A massive ecological study that's happening across the United States, and which is designed to track the impact of long term changes like a warming climate, is deliberately releasing a highly potent and persistent greenhouse gas in national parks and forests.
The most potent greenhouse gas known to date is sulfur dioxide. It lasts in the atmosphere for thousands of years and is more effective at trapping heat.
The impact of burning more than a million pounds of coal is the same as the release of around108 pounds of gas.
That may not seem like a big deal in the grand scheme of global emissions, but government scientists working at federal parks and forests have objected to using this gas on public lands due to the fact that alternative gasses are readily available.
The kerfuffle has been played out quietly. It comes at a time when all kinds of researchers are thinking about the climate effects of past practices, with some saying that scientists who understand the seriousness of the climate crisis have a special obligation to set an example to the public.
NPR was told by the National Science Foundation that it supports an evaluation to see if phasing out the use of this gas would affect the quality of the information being gathered.
A watchdog group is calling for a halt to the release of this gas on public lands.
We're using a small amount.
In order to study how quickly gasses can move from the water into the air, ecologists have burbled small amounts of sulfur. One reason that's of interest is that, although inland waterways cover only a small fraction of the Earth's surface, researchers believe these running waters could be an important source of greenhouse gasses.
Bob Hall, a professor of stream ecology at the University of Montana, said that they always said that they were using just a tiny amount of sulfur dioxide.
It's perfectly unreactive and we only have to add very tiny quantities to make it that way. Hall once calculated that the amount he used in his experiment had about the same climate impact as burning 35 gallons of gasoline.
The National Ecological Observatory Network, or NEON, is an ambitious government-funded effort to track ecological changes, and it's not surprising that tests involving sulfur hexafluoride were built into the standard protocols of the network. Its goal is to collect all kinds of data on 81 different locations over the course of three decades.
"The idea is to understand the effects of things like climate change, land use change, and invaders on the environment," says Kaelin Cawley, who works at Battelle, the nonprofit applied science and technology organization that operates NEON.
The construction of its monitoring instruments took twenty years to be planned. It started functioning at full tilt in 2019.
According to documents obtained through a public records request by Public Employees for Environmental Responsibility, a scientist at Yellowstone National Park started to question why NEON was releasing sulfur hexafluoride.
The consequences of the environment.
In a November, 2020 email to another National Park Service official, hydrologistErin White pointed out that NEON's protocols called for it to annually release 3.3 pounds of SF6 in the park. White calculated that over the 30-year lifetime of the project, the use of SF6 would be equivalent to burning over one million pounds of coal.
The environmental consequences of a small SF6 application in the park is significant, even though NEON staffers thought it would be difficult to switch to an alternative gas.
It's ironic to study carbon cycling with a lot of greenhouse forcing.
Bob Hall is a professor on stream ecology.
The climate impact from the scientific use of NEON has to be kept in perspective according to Bobby Hensley, who works on NEON for Battelle.
"There's hundreds of thousands of vehicles driving through that park every single day, so I don't want to criticize that park, but, I mean, there's hundreds of thousands of vehicles driving through that park every single day," he said. People can't be told that they can't visit the park. They can tell you not to use SF6.
Government officials shared their concerns with people who oversaw sites where NEON had released the gas. Emails were sent to the Bureau of Land Management and the United States Forest Service. Forest service lands were where most of the NEON sites with streams were located.
According to the National Park Service's Air Resource Division, the release of SF6 will be equivalent to burning millions of pounds of coal over the course of 30 years. If you're aware of this issue, we'd like to hear from you.
Representatives of the park and forest services held a virtual meeting with NEON employees. According to emails sent after the meeting, the public land officials wanted to stop using this gas.
The experts were convened by NEON to figure out if they could stop using the gas.
Hall said that he had moved away from using SF6 in his studies of streams because it was so potent. Hall and a colleague wrote in a paper that it was ironic that they were studying carbon cycling using a tracer gas.
This isn't in line with the mission.
Over time, the physical features of streams don't change much. NEON's advisers decided that it would be okay to just make sure the study used SF6 for each site and then leave it at that, rather than switch to an alternative gas that would require new instruments and training.
"We have discontinued it recently at several of our sites, but not all of them," said Cawley, who noted that the water level in streams might currently be too low to get the data they want. Some of the sites still need to be covered.
Charlotte Roehm, the Program Director for NEON, told NPR in an email that Battelle was evaluating the impact of phasing out the use of SF6 and that the team that manages NEON was supportive of doing that.
The equivalent of greenhouse gas emissions from driving an average car over 460,000 miles is what NEON used in the year 2021. The new plan was for the gas to be used up to three times per year at up to 10 sites.
"Eventually we will stop using SF6 when all sites have enough data to draw conclusions about gas exchange rates across a wide range of flows at a site" stated the memo.
The Public Employees for Environmental Responsibility want them to stop using SF6.
Chandra Rosenthal is the director of the non-profit's Rocky Mountain office. The mission of these agencies is not compatible with this.
She says that the government workers who manage those federal lands are not happy about the use of this gas.
Her group sent a letter to the director of the National Science Foundation asking them to stop funding projects that use SF6 on federal lands and to assess the value of using SF6 and other greenhouse gasses. The letter was sent to the Secretary of the Interior and the Secretary of Agriculture. The letter says that similar research projects have switched to argon.
One researcher who uses small amounts of SF6 for studies of gas exchange in the ocean, rather than streams, thinks NEON's protocols could have been set up differently.
I wouldn't do it the same way. David Ho, an oceanographer with the University of Hawaii, said that he wouldn't be bubbling it in because it would use a lot. They haven't considered the best way to do it.
Even if the amount that's been released by NEON and other scientific studies is nothing compared to the amount of SF6 released globally from industrial sources, the concerns about it still seem reasonable to streams researcher Walter Dodds.
It is completely understandable that it may be an overreaction. Dodds says we all worry about what our own footprints are. We should be aware of the potential for harm and minimize the amount of times we use it and the amount of gas that we use.
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