viability of using natural gas as a ‘bridge’ to a low-carbon energy system, as well as key concerns that would need to be addressed, are examined in the paper: "Natural Gas: Guardrails for a Potential Climate Bridge" (Stockholm Environment Institute, 2015). Beside technical issues, the authors take economical and political factors into account and recommend guardrails for a successful climate policy including natural gas as a major bridge technology.