Every month, researchers at Lamont-Doherty Earth Observatory and across the Columbia Climate School publish work that deepens our understanding of the planet.
This month, we wrote about the 2026 Environmental Performance Index; how gas bubbles shaped Kīlauea’s 2018 lava flow; and the Pacific’s contrasting effects on wildfires in Australia and the U.S. Southwest.
Here are additional studies by our researchers that are worth noting.
Tiny Plankton Could Affect an Ocean Carbon-Removal Strategy
Scientists are exploring whether adding alkaline substances like crushed olivine rock to seawater could increase the ocean’s capacity to absorb carbon dioxide from the atmosphere. But marine organisms may influence how well this proposed strategy works.
In a new study, researchers grew a species of shell-building plankton called Globigerina bulloides under two ocean alkalinity enhancement scenarios. They found that the high alkalinity caused the organisms to build denser shells and add more calcite as they grew. Because shell formation consumes alkalinity, this response could make the method slightly less effective at removing carbon dioxide from the atmosphere.
Why it matters: Ocean alkalinity enhancement is being considered as a potentially scalable way to remove atmospheric carbon dioxide. The results suggest that estimates of its effectiveness should account not only for changes in seawater chemistry, but also for how marine organisms respond.
“These results offer an exciting first glimpse of how marine life may respond to ocean alkalinity enhancement,” says coauthor Bärbel Hönisch, a paleoceanographer at Lamont and professor in Columbia’s Department of Earth and Environmental Sciences. “But this is one species in a laboratory, not an entire ecosystem, so we need to study more organisms under more realistic conditions before drawing conclusions about large-scale use.”
Other Columbia-affiliated authors: Ingrid Izaguirre and Yoon Kim, students in the Department of Earth and Environmental Sciences at the time the work was conducted.
Wastewater May Have Triggered the Largest Earthquake in Oklahoma From Afar
Oil and gas operations produce saline wastewater that is often injected deep underground for disposal, where it can change the pressure within surrounding rocks and trigger earthquakes. After a magnitude-5.8 earthquake struck near Pawnee, Oklahoma, in 2016, scientists wanted to know whether the wastewater reached the deep fault or triggered it from farther away.
In a new study, researchers used electrical imaging to trace where the wastewater likely traveled underground. They found little evidence that large amounts of wastewater had reached the fault by the time of the earthquake. Instead, the fluid appears to have spread sideways through shallower rock while pressure from the injection led to stress changes that traveled deeper and triggered the earthquake.
“Injection fluid does not have to reach a deep fault to trigger an earthquake. The next step is learning how these far-reaching stresses interact with deep ancient faults and how to incorporate them into safer injection practices,” says lead author Huy Le, a graduate student in Columbia’s Department of Earth and Environmental Sciences.
Why it matters: Underground injection is used for wastewater disposal, geothermal energy and carbon storage. The findings show that assessing earthquake risk requires tracking not only the fluids themselves, but also the stresses they transmit through surrounding rock.
Other Columbia-affiliated authors: Folarin Kolawole, Lamont-Doherty Earth Observatory and Columbia’s Department of Earth and Environmental Sciences; and Kerry Key, formerly of Lamont-Doherty Earth Observatory and now at Deep Blue Geophysics.
The Continents May Have Helped Set the Stage for Earth’s Ancient Ice Ages
Over the past 530 million years, Earth has experienced only a handful of major ice ages, separated by long warmer periods. Scientists have long sought to understand why ice ages appeared when they did—and why they were absent for so long.
In a new review, Lamont geophysicist Dennis Kent and Giovanni Muttoni of the University of Milan, Italy, analyzed 53 reconstructions of how the continents shifted over that period. They found that ice ages tended to occur when land was distributed unevenly between the Northern and Southern Hemispheres. The researchers propose that this imbalance may have promoted extra cloud cover over the hemisphere with more ocean. By reflecting sunlight back into space, those clouds could have compensated for that hemisphere’s darker ocean surface and increased Earth’s overall reflectivity. The planet would then have absorbed less solar energy, making conditions more favorable for large ice sheets.
“Carbon dioxide is the only greenhouse gas scientists have tried to reconstruct across geologic time, but changes in carbon dioxide alone do not consistently explain the timing of ancient ice ages,” says Kent.
Why it matters: The paper seeks to understand why major ice ages occurred—or failed to occur—over the past 530 million years. It evaluates the roles of continental positions, atmospheric carbon dioxide and long-term changes in how much sunlight Earth reflected and absorbed. The findings suggest that plate tectonics, clouds, surface reflectivity and the carbon cycle worked together to shape Earth’s long-term climate.