Extraction of Earth's oil, gas and coal
reserves is probably unleashing vastly more methane (CH4) into the air than is currently being
estimated. Methane is a potent greenhouse gas and significant contributor to
the dangerous heating of our planet.
by Larry Powell.
Pump jacks extract crude oil from the Bakken field southeastern Saskatchewan, Canada. Are such operations releasing even more methane than we once thought? A PinP photo.
Using the largest ice drill in the world (below), the researchers “looked back in time” to the 17 hundreds, by drilling deep into the ice in Greenland and Antarctica.
The Blue Ice Drill, used to collect
the cores used in this study.
Photo by B. Hmiel.
By analyzing air bubbles trapped, both in the ice cores and the snow, they were able to measure how much methane was escaping into the air at the time. Since this was the “pre-industrial era,” before major human expansion of fossil fuel development began, those emissions would have virtually all come from natural sources like natural gas seeps from beneath the ocean floor and mud volcanoes (below) and ancient, but mostly undisturbed deposits of fossil fuels.
The findings were surprising. Methane originating from those natural sources were shown to be minimal - only about 1.6 teragrams per year, or 5.4 teragrams, at most. (A teragram is equal to one trillion grams.) As the study concludes, that was "an order of magnitude lower than the currently used estimates." Put another way, those estimates are probably some ten times higher than these new test results show.
Mud volcanoes on the Nahlin
Plateau, BC, Canada.
Are such sites not quite the
they were once considered? Photo by Hkeyser.
Ice cores from the 1870s, however, tell a different story. They show significantly higher methane levels. By then, the industrial revolution had begun, with major extraction of fossil fuels well under way. While fossil fuel extraction would have been the main factor in the increase, other human activities such as rice farming and domestic livestock production would likely also have played a part.
So, the lesson learned from all of this? Emissions due to human activity have been underestimated by anywhere from 25% to 40%. In other words, they are much larger than previously suggested.
Regardless of whether it springs from manmade or natural origins,
methane is still a potent greenhouse gas (GHG), capable of trapping heat and
impacting the climate. And it's up to 36 times more efficient at doing so than is carbon dioxide (C02), the most common GHG. Atmospheric concentrations of methane have more
than doubled since the pre-industrial era.
"The Global Carbon Project" refers to rising methane levels as "an increasingly important component for managing realistic pathways to mitigate climate change. It's an umbrella group of scientific organizations gathering together a common knowledge base in order to "slow down and ultimately stop the increase of GHGs in the atmosphere."
The lead author of this latest research, Dr. Benjamin Hmiel of the
University of Rochester tells PinP that, even after
methane is combusted, it still has an impact. While it no longer exists as methane, it transforms into carbon dioxide, the most common greenhouse gas.
Dr. Hmiel's international team consisted of 19 scientists from eleven institutions.
The researchers hope their findings will "emphasize the human impact on the atmosphere and climate and will help inform strategies for targeted emissions reductions to mitigate the effects of climate change."
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