Despite thorough preparations, flying the drone is still nervewracking.
Dr. Manoela Machado, a Research Scientist at Woodwell Climate, has double- and triple- checked her calculated flight path over a study plot in the Cerrado, Brazil’s natural savanna. The drone can essentially fly itself, and she’ll be monitoring its speed, altitude, and battery life from her handheld controller on the ground, but many things could still go wrong. High winds, an unforeseen obstruction, loss of connectivity— all could jeopardize the mission, potentially dropping the expensive equipment 40 meters into the woodland canopy below.
Aboard Machado’s drone sits a powerful piece of technology – a LiDAR sensor. Developed originally for use in meteorology, this remote sensing technique now has widespread applications across scientific fields, from archaeology, to urban planning, to climate science. At Woodwell Climate, Machado and others employ LiDAR to create detailed three dimensional models of landscapes, which provide valuable insight into the structure of ecosystems and the amount of carbon stored in them— all with just a few (million) pulses of light.
What is LiDAR?
LiDAR stands for Light Detection and Ranging. Put simply, it is a sensor that uses laser light to measure distance.
Similar to other technologies like sonar and radar, which use sound and radio waves, respectively, LiDAR is an example of an “active” sensor. “Passive” sensors like cameras collect ambient light, while LiDAR actively pings the environment with beams of laser light and records the time those beams take to bounce back. The longer the return time, the further away an object is. That distance measurement is then used to calculate the precise location in three-dimensional space for each reflection.
This process is repeated millions of times during a single scan, resulting in a dense cloud of point locations. With some advanced computing, the data can be assembled into a 3D picture of the landscape.
“It’s effectively three dimensional pointillism,” says Woodwell Climate Chief Scientific Officer, Dr. Wayne Walker, who has been using LiDAR in his studies for 25 years.
Far more detailed than an oil painting however, a LiDAR model can reconstruct nearly every leaf, twig, and anthill on a landscape.
“Once you construct that cloud of millions of points, you get to walk inside the forest again,” says Machado. “When you finish processing the data and see the cloud you go, ‘I remember that tree! I remember standing there!’ It’s mesmerizing.”
For a project like Machado’s, scanning a few dozen hectares, the sensor is usually placed on a drone. Larger study areas require sensors mounted on low-flying airplanes or even satellites, but for small ground-based applications there are sensors one can carry, mount on a tripod, or attach to a backpack. Some newer phone models even have LIDAR apps built in. Regardless of how LIDAR is deployed, it remains a straightforward method of data collection. Just point the sensor at what you want to scan and within minutes, you’ve captured the data for a detailed three-dimensional model of your area of interest.
Estimating the weight of a forest
What Machado and Walker are often after from a LiDAR scan is a measurement of biomass, or the total weight of the organic matter present in an ecosystem. Plants store carbon in the form of organic matter, so biomass measurements are an easy way to estimate an area’s carbon storage.
However, measuring a forest’s biomass directly would require cutting down all the trees, drying them out, and weighing what’s left — impractical and needlessly destructive— so scientists use proxy measurements. Walker likens the process to trying to estimate the weight of a human without access to a scale.
“What are the measurements you might use if you couldn’t actually physically measure weight? You might record height, waist size, inseam, and if you obtain enough of these measurements you can start to build a model that relates them to weight,” says Walker. “That’s what we’re trying to do when we estimate the biomass of an entire forest.”
Raw LiDAR data is only a measurement of distance, but by classifying each point based on its location relative to the cloud, researchers are able to extract the proxy measurements needed to model biomass across the ecosystem. Before LiDAR, these proxy measurements— things like trunk diameter, height, and tree species— had to be recorded entirely by hand, which limits data collection based on human time and resources. The time-saving addition of LiDAR has vastly expanded the possible scale of study plots. While field measurements are still essential to calibrate models, LiDAR is one of the only technologies that can give scientists enough detail and scope to assess carbon stocks over entire ecosystems.
“There is no other kind of sensor that even comes close to LiDAR,” says Walker.
The power and potential of LiDAR
At Woodwell Climate, researchers have employed the power of LiDAR to map biomass and carbon from Brazilian forests, to the Arctic tundra. Outside of the Center, the technology has found applications in archaeological surveys, lane detection for self-driving cars, and topographical mapping down to a resolution of half a meter.
But the detail that makes LiDAR so powerful can also make the data a challenge to work with. A single scan produces millions of data points. According to Geospatial Analyst and Research Associate, Emily Sturdivant, who analyzed LiDAR data for Woodwell’s Climate Smart Martha’s Vineyard project, that wealth of data often overwhelms our ability to extract the full potential of information available in one point cloud.
“LiDAR creates so much data that when you look at it, it’s hard not to be blown away imagining all the different things you could do with it. But then reality kicks in,” says Sturdivant. “It’s challenging to take full advantage of all those points with our current processing power. It’s a matter of the analysis technology catching up with the data.”
Processing LiDAR data requires large amounts of computing time and storage space, especially when performing more complex analyses like segmenting the data on the scale of individual trees. As machine learning and cloud computing technologies advance however, this becomes less of an obstacle, and the potential insights from LiDAR datasets will advance along with them.
LiDAR can be an expensive endeavor, too. Drones with the right equipment can cost tens of thousands of dollars, as can hiring a plane and pilot and paying for jet fuel, so data sharing has been important in making the method more cost effective. U.S. government agencies like NASA and the USGS have facilitated the collection of LiDAR data through satellites and plane flights, making the data available for public use. Woodwell Climate research has benefitted from these public datasets, using them to inform landscape studies and carbon flux models.
According to Sturdivant, the reliable production of public data has been greatly beneficial to advancing LiDAR-based studies, though it now faces risks from federal cuts to science agency funding.
“One of the greatest advantages of having publicly supported data is the consistency, but that’s exactly what’s now at risk,” says Sturdivant. “Public accessibility has been so important in allowing new scientists to learn and experiment and then help everyone else learn.”
Each new LiDAR scan represents a trove of information that could be used to better understand our changing planet, making it critical to continue supporting and collecting LiDAR data. Its intensely visual and highly detailed nature has made it one of the most powerful tools we have for understanding something as complex as a forest.
“And on top of that,” says Machado “It’s just visually beautiful.”
One of President Trump’s first actions this past week—and also in his first term—was to announce the withdrawal of the United States from the Paris Agreement. It is a step that is both misinformed and misguided. But how much difference will it make? Here’s what you need to know.
1. Significance of the Paris Agreement
The Paris Agreement was adopted by 197 countries in December 2015 and has been the underpinning of international climate action for nearly a decade. The goals and strategies it sets out are critically important to maintaining a stable climate, which is the foundation of successful societies and economies. The Parties to the Paris Agreement are legally obliged to submit national climate plans, known as Nationally Determined Contributions (NDCs) every five years. However, the content and level of ambition of those NDCs are (as the framing “nationally determined” makes clear) up to the Party itself.
2. Immediate legal implications
The Paris Agreement stipulates that any nation’s withdrawal takes effect one year after an official notice has been submitted to the Secretary-General of the United Nations. In the case of the United States, the earliest effective date of official withdrawal is, therefore, sometime in January 2026. After that, the country will not be bound by its obligations under the Paris Agreement. Those include the submission of NDCs every five years, accounting of progress toward commitments, the submission of biennial transparency reports, and the general obligation to provide climate finance. The United States will also lose, in particular, its right to vote on decisions within the governing body of the Paris Agreement, to nominate members to institutions serving the Paris Agreement, and to participate in emission trading under the Paris Agreement. However, as the United States submitted a new NDC and a biennial transparency report in December 2024, it is currently in compliance with the key obligations under the Paris Agreement.
3. What withdrawal from the Paris Agreement doesn’t do
The executive order of January 21, 2025 does not withdraw the US from the UN Framework Convention on Climate Change (UNFCCC), the 1992 treaty that established the international climate negotiation process. The language of the executive order indicates that this is deliberate—the US will retain its right to vote in the Conference of Parties, as well as its reporting obligations under the UNFCCC. This is possibly due to the fact that a withdrawal from the UNFCCC, a treaty ratified by the U.S. Senate in 1992, requires a two-thirds majority in the Senate. It is also notable that no action has been taken to withdraw the NDC submitted by the Biden Administration in December 2024.
4. The policy impact
The United States’ withdrawal makes maintaining—let alone enhancing—the ambition of emission reduction efforts across the world significantly more difficult. When a major emitter “free-rides,” it de-motivates ambition by others. However, although the U.S. has the second-highest GHG emissions in the world, and has always been a key player in global climate collaboration, it is important to bear in mind that 194 other countries representing approximately 90% of global emissions have not withdrawn from the Paris Agreement.
The executive order is targeted at stopping any U.S. climate finance contributions. This will mean that the new global climate finance goal of $1.3 trillion per year by 2030, agreed upon in Baku, has become much harder to achieve. This will impact the poorest countries directly, as well as degrading the international community’s trust in the effectiveness of the process.
5. What happened last time
President Trump also withdrew the U.S. from the Paris Agreement during his first administration. Then, as now, one of the primary impacts was to create a leadership vacuum. In that case, that vacuum was largely filled by other nations, plus state, local, and business leaders. The resulting groundswell generated momentum that carried into the Biden Administration and the U.S. re-entry into the Paris Agreement. While much of that foundation remains strong, trends in the private sector have shifted, with a growing number of major corporations and financial institutions backing away from their climate commitments. Global geopolitics has also evolved, raising questions about what role other governments, in particular China, might play in reaction to the United States’ withdrawal from the international governance structures.
After millennia as a carbon deep-freezer for the planet, regional hotspots and increasingly frequent wildfires in the northern latitudes have nearly canceled out that critical storage capacity in the permafrost region, according to a new study published in Nature Climate Change.
Read more on Permafrost Pathways.
Ecological warning lights have blinked on across the Arctic over the last 40 years, according to new research, and many of the fastest-changing areas are clustered in Siberia, the Canadian Northwest Territories, and Alaska. The analysis of the rapidly warming Arctic-boreal region, published in Geophysical Research Letters this week, provides a zoomed-in picture of ecosystems experiencing some of the fastest and most extreme climate changes on Earth.
Many of the most climate-stressed areas featured permafrost, or ground that stays frozen year-round, and experienced both severe warming and drying in recent decades.
To identify these “hotspots,” a team of researchers from Woodwell Climate Research Center, the University of Oslo, the University of Montana, the Environmental Systems Research Institute (Esri), and the University of Lleida used more than 30 years of geospatial data and long-term temperature records to assess indicators of ecosystem vulnerability in three categories: temperature, moisture, and vegetation.
Building on assessments like the NOAA Arctic Report Card, the research team went beyond evaluating isolated metrics of change and looked at multiple variables at once to create a more complete, integrated picture of climate and ecosystem changes in the region.
“Climate warming has put a great deal of stress on ecosystems in the high latitudes, but the stress looks very different from place to place and we wanted to quantify those differences,” said Dr. Jennifer Watts, Arctic program director at Woodwell Climate and lead author of the study. “Detecting hotspots at the local and regional level helps us not only to build a more precise picture of how Arctic warming is affecting ecosystems, but to identify places where we really need to focus future monitoring efforts and management resources.”
The team used spatial statistics to detect “neighborhoods,” or regions of particularly high levels of change during the past decade.
“This study is exactly why we have developed these kinds of spatial statistic tools in our technology. We are so proud to be working closely with Woodwell Climate on identifying and publishing these kinds of vulnerability hotspots that require effective and immediate climate adaptation action and long-term policy,” said Dr. Dawn Wright, chief scientist at Esri. “This is essentially what we mean by the ‘Science of Where.’”
The findings paint a complex and concerning picture.
The most substantial land warming between 1997-2020 occurred in the far eastern Siberian tundra and throughout central Siberia. Approximately 99% of the Eurasian tundra region experienced significant warming, compared to 72% of Eurasian boreal forests. While some hotspots in Siberia and the Northwest Territories of Canada grew drier, the researchers detected increased surface water and flooding in parts of North America, including Alaska’s Yukon-Kuskokwim Delta and central Canada. These increases in water on the landscape over time are likely a sign of thawing permafrost.
Among the 20 most vulnerable places the researchers identified, all contained permafrost.
“The Arctic and boreal regions are made up of diverse ecosystems, and this study reveals some of the complex ways they are responding to climate warming,” said Dr. Sue Natali, lead of the Permafrost Pathways project at Woodwell Climate and co-author of the study. “However, permafrost was a common denominator—the most climate-stressed regions all contained permafrost, which is vulnerable to thaw as temperatures rise. That’s a really concerning signal.”
For land managers and other decisionmakers, local and regional hotspot mapping like this can serve as a more useful monitoring tool than region-wide averages. Take, for instance, the example of Covid-19 tracking data: maps of county-by-county wastewater data tend to be more helpful tools to guide decision making than national averages, since rates of disease prevalence and transmission can vary widely among communities at a given moment in time. So, too, with climate trends: local data and trend detection can support management and adaptation approaches that account for unique and shifting conditions on the ground.
The significant changes the team detected in the Siberian boreal forest region should serve as a wakeup call, said Watts. “These forested regions, which have been helping take up and store carbon dioxide, are now showing major climate stresses and increasing risk of fire. We need to work as a global community to protect these important and vulnerable boreal ecosystems, while also reining in fossil fuel emissions.”
Explore these 15 maps by award-winning Woodwell Climate cartographers Greg Fiske and Christina Shintani. Created in 2024, each tells a story about the immense beauty of the high north, the dramatic changes unfolding as the Arctic continues to warm three to four times faster than the rest of the world, and the equitable solutions being developed to address climate impacts in the region
Read More on Permafrost Pathways.
A new study, published in Environmental Research: Climate and co-authored by Senior Scientist Dr. Jen Francis at Woodwell Climate Research Center, finds that despite abnormal warmth globally, and especially in the Arctic, severe winter cold-air outbreaks will continue, and perhaps become more frequent across the Northern Hemisphere.
“Even though the globe is warming and cold records are falling less often, we are still seeing surprisingly severe cold spells that sometimes last for many days and invade regions unaccustomed to severe cold,” said Dr. Francis. “It seems really counterintuitive, but there will be plenty of ice, snow, and frigid air in the Arctic winter for decades to come, and that cold can be displaced southward into heavily populated regions by Arctic heat waves.”
“In this comprehensive review of recent literature augmented with new analysis, we find the ongoing warming of the Arctic may provide an explanation,” added study lead-author Dr. Edward Hanna.
The stratospheric polar vortex is a mass of cold whirling air that forms high above the Arctic surface in response to the large north/south temperature difference that develops during winter. During recent warm winters with a relatively warmer Arctic, however, this vortex has tended to weaken, which can disrupt the normal flow of the jet stream below it (a river of wind above northern midlatitudes) and lead to conditions called ‘blocking’, which in turn allow pockets of cold Arctic air to plunge much farther south than normal.
This review provides a new analysis of recent research that offers further clarity around these complicated interactions. According to study co-author Dr. Muyin Wang, “An improved understanding of Arctic-midlatitude climate linkages is likely to benefit seasonal prediction and extreme weather preparedness, as well as the understanding of climate change.”
Researchers also underscore the need for urgent action to address the climate crisis, and mitigate and adapt to the consequences of increasingly extreme weather. “The Arctic may seem irrelevant and far away to most folks, but our findings show that the profound changes there affect billions of people around the Northern Hemisphere,” said Dr. Francis. “To reverse these trends, and better protect our communities and our planet, we must take bold and rapid action now to reduce the burning of fossil fuels and the build-up of heat-trapping gases in the atmosphere. The tools to achieve this exist if we can muster the will.”
The study resulted from an international workshop held in Lincoln, UK, in 2023, and was supported by the International Arctic Science Committee, the World Climate Research Programme’s Climate & Cryosphere project and the University of Lincoln. The full text can be read here.
A chapter of the National Oceanic and Atmospheric Administration’s (NOAA) 2024 Arctic Report Card, published today, presents a new, comprehensive pan-Arctic carbon assessment that, when accounting for wildfire emissions, finds that the Arctic tundra has shifted from storing carbon to being a source of carbon emissions to the atmosphere.
While the Arctic has been a carbon “sink” for thousands of years—storing more carbon than it releases—the Arctic Report Card chapter, Arctic Terrestrial Carbon Cycling, explores how rapid Arctic warming is prompting a range of ecosystem changes that are leading to increased emissions throughout the region. Among these are thawing permafrost (perennially frozen ground), wildfires, and plant and microbial changes.
In particular, the assessment, led by scientists at Woodwell Climate Research Center, finds that 2024 marked the second-warmest average yearly permafrost temperatures on record for Alaska, and the second-highest year for wildfire emissions north of the Arctic Circle.
“The Arctic is warming up to four times the global rate, and we need accurate, holistic, and comprehensive knowledge of how climate changes will affect the amount of carbon the Arctic is taking up and storing, and how much it’s releasing back into the atmosphere, in order to effectively address this crisis,” said Dr. Sue Natali, Woodwell Climate scientist, chapter lead and lead of Woodwell Climate’s Permafrost Pathways project. “This report represents a critical step toward quantifying these emissions at scale which is critical for understanding their impacts on global climate and informing equitable mitigation and adaptation strategies.”
“In recent years, we’ve seen how increasing fire activity from climate change threatens both communities and the carbon stored in permafrost, but now we’re beginning to be able to measure the cumulative impact to the atmosphere, and it’s significant,” said Dr. Brendan Rogers, Woodwell Climate scientist, chapter co-author, and co-lead of Woodwell Climate’s Permafrost Pathways project.
“This year’s report demonstrates the urgent need for adaptation as climate conditions quickly change,” said Twila Moon, lead editor of the 2024 Arctic Report Card and deputy lead scientist at the National Snow and Ice Data Center. “Indigenous Knowledge and community-led research programs can inform successful responses to rapid Arctic changes.”
Contributions to the chapter were also made by Woodwell Climate scientists, Dr. Kyle Arndt, Dr. Jacqueline Hung, Greg Fiske, Stefano Potter, and Dr. Anna Virkkala, as well as collaborators at University of Alaska-Fairbanks, Northern Arizona University, and Université de Montréal.
The Arctic Report Card combines the best available research from over 97 scientists from 11 countries, including seven from Woodwell Climate. Its chapters reveal record-setting observations of a rapidly warming Arctic, including rising air temperatures, declines of large inland caribou herds, and increasing precipitation. These climate impacts and others threaten the health, subsistence, and homes of many Indigenous communities living in the Arctic.
The full Arctic Report Card can be read here.
“What if you’re not on the map?”
Dr. Kelsey Leonard of the Shinnecock Indian Nation addressed this question to a room of Geographic Information System (GIS) professionals at Esri’s global mapping conference in 2023. Leonard, who uses maps to advance Indigenous water justice, asks this question to raise awareness about the absence of Indigenous land and languages in GIS tools. The removal of traditional place names in physical spaces, cartographic maps, and geospatial software often contributes to the erasure of Indigenous culture and history.
The Permafrost Pathways project, like Leonard, is working to change that.
Read more on Permafrost Pathways