Turkmenistan methane point source detections and retrievals from Landsat 5 (1986-2011)

Global atmospheric methane concentrations rose by 10-15 ppb/yr in the
1980s before abruptly slowing to 2-8 ppb/yr in the early
1990s. This period in the 1990s is known as the "methane
slowdown" and has been attributed to the collapse of the former
Soviet Union (USSR) in December 1991, which may have decreased the methane
emissions from oil and gas operations. Here we develop a methane
plume detection system based on probabilistic deep learning and
human-labelled training data. We use this method to detect
methane plumes from Landsat 5 satellite observations over Turkmenistan
from 1986 to 2011. We focus on Turkmenistan because economic data
suggest it could account for half of the decline in oil and gas emissions
from the former USSR. We find an increase in both the frequency
of methane plume detections and the magnitude of methane emissions
following the collapse of the USSR. We estimate a national loss
rate from oil and gas infrastructure in Turkmenistan of more than 10% at
times, which suggests the socioeconomic turmoil led to a lack of oversight
and widespread infrastructure failure in the oil and gas
sector. Our finding of increased oil and gas methane emissions
from Turkmenistan following the USSR's collapse casts doubt on the
long-standing hypothesis regarding the methane slowdown, begging the
question: "what drove the 1992 methane slowdown?"