Story at a glance
- Researchers analyzed ancient air extracted from within the Greenland ice sheet to measure levels of atmospheric methane before humans started burning fossil fuels.
- They found levels of naturally released methane are about 10 times lower than past research reported.
- Researchers called it positive news, noting humans have more control to cut the powerful greenhouse gas.
A new study claims the oil and gas industry have had a much more dramatic impact on the climate than previously thought, as the amount of methane humans are emitting into the atmosphere via fossil fuels could be as much as 40 percent more than early estimates showed.
The study published in the journal Nature today suggests human-released methane emissions might be 25 to 40 percent higher than past estimates.
“As a scientific community we’ve been struggling to understand exactly how much methane we as humans are emitting into the atmosphere,” Vasilii Petrenko, professor of earth and environmental sciences at the University of Rochester and co-author of the study, said in a statement.
“We know that the fossil fuel component is one of our biggest component emissions, but it has been challenging to pin that down because in today’s atmosphere, the natural and anthropogenic components of the fossil emissions look the same, isotopically.”
Methane is a powerful greenhouse gas and is the second largest contributor to global warming after carbon dioxide. Methane emissions have increased by about 150 percent over the past three centuries, but researchers have struggled to determine exactly where the emissions originate, as methane can be emitted naturally or from human activity.
In order to separate the natural and anthropogenic components, researchers used ice core measurements from Greenland from between 1750 and 2013, as well as previous data from Antarctica, and extracted the ancient air from bubbles inside to analyze the chemical composition. They found almost all methane emitted into the atmosphere was biological until about the time humans started using fossil fuels, until the mid-19th century.
The study found levels of naturally released methane are about 10 times lower than past research reported.
The study’s lead author Benjamin Hmiel called the findings from the study good news.
“I don’t want to get hopeless on this because my data does have a positive implication: most of the methane emissions are anthropogenic, so we have more control. If we reduce our emissions, it’s going to have more of an impact,” Hmiel said in a statement.