The report  "Has US Shale Gas Reduced CO₂ Emissions?" from the Tyndall Centre for Climate Change Research calls for a meaningful cap on global carbon emissions in order to take full advantage of the potential benefits from a coal-to-gas switch in power generation. The report examines the recent emissions savings in the US power sector, influenced by shale gas, and the concurrent trends in coal exports that may increase emissions in Europe and Asia. 

US CO₂ emissions from domestic energy have declined by 8.6% since a peak in 2005, the equivalent of 1.4% per year. Part of this decline is related to the switch from coal to gas in US power generation. During this time, there has been a substantial increase in coal exports from the US (2008-2011) and globally, coal consumption has continued to rise. The calculations presented in the report suggest that more than half of the emissions avoided in the US power sector may have been exported as coal.

The report states that "without a meaningful cap on global carbon emissions, the exploitation of shale gas reserves is likely to increase total emissions. For this not to be the case, consumption of displaced fuels must be reduced globally and remain suppressed indefinitely; in effect displaced coal must stay in the ground. The availability of shale gas does not guarantee this. Likewise, new renewable generating capacity may cause displacement without guaranteeing that coal is not burned, but it does not directly release carbon dioxide emissions through generation."