Research Assistant Colleen Smith crouches low to the ground over a tray of crumbled soil. Using a boxy grey device that looks like a heavy-duty flashlight, she presses the flat glass end against the soil and fires a beam of infrared energy that bounces off the soil and back into the device’s sensor.
In moments, a readout pops up on a tablet screen, showing a spectrum of reflected light. With some analysis, Smith will have data on the chemical makeup of this patch of ground. With enough data points, she could estimate the soil properties of an entire field, pasture, ranch or farm, and how it might be changing over time.
Soil spectroscopy is a newer but fast-growing technique employed by scientists studying soil composition. At Woodwell Climate Research Center, a group led by Carbon Program Director Dr. Jonathan Sanderman has been spearheading its use to help improve the availability and affordability of reliable soil quality information, which is essential if we want to get serious about soil carbon sequestration as a natural climate solution.
“The heart of the technology is essentially getting the fingerprint of the soil, which tells us something about the overall chemical makeup of that sample,” says Dr. Sanderman.
The principles of soil spectroscopy are based in nuclear physics. Elements in the soil react in unique ways to the energy from the electromagnetic spectrum, reflecting some wavelengths and absorbing others. The reflected wavelengths give scientists clues to which minerals and elements are present and in what quantities.
That information can then be related to certain soil properties, like whether it’s suitable for certain crops, or whether it’s effectively sequestering carbon. The former is valuable information for producers like ranchers or farmers who need to make land management decisions. The latter is what climate researchers are most interested in. Soil spectroscopy represents an opportunity to marry the interests of both.
In a single scan, soil spectroscopy can estimate carbon, nitrogen, phosphorus, moisture, pH levels, and more. Traditional methods rely on multi-step chemical analyses to get you the same information— a time consuming and expensive process that could involve grinding, drying, weighing, mixing with reagents, and other steps to extract information on just one or two indicators of soil quality.
“With soil spectroscopy, you can get a pretty large suite of properties from one sixty second scan. A lab needs easily $2 million worth of instruments to be able to make all the same measurements using traditional methods,” says Dr. Sanderman. The most precise soil spectrometers can cost $100,000, but lower resolution and portable ones are substantially cheaper. “The speed and cost of spectroscopy are unmatched.”
These benefits make soil spectroscopy a method with big potential, but according to Dr. Sanderman there is still work to be done in refining the methodology to get universally accurate data. Alongside collaborators from the University of Florida and OpenGeoHub, he started the Soil Spectroscopy for the Global Good project (SS4GG) to jumpstart that work.
The project focused on two main efforts. The first was an extensive inter-laboratory comparison to understand how much the accuracy of scans varies between different instruments. Twenty laboratories across the globe participated, scanning identical samples which were then compared to the output from a lab widely regarded as the gold-standard in accuracy. The results were published in Geoderma late last year.
“We demonstrated that there is lab-to-lab variability, but also that there are procedures we can use to correct for differences between laboratories and get better integration of data,” says Postdoctoral Researcher, Dr. José Safanelli, who coordinated the study.
The second goal was to pool data from different labs into one accessible and open-source resource that also provides tools to analyze the data. The Open Soil Spectral Library (OSSL) now hosts over 100,000 soil spectra from across the globe that scientists can incorporate into their research and offers an engine for analysis. The idea is that with more people using and contributing soil spectral data, the faster the technology and the information gained from it will advance.
“We hope that the OSSL will be a driver of the soil spectroscopy community, advancing the pace of scientific discovery, and promoting innovation,” says Dr. Safanelli.
Throughout the project, SS4GG efforts remained dedicated to transparency.
“We were always available to answer questions. We shared best practices and gave advice on which instruments are better, which manufacturers are the best in the market, and which procedures to use to collect spectra,” says Dr. Safanelli.
According to Dr. Sanderman, that openness fostered trust and collaboration— in both contributing data to the OSSL and participating in the inter-laboratory study— strengthening the community of scientists using soil spectroscopy.
“As we built momentum, more groups began to contribute,” says Dr. Sanderman. “It’s been great to see people realizing the value of collaborative, open science. People are now taking advantage of the foundation we’ve built.”
The soil spectroscopy community convened this past year for several webinars and presentations, including the Agronomy, Crop, and Soil Science Society meeting, where Drs. Sanderman and Safanelli hosted a training workshop and symposium on spectroscopy, as well as a two-day immersive workshop on the future of the field.
“We all benefit when this technology is more widely used,” says Smith.
Speeding up the pace of soil science is key for developing climate solutions. Agricultural soils represent a large potential carbon sink; changes in farming and ranching practices can encourage sequestration of carbon in the soils. Soil carbon markets, and other payment for ecosystem services schemes could incentivise producers to make sustainable management decisions and soil spectroscopy could be a useful tool to track their contributions.
“The ultimate goal is to better monitor soils across landscapes to make food production more sustainable,” says Dr. Safanelli.
The handheld device that Smith was using is a test case for the speed and convenience of soil spectroscopy for analyzing soil carbon. If testing the quality of your soils can be as simple as a 60 second measurement with a low-cost piece of portable equipment, and the scan can get you additional information about soil fertility, then why not participate?
“We are trying to verify that we actually are sequestering carbon, and that requires lots and lots of measurements. So this is where we start moving into field-based spectroscopy,” says Dr. Sanderman. “If we can eliminate bringing the sample back to the lab altogether, we’re cutting our costs by another order of magnitude and could potentially scan several hundred points in a field in a day.”
Smith theorizes that cost could be further diffused through farming cooperatives or extension offices offering soil testing using inexpensive spectrometers. “Soil spectroscopy could be an easier way to get answers to big questions,” says Smith. “And that’s exciting.”
With the OSSL now up and running, the team is now focusing efforts on maintaining the growing network of interested soil researchers, pursuing new opportunities for collaboration as they arise.
“The network is getting stronger,” says Dr. Safanelli. “More people are coming and reaching out to us. That’s our biggest contribution: creating a network and sharing information across the community.”
This year, Woodwell Climate’s Just Access Initiative went global. Just Access works in close partnership with communities to provide tailored, actionable climate risk reports for Rio Branco, Brazil; Addis Ababa, Ethiopia; Summit County, Utah; and Lawrence, MA. At COP28, Just Access released their latest report in collaboration with the Ministry of Environment and Sustainable Development of the DRC, which focused on climate risks and potential solutions in the country and identified carbon markets as a potential funding mechanism for adaptation efforts.
Just Access collaborates with local officials and advocates to ensure the final reports cover information critical to their community’s planning. So far, 14 reports have been completed and more are on the way.
Read the report.
In January of 2023, the Biden Administration restored protections against logging and road-building for more than 9 million acres of the Tongass National Forest, the world’s largest intact temperate rainforest.
This came after Woodwell Climate’s Dr. Wayne Walker and Geospatial Analyst Seth Gorelik, along with long-time collaborator Dr. Dominick DellaSalla of Wild Heritage, delivered a research report to the Biden administration showing massive carbon stores in Tongass National Forest and highlighting the importance of roadless areas.
In 2023, Science on the Fly’s (SOTF) focused their activities on stewarding their community of scientists. Together they collected more than 3,000 water samples from hundreds of locations around the globe. SOTF leverages the passion and dedication of the global fly fishing community to gather data on the health of rivers across the world. With this data, SOTF can improve our understanding of how watersheds and river systems change over time due to climate change and local effects.
Read about the project’s activities this year.
We sent 10 Polaris Project students into the field this summer. The Polaris Project engages the brightest young minds from a diversity of backgrounds to tackle global climate research in one of Earth’s most vulnerable environments: the Arctic.
Students conducted their own research projects over two weeks at a field research station near Bethel, Alaska. Afterwards, they returned to the Center to analyze samples, and presented their findings at the American Geophysical Union meeting in December.
Woodwell Climate also hosted several interns through the Partnership Education Program. These undergraduate students participated in research and communications activities across the center.
Read PEP intern, Jonathan Kopeliovich’s story about research in Howland Forest.
Woodwell Climate has been conducting tropical forest research in Brazil for nearly two decades alongside partner organization IPAM Amazônia. This year, Water Program Director, Dr. Marcia Macedo and collaborators, including Dr. Ane Alencar of IPAM, convened a multi-day workshop in Brazil that produced a policy brief on forest degradation. They then organized experts to submit public comments on Brazil’s updated policy for controlling Amazon deforestation, which for the first time also addresses forest degradation.
Read the policy brief here.
Across the globe, Permafrost Pathways partner, Alaska Institute for Justice (AIJ), hosted a “Rights, Resilience, and Community-Led Adaptation” workshop on Dena’ina homelands in Anchorage, Alaska. The two-day workshop created space for Tribes to share their expertise with each other and connect face-to-face with federal and state government representatives to access resources and technical assistance.
Read more about the workshop.
Our experts showed up as thought leaders this year at several high profile events. As just a few examples, Woodwell Climate’s Arctic Program Director Dr. Sue Natali and Senior Science Policy Advisor Peter Frumhoff both spoke on panels alongside other leading voices in climate at SxSW in Austin, TX. Senior Geospatial Analyst, Greg Fiske attended the Esri User Conference, where his topographic map of Alaska garnered two awards. And Assistant Scientist, Dr. Ludmilla Rattis gave a talk at TED Countdown about her research on the role of Tapirs in rainforest restoration. (Recording coming in early 2024)
Woodwell Climate team members showed up in over 5,000 media stories this year. Our scientific leadership provided quotes for a broad range of high profile climate stories in New York Times, Reuters, Boston Globe, CNN and Grist, just to name a few. Senior Scientist Dr. Jen Francis was quoted over 4.2K times, appearing in major news outlets like the Washington Post and AP News to provide accessible context about the links between climate change and extreme weather events.
Last fall, Scotty Creek Research Station in Canada—one of the only Indigenous-led climate research stations in the world—was almost entirely consumed by a late-season wildfire. Woodwell Climate’s Permafrost Pathways project is providing rebuilding support to the Łı́ı́dlı̨ı̨ Kų́ę́ First Nation. Project scientists Dr. Kyle Arndt and Marco Montemayor visited the site for two weeks this spring to restore an essential carbon monitoring tower.
Our researchers published 80 peer-reviewed scientific publications this year. From the Arctic to the Tropics, from soil concentrations to river concentrations, Woodwell Climate had a part in discovery.
Explore all our publications.
Woodwell Climate’s President & CEO Dr. Max Holmes brought Woodwell Climate to the main stage of CERAWeek, Green Accelerator Davos, GenZero Climate Summit in Singapore, Climate Week NYC, and Mountainfilm Festival. He discussed cutting-edge climate science alongside notable figures like Bill McKibben and former Colombian President Iván Duque Márquez.Read about Dr. Holmes’ time at Davos.
Carbon cycling is an essential part of life on the planet. Plants and animals use the element for cellular growth, it can be stored in rocks and minerals or in the ocean, and of course it can move into the atmosphere, where it contributes to a warming planet.
A new study led by Dr. Megan Behnke, a former Florida State University doctoral student and Woodwell Polaris Project participant who is now a researcher at the University of Alaska, found that plants and small organisms in Arctic rivers could be responsible for more than half the particulate organic matter (a carbon-rich nutrient) flowing to the Arctic Ocean. That’s a significantly greater proportion than previously estimated, and it has implications for how much carbon is sequestered in the ocean versus how much moves into the atmosphere.
Scientists have long measured the organic matter in rivers to understand how carbon cycles through watersheds. But this research, published in Proceedings of the National Academy of Sciences, shows that organisms in the Arctic’s major rivers are a crucial contributor to carbon export, accounting for 40 to 60 percent of the particulate organic matter—tiny bits of decaying organisms—flowing into the ocean.
“When people thought about these major Arctic rivers and many other rivers globally, they tended to think of them as sewers of the land, exporting the waste materials from primary production and decomposition on land,” said Dr. Rob Spencer, a professor in the Department of Earth, Ocean and Atmospheric Science at FSU, and collaborator on the paper. “This study highlights that there’s a lot of life in these rivers themselves and that a lot of the organic material that is exported is coming from production in the rivers.”
Scientists study carbon exported via waterways to better understand how the element cycles through the environment. As organic material on land decomposes, it can move into rivers, which in turn drain into the ocean. Some of that carbon supports marine life, and some sinks to the bottom of the ocean, where it is buried in sediments.
The study was supported by the Arctic Great Rivers Observatory, and it examines six major rivers flowing in the Arctic Ocean: The Yukon and Mackenzie in North America, and the Ob’, Yenisey, Lena, and Kolyma in Russia. Using data collected over almost a decade, they built models that used the stable and radioactive isotope signatures of carbon and the carbon-to-nitrogen ratios of the particulate organic matter to determine the contribution of possible sources to each river’s chemistry.
Not all particulate organic matter is created equal, the researchers found. Carbon from soils that gets washed downstream is more likely to be buried in the ocean than the carbon produced within a river. That carbon is more likely to stay floating in the ocean, be eaten by organisms there and eventually breathed out as carbon dioxide.
“It’s like the difference between a french fry and a stem of broccoli,” said Dr. Behnke. “That broccoli is going to stay in storage in your freezer, but the french fry is much more likely to get eaten.”
That means a small increase in a river’s biomass could be equivalent to a larger increase in organic material coming from the land. If the carbon in that organic matter moves to the atmosphere, it would affect the rate of carbon cycling and associated climate change in the Arctic.
“I always get excited as a scientist or a researcher when we find new things, and this study found something new in the way that these big Arctic rivers work and how they export carbon to the ocean,” Dr. Spencer said. “We have to understand the modern carbon cycle if we’re really going to begin to understand and predict how it’s going to change. This is really relevant for the Arctic at the rate that it’s warming and due to the vast carbon stores that it holds.”
The study was an international endeavor— a feature that, Dr. Behnke notes, is critical to Arctic work, especially as climate change advances.
“That pan-Arctic view of science is more important than ever,” Dr. Behnke said. “The changes that are occurring are far bigger than one institution in one country, and we need these longstanding collaborations. That’s critically important to continue.”
A new study published in the peer-reviewed journal Forests and Global Change presents the nation’s first assessment of carbon stored in larger trees and mature forests on 11 national forests from the West Coast states to the Appalachian Mountains. This study is a companion to prior work to define, inventory and assess the nation’s older forests published in a special feature on “natural forests for a safe climate” in the same journal. Both studies are in response to President Biden’s Executive Order to inventory mature and old-growth forests for conservation purposes and the global concern about the unprecedented decline of older trees.
Scientists have long demonstrated the importance of larger trees and older forests, but when a tree is considered large or a forest mature has not been clearly defined and is relative to many factors. This study develops an approach to resolve this issue by connecting forest stand age and tree size using information in existing databases. This paper also defines maturity by reference to age of peak carbon capture for forest types in different ecosystems. But the approach is readily applicable across forest types and can be used with other definitions of stand maturity.
Key findings include:
Researchers used thousands of forest plots obtained from the U.S. Forest Service “Forest Inventory and Analysis” (FIA) dataset to determine the amount of carbon absorbed from the atmosphere that accumulates and is stored in individual trees as they mature. As trees age, they absorb and store more carbon than smaller trees, making them uniquely important as nature-based climate solutions. Additionally, as the entire forest matures, it collectively accumulates massive amounts of carbon over centuries in vegetation and soils. The study identified the forest age at which carbon accumulation is greatest, and used that as the threshold for defining a “mature” forest. Scientists also determined the median diameter of trees at this threshold age and how much of the forest carbon of the larger trees in mature forests is unprotected from logging. The amount of carbon in unprotected larger trees in mature stands of the 11 forests studied, representing only 6% of federal forest land, is equivalent to one-quarter of annual emissions of carbon dioxide from fossil fuels in the U.S. This is consistent with prior work.
According to lead researcher, Dr. Richard Birdsey of Woodwell Climate Research Center, “our study determined when an individual tree in a forest can be considered mature and when the forest itself is at an optimal rate of carbon capture and storage for conservation purposes. It is directly responsive to the president’s executive order.”
The Biden administration has set bold emissions reduction targets of 50-52% of 2005 levels and recently announced a “roadmap for nature-based solutions” as part of this effort. However, the roadmap neglects to connect the importance of protecting older forests to the climate targets. Federal agencies are proceeding with an inventory of mature and old-growth forests in response to the executive order, but policies regarding their management have not yet been established. By protecting older forests and trees on federal lands from avoidable logging, the Biden administration can help close the gap on its emissions reduction goals. The methodology in this paper provides a readily implementable path for critical policy solutions.
According to Dr. Dominick DellaSala, Chief Scientist at Wild Heritage, “there seems to be a big disconnect between what the White House is wanting and how federal agencies are responding to the president’s forest and climate directives. While the Forest Service recently withdrew a controversial timber sale in older forests on the Willamette National Forest in Oregon (“Flat Country Project”) because it was inconsistent with the president’s directives, dozens of timber sales in older forests remain on the chopping block.”
Dr. Carolyn Ramírez, Staff Scientist with the Forests Project at the Natural Resources Defense Council, pointed to the findings as supporting the push by over 100 conservation groups – the Climate Forests Campaign – for a national rulemaking to protect mature forests and big trees from logging for their superior climate and biodiversity benefits: “This work reinforces how essential mature forests on federal lands are to securing our climate future. It’s now up to the agencies to protect these carbon storing champions from the chainsaw with formal safeguards. Our approach shows that logging protections grounded in a straightforward, age-based cutoff—such as 80 years, as many are calling for—would protect significant amounts of carbon, accommodate forest growth differences, and be readily usable in the field.”
Millions of acres of rangelands managed by the U. S. Bureau of Land Management are not meeting land health standards, according to a recent report from watchdog organization Public Employees for Environmental Responsibility. Range degradation is also happening on U.S. Forest Service and privately held lands. Healthy rangelands are vital to the economic and public health of the communities that depend on them, which includes ranchers, Indigenous nations, and recreationists. Failing rangelands undermine these groups, lead to loss of habitat, and result in landscape degradation, and they also minimize our ability to mitigate climate change through carbon sequestration. Taking policy action to ensure the longevity of rangelands has the potential to increase climate mitigation potential and improve the health of U.S. ecosystems.
Covering more than 31 percent of the U.S., rangelands are any wilderness or rural open space grazed by domestic or wild herbivores, including grassland, shrubland, and pasture. Rangelands provide a wide array of ecosystem services, including food for livestock, habitat for wild species, and climate regulation through the uptake of carbon dioxide (CO2) by growing plants and the transfer of this sequestered carbon into the soil (as soil organic carbon). Globally, rangelands store 20 percent of the world’s soil organic carbon and U.S. rangelands may have the capacity to offset 2.5 – 3 percent of U.S. CO2 emissions from fossil fuels, but only if the rangelands are considered in “full health”.
The capacity for rangelands to sequester carbon is increasingly threatened by drought and overgrazing and there is an urgent need for improved land use planning to tackle these issues. However, the lack of an integrated monitoring system makes it difficult to know what changes to land management are needed on the individual ranch scale.
An important first step, then, to fostering healthy rangelands is establishing an open-access region-wide range monitoring platform that ranchers can use to verify and track changes in rangeland ecosystem condition and carbon storage across entire land units. Large-scale monitoring for these indicators will make it clearer where land is being effectively managed, and where it is not.
Dr. Jennifer Watts focuses on how climate change and human disturbance are affecting vegetation, soils, and the carbon cycle. She and her colleagues are currently working to develop a monitoring platform to provide stakeholders access to land health information.
“Having free, easy access to long-term information about lands will empower us to become fully aware of how our land use is impacting the health and future of rangeland ecosystems,” Dr. Watts explains. “This gives us the ability to invest in alternative management approaches that provide a more sustainable future for our lands while protecting our communities and ecosystems in the face of climate change.”
Reward systems can then be established across different scales to incentivize land use that improves ecosystem services. Monitoring platforms can be used in conjunction with clear land management directives to ensure rangelands are managed in a way conducive to ecosystem health.
Overgrazing is one of the biggest drivers of rangeland carbon loss and land degradation. It not only undermines the carbon storage potential of rangelands but also compromises other ecosystem services and limits future grazing capacity for livestock and wildlife. Consequently, it is in the best interest of everyone–ranchers, conservationists, Indigenous groups, and recreationists–to ensure that grazing on rangelands is managed in a way that increases vegetation cover, diversity, and rooting depth, while minimizing bare ground. Grazing practices can be addressed through process-oriented approaches.
Practicing management intensive grazing could help limit overgrazing. This adaptive technique involves concentrating grazing animals in one place for a very short period of time and then moving them to a different location. This ensures that the ecosystem has a chance to recover and regrow following a concentrated period of grazing. Ranchers will need technical assistance to develop grazing and management plans. Given that this is a practice under the Environmental Qualities Incentive Program (EQIP) it is likely to receive a boost in funding from the 2022 Inflation Reduction Act. Building more programs, at the federal, state, and county level, that reward ranchers for shifting grazing techniques to those that support the sustainability of ecosystem services and provide equipment needed to support fencing and water distribution could be a way to incentivize more effective land management.
Manipulating grazing fees to more accurately represent the costs associated with maintaining the integrity of rangelands is another option for fostering healthier rangelands given the current low fees and stagnant pricing of grazing fees. Furthermore, revenue generated from increasing grazing fees on public lands could be used to support a monitoring system for all U.S. rangelands.
Most stakeholders agree that better rangeland monitoring, soil health, and payment for land improvements are important, but a big question is how to actually pay for these services across multiple levels of governance. Exploring how to leverage different options for funding, then, will be the necessary next step in supporting thriving rangeland ecosystems and reaping the potential climate benefits.
At age 12, Woodwell Assistant Scientist, Dr. Jennifer Watts was accustomed to black dirt—the rich, wet, crumbling, fertile stuff she dug through on her family’s hobby farm in Oregon. But after moving with her parents and siblings to a roughly 224-acre dairy farm in Minnesota, all she saw around her was light brown, dry earth.
“A lot of the farms around us were a mix of dairy farms and really intense cropping rotations of corn and soybean,” Dr. Watts says. “And I started to notice, where there was tillage, how depleted the soil looked.”
In the United States, farmland covers more than 895 million acres (an area larger than the size of India), and it has a proportionately massive footprint on the environment. Intensive agriculture pulls nutrients out of the soil and doesn’t always return them, converting natural grasslands into monocultures and releasing large amounts of stored carbon in the process.
But what Dr. Watts saw throughout a childhood spent tending to her family’s farm, was that changing the way agricultural land is managed can sometimes reverse those impacts. In converting their cropland to pasture, to support an organic, grass-based dairy farm, Dr. Watts and her family stumbled upon the principles of regenerative agriculture. A practice that can produce food in a way that works with the ecosystem, rather than against it, and has implications for climate mitigation as well.
“It became, for me, an unintentional transformative experiment that my family conducted on our farm,” Dr. Watts says. “By the time I graduated high school, our lands were so lush and green. It was a healthy, productive, diverse ecosystem again.”
When Dr. Watts talks about her father’s idea to move to central Minnesota and start a dairy farm, she calls him a “rogue.” Originally from Alaska, he intended to work in fisheries, but had to change course after a cannery accident. Searching for something that would allow him to still spend his days outside, he settled on farming.
From the beginning, the Watts’ farming practices were considered unconventional in their rural Minnesota community. Firstly, they planted wild grasses and legumes like clover and alfalfa. Then, they left it alone. No tilling in the springtime alongside their neighbors; they simply let the plants establish themselves and moved the cattle frequently (with the help of a cow dog named Annie) to avoid overgrazing.
“After the first couple of years, I started noticing we had a lot more biological diversity in our fields, relative to our neighbors. We had a lot more bees buzzing, and butterflies, and we were popular with the deer and ducks,” Dr. Watts says. A few more years, and the soil started becoming dark and earthy-smelling again, like the soil she remembered from Oregon.
What was happening on their “rogue” dairy farm, was a gradual, partial reclamation of a lost grassland ecosystem— one that used to stretch across the midwest United States and was tended by native grazing species like bison or elk. Grazing plays a major role in cycling nutrients back into the soil, building up important elements like carbon and nitrogen. The near extinction of bison and the proliferation of monoculture cropping have broken this cycle—but cows have the potential to fill the gap left by ancient grazers, re-starting that process. Simple adjustments to management techniques, like lengthening time between grazing a pasture, can give the land time to recover.
This also has implications for how we combat climate change—a term Dr. Watts wasn’t familiar with until later in high school, when family trips back to Alaska revealed the glaciers she loved to visit were shrinking.
“Seeing the glaciers was our favorite thing to do with my grandma, but they were beginning to disappear. And one year, suddenly, I noticed these informational panels along the walk exiting the National Park talking about this thing called climate change,” says Dr. Watts.
Dr. Watts was also seeing another pattern emerge on the farms in her midwest community. Water was becoming a little scarcer. Many of the farms around her family’s had begun investing in irrigation—something that was previously unnecessary, and remained so for the Watts’ farm. Their rich, black soil held onto the water for longer.
As she grew up and (with the help of a pre-Google web search over dial-up internet) charted a course for her career as an ecologist, Dr. Watts began to study the science underlying these patterns she was noticing, and connected them to climate change.
Growing plants draw carbon from the atmosphere. When plants die and decay, some of that carbon is released to the air to be drawn back down again by a new season of growth, while some is stored away as organic matter in the soil. Over centuries, this process forms a stable sink of carbon on the land. Regenerative grazing—the way the Watts family did it—stimulates more plant growth to keep this cycle turning, while overgrazing or removing grazers entirely can halt the process, allowing for erosion, less healthy root systems, and the degradation of the carbon sink. In the U.S., rangelands have historically contributed more to the depletion of soil carbon, but Dr. Watts’ research with Woodwell has demonstrated that, with proper management, rangelands and other agricultural lands have the potential to contribute positively to the climate equation again.
For the past two summers, Dr. Watts, alongside the Woodwell Rangelands team and collaborators, has driven across the western U.S. to collect biomass and soil samples and measure carbon flux from working ranches and federal grazing leases in Montana, Colorado, and Utah. These measurements will help calibrate a new satellite remote sensing-informed model that can track how much carbon is being stored on grazing lands. The model will be hosted on the Rangeland Carbon Management Tool(RCMT) platform—a new web application she and researchers at both Woodwell and Colorado State University are developing to give land managers access to carbon and other ecosystem data for their lands.
The idea is that, with a tool like this in hand, ranchers can account for carbon dioxide flowing into and out of the rangeland ecosystem, and track how this changes over time in response to land management adjustments. It will also show changes in correlating ecosystem metrics like plant diversity and productivity, as well as soil moisture—two things that are crucial to maintaining a healthy and economically viable range. With this information, Dr. Watts and colleagues hope to encourage a regional shift in ranch management strategies that protect and rebuild stores of soil carbon, while providing ranchers with essential co-benefits.
Dr. Watts has been working with Jim Howell, owner of sustainable land management company Grasslands LLC, to connect with individual ranchers and discuss how a tool like this could help their operations. Though ranchers can be a tradition-bound group, Dr. Watts says seeing data that confirms their anecdotal experiences of hotter winters, drier summers, longer droughts, and other climate-related changes has opened them up to making changes.
“There are so many times when we just see the ‘aha moment’ in the manager or the land owner’s face, because they’re suddenly able to see these patterns from a very different perspective,” says Dr. Watts. “Most people, we have strong memories, we know that something’s different, but to be able to show that through data and not only memories—it’s so powerful.”
In addition to ecosystem co-benefits, storing carbon on rangelands could have direct economic benefits for ranchers as well. The RCMT will provide baseline data that could be used to verify credits within a voluntary soil carbon market. Rangelands historically haven’t been included in carbon markets because of gaps in monitoring data that the RCMT will help fill. The data could also be useful for local or state governments setting up payments for ecosystem services schemes in their region that would provide money directly to ranchers in exchange for storing carbon on their lands.
Of course, cattle aren’t without their complications, and ranching practices are just one element of a global meat and dairy industry that contributes to 15 percent of global emissions. But Dr. Watts’ roots as a dairy farmer make her enthusiastic about the possibilities this solution holds to both mitigate emissions and keep an important American livelihood resilient as climate conditions change.
“It’s just one aspect in this really complicated global system,” says Dr. Watts. “But if we manage our ecosystems better, building more intact environments where we can, this can sequester more carbon while restoring ecosystem health and productivity. It’s not the solution, but it is a solution that can benefit our planet while supporting rural communities.”
“Talk to Jim. Jim knows everything.”
That’s what everyone told Woodwell Assistant Scientist, Dr. Jennifer Watts, when she started writing up a research plan to study soil carbon on U.S. rangelands. “And indeed, he does,” Dr. Watts says. “He knows everything about the region, about grazing management, species management, anything having to do with land management on these ranches.”
With his felt Stetson, dusty jeans, and perennial tan, ranch manager Jim Howell looks a bit like the kind of cowboy Hollywood might dream up. And in a way he is—despite looking at home on the range, Howell grew up in Southern California. But he spent his summers out in Colorado’s Cimarron mountains, working on his grandfather’s cattle ranch.
Those summers were Howell’s introduction to the idea that the way livestock are managed can change their impact on the land—a thread that would pull him through a college degree in animal production, towards a career “knowing everything” about holistic ranch management. He was first clued into this concept while walking the fence line separating his family’s property from a patch of public land being used to graze sheep.
“I noticed there were lots of very healthy, perennial, bunch grasses on the sheep side, while our side of the fence had degraded to mostly silver sagebrush, Kentucky bluegrass, and dandelions,” says Howell. “And I just didn’t understand why the differences were so stark.”
Howell’s cattle were stocked continuously on the land, low in number but able to graze year round, while the sheep grazing permit required rotation. There might be a great flock of sheep up there one day and nothing but grass for the remainder of the year. That difference, it turned out, dramatically altered the kinds of plants that could flourish on the land.
“I became aware then that the way that we’d been managing our cows in our country up there was leading to its slow, long-term, ecological degradation. And I didn’t know what to do about it,” says Howell.
There have always been animals grazing the American West—before colonizers, even before native peoples. On the Great Plains there were bison; in the mountains and high altitude deserts of Southwestern Colorado, it was bighorn sheep and pronghorn antelope, as well as elk and mule deer. All three are rare sights now, with populations decimated by overhunting and habitat degradation.
Now, if you see any animal grazing on these ranges, it’ll probably be cattle.
Despite displacing native species, cows can still fill a natural niche in the rangeland ecosystem. Antelope, bison, sheep, and cows all belong to a group of animals called ruminants—animals that can digest grass. Many grasslands have co-evolved with ruminant species; their roaming feasts influence plant growth the same way pruning might affect the shape of a tree. Occasional shearing by a hungry cow stimulates new grass growth. It also creates a more competitive environment that supports a diverse array of plant species.
Grazing also plays a part in cycling nutrients and storing carbon in the soil. In a frequently dry climate like this one, digestion breaks down plant matter much faster than it would decay in the environment. Manure fertilizes new plant growth and returns carbon to the soil. Let this process continue unencumbered for a couple hundred thousand years, and you can build up a valuable carbon sink. And as long as the number of cattle isn’t rising, the oft-cited methane emissions from cow burps are minimal and cycled back down into the plants that grow up after grazing.
Since settlers arrived, however, the land has been put through centuries of abuse. Public lands were, for a long time, left open to unregulated grazing. Many rangelands have been over-stocked and grazed too frequently in order to make a profit and meet growing global beef demand. Land has been ecologically degraded, valuable topsoil was lost, and carbon stores declined as a result.
It would be easy to blame cows for this. But really, they’re not behaving much differently than pronghorn or bison would. They eat what’s in front of them. And they eat the tastier plants first. Howell likens it to a salad bar.
“If you go into a salad bar and there’s some lettuce that has been sitting there for three months, and some of it that’s just been replaced that morning, you take the new stuff. So that’s exactly what the cow does,” Howell says. “If she’s not made to move anywhere new, she’s just going to keep coming back and grazing the regrowth of the good stuff as long as it’s there.”
Pretty soon, perennial grass species, important for their deep roots that help prevent erosion and store carbon and water longer, are grazed into nothing. All that’s left are the sagebrush, dandelions, and other less desirable plants that Howell noticed dotting his family ranch.
“So the whole thing is about how the cows are managed, it’s not the cow itself that is a problem,” says Howell.
But if bad management can degrade the land, then good management should be able to restore it. While studying animal science in college, Howell encountered the concepts of “holistic management”, a term that began to decode this relationship between management practices and the health of the land. Controversial at its introduction a half century ago, holistic ranching has been gaining traction, and Howell and his ranch management company, Grasslands LLC, have helped urge its uptake.
The core principle is to make management decisions that restore lands and keep cattle in balance with the rest of the ecosystem—helping them fill the niche of the ancient grazers. This comes with a host of co-benefits, including water retention and higher plant productivity, that actually end up improving economic profitability for ranches in the long run. Simple adjustments, like lengthening the time between grazing a pasture again and wintering cows on native ranges instead of hay, can turn cattle from an ecosystem destroyer to an ecosystem helper.
“The trick is to let the cows do all the hard work,” says Howell.
Dr. Watts and Woodwell Senior Scientist Dr. Jonathan Sanderman, along with Dr. Megan Machmuller of Colorado State University, are interested in quantifying those co-benefits. Especially carbon storage.
“In the western US on our rangelands, just like in our croplands, we can change how we manage in a way that potentially could become a natural climate solution,” says Dr. Watts. “One where we’re bringing in more carbon than we’re emitting and we’re creating ecosystems that not only are beneficial for carbon sequestration, but also have more biodiversity, offer more habitat for wildlife, and more water conservation.”
In order to prove that value however, scientists need a baseline understanding of how much carbon is currently stored across both traditionally-and holistically-managed rangelands. It’s hard to get an estimate for such a large area (roughly 30% of the U.S. is covered with rangelands), so they are using a remote sensing model, which they verify with strategic on-the-ground sampling.
Howell’s work also created the perfect conditions for the research team to study the long term carbon benefits of altered ranching practices, which is a tricky thing to test empirically. Ranchers must constantly adjust their management techniques to stay profitable.
“In a classical research setting, you try to control all the variables but one, but in real life that’s not what happens,” says Howell. “Nothing is controlled. Day to day, you have to adapt to constantly changing conditions.”
But the ranches Howell’s company works with make those day-to-day decisions based on the principles of holistic management, so tracking carbon on those ranches over time offers the opportunity to generate baseline data on how they differ from more traditionally managed ones.
Howell also brought the expertise of a life spent on the range. He can identify just about any plant growing in the pasture, tell you which are native, which are invasive, and which used to be the preferred food of prehistoric ground sloths. His eye is trained to see diversity even in martian-esque deserts and read the history of the land in the structure of the soil. In May of 2022, Howell guided Drs. Sanderman, Watts, and Machmuller and their teams on a sample collection trip through Southwest Colorado and Utah. The researchers took soil cores, plant samples, moisture and temperature readings, and analyzed carbon fluxing in and out of the pasture.
The ultimate goal is to create a rangeland carbon management tool that will make the soil carbon data model accessible directly to ranch managers. Dr. Watts hopes having that data in hand will enable more ranchers to make management decisions with climate in mind. Dr. Sanderman also notes that it could be useful in eventually helping ranchers get paid for sustainable practices.
“Rangelands haven’t been included in voluntary carbon credit markets like cropping systems have,” says Dr. Sanderman. “Monitoring is a big problem because there’s so much land—How do you keep track of all that? That’s what our tool will be able to offer.”
There are limits to what grazing can accomplish, though. The lands out west aren’t suitable for large-scale cropping, being too dry or too mountainous, which makes them perfect for cattle. But when the animals take up space on land that would otherwise be used to produce crops—or worse, penned into feedlots—their benefits are compromised. Howell also notes that some grazing lands are already as saturated with carbon as they can be. And there remains the fact that ranching will get more complicated as the climate changes.
At the Valdez ranch in Delta, Colorado, Dr. Sanderman and research assistant Colleen Smith unfold a collapsible table in a field of cracking mud, dotted with the brittle stick skeletons of dead grass. Nearby, Dr. Machmuller is assisting Howell in extracting a long metal cylinder from the ground. It was plunged into the soil by a hydraulic corer attached to a pickup truck that’s idling in the field. Howell and Dr. Machmuller lay it out horizontally on the table and slide out the soil core—a 50 centimeter long history of the land beneath their feet.
Howell breaks open a section of the core with his fingers, revealing clusters of white crystals. This is a pasture that has been abused; over-irrigation by previous owners brought salts to the surface. Now nothing will grow here and wind gusts threaten to blow away loose topsoil. It’s a sacrifice zone. The current owners are considering installing solar panels instead.
Water is a big issue for ranchers and it’s threatening to get bigger. The region is constantly dipping in and out of severe drought, and in a place that depends heavily on winter snows for its groundwater and rivers, a warmer, drier climate is a threat.
Agriculture will depend more on irrigation as the climate warms and precipitation patterns change. But this empty pasture is proof that it’s not always a viable solution, and will become less so as climate change advances.
It enforces the urgency of the work Howell and team are doing. The faster we can draw carbon out of the atmosphere, the more successful these ranches are likely to be in the long term. The better managed the ranch, the more resilient it will be in the face of tough conditions.
In the end, Dr. Watts says, the outcome rests in the hands of ranch managers—people like Howell.
“Land managers are the ones that ultimately are going to make or break this country.”
In terms of climate mitigation, forests are like green gold—working overtime to cool the planet, while also supporting a wealth of biodiversity. But we have not been saving them as one would a precious asset. Despite pledges to end deforestation, old growth forests are being cut down at alarming rates. And planting new trees is widely prioritized and incentivized over protecting existing forests. Across the board, standing forests are vastly undervalued. This has to change if we are to stand a chance of limiting warming to internationally agreed targets.
According to a recent study from scientists at Woodwell and the University of Virginia, tropical forests alone are holding back approximately 1 degree Celsius of warming. About 75% of that cooling effect is due to carbon sequestration. Forests grow, trees lock away carbon in their trunks and roots and shunt it into the soil. The other 25% comes from the innate properties of forests that work to cool vast regions of the globe.
Through photosynthesis, plants release water vapor into the air in a process called evapotranspiration. The vapor contributes to cooling near the ground, as well as cloud formation higher in the atmosphere that reduces incoming solar radiation. The shape of the tree canopy also contributes. So-called canopy “roughness” disrupts air flow above the forest. The more uneven the canopy, the more turbulent the air, which disperses heat away from the surface. In the tropics, evapotranspiration and canopy roughness are high, which means that surface temperatures remain relatively low, with the heat dispersed throughout the deep atmosphere.
Forests also naturally produce molecules called biogenic volatile organic compounds (BVOC), which can either contribute to cooling by encouraging the formation of clouds, or to warming by creating ozone and methane. In the tropics, the net effect of these chemicals is cooling.
The cumulative result of these properties is that when forests are removed, the land around them begins to heat up even faster, which can increase the frequency of extreme heat and drought events. Without forests, some regions will become a lot less resilient to sudden shocks. And the release of carbon contributes to global warming which further exacerbates hot, dry conditions.
“Forests act like air conditioners,” says Woodwell Assistant Scientist, Dr. Ludmila Rattis, who studies the impacts of deforestation on agriculture in Brazil. “Deforesting in the face of climate change is like getting rid of your air conditioners before an upcoming heatwave.”
Protecting forests, and maintaining the cooling services they provide, is vital to limiting warming. But, with forests covering 30% of the Earth’s land, prioritizing protection is a massive task. And when it comes to carbon storage, not all forests are equally valuable. Older, healthier forests tend to have a more secure hold on their carbon.
“Mature forests have higher biodiversity and create their own microclimate,” says Woodwell Associate Scientist, Brendan Rogers. “They’re more resistant to drought and other types of disturbance. And because of that, they tend to be more stable in the face of environmental perturbations over time.”
New research from Woodwell and Griffith University has developed a method of identifying high-value forests using satellite imagery. Estimating the metric of “forest stability” through satellite data on the light reflected by vegetation and a water stress index of the tree canopy, researchers were able to determine gradients of stability within forest patches in the Amazon and boreal forests.
Using a gradient of forest stability allows for a better prioritization of forest protection strategies based on their carbon value.
“The first priority is to protect stable forests from further human disturbance,” says paper co-author Dr. Brendan Mackey. “The second priority is to identify forest areas where restoration efforts will be most cost effective.”
But if the state of existing forests is any indication, forest protection continues to be deprioritized. Many wildfires are left to burn unless they threaten human settlements. Governments continue to incentivize deforestation for development or agricultural expansion. Indigenous and local communities are not compensated for their work stewarding their territories and keeping forests safe. And the warmer the planet gets, the more susceptible even protected forests become to drought, fire, and disease.
Research has shown that stewarding standing primary forests, and reviving degraded ones, represents the greatest opportunity for near-term carbon storage and removal. A study of global land-based carbon storage potential found that improved management of existing forests alone could store approximately 215 billion metric tons more than they currently do.
Protecting forests is cost effective, too. For example, in the United States, investing in fire fighting in Alaska’s boreal forests would require just $13 per ton of CO2 emissions avoided. That’s easily on par with other mitigation strategies like onshore wind or solar energy generation.
Effective strategies for protecting forests already exist, they’ve just been suffering from a lack of force—and often funding—behind their implementation. For example, forest carbon markets—where landowners and forest stewards are paid to protect standing forests that are otherwise vulnerable to deforestation—have the potential to keep forests safe while offsetting emissions from other sectors. But nascent carbon markets are inefficient, with weak standards for verifying the quality of credits being sold, and lacking the transparency needed to ensure credits are actually reducing overall emissions, rather than greenwashing carbon-intensive business practices.
Credits are also priced incorrectly for their relative climate value—the market currently values reforestation credits more highly, reducing incentive for landowners to conserve standing, old-growth forests when there is a better livelihood to be made in legally deforesting land for other uses. A truly effective carbon markets system would require large investments in science that can verify credit standards.
Forests are like our global carbon savings accounts—when we cut them down, we’re drawing out money and limiting our ability to collect interest and keep growing our funds. Successful mitigation can’t be accomplished without taking the full value of forests into account and strengthening policies to reflect that. If they aren’t, the planet will pay a far greater price for it as temperatures rise.
“We can’t afford to keep cutting forests. We need to reduce emissions now, and protecting forests is one of our best available solutions. Despite the obstacles, it’s worth the investment,” says Dr. Rogers.