Financial Times, 19 June 2019:
The main cause of rising atmospheric methane has been the subject of intensive research, but we are not as ignorant as Professor Jonathan Stern makes out. (Letters, June 5). Methane levels plateaued in the 1990s but have been rising again over the past decade by 8 parts per billion a year. Tropical wetlands and fossil fuel releases are both potential sources, but this debate was resolved by a Nasa-led study published in December 2017 which concluded that fossil fuels were contributing more than biogenic sources to the extra methane. Prof Stern is also mistaken if he thinks that oil and gas facilities can provide data that will clarify the amount of methane being released, since ground-based measurements consistently underestimate the extent of leakage. Aircraft sampling and satellite measurements over the US have produced higher values equivalent to 1.5 per cent of natural gas production. This is a crucial observation because methane releases amounting to 2 per cent of production cancel out the climate change benefit of burning gas instead of coal. Fracked gas probably releases more methane than conventional gas due to the greater number of wells. Liquefied natural gas has a larger carbon footprint than coal as the process of liquefying gas is very energy intensive. So the current strategy of the fossil fuel industry, which is to replace coal with gas, and to market LNG as a clean fuel, is based on a total misconception.
Dr Robin Russell-Jones
Scientific Adviser, All-Party Parliamentary Group on Air Pollution,
Marlow, Buckinghamshire, UK