After tracking greenhouse gases emissions in the Earth’s atmosphere for more than 30 years, Pieter Tans says there are three things he knows for sure.
First, “humans are 100% responsible for the increase in greenhouse gases we are observing,” said the chief of the Carbon Cycle Greenhouse Gases Group at the National Oceanic and Atmospheric Administration.
He explained that scientists know this thanks to ice. Research on bubbles of air trapped in ancient ice show that, for millions of years, the amount of carbon dioxide in the atmosphere ranged from 180-280 parts per million. Since humans started burning fossil fuels in earnest during the Industrial Revolution, that number has risen to 400 parts per million.
A scientist checks a sample canister in the Carbon Cycle Greenhouse Gases lab.
The second is a matter of basic physics: More greenhouse gases, like carbon dioxide and methane, means more heat trapped in the atmosphere and higher global temperatures. “We understand in great detail how greenhouse gases absorb radiation,” Tans said.
Third, they know that those gases are going to stick around for a long time. Plants and oceans are constantly pulling carbon dioxide out of the air, but the amount produced by humans has far overwhelmed natural process. That excess is going to remain in the atmosphere for thousands of years, Tans said, multiplying the climate-changing effects of continued carbon production.
Which leads him to one final conclusion.
“I know that we have a very serious predicament globally,” Tan said. “I know this.”
The way out of that predicament is for humans to reduce emissions of greenhouse gases by ending their reliance on fossil fuels, he said. He’s got a lot of advice on how that can be done, from retrofitting buildings to use less energy, to improving public transportation systems around the world.
But Tans’ personal contribution to the effort starts much earlier than that. He and his colleagues spend their days tracking greenhouse gases and ozone-depleting compounds, in part to help policymakers decide whether emissions reduction efforts are succeeding.
That tracking is done with great precision and transparency, starting in their Boulder lab. There are more than 70 air sampling points around the world, and more than 30 labs analyzing those samples. Tans’ team must make sure all of their machines are producing accurate readings.
Lining the walls of the NOAA lab are tall canisters with known quantities of gases, which the staff uses to calibrate their machines every morning and throughout the day between tests. The goal is to create canisters with standardized air samples, which are sent out to partner labs. If the measurements of the standard samples at the partner labs match the measurements from Tans’ lab, everyone is on the same page.
The data collected is available directly to the public on the group’s website. Tans said they don’t hand-select data before publishing it, and even results they have flagged as potentially having issues are still available.
“Nothing we do is secret - everything is out in the open on the web,” he said. “If we want to guard against climate deniers and high-priced lawyers, one of the defenses is that everything is transparent.”
With all that he knows about greenhouse gases, it can be hard for Tans to see the world – and especially the U.S. – not taking climate-change research and policy more seriously.
But Tans said he’s not stopping now. He and the rest of his research network will continue to collect their samples, calibrate their machines and report their findings to the world.
“I’m not really discouraged,” he said. “I’ll just keep doing the best I can.”