Enhanced weathering: When climate research takes unexpected turns

Enhanced weathering: When climate research takes unexpected turns

By Brittany Edelmann and Carly Menker, Dec. 5, 2021 –

Oxford University Ph.D. student Frankie Buckingham collected the 30, 1-meter-long cylindrical tubes of soil she needed for climate research in August 2018 on a British farm in North Oxfordshire. The farm had previously cultivated oats and barley in the soil. A variety of crushed rocks and minerals, such as basalt, olivine and volcanic ash, were added to the 30 cores and then positioned on the roof of Oxford’s Earth Sciences Department building. From October 2018 to June 2021, Buckingham analyzed the soils to watch for the effects of enhanced weathering on climate change impacts. But, what she found wasn’t quite what she expected.

Buckingham’s study focused on “enhanced weathering” as a carbon dioxide removal technique involving the application of crushed rock to agricultural soil.

Carbon dioxide in the atmosphere is a thermostat for climate change, holding in heat that drives global warming and driving changes in our climate as we know it. Carbon dioxide levels today are more than 35% higher than at any point in at least the past 800,000 years and rose 30% just since 1970. The last time the atmospheric CO2 levels matched today’s concentrations was over 3 million years ago, during the Mid-Pliocene Warm Period. Temperatures then ranged from 2 degrees to 3 degrees Celsius (3.6 degrees to 5.4 degrees Fahrenheit) higher than during the pre-industrial era and sea level leveled off at 15 to 25 meters (50 to 80 feet) higher than today, according to the National Oceanic and Atmospheric Administration (NOAA).

Enhanced weathering is a process that aims to accelerate natural silicate weathering during which carbon dioxide reacts with rocks, a process that usually takes millions of years. Silicate weathering begins with the reaction between water, carbon dioxide and silicate rocks, which breaks down the rock. Eventually, the dissolved components are washed into the ocean where the carbon is stored for hundreds of thousands of years, either as mineral sediments or dissolved in the water, according to Buckingham. Enhanced weathering amps up this process by breaking down silicate rocks, such as basalt, into tiny pieces in a way of skipping slow weathering processes. The powder made from this is spread on agricultural land and the process can be further accelerated by fungi and roots in the soil.

Buckingham, on the roof of her research building, extracts water from the soil cores for further analysis of enhanced weathering processes. (Photo credit: Frankie Buckingham)

As a young child, Buckingham was already interested in climate change. She obtained a master’s degree in Earth Sciences from the University of Oxford, focusing on past periods of climate change and studying cave deposits.  During her Ph.D. program, she switched gears to try to answer the question of “how we might be able to prevent rising global temperatures?”

“The emergency of the climate crisis makes it a thrilling area to work in,” Buckingham said.

Buckingham started her presentation about her research at the 2021 Comer Climate Conference talking about The Paris Agreement, an international treaty pledging to limit greenhouse gas emissions so that the average global temperature rise is kept under 2 degrees Celsius and preferably under 1.5 degrees. Despite having already sparked low-carbon solutions and new markets, there are still many actions that need to be implemented, one of them being negative emission technologies to help remove carbon dioxide from the atmosphere. This is where enhanced weathering comes in.

Buckingham’s results so far focus strictly on crushed basalt instead of crushed olivine, which most researchers have used. Why has research favored olivine? It has been shown to dissolve the quickest, absorbing CO2 in the process, Buckingham said. But further research indicated that olivine releases harmful chromium and nickel into the soils, something that takes a toll on the environment.

Assumptions made from previous research using simple experiments conducted in the laboratory – beaker experiments – gave a more optimistic view of the weathering process, Buckingham said. Her research differed because it was conducted in a way that was “as close to the field (as) you can get.”

Buckingham explained findings on why some mineral treatments dissolve quicker. She connected her field research back to beaker research with olivine, which revealed that olivine is one of the mineral that dissolves the quickest. Contrary to original expectations, Buckingham’s research showed crushed basalt actually dissolves three to four orders slower than previously expected.

Buckingham cuts soil core into 10-centimeter segments and measures for different physical properties. (Photo credit: Frankie Buckingham)

She elaborated on how many current enhanced weathering calculations assume that basalt can be applied to crops year after year – safely compared with olivine – and that it will dissolve. But, when looking at the crushed basalt in the soil cores, her research revealed that 99% of the crushed basalt does not dissolve.

“Within 50 years, you will have 25 centimeters (10 inches) of a basalt layer,” Buckingham said, which can affect agriculture and farmers who use the crushed basalt in their soil.

Previous thinking also expected the dissolution products (the components that separated from the rock) to travel from the soil into the oceans to help stem ocean acidification and increase the pH content within the ocean water. By consuming acidic ions during dissolution and by releasing important ions such as calcium and magnesium,  enhanced weathering sequesters CO2  and helps counteract ocean acidification.

But, Buckingham found that the “dissolution products were retained in the core.”

“The dissolution products can be sticky and can be chemically removed from the water,” Buckingham said, which prevents the dissolution products from getting into the oceans.

Negative emission technologies

Enhanced weathering is one type of negative emission technology to remove CO2 from the environment. And, as Buckingham’s research shows, more than one process is needed to have an impact on the pace at which the world generates CO2 emissions from fossil fuel use. There are “a plethora of negative emissions technologies” to help combat climate change, according to Buckingham. We cannot rely on just one, she said.

Some other examples include planting new trees, biochar, ocean alkalinization and bioenergy carbon capture and storage. Mature trees don’t sequester carbon dioxide as quickly, so this is where young trees come in to help. Organic material is burned into biochar, which then locks up the carbon. Ocean alkalinization can help to draw down carbon dioxide by spreading alkaline crushed rocks directly into oceans, which ultimately will raise the alkalinity of the ocean water. Bioenergy with carbon capture and storage (BECCS) is a process where biomass, such as crops or wood, that sequester carbon dioxide when grown, are burned for heat and electricity. The carbon dioxide emitted during burning is captured and transported for underground storage.

Where do we go from here?

Buckingham emphasized how her research shows that enhanced weathering may not draw down as much carbon dioxide as previously anticipated and can have “major impacts to soil chemistry.” But “that’s not a reason to lose hope,” she said. Her research was done in the U.K., as opposed to a warmer, more humid climate like the tropics. In tropical climates, more CO2 is drawn out faster due to the quicker breakdown of crushed rock and minerals.

Research is done to figure out answers to questions. The hope is that positive findings result, she said.

This research showed different results from previous assumptions. Jeff Servinghaus, professor of Geosciences at the Scripps Institution of Oceanography at the University of California, San Diego, expressed gratitude to Buckingham at the conference.

“It’s very important work, because you know if we chase down dead ends, that’s just wasted time and money, right? So thank you for that,” he said

Geologist Richard Alley, emcee of the Comer Conference and a geosciences professor at Pennsylvania State University, said the more research that is done, the clearer it is that it’s easier to keep carbon dioxide out of the air than taking it out.

“If you can enrich your soil that’s good and if you can take a little carbon dioxide down that’s great, but don’t count on that to solve the problem,” Alley said.

“And although this might sound quite negative, it highlights the more realistic situation that we need to be aware of,” Buckingham said.

Brittany Edelmann is a registered nurse. She is health, environment and science reporter and a Comer Scholar at Medill. Follow her on twitter @brittedelmann

Carly Menker is a health, environment and science reporter for the Medill News Service and a Comer Scholar at Medill.  Follow her on Twitter @carlymenker.

COVID-19’s minimal climate impact highlights need for momentous action now

COVID-19’s minimal climate impact highlights need for momentous action now

By Liam Bohen-Meissner, Jan 28., 2021

PODCAST  Global carbon dioxide emission dropped 7 percent worldwide due to a decrease in human activity after COVID-19 brought much of the world to a standstill. Despite this, the climate impacts of COVID-19 turned out to be negligible, with 2020 tied with 2016 as the hottest year on record. Global temperatures have risen 1 degree Celsius (1.8 degrees Fahrenheit) over the past decades and are expected to meet or exceed the 1.5 degree ceiling set by the Paris Climate Agreement by 2030 without drastic decreases in fossil fuel emissions..

If a global pandemic is not enough to put a dent in climate change, then what hope do we have? Local Illinois climate experts provide their insight on what changes must be made if we are to succeed in this battle with the climate crisis.

Liam Bohen-Meissner is a health and politics reporter at Medill.

Melting glaciers on Mount Everest could threaten freshwater for millions and world economies

Melting glaciers on Mount Everest could threaten freshwater for millions and world economies

By Shivani Majmudar, Dec. 18, 2020 –

Amid this year’s global pandemic, the world is also fighting more frequent and severe hurricanes, larger wildfires and prolonged heat waves—indicative that climate change is real and it’s happening now.

“We’re at the blinking yellow light,” said Laura Mattas, a graduate research student at the University of Maine’s Climate Change Institute.

Mattas studies the Khumbu Glacier, located on the Nepalese side of the Himalayan mountain range. She’s working to identify and document its movement during the Last Glacial Maximum, the last period when ice sheets were at their greatest extent. The retreat of past glaciers provides scientists with the clues they need to predict the social and economic impact of human-driven accelerated climate change.

Her preliminary research, which she presented at this year’s virtual Comer Climate Conference, suggests this was between 18,000 and 23,000 years ago.

As warming temperatures and increased greenhouse-gas emissions melt glaciers, it also depletes the freshwater supply upon human and wildlife communities depend. (Shivani Majmudar/MEDILL)

Glaciers are strong measures of the total energy in a system because they respond to global temperature and precipitation fluctuations. In recent decades, glaciers have retreated significantly, as Earth’s rising average temperature melts ice more quickly than snow accumulates to replace it.

Beyond a marker for change, glaciers also provide a critical human and ecological resource: freshwater. As glaciers melt, not only are oceans desalinated to some degree, impacting the viability of marine life, but freshwater flowing into the oceans is lost in the salty mix. Water that millions of people rely on for household consumption, agriculture, and electricity is slowly draining.

The ripple effect of high glacial activity can even have far-reaching impacts on economic stability. For example, the eventual depletion of a primary source of water will cause a dramatic disruption of the supply chain that serves as the backbone of the economies of China, India, and the other countries that rely on water from the Hindu-Kush-Himalaya mountain range. Consumer prices would likely rise to counterbalance the expense of importing freshwater or desalinating seawater.

Melting mountain glaciers pose the same threats across the world. Closer to home, the mountains of California and Colorado are rapidly losing snow pack. Without action to slow climate change, serious environmental, health and economic consequences remain at stake.

Mattas is one of many environmental researchers studying the past to help inform our climate future at a time when the urgency for climate policy is assaulted by wavering acceptance of science. Veteran climate scientist Richard Alley, a professor at Pennsylvania State University and the master of ceremonies for the annual Comer Climate Conference, argues that climate history is the most reliable predictor of our future environment and the strongest asset to rebuild public trust in science.

“We need to keep people’s minds on the fact that we can solve these problems if we deal with them,” Alley said. “We’ve been successful in the past when we have used science and we have gotten along with each other.”

Mattas is particularly interested in the Khumbu Glacier because of its unique location. It is surrounded by both the cold atmospheric temperatures of the Himalayan mountain range and hot air masses from the warmest waters on Earth, the Indo-Pacific warm pool. This climate positions the mountain glacier well as an incubator of climate change around the world.

Freshwater from the glaciers of the Hindu-Kush-Himalayas feeds into the largest rivers across Asia, including the Ganges and Brahmaputra in India and the Yellow and Yangtze River in China. It directly supplies water to almost 2 million people.

Mattas’ research mapping the patterns and rates of glacial activity requires a combination of field work and data analysis. In April 2019, she and her team trekked the Khumbu Glacier in Dingboche, Nepal to collect samples of moraine—a landscape of rocks, gravel, and dirt that were once embedded in a glacier’s base but are gradually deposited at the glacier’s terminal edge, leaving a trail as it moves.

Glaciers retreat first in thickness before physically melting away. The team found that the modern Khumbu Glacier has approximately 600 meters less snow accumulation than during the Last Glacial Maximum, when the glaciers began to retreat about 18,000 years ago, evidencing how the glacier is shrinking as a result of the warming climate.

Moraines, signature hedges of rock cast off by the melting glaciers, also offer valuable insight into how long ago the rock emerged from the ice and has been exposed the air. The team measures the amount of Beryllium-10 in the sample, an isotope that forms in quartz when high-energy cosmic rays in the Earth’s atmosphere hit its surface. The concentration of 10Be offers a time machine for tracking how long the rock has been ice-free. Scientists call this clock cosmogenic nucleotide dating.

Additionally, they performed detailed photogrammetry, mapping that used the highest-resolution drones to have ever captured Mount Everest. Sampling and analyzing the rocks in the moraines surrounding the modern Khumbu Glacier allowed Mattas and her team to create a chronological, geomorphologic map of the periglacial and glacial landform activity in the Dingboche, Nepal, region.

The high-resolution drone Mattas and her team used was critical for their mapping and photogrammetry efforts. The image of the moraines at the Khumbu Glacier were the drones captured (right) were much more detailed than the most recent Google satellite image of the same area (left). (Laura Mattas/University of Maine)
A preliminary version of Mattas’ chronological, geomorphological figure, mapping the timing and extent of the Last Glacial Maximum for the Khumbu Glacier. From the inward to outward moraines, or most to least glacial movement, moraines formed around 18, 29, 36, 37, and 67,000 years ago. (Laura Mattas/University of Maine)

The preliminary 15 ages of moraines documented thus far suggests the timing of the Last Glacial Maximum for the Khumbu Glacier is consistent with similar research of glaciers around the world. Maps like the one Mattas has created are not only helpful for scientists to understand the rate and extent of glacial activity due to climate variability, but also serve as an important visual tool for the public and policymakers to recognize one impact of changing environmental conditions.

“[Maps] can tell us whether we need to prepare for giant floods and make flood walls or if this is a slow-moving process where we just raise the river banks,” Mattas said, The faster we can answer these questions, the better we can protect the communities who would be directly hit, she added.

Shivani Majmudar covers health, environment and science at Medill. You can follow her on Twitter at @spmajmudarr.

Next generation climate scientists study Earth’s responses to rapidly rising temperatures

Next generation climate scientists study Earth’s responses to rapidly rising temperatures

By Grace Rodgers, Dec. 18, 2020 –

In a race against climate change, Yuxin Zhou, 26, is among the next generation of climate scientists studying the Earth’s responses to rapidly rising temperatures, threatening life on the planet.

As a fifth-year Ph.D. student at Columbia University’s Lamont-Doherty Earth Observatory, studying how the Earth’s climate behaved in the past is the best way for Zhou to understand the pace and consequences of climate change today.

In a similar way, to understand Zhou’s pathway into climate science, it’s important to look back on his journey to the present.

After graduating high school in Nanjing, China, Zhou moved to the United States to study computer science at the University of Southern California, Los Angeles. However, less than one year into the undergraduate program, he switched to geological sciences, inspired by his first earth science class.

“My deepest memory is my professor talking about his experience going into a submersible for research. He said it’s like looking down from an airplane onto New York City streets because it’s bustling with life,” Zhou said. “It was really that class that captured me and helped me become interested in earth science.”

Yuxin Zhou and Pablo Alasino working performing field work in Argentina.
While in Argentina as a University of Southern California undergraduate student, Zhou worked with professor Pablo Alasino (left) on geological mapping. (Yuxin Zhou//Columbia University)

While in undergrad, he also participated in multiple research opportunities in geochemistry, one of which was a summer fellowship at the Woods Hole Oceanographic Institution. He also gained publications in Nature Geoscience and Journal of Geophysical Research – Atmosphere.

From there, he moved cross-country to pursue a degree in earth and environmental sciences at Columbia University’s Lamont-Doherty Earth Observatory just outside of New York City.

“I just really wanted to continue to do the research, and earning a Ph.D. was the natural next step,” Zhou said.

As a current fifth-year Ph.D. student, Zhou’s research focuses on the factors destabilizing the circulation in the North Atlantic, spanning the past 150,000 years

Jerry McManus, a geochemistry professor and researcher at Lamont-Doherty, works closely with Zhou as his research advisor and has seen his growth as a young scientist in the field.

“He started his Ph.D. working on more recent climate issues, and then became interested in paleoclimate and in geochemistry. He’s gone up a learning curve and has done brilliantly,” said McManus. “I work with wonderful, bright junior people, and if I can stay out of their way and help them to do their great work, then that works out the best all-around.”

Yuxin Zhou standing at a podium presenting his research at the Goldschmidt geochemistry conference in Barcelona.
While at the Goldschmidt geochemistry conference in Barcelona, Zhou presented his research on the history of iceberg discharge in the western North Atlantic. (Athena Nghiem//Columbia University)

In early October, both Zhou and McManus presented their new research at the Comer Climate Conference, an annual summit where climate scientists from around the world gather to present emerging research.

Zhou’s presentation focused on his new method to track and measure the amount of freshwater released by melting icebergs following Heinrich events. Icebergs break off from glaciers into the ocean all the time, but Heinrich events are special in that a large number of icebergs do so in a short amount of time. These events can impact ocean circulation and in turn, weather temperatures, storms and rainfall across the globe.

Unlike existing research on iceberg melting in the North Atlantic, Zhou’s new method measures the amount of freshwater and the location of freshwater released. Much of his research is based on new and previously published measurements of sediment cores collected from ocean floors in the North Atlantic.

In measuring these sediment cores, Zhou can identify specific elements and isotopes within sections of the core that correlate to the amount of freshwater released by melting icebergs during a certain period of time. The correlations follow past ice ages and warm spells, which can help predict the pace of climate change today.

“I have the opportunity to use and apply cutting edge technologies to analyze the cores,” Zhou said. “It’s very inspiring to me because you’re not thinking about your own or your own generation’s scientific career, but 10s of years in the future.”

While at Lamont-Doherty, Zhou has worked alongside Celeste Pallone, a 2nd-year Ph.D. student.

“The biggest things I’ve learned from his work is both how he does lab work, but also how he organizes and prepares his data,” said Pallone. “I’ve learned what kind of statistical methods he uses to back up his claims, and just how to do good science.”

Yuxin Zhou standing at a booth with Jennifer Middleton presenting their research at the annual Lamont-Doherty Earth Observatory open house.
During the annual Lamont-Doherty Earth Observatory open house, Zhou worked with a team (right: Jennifer Middleton, a postdoc researcher) on an exhibition about iron availability in the ocean. (Yuxin Zhou//Columbia University)

In addition to earning his Ph.D., Zhou hopes to remain in academia, working with students in science. For the past two years, Zhou has volunteered for the nonprofit Girls Who Code, teaching high school girls how to create a website. He has also worked as the Graduate Student Committee chair at Lamont-Doherty Earth Observatory, advocating for student concerns to the department and pushing for student representation on hiring committees.

“Having an inclusive teaching environment and active learning experience is very important to me,” Zhou said. “We want to make sure that hiring has a certain voice on it, and hopefully, that will translate to more diversity, equity, and inclusion.”

Looking into the future, Zhou hopes to work with other climate scientists to help predict and mitigate the effects of climate change. Having comparisons between data observations and model simulations can be a very powerful tool to narrow down estimates on the freshwater fluxes and their impacts, Zhou said.

“What we’re seeing now is unprecedented. We do have some imperfect analogs of the current scenario in the past,” Zhou said. “But by better understanding those past events, we establish a baseline of what may happen in the future.”

For a deeper dive into Zhou’s research process, read “Breaking down clues to climate change from ocean floors to measure iceberg melting“on Medill Reports.

Grace Rodgers is health, environment and science reporters at Medill. You can follow her on Twitter at @gracelizrodgers.

Rare-earth metal reveals ancient ocean currents linked to climate triggers

Rare-earth metal reveals ancient ocean currents linked to climate triggers

By Marisa Sloan, Dec. 18, 2020 –

Despite the sci-fi name of this rare-earth element, neodymium is actually pretty common. The silvery metal is used in everything from cell phones and wind turbines to tanning booths and electric guitars.

But it’s the neodymium found thousands of meters below the ocean’s surface that captured the interest of Dr. Sophie Hines, a postdoctoral research fellow at Columbia University’s Lamont-Doherty Earth Observatory.

Hines traced the metal trapped within ancient marine sediments to reconstruct changes in ocean circulation reaching as far back as one million years ago. She presented her research at the Comer Climate Conference, an annual meeting of climate scientists that was held virtually this October.

“The ocean neodymium cycle is something that people have been studying for a long time,” she said. “But there are still parts that we’re learning.”

Because the global ocean circulation system brings water from the surface down to the deep ocean, it is thought to play an important role in trapping atmospheric carbon dioxide and triggering global climate changes.

According to Hines, different forms of neodymium wind up in the ocean through the weathering of various rocks and minerals. The neodymium composition of the North Atlantic Ocean, which is characterized by older continental crust, is distinct from that of the Pacific Ocean, which has more volcanoes and newly erupted material. These differences make it easier for climate scientists to trace the movement of seawater away from its sources and reconstruct changes in deep ocean currents.

“Trying to figure out how the ocean impacted climate in the past is interesting in and of itself,” Hines said. “But it also serves as an important calibration data set to make sure that the models we’re using to look at future climate change are accurate.”

Right now, the oceans provide a huge “carbon sink,” absorbing much of the carbon dioxide emissions from fossil fuels that are warming the planet at a threatening pace. The less carbon dioxide there is in the atmosphere, the colder the planet becomes.

According to a 2019 report by the Intergovernmental Panel on Climate Change, smaller glaciers will melt by more than 80% by the end of the century if greenhouse gas emissions continue on their current trajectory. The resulting influx of fresh water will likely disrupt ocean currents and, by extension, the climate in a way humans have yet to see.

Even if emissions were stabilized tomorrow, it would take many years for the oceans to adjust to the 1° C rise in global temperatures that has already occurred.

In 2016, Hines joined a two month-long deep-sea drilling expedition to South Africa’s Cape Basin on a whim when another researcher couldn’t make the trip. Although she was wrapping up the final year of her PhD program, she had yet to work in the field and didn’t know what to expect.

Location map of Integrated Ocean Drilling Program Site U1479, approximately 85 nautical miles southwest of Cape Town, South Africa
Location map of Integrated Ocean Drilling Program Site U1479, approximately 85 nautical miles southwest of Cape Town, South Africa. Water in this region comes from a complex mix of sources, including the North Atlantic, Indian and Southern Oceans. (Marisa Sloan/MEDILL)

“I was on the day shift, which [was] from noon until midnight,” Hines said. “Every day we did all this science, and then in the time we had off we hung out and watched movies and watched the stars at night.”

The first few weeks were new and exciting, she said. Each scientist onboard had his or her own tasks to do, ranging from dating the 9-meter-long sediment cores by their micro-fossils to squeezing water out of them with a hydraulic press.

By the time the sixth week rolled around, however, everyone was stepping on each other’s toes.

“Then we made it to Cape Town and had a big party,” she said, laughing. “I remember being most excited to have a beer and eat a salad by the end.”

The Cape Basin, where Hines traveled in search of ancient sediment cores, lies in The South Atlantic Ocean between the North Atlantic and the Pacific. Her chemical analysis shows a shift toward more Pacific-like water in the area during the last glacial period, from approximately 110,000 to 12,000 years ago⁠, perhaps revealing an ocean circulation that sequestered carbon dioxide-rich water in the Pacific and stored it in the South Atlantic.

Bob Anderson, a founder of the international program GEOTRACES and professor at Columbia’s Lamont-Doherty Earth Observatory, said her results correlate well with similar studies on carbon and carbonate ions.

“I agree [with Hines], but I don’t think we can make that as a final conclusion yet,” he said. “We know from a lot of neodymium data coming out right now that it’s more complicated than people used to think.”

In fact, another study published earlier this year posits an opposite conclusion. It suggests the changes in neodymium concentration in the South Atlantic may actually be a result of changes in the North Atlantic, rather than a switch to water from the Pacific.

“What I think we need are more records from the shallow to mid-depth North Atlantic and from the Pacific,” Hines said.

That’s the goal of Anderson’s program GEOTRACES, which is designed to study traces of neodymium and a barrage of other elements found within all of the earth’s major ocean basins. So far, scientists from approximately 35 nations have been involved in the expeditions to better understand how the chemical environment affects ecosystem function and vice versa.

Anderson said he expects those mysteries will be better understood in the next few decades, although he will likely be cheering on scientists like Hines from the sidelines by then.

“It will take combining the data that I collected with other people’s data to try and get a more holistic understanding of what happened,” Hines said. “That’s the hard part. And it’s also the fun part.”

Marisa Sloan is a health, environment and science reporter at Medill. You can follow her on Twitter at @sloan_marisa.

New glacial chronology lays groundwork for understanding rapid melt of modern ice sheets with climate change

New glacial chronology lays groundwork for understanding rapid melt of modern ice sheets with climate change

By Grace Rodgers, Dec. 18, 2020 –

Researchers have long tracked the timing and retreat patterns of the North American Laurentide ice sheet, the greatest ice sheet to exist in the Ice Age. During that time, nearly two-thirds of the rise in the global sea level was caused by the melting of the Laurentide — the majority of which occurred over 10,000 years.

“That’s an interesting, dynamic problem. In many senses, they’re very few other elements that size on the planet that change that rapidly,” said Thomas Lowell, a geology professor at the University of Cincinnati.

For over 40 years, Lowell has studied the Laurentide and tracked two key behaviors the ice sheet exhibited during climate changes: the amount of meltwater and ice margin retreat. Lowell presented his most recent research on these two behaviors at the annual Comer Climate Conference, an annual summit where climate scientists from around the world gather to present emerging research.

Over a five-year research process, Lowell and a team of scientists assembled the first-ever annual chronology tracking the amount of meltwater released and the rate at which the Laurentide retreated. The chronology begins nearly 12,700 years ago and spans a 1,500-year transition between the late Younger Dryas, a geologic interval of colder temperatures, and the Holocene boundary, a geologic interval of warmer temperatures.

Lowell predicted the measurements would show a slower retreat rate and less meltwater during the cold interval, and a faster retreat rate and more meltwater during the warm interval. However, the chronology revealed the meltwater doubled at the transition between the cold and warm interval, while the ice sheet retreated at a constant rate.

“If you melt a glacier more, you expect it to shrink faster. But the interval that we recorded, [the retreat rate] didn’t seem to be paying attention [to the temperature],” said Lowell. “Even though it was melting faster, it was still backing up and retreating at the same rate.”

While melting in warmer temperatures was expected, Lowell was surprised the glacier retreated at the same rate despite the higher meltwater.

“There’s nothing super exciting about the [meltwater] findings, but coupled with the [retreat rate] findings, they seemingly conflict with each other,” said Lowell.

The team of scientists working on the frozen ice using measuring equipment.
The team of scientists spent roughly four weeks researching and plotting core sites for the varve chronology. Afterward, the team spent roughly six weeks collecting the sediment cores across frozen lakes in Central North America. (Dr. Andy Breckenridge//University of Wisconsin)

To quantify the amount of glacial meltwater, Lowell and the team of scientists recovered roughly 1,000 meters total of sediment cores, one meter at a time across lakes in Central North America. Back in the lab, scientists measure the core’s “varves”, the thickness of sediment layers deposited in one year. Each varve indicates the amount of melting that occurred in one year: the thicker the layer, the more meltwater.

Altogether, the sediment cores serve as a chronology of meltwater. Measuring varve units can be critical for assessing the response of both past and present ice sheets to climate change.

“[Varves] were an archive that we really needed to understand the ice,” said Dr. Andy Breckenridge, lead author and a geology professor at the University of Wisconsin. “We knew the record was there and we designed a strategy where we were going after modern lakes to reconstruct it.”

The Geographic Information System equipment taking a photo of a sediment core.
Using a Geographic Information System at the University of Minnesota, Breckenridge captures a high-resolution image of the sediment cores to measure each varve. (Dr. Andy Breckenridge//University of Wisconsin)

Breckenridge measured each sediment core, beginning by taking high-resolution scans to survey the varve thickness and color. Lighter layers indicate summer seasons, meaning the sediment is coarser due to warmer temperatures. Darker layers indicate winter seasons, meaning the sediment finer grain due to colder temperatures. Once tallied on a spreadsheet, Breckenridge identifies thickness patterns to organize the varve chronology.

While one half of the cores are used for data collection, the other half is stored in a refrigerated warehouse allowing researchers from around the world to come and study the chronological cores.

“[Other researchers] are going to be able to request samples from our cores,” Breckenridge said. “And that’s already happened at some of our sites. I know some of our cores have been used for a carbon storage question”

Now that these findings are published, Lowell’s current research question asks: are these melting patterns a behavior of the whole ice sheet or just a small part of it, and if so, is that small part important. Further research into past and present glacial melting is critical to help us understand sea level change that threatens the livelihood of millions around the world.

“The ice sheets have the potential to change sea level, enough to really matter to society,” said Lowell.

Grace Rodgers is health, environment and science reporters at Medill. You can follow her on Twitter at @gracelizrodgers.

Trump warns the Green New Deal will ‘take out the cows.’ Here’s the science showing why that’s a myth.

Trump warns the Green New Deal will ‘take out the cows.’ Here’s the science showing why that’s a myth.

By Carlyn Kranking and Grace Rodgers, Nov. 19, 2020 –

At the first 2020 Presidential debate, President Donald Trump said that Green New Deal supporters “want to take out the cows” to reduce greenhouse gas emissions.

Not only is this claim untrue, but eliminating cows, which notoriously produce the greenhouse gas methane, isn’t necessary to address climate change, according to University of Oxford researchers.

“It would be good if you maybe ate less beef, had less milk — but we don’t need to completely get rid of all the cows,” said John Lynch, postdoctoral researcher at the University of Oxford.

Lynch studies ways to anticipate the impacts of greenhouse gases and suggests that the greenhouse gas carbon dioxide is more important to address than methane. It takes much less time to reverse the impact of methane emissions than it does to undo the effects of carbon dioxide, so it’s possible to delay addressing methane, he said. His suggestion has huge implications, because the way greenhouse gases are reported and compared in policies today doesn’t make it clear how differently these gases behave.

The Global Warming Potential (GWP) is a metric used to compare how much different greenhouse gases will warm the atmosphere across a given period into the future. Organizations including the U.S. Environmental Protection Agency and U.N. Intergovernmental Panel on Climate Change publish the GWP in their reports.

However, Lynch’s research shows that, for some purposes, the GWP metric may be misleading. Reporting all gases as though they were on the same playing field, experts say, does not account for key differences between them, especially between methane and carbon dioxide.

“Metrics that try and treat the gases in the same way are always going to have limitations,” Lynch said.

A figure from Lynch’s report demonstrates the differing effects of carbon dioxide and methane on warming over time.

In the first few decades after it’s emitted, methane causes more warming per kilogram than carbon dioxide does. Methane, however, breaks down after about 12 years, while carbon dioxide accumulates in the atmosphere, warming the planet for millennia.

Calculating warming potential over 100 years, for instance, does not account for how strongly methane warms the planet initially, nor does it account for the full effects that CO2 emissions will have.

So, if the GWP measurement is misleading, what does this mean for potential policies based on that statistic?

It would be best to cut both carbon dioxide and methane emissions, Lynch said. But because governments have limited will and resources to address the problem, he said it is more important to achieve net zero carbon emissions before cutting methane.

“If we prioritize the methane, first we will have a large quick benefit” as methane levels in the atmosphere rapidly fall, Lynch said. “But in the meantime, we will have carried on emitting all the CO2 that we decided not to bother with because methane looks easy. And then, in a couple of decades, we’ll be stuck with that CO2 warming, whereas if we just delayed our action on methane, we’d still be able to reverse that.”

Still, governments should not ignore methane emissions in climate policy, as all greenhouse gases warm the planet, Lynch said. But ultimately, the most important thing to do is to get to net zero carbon dioxide, because that’s the gas with the longest-lasting and biggest impact on global warming.

“There’s a lot of harm in delaying things that address carbon emissions,” said physicist Raymond Pierrehumbert, a professor and statutory chair in the physics department at the University of Oxford.

These long-lasting emissions will warm the planet, causing more extreme weather conditions, droughts, floods and rising sea levels. The longer it takes to reach net-zero CO2 emissions, the more severe these effects will be.

That’s why Lynch feels we “don’t really have a choice” on whether or not to decrease carbon emissions.

“All of your energy needs to be decarbonized,” Lynch said. “If we don’t, we’ll never stop the temperature going up.”

Carlyn Kranking and Grace Rodgers are Health, Environment and Science reporters at Medill. You can follow them on Twitter at @carlyn_kranking and @gracelizrodgers. 

4,000 floating robots take on climate change

4,000 floating robots take on climate change

By Elena Bruess, Oct. 16, 2019 –
I ziplined recently with a scientist who told me that her work involved almost 4,000 floating robots and a massive global computer database that could help her predict the future of our world’s climate.

This was during a break in the Comer Climate Conference and the woods behind conference headquarters held many mysteries, including a zipline and now – for me – the world’s most interesting researcher. I quickly scribbled “should probably catch up with her” in a notebook.

I did. She gave a presentation on her work the next day to climate scientists from across the nation gathered at the annual science meetup in southwestern Wisconsin.

My fellow zipliner is Becki Beadling, a Ph.D. Candidate in geosciences at the University of Arizona at Tuscon. Her work involves climate model simulations and in-field observations specifically focusing on climate change in relation to carbon uptake in the Southern Ocean.

A climate model replicates interactions between important factors that drive the climate, such as temperature, salinity, pressure as well as carbon cycling. The climate model database is called the Coupled Model Intercomparison Project – CMIP for short. The project goes hand-in-hand with the U.N.’s recent climate change reports, generating data from modeling centers all over the world. All the centers are running the exact same experiments and all the data is available through this database for anyone involved.

It’s a big system.

Unfortunately the models can be off the mark.

“The only way we can trust these models is by verifying them against past observations, historical observations and what’s happening now. I want to know how well these models represent these properties,” Beadling said, during another conference break. “And then looking into the future, how well the circulations and properties in this region are projected to change.”

According to Beadling, the models give us a range of possible scenarios of what might happen as the planet warms, glaciers melt, sea levels swamp coastlines and drought threatens millions. The comparison between what the computer analyzes and the actual observations can offer climate researchers a better idea of what to expect in the future. The closer the current observation is to the model, the more accurate the model can be to predict the pace and range of future change.

Geoscientist Becki Beadling, 29, abroad a US GO-SHIP on course from Syndey, Australia, to Papeete, Tahiti, in 2017. During her trip, the team released a number of SOCCOM “robot” floats to observe elements in the water. (Courtesy of Rebecca Beadling)

Observing the elements in the oceans can be a time-consuming and expensive task, though. A couple of years ago, Beadling went on a cruise. This was not your average trip to the Bahamas, but rather a research ship that is meant to measure the properties in the ocean. The same as the models: temperature, salinity, dissolved oxygen, nitrate, etc. The researchers release robot floaters called SOCCOM Floats at the same transects of the ocean decade after decade.

Each floater spends 10 days dipping down and back up, beaming data to the researchers on the land and then the cycle continues again.

The chart above depicts how a “robot” float works. SOCCOM floats work in the same way, but check for more than just temperature, salinity and pressure (Courtesy of Argo)
CAD drawing of a SOCCOM biogeochemical robot float. (Rick Rupan, University of Washington)

“It’s very new. Humans could not look at the great abyss of the global ocean, 71% of the Earth’s surface, because we could only go where we go in a ship,” said Joellen Russell, a biogeochemical dynamics professor at the University of Arizona and the chair of Integrative Science. Similar to Beadling, she works with the global database. She also attended the conference. “Now the robots do our work for us, and they keep working day-in and day-out, it doesn’t matter.”

According to Russell, there are just under 4,000 robots floating around right now, as Beadling mentioned.

Every dot on the map represents a “robot” float in the ocean as of October 11. (Courtesy of Becki Beadling)

When consulting the mix of the robot data and the current CMIP simulations, Beadling, Russell and other climate researchers can attempt to predict what our oceans will look like in the next century. Specifically they look to the Southern Ocean.

“When we think about modern climate, roughly 90% of the excess heat that’s trapped on our planet from greenhouse gas emissions has gone into our oceans. And the Southern Ocean is taking up the most,” Beadling said. “Heat and carbon are the most important components when thinking of the past, present and future of climate.”

The additional heat is in large part generated by human-driven emissions from fossil fuels, emissions that create the greenhouse gas carbon dioxide. CO2 holds heat in the atmosphere and is considered the thermostat of climate change. Even with ocean uptake, CO2 levels in the atmosphere have increased by more than 35 percent to more than 400 parts per million since the beginning of the Industrial Age.

According to Beadling, if we can better understand what those climate changes are going to be and how our oceans are going to react to all this warming, then we can have better projections of what we are facing from climate change and how to better prepare. Right now, the ocean is doing us a favor taking in all this carbon. But the question is for how long will it be able to do so and how fast might the Earth warm once ocean uptake of carbon slows or halts all together?

Looking ahead, a lot is uncertain for climate researchers such as Beadling. But, considering the work being done here, a big global database with a few thousand floating robots could eventually do the trick.

Photo at top: Beadling and colleagues prepare to toss the SOCCOM “robot” float in the ocean. The float will be collecting information for around 7 years. (Courtesy of Becki Beadling)

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