Atmospheric methane is rocketing and the climate change implications are huge

A new study has revealed that atmospheric methane levels increased substantially over the last four years, raising questions over whether the Paris Agreement goals can be met. According to the research, the increase in atmospheric methane started in 2007, but accelerated 'very rapidly' starting in 2014, persisting at that clipped rate through 2017. The reasons for this surprise increase remain unclear.

The findings were detailed in a study recently published in the journal Global Biogeochemical Cycles, where researchers report that the atmospheric methane rise happened at rates that haven't been seen since the 1980s. Though the growth happened globally, there were particularly notable increases in the northern mid-latitudes and tropics.

The reasons behind this increase aren't entirely known, though the researchers say it may be due to increased emissions and possibly a drop in the destruction of atmospheric methane. There's a key concern behind this noted increase, and it's that the rise since 2007 was not anticipated as part of the future greenhouse gas scenarios related to the Paris Agreement.

The scenarios that would enable meeting the Paris Agreement climate goals didn't factor in an increase in atmospheric methane levels. Though the atmosphere contains less methane than carbon dioxide (CO2), it is particularly adept at trapping heat, making any increases a big problem. Methane emissions result from both natural sources and human activities, including raising cattle and running fossil fuel systems.

A rise in atmospheric methane began in the 19th century, rising slowly up through the mid-1990s, at which point they stagnated at approximately 1775 parts-per-billion (ppb). Efforts to address greenhouse gas emissions resulting from human activities were expected to trigger a trend in lower atmospheric methane levels. That didn't happen, though, and scientists noted a slow increase starting in 2007.

According to this latest research, the rate of this increase started accelerating in 2014 and continued to do so through 2015, 2016, and 2017. Overall, the atmospheric methane levels increased from 1775 ppb in 2006 up to 1850 ppb in 2017. No single explanation for the increase has been presented, but experts continue to investigate the cause.