Limiting human-induced global warming to under 2 degrees Celsius would put an estimated 65% dent in upstream natural gas investment through 2040, according to new analysis by Wood Mackenzie.

Although natural gas is the cleanest-burning fossil fuel, there is more to the story of the molecule’s total climate-warming impact, researchers said Wednesday.

Liquefied natural gas (LNG), for example “ranks among the most emission-intensive resource themes across the upstream sector,” researchers said. “Significant emissions are released through the combustion of gas to drive the liquefaction process” and any carbon dioxide (CO2) removed prior to entering the plant “is often vented into the atmosphere,” they added.

Emissions of the highly potent greenhouse gas methane are...