Amongst the Polygons
exploring a permafrost field site Jago River, Alaska
The capillaries of the Arctic hydrologic system are expanding through the degradation of ice-rich permafrost.
Little is known about the extent, expansion rate, and role of the developing connected ice-wedge trough network at watershed-scale in increasing lateral carbon and water export and, even less so, pan-Arctic fluxes.
Has the new or expanded capillary drainage network become so extensive across the Arctic tundra that it has resulted in increased river runoff and dissolved organic carbon export?
Amazingly, forests are still sucking up as much carbon as they were 30 years ago. But there’s a catch.
Besieged by logging, fires, and pests, this global balancing act might not last long.
Each year, burning fossil fuels puffs tens of billions of metric tons of planet-warming carbon dioxide into the atmosphere. And for decades, the Earth’s forests, along with its oceans and soil, have sucked roughly a third back in, creating a vacuum known as the land carbon sink. But as deforestation and wildfires ravage the world’s forests, scientists have begun to worry that this crucial balancing act may be in jeopardy.
A study published in the journal Nature on Wednesday found that, despite plenty of turmoil, the world’s forests have continued to absorb a steady amount of carbon for the last three decades.
Will the Seine be clean enough by the Olympics? Not even the experts know yet
With the Paris Olympics less than two weeks away, a question hangs over the Games: Will the Seine River be clean enough for athletes to swim in?
Triathlon and marathon swimming are scheduled to take place in the Seine, where it has been illegal to swim for more than a century. Despite the city’s efforts to clean up the long-polluted river, the water has tested unsafe for humans in recent weeks, and cleaner on other days. The Games run from July 26-Aug. 11.
To clean up the river, Paris invested 1.4 billion euros ($1.5 billion) in building infrastructure to catch more stormwater when it rains — the same water that contains bacteria-laden wastewater that enters the river during periods of heavy rain and makes it unsafe to swim in.
Continue reading on Associated Press.
Despite facing regional threats like deforestation and wildfires, the world’s forests continue to be a powerful weapon in the fight against climate change. A new study reveals these vital ecosystems have consistently absorbed carbon dioxide for the past three decades, even as disruptions chip away at their capacity. The study, based on long-term ground measurements combined with remote sensing data, found that forests take up an average of 3.5 ± 0.4 billion metric tons of carbon per year, which is nearly half of the carbon dioxide emissions from burning fossil fuels between 1990 and 2019.
The study titled “The enduring world forest carbon sink,” published in the June issue of the journal Nature, highlights the critical role of forests in mitigating climate change. The study further shows that deforestation and disturbances like wildfires are threatening this vital carbon sink.
The research is co-led by U.S. Department of Agriculture (USDA) Forest Service Northern Research Station Senior Research Scientist Yude Pan and Woodwell Climate Senior Scientist Richard Birdsey, and includes 15 additional co-authors from 11 countries.
Some of the key findings include:
- Boreal forests in the Northern Hemisphere, spanning regions like Alaska, Canada, and Russia, have experienced a significant decline in their carbon sink capacity, dropping by 36%. This decrease is attributed to factors including increased disturbances from wildfires, insect outbreaks, and soil warming.
- Tropical forests have also seen a decline, with deforestation causing a 31% decrease in their ability to absorb carbon. However, regrowth in previously abandoned agricultural lands and logged areas has partially offset these losses, keeping the net carbon flux in the tropics close to neutral.
- Temperate forests, on the other hand, have shown a 30% increase in their carbon sink capacity. This rise is largely due to extensive reforestation efforts, particularly in China.
“Our research team analyzed data from millions of forest plots around the globe,” Pan explained. “What sets this study apart is its foundation in extensive ground measurements – essentially, a tree-by-tree assessment of size, species, and biomass. While the study also incorporates remote sensing data, a common tool in national forest inventories and landsurveys, our unique strength lies in the detailed on-the-ground data collection.”
“The persistence of the global forest carbon sink was a surprise given global increases in wildfire, drought, logging, and other stressors,” according to Birdsey. “But it turns out that increasing emissions in some regions were balanced by increasing accumulation in other regions, mainly re-growing tropical forests and reforestation of temperate forests. These findings support the potential for improving protection and management of forests as effective natural climate solutions.”
The study describes how certain land management policies and practices can help preserve this global carbon sink. According to co-author Professor Oliver Phillips from the University of Leeds, who coordinates the pan-tropical ForestPlots.net coalition of scientists supporting key networks such as AfriTRON and RAINFOR, “the extraordinary persistence of the carbon sink shows that forests have mostly coped with climate change, so far. Deforestation, fire, and logging are damaging forests everywhere, but drought less so. Helping Earth’s forests resist climate change will mean keeping them as intact, healthy and vibrant ecosystems.”
Findings support a focus on curtailing deforestation across all forest biomes, for example, promoting forest restoration on lands that may be unsuitable for agriculture, and improving timber harvesting practices to minimize emissions from logging and related activities. The research also highlights the limitations in data collection, particularly in tropical regions. The study calls for increased research and establishment of more ground sampling plots in these areas to reduce uncertainties in carbon estimates and improve understanding of the global carbon budget.
On May 18th, Morris Alexie, Permafrost Pathways Tribal Liaison for the Alaska Native Village of Nunapicuaq (Nunapitchuk), traveled for three days to South America to join EarthRights International and other Indigenous leaders from around the world at the Public Hearing on the Advisory Opinion on Climate Emergency and Human Rights.
Read more on Permafrost Pathways
What are ice wedges, and why are they important to climate change?
“I think ice wedges are what make permafrost interesting,” says Dr. Anna Liljedahl.
Liljedahl works on Woodwell Climate’s Arctic team as an Associate Scientist. She aims to understand how climate change is affecting water storage and movement. Much of her recent work focuses on ice wedges and how they are reacting to warming Arctic summers. But just what are ice wedges anyway?
Ice wedges are one of the three main features of the Arctic’s land surface. Permafrost, ground that remains below 0˚C for at least two consecutive summers, lies under a thinner layer of thawing and refreezing soil, called the active layer. When permafrost cracks during cold winter days, snowmelt and runoff water seep into the empty space. These eventually freeze and create a wedge-shaped spear of ice that extends vertically down into the permafrost.
Ice wedges actively re-shape the tundra. When they freeze, they grow and expand outward, pushing against the bordering permafrost and active layer. With nowhere else to go, permafrost and soil push upwards, and ridges form on the surface of the tundra. The ridges interlock and form distinct shapes, referred to as ice-wedge polygons.
The ridged borders of ice-wedge polygons form directly above expanding ice wedges below the surface, and are therefore more elevated. The lower internal portion of the polygon allows pools of water from runoff and snowmelt to form atop the active layer. These polygons are visible all the way from space.
Thanks to satellite imagery, scientists like Liljedahl are able to monitor ice-wedge polygons remotely. Satellite images date back to the mid-20th century and can be used to observe changes in the landscape overtime.
During unusually warm summers, the tops of ice wedges can melt, which removes underlying support of the ground surface, causing slumps along the borders of ice-wedge polygons. These leveling borders form channels that siphon the water from pools in the centers of neighboring polygons. The resulting runoff streams can drain small pools and even larger lakes that took thousands of years to form.
With the progression of climate change, these drainage systems have become more common. Liljedahl refers to them in the title of her manuscript, just published in the July issue of Nature Water, “The Capillaries of the Arctic Tundra.”
The increase in creation of new “capillaries” in the Arctic is impacting not only the topographical landscape of the region, but also the livelihoods of all beings that find their home there.
At first, the melt of these ice wedges can spark an uptick in the variation of vegetation due to moisture along the sides of the channel. This, however, is temporary. When the ice wedges stabilize again in the winter, this variation decreases once more.
Aquatic mosses— one of the most productive vegetal forms in the Arctic, equivalent in productivity to Arctic shrubs— inhabit pools formed alongside the edges of ice-wedge polygons. They lose their homes when bodies of water drain away. Major vegetation changes can alter carbon storage, availability, and emissions across the tundra.
Humans are also impacted. Homes become too dangerous to live in as the ground supporting vital infrastructure collapses. Roads connecting communities to important resources are destroyed by subsiding ground.
Despite their widespread impact, ice wedges are often overlooked in Arctic climate models. Historically, their inclusion “costs too much computer time,” Liljedahl says, to factor in. Many climate models take a holistic approach to the Arctic landscape, as opposed to focusing on smaller details.
To remedy this, Liljedahl suggests utilization of developing technology such as Artificial Intelligence (AI). Classifying the Arctic landscape by type, for example, into high-center polygons, low-center polygons, and capillary networks, would factor ice wedge change into climate models. As AI advances and becomes a more common research tool, it could help decrease the human computing time that Liljedahl identifies as a barrier.
Arctic research is likely to change drastically in the coming years. With new technologies, and as we learn more about the Arctic landscape, research models will likely become more inclusive of the varied features within it, and much more accurate.
“There are exciting years ahead,” Liljedahl says, “I think we’re going to see some cool stuff coming out [of tundra research] in the next five to ten years.”
A new study, just published in the journal Nature Communications Earth & Environment, finds that severe droughts in the Amazon basin over the last two decades have led to longer periods of low water levels and triggered profound impacts on the local population.
The severe droughts in 2005, 2010, and 2015-2016, in particular, not only drastically reduced water levels in a substantial part of the world’s largest river system, but also resulted in low water level periods exceeding 100 days, a month longer than expected.
These droughts have major impacts on rural, remote Amazonian communities who heavily rely on inland water transport to access goods and services, reach urban centers, and maintain their livelihoods. The study concludes that during severe droughts, when such water transport is not available, nearly 50% of non-Indigenous localities and 54% of Indigenous villages in the Brazilian part of the Amazon basin are prone to isolation. These droughts also expose Amazonian communities to scarcity of goods, restricted access to healthcare and education, limited access to fishing and hunting sites, and other major impacts.
“This is the new reality of the Amazon,” said Dr. Letícia Santos de Lima, researcher at the Institute of Environmental Science and Technology of the Universitat Autònoma de Barcelona (ICTA-UAB) and lead author of the study. “Scientists have been warning for years that the Amazon basin is facing a substantial increase in the frequency and intensity of extreme events due to climate change, on top of severe changes in its hydrological system due to deforestation and forest degradation. These past droughts as well as the most recent one, 2023-2024, are showing that the impacts on the ecosystems extend severely to the Amazon population.”
“The Amazon faces increasingly severe droughts due to global warming, with very real consequences for the communities that live there,” added Dr. Marcia Macedo, Woodwell Climate Research Center scientist and study co-author. “To better prepare for these extreme climate events, we need climate solutions that prioritize water resources alongside efforts to curb carbon emissions. This will be key for sustaining resilient ecosystems and communities in the Amazon and around the world.”
The paper states that “actions to cope with recent droughts in the Amazon have been reactive rather than proactive and grounded in preparedness and adaptation principles,” and calls for Amazon countries to “develop long-term strategies for mitigation, adaptation, and disaster response.” The authors also stress that any solutions to isolation must not also worsen the problem. For example, roads would not be an effective solution as they are a well-known driver of deforestation, which leads to changes in rainfall, contributes to a higher volume of sediments in rivers, and would impair navigability even further.
Using an interdisciplinary approach, researchers combined spatial analysis, methods from hydrology, and news media content analysis to deliver the first spatiotemporal assessment of cross-sectoral impacts of droughts in the Amazon basin.
Offsetting carbon alone won’t hold water
As I look out over the river from a floating cabin at the Mamirauá Sustainable Development Reserve in central Amazonia, it’s hard to imagine that water could become an issue here. It is the end of the rainy season and river levels, as usual, have peaked at 9-12 meters above their dry season mean. To my delight, we took canoes for a “hike” on the forest trails and spotted large fish like tambaqui and pirarucu , temporarily released from the confines of the riverbanks. The riverside communities we visit are practiced in dealing with these large seasonal fluctuations, having built their houses on stilts high on the riverbank and using boats to negotiate the ebbs and flows of the river, which they rely on for their livelihoods and transportation.