Environment

NASA Just Took Away a Major Argument Used by Climate Change Deniers

New satellite studies give us a much better picture of exactly how humans are changing the planet.

Many climate change deniers debate whether humanity has played a significant role in changing environmental conditions. In the past, it has been difficult to parse out mankind's contribution to carbon emissions from changes caused by the Earth’s own natural climate system. Now, thanks to new research provided by a NASA satellite, we may have found the definitive answer to that question.

Using information gathered from NASA’s Orbiting Carbon Observatory-2 (OCO-2), a team of researchers from Michigan Technological University recently published the results of five studies in the journal Science. Due to the massive amount of data provided by this three-year NASA mission, the researchers have been able to track global CO2 emissions from both natural and industrial sources.

NASA's OCO-2 carries a single instrument consisting of three high-resolution grating spectrometers that measure properties of light within the electromagnetic spectrum. (image: NASA)

It’s all thanks to that industrious OCO-2 satellite. Since 2014, OCO-2 has been orbiting Earth over 14 times a day, gathering around 100,000 measurements each time and allowing scientists to observe CO2 concentrations in hard-to-reach areas such as the middle of the ocean and the Amazon rainforest. As a result, for the first time ever, we now have a complete map of how carbon dioxide moves around in our atmosphere, particularly with regards to how the gas is absorbed and emitted.

So what have we learned? For one, we now have an idea of how the shifting patterns in tropical Pacific Ocean temperatures that precipitate El Nino storms affect global CO2 levels. There’s also information on how plant photosynthesis has begun to respond to the increased amount of carbon present in the atmosphere. Another significant find from one of the studies has to do with CO2 produced by volcanic eruptions.

Power plants more harmful than volcanos

“Many people may not realize that volcanoes are continuously releasing quite large amounts of gas, and may do so for decades or even centuries,” said volcanologist Simon Carn, a Michigan Tech professor and a lead author of the study. “Because the daily emissions are smaller than a big eruption, the effect of a single plume may not seem noticeable, but the cumulative effect of all volcanoes can be significant. In fact, on average, volcanoes release most of their gas when they’re not erupting.”

In the past, this fact has been used to fuel a myth that volcanoes are the main culprits when it comes to the production of greenhouse gases. Until OCO-2, it’s been impossible to completely rule out this theory by measuring exactly how much carbon dioxide volcanoes produce. One of the published studies chose to focus on this precise question, and found that power plants actually contribute far greater amounts of CO2 to the atmosphere than passive volcanos do.

“The highest emitters [among] the volcanoes are equal [to], or superseded by, about 70 fossil fuel power plants on Earth,” Florian Schwandner, the paper’s lead author, told Bloomberg. “What that shows us is that volcanoes are likely not a significant source of CO2.”

Overall, the study found that volcanoes emit around 540 megatons of carbon dioxide a year—a paltry amount compared to the 38,200 megatons produced by humans.

Solving scientific puzzles

Equipped with this knowledge, we now have a much better picture of exactly how humans are changing the planet. In the past, for instance, using ground-based monitoring devices meant it was difficult to differentiate between urban and rural pollution. But with the data from the satellite, we now know that cities produce over 70 percent of humanity’s CO2 emissions.

“This is really a first for the carbon cycle community,” Abishek Chatterjee, a scientist at the University Space Research Association, told The Verge. Chatterjee co-authored one study that looked at how an El Niño had affected the ocean. A major question scientists sought to answer in the past was how CO2 levels changed during tropical storms in terms of land and ocean absorption. Thanks to OCO-2, Chatterjee said, “[we] have solved that critical scientific puzzle.”

The major implication of these findings is how they can help predict changes brought about by global warming—information that will assist policymakers to put forward plans to help communities be better prepared.

Another finding from one of the studies measured CO2 levels over Los Angeles. The results found that in winter, plants absorb less CO2, which means higher levels in the air. This observation may not seem particularly useful, but it highlights the speed with which the OCO satellite can scan cities for pollution and improve subsequent response times.

A great example of how this could help, explained Schwandner, has to do with monitoring active volcanoes. Having already observed the Yasur volcano in Vanuatu, researchers now have accurate measurements of how much CO2 the volcano produces a day. If those levels were to suddenly drastically rise—a clear sign of volcanic activity—scientists could predict an eruption. “We can’t stop a volcano, but we can evacuate people,” Schwander said. “And the earlier we get the heads-up, the better.”

This is just one example of the ways in which this innovation in CO2 observation might assist humanity in the future. While it’s not going to dig us out of the mess we're in, it brings us one step closer to identifying the extent of our climate change condition. And just maybe, with more knowledge will come acceptance, and who knows, maybe even action.

Robin Scher is a freelance writer from South Africa currently based in New York. He tweets infrequently @RobScherHimself.