Scientists at the UK’s National Physical Laboratory are using monitoring equipment to track our impact on the planet more accurately than ever before.
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Photograph: J.L. Lee/NIST
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Scientists at the National Physical Laboratory in Teddington, South West London, are using precise monitoring equipment to measure pollutants and track our impact on the planet more accurately than ever before.
The lab's latest tool is Boreas, a laser spectrometer designed to collect and analyze methane—a greenhouse gas emitted by dozens of human activities, from agriculture to burning fuel. At an unassuming telecommunications tower in Heathfield, Surrey, Boreas works 24 hours a day in all weather conditions to sample large volumes of air.
The machine uses a length of tubing filled with fine plastic beads, which is then cooled to -160 degrees Celsius, allowing researchers back at NPL headquarters to cryogenically separate the methane particles from oxygen and nitrogen, which freeze at much lower temperatures.
The aim is to determine the relative concentration of different methane molecules and gain a better understanding of where the pollutants are coming from, explains Emmal Safi, a higher research scientist at NPL. “While previous devices have been able to measure methane concentrations, that data alone doesn’t tell us much about what the source of methane is,” she says.
Methane is a molecule composed of one carbon atom surrounded by four hydrogen atoms (its chemical formula is CH4). There are, however, different types of methane in the air, called methane isotopologues. “Different processes make methane with very small differences in the relative amount of each isotopologue, so the relative proportion of each can be used as a signature to determine its source,” says Safi.
So far, the readings are showing researchers what they’d expected: “We are seeing methane that has the signature of the northern hemisphere background—relatively clean air from the Atlantic—and some local agricultural sources,” says Chris Rennick, also a higher research scientist on the Boreas team. “It depends on the direction of the wind on any given day.
What makes Boreas unique is its potential: In the future, NPL hopes to build more devices like it and deploy them to different regions, including the Arctic, where potentially large amounts of methane could be trapped in permafrost.
“We’re using the data from our Heathfield lab to contribute to the UK’s methane emissions estimates,” Rennick explains. “However, there are many other networks in many other countries which would also benefit from the measurements that Boreas can make—this would allow the instrument to help reduce global methane emissions.”
Boreas is one of dozens of unique pieces of equipment measuring pollutants at NPL. One of the most historically significant is the Kibble Balance, a set of high-precision scales developed in the 1970s to compare electrical and mechanical power. Fifty years on, the device is used to weigh individual air particles to determine methane concentrations.
The key role of researchers such as those working on Boreas is not to conduct climate research, however, or even to present evidence of climate change itself. They are metrologists by trade—there to study and monitor the science of measurement to keep the science as accurate as possible.
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In doing so, metrologists act as the gatekeepers to “absolute truth” as Richard Barker, head of energy and environment at NPL, describes it. “Scientific measurement is the discipline trying to get as close to the truth as possible,” he explains. “What we do is figure out how close are we to that?”
If that sounds philosophical, it is. Most of us will never question why a gram is a gram or a kilometer is a kilometer. But for metrologists like Barker, the accuracy of these measurements is an ever-evolving conversation. When world leaders met in Glasgow to discuss climate action at COP26, Barker was there too, making the case for greater accuracy in scientific measurement.
Historically, NPL has been responsible for calibrating the way we measure and determining the terms with which we do so—grams, meters, seconds, and so on. More recently, the lab has named greenhouse gas emissions measurement as one of its key focus areas.
The move came from a growing realization that predictions about the rate of climate change were being made purely on statistical modeling, with no indication of certainty. “Just look at the magnitude of the questions that we're asking and the scale of investment that governments and industry are going to have to make to address climate change—we are talking trillions of dollars,” Barker says. “It raises this question of how close to the truth are we?”
While scientists can take a measurement such as sea temperature and recognize an increase, the variability caused by external factors and unreliability of instruments used means that it typically takes 20 years for a trend like rising sea temperatures to be agreed upon as fact—which doesn’t leave much time for nations to meet net zero targets.
Barker has an even bigger idea up his sleeve: Through the European Space Agency’s Truths Mission, the NPL plans to send reference equipment into space to allow satellite measurements to be recalibrated in orbit. The hope is that the mission will create a tenfold improvement in the accuracy of environmental observation data.
Ultimately, scientists will no longer have to wait so long to make forecasts or determine a trend in temperature changes—which could have a major impact on the pace of climate action. “Metrology is largely invisible, but it’s integral to all that scientists do,” Barker says.
Links
- Now is the time to ensure accuracy, traceability, consistency, and confidence in climate measurement
- Supporting the transition to decarbonised energy sources
- Understanding emissions from agriculture and observation of land systems
- New methane concentration technologies to support greater understanding of the UK greenhouse gas emissions inventory
- Environmental monitoring: UK NPL-EAM develops new spctrometry instrument Boreas
- New methane enrichment technology for monitoring greenhouse gas emissions
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