In the midst of the climate crisis, scientists and policy makers must have access to accurate data about patterns in Earth’s past atmosphere. A team of researchers from the Lamont-Doherty Earth Observatory (LDEO) at Columbia University aims to compile all of the best available data on carbon dioxide (CO2) levels in the ancient atmosphere on one website, easily accessible to everyone.
Instrumentation used to directly measure atmospheric CO2 dates back to only the 1950s. For all the millennia before that, scientists must use proxies, often isotope clues left behind in fossils and sediments that allow researchers to reconstruct ancient climates and examine long-term atmospheric trends. These trends, spanning millions of years, help scientists predict how the climate might respond to future changes.
Proxies come from a diverse array of sources—fossil leaves, shells, and soils—and require different types of analyses. The ability to combine different proxies provides a more holistic reconstruction of ancient climate than using just one indicator, but the numerous origins can also create confusion and slow research progress.
“I’ve already been to quite a few talks where I’ve seen people using paleo-CO2 data, and a lot of them have used out-of-date data,” said Ross Whiteford, a postdoctoral researcher at LDEO who presented about the website at the AGU’s Fall Meeting 2019 in San Francisco. “Not that I blame those people at all, because if I were to use data from another discipline, I also wouldn’t know where to start.”
As the LDEO group compiles all proxy data in one central location, they also want to standardize the way scientists analyze and compare different proxies. In some cases, this standardization requires researchers to reanalyze previously published data to fit the new procedures.
“Through time, you get this fragmentation from people doing slightly different things physically with the sample and computationally in terms of processing,” Whiteford said. “Tidying that back up after the fact is quite difficult.”
Once all the published data have been compiled and organized, LDEO researchers will add them to paleo-co2.org. The site came online recently and, researchers say, will continue to grow and evolve. “It’s just very, very bare-bones at this point,” said Bärbel Hönisch, the LDEO geochemist who leads the project.
Paleo-co2.org will eventually contain raw data contributed by scientists around the world, proxy descriptions, plots and data visualizations, and frequently asked questions about paleoclimatology and the proxies used to study it. Interactive graphics, videos, and explanations will help inform students, policy makers, and other researchers about using individual proxies and interpreting the data.
“Nobody is an expert at every single proxy,” said Hönisch. “It’s really an effort to bring people together so that we all understand better how each other’s proxy is working and how much confidence we can place in those estimates.”
The Future of Past Data
In addition to increasing confidence in published estimates, communication between researchers who work with different proxies will also reveal gaps that need further research. “It’s identifying the places where we need funding to fill in the record,” said Jennifer Hertzberg, an Earth scientist from Old Dominion University in Norfolk, Va., who is not involved in paleo-co2.org.
Researchers at LDEO are working with paleo-CO2 data from the past 65 million years, but they plan to extend the database to include data points stretching back 450 million years—the earliest records published so far.
“It’s a massive undertaking,” Hertzberg said, adding that it needed to be done. “It’s reached the point that there were so many people publishing these different types of records based on different proxies that it was the time to bring it all together.”
The project also aims to make climate science more accessible to the public. “What’s exciting to me is to see that small groups of experts like this have enough coherence to come together and make a product that’s going to be easier to understand and to communicate,” said Vicki Ferrini, a geoinformatics researcher at LDEO.
“We all are pretty deep into what we do, and it’s hard for us to distill and simplify and get that message out in a way that’s easily digestible by different communities,” Ferrini said. Through paleo-co2.org, researchers plan to bridge that gap.