Beneath every step we take, soils hold one of the planet’s largest reservoirs of carbon, a vast, slow-moving bank of organic matter that quietly regulates how much of the world’s carbon stays locked away and how much escapes into the atmosphere as greenhouse gas. Now a sweeping new review warns that climate-driven extremes, droughts, floods, and wildfires, are rewriting the rules of that subterranean economy in ways that conventional models and land-management practices have not yet caught up with. The analysis, led by environmental scientist Nanthi Bolan of the University of Western Australia and colleagues, including a corresponding authorship by Bolan himself, synthesizes a substantial body of global evidence on how extreme weather reshapes carbon inputs to soil, microbial processing, erosion, and the sequestration of carbon that underpins soil health, water retention, nutrient cycling, and agricultural productivity.

The work, published in the journal Carbon Research, is notable for the scale of its underlying evidence base. On 14 January 2026, the authors searched Google Scholar, PubMed, and Web of Science using terms spanning climate change, extreme weather, soil carbon, microbial activity, decomposition, erosion, dissolved organic matter, and leaching. The initial sweep returned 14,218 records; after removing duplicates and screening for eligibility, 3,754 articles remained for bibliometric and qualitative analysis. From those, 187 publications were selected for detailed synthesis based on relevance, methodological rigor, and the substantive quality of their findings. Keyword co-occurrence patterns were mapped with VOSviewer, a bibliometric tool that reveals the intellectual architecture of a research field. The result is a critical review grounded in structured literature screening rather than new experimental data, but its synthesis offers one of the most comprehensive maps yet of how extremes rearrange the soil carbon cycle.

The review’s central finding is that no two extremes act alike. Drought, the most widespread disturbance, operates largely through the plant side of the equation. When rainfall fails, photosynthesis slows, plant biomass production falls, and the total flux of carbon entering soils through roots, residues, and litter declines. There is a nuance here: under moderate water stress, plants may temporarily shift a greater proportion of their fixed carbon belowground, investing in roots to chase moisture. But prolonged drought overwhelms that compensatory response. Microbial biomass shrinks, litter decomposition stalls, and the living engine of the soil carbon cycle idles. Then comes the deceptive twist: when rain finally returns, rewetting triggers a rapid pulse of carbon dioxide as starved soil microbes seize upon the accumulated substrates left behind by months of suspended activity. That post-drought CO₂ flush, the review emphasizes, can erase much of the apparent “savings” that accumulated during the dry period. Across the assembled evidence, repeated and multi-year drought was consistently associated with declining soil organic carbon, with grasslands and arable croplands showing particularly pronounced losses, ecosystems that happen to anchor much of the world’s food production.

Flooding tells the opposite story, but it ends in many of the same places. Water saturation chokes off oxygen diffusion through soil pores, forcing microbial metabolism into anaerobic pathways. That shift changes everything downstream. Prolonged waterlogging can drive the chemical reduction of iron oxyhydroxides, minerals that in oxygenated conditions act as microscopic glues binding organic carbon to soil particles. When those minerals dissolve, the carbon they held is released as dissolved organic carbon, which can then be stripped away by erosion and leaching and exported to rivers, lakes, and ultimately the ocean. The review stresses, however, that flooding is not unambiguously a carbon loss story. Wetlands and other periodically inundated ecosystems can accumulate and retain enormous carbon stocks precisely because water constrains decomposition. Whether a flood event releases carbon or banks it depends on the interplay between plant inputs, oxygen availability, and hydrological transport, a delicate balance that shifting rainfall regimes are actively destabilizing.

Wildfire is the most dramatic and immediately visible of the three forces, and its effects cascade on multiple timescales. Combustion directly strips vegetation, litter, and soil organic matter, transferring carbon to the atmosphere in hours. But fire also rearranges the physical and biological landscape of the soil in subtler ways: it can increase erosion by removing protective ground cover, alter soil wettability in ways that change hydrological behavior, restructure microbial communities, and expose previously protected carbon, once shielded inside aggregates or mineral associations, to fresh decomposition. There is a paradoxical bright spot. Pyrogenic carbon, the charcoal-like residue of incomplete combustion, is chemically recalcitrant and can persist in soils for centuries or millennia, functioning as a long-term carbon sink. Whether a fire leaves a landscape as a net carbon source or stabilizes some of its carbon in pyrogenic form depends on fire severity, soil moisture, fuel load, ecosystem type, and the trajectory of post-fire recovery. The review is clear that this balance cannot be predicted from fire alone; it is contingent, site by site, on conditions that vary widely across the globe.

Perhaps the most consequential theme running through the synthesis is that carbon responses cannot be inferred from the type of extreme event alone. Land use, soil mineralogy, hydrology, salinity, vegetation composition, microbial community makeup, and the timing of events within a season all determine whether carbon ends up stored, mobilized, or released. Iron and aluminum oxyhydroxides and clay minerals, for instance, provide mineral protection that can shield organic matter even under stress, while sandy or low-clay soils offer little such refuge. Managed croplands respond differently from native grasslands; saline coastal soils behave differently from acidic forest soils. And compound events, drought followed by wildfire, or alternating drought and flooding in rapid succession, may produce effects that are qualitatively different from those of isolated disturbances, as when a dried landscape burns more intensely, or when post-fire soils, stripped of vegetation, wash away in the first heavy rain. The review argues that the climate science and soil science communities have largely studied these disturbances one at a time, while the real world increasingly delivers them in combination.

The implications for climate mitigation and adaptation are substantial. Soil organic carbon is frequently invoked in national climate pledges and voluntary carbon markets as a bankable sink, yet the review suggests that the security of that bank depends heavily on how often and how severely extremes strike. If multi-year droughts steadily drain carbon from grasslands and croplands, or if fires repeatedly reset accumulation cycles, the effective permanence of soil carbon storage becomes far more fragile than many accounting frameworks assume. Conversely, protecting and rebuilding soil carbon delivers benefits well beyond climate: it improves water retention in drought-prone regions, supports nutrient cycling, stabilizes soil structure against erosion, and sustains the microbial diversity on which fertility depends. Carbon stewardship, in other words, is not separable from food security or ecosystem resilience; it is the same problem viewed from different angles.

The authors are candid about the limits of the current evidence base. The article does not report newly generated datasets and does not present a dedicated limitations section, and its conclusions rest on a qualitative synthesis of selected publications. Consequently, they call for improved and more consistent evidence across soil types, land uses, and both terrestrial and aquatic environments, and across multiple temporal scales, from the instantaneous CO₂ pulse after rewetting to the multi-decadal trajectory of carbon storage. Standardizing measurements of carbon pools, microbial functions, and event intensity, they argue, would make results comparable across ecosystems and enable more confident generalization, something the field currently struggles to achieve given heterogeneous methods and site-specific reporting.

Looking forward, the review sketches a research agenda that is as technologically ambitious as it is mechanistically focused. The authors recommend integrating high-resolution remote sensing with ground observations, advanced spectroscopy, molecular analyses, and integrated modeling to track carbon as it moves through soils and into waterways. They single out several priorities: characterizing microbial genomic and functional diversity as it responds to stress, quantifying carbon stoichiometry, probing the interactions between organic matter and iron and aluminum oxyhydroxides, understanding clay-mineral protection mechanisms, tracking long-term storage outcomes, and systematically studying the sequencing of compound extreme events. Each of these threads addresses a gap in the mechanistic chain that links a weather event in the atmosphere to a molecule of carbon, stabilized or released, in the soil.

What emerges from the review is a picture of the soil carbon cycle not as a stable background process but as a dynamic, contested system whose behavior under climate extremes is far less predictable than once assumed. The same storm that floods a rice paddy and exports carbon to a river delta may, a few hundred kilometers away, end a drought and briefly green a grassland, with opposite consequences for the atmosphere. As extremes grow more frequent and more compound, the review makes the case that understanding, and safeguarding, the carbon held beneath our feet will require science that is as interconnected and as restless as the weather itself.

Keywords

soil organic carbon, extreme weather, drought, flooding, wildfire, carbon sequestration, microbial activity, dissolved organic carbon, erosion, pyrogenic carbon, climate change, soil health

After ten years of fieldwork in Taiwan’s remote mountain regions, researchers have identified an 84.1-meter (276-foot) Taiwania fir, now recognized as the tallest tree documented in East Asia. The team also found dense forests containing dozens of giant Taiwania firs, suggesting that other giant trees may remain hidden in Taiwan’s rugged interior.

The study, published in Frontiers in Forests and Global Change, was conducted by a team led by Rebecca Chia-Chun Hsu of the Institute of Taiwan Forestry Research, in collaboration with researchers Chi-Kuei Wang and Chung-Cheng Lee of National Cheng Kung University. Starting in 2014, the group, known as the Taiwan tree seekers, located and measured trees that had previously gone unrecorded by combining traditional field surveys with laser-based mapping and the help of citizen scientists.

The researchers found that the giant trees generally grow at elevations of about 2,087 meters and on slopes with an average inclination of 40 degrees. This combination of elevation and rugged terrain makes conventional tree surveys extremely difficult.

A Decade of Ground-Truthing

In August 2014, a systematic search began when scientists from the Taiwan Forestry Research Institute visited the Cilan conservation area to measure the ‘Chilan Three Sisters’, a group of Taiwania firs known locally but not formally recorded. The tallest tree was 69.3 meters high and had a trunk almost three meters wide. The Tree Project, a group of professional climbers from Australia, photographed the trees in 2017 and helped draw greater attention to Taiwan’s giant forests.

During a subsequent expedition near Mt. Benya and Great Ghost Lake, the team hiked for four days with their equipment to reach the study area. This experience showed how difficult it is to estimate the height of giant trees from the ground, since visual estimates can be unreliable in densely wooded, multi-layered old-growth forests. Although the team measured one tree at 71.7 meters, they concluded that ground-based surveys alone would not be sufficient for such a large and complex landscape.

LiDAR and a Problem With the Landscape

To improve their search, Hsu’s team collaborated with Wang and Lee’s remote sensing group at National Cheng Kung University and adopted LiDAR technology. LiDAR uses laser pulses from aircraft to create three-dimensional models of the forest, including estimates of tree height. However, Taiwan’s rugged topography caused the automated software to misinterpret cliffs and abrupt elevation changes as extremely tall trees.

Human reviewers proved more effective than the automated software at identifying these geological false positives. In 2020, hundreds of citizen scientists began examining the LiDAR profile images manually to distinguish real cases from artifacts. By the end of 2022, the Taiwan Giant Tree Map had identified 941 trees taller than 65 meters.

The researchers concluded that combining airborne laser scanning with crowdsourced image reviews and expert analysis can greatly reduce terrain-related errors in estimating tree heights.

Finding the “Heaven Sword”

In 2023, the mapping project led the team to a candidate for Taiwan’s tallest tree, which could be reached after traveling 20 kilometers down a river and then spending two days climbing. A direct measurement established the tree’s height at 84.1 meters, making it the tallest tree ever documented in Taiwan and East Asia. The team called it the ‘Heaven Sword of the Da’an River’. The Indigenous Rukai people have a name for trees of this kind and describe them as ones that ‘hit the moon’. By early 2026, researchers had documented 10 Taiwania firs taller than 70 meters, including two that exceeded 80 meters.

The mapping effort also brought the team back to the Great Ghost Lake region, nearly ten years after their initial visit. There, they identified about 30 large Taiwania firs growing together in an ancient stand, which the team began calling ‘temples of giants.’ In a hectare of forest near Mt. Benya, they recorded 11 individual trees exceeding 65 meters in height.

What the Giants Are Storing

The importance of these forests goes beyond their height. In 2024, Hsu’s team, in collaboration with 15 citizen scientists, surveyed Tao Tree Valley, home to Taiwan’s third-tallest tree, to determine how much carbon the forest stores. They found a carbon density of 1,384.5 megagrams per hectare, without including the root systems. The estimate is comparable to carbon-storage densities reported for some of the world’s most carbon-rich forests, including giant eucalypt forests in Tasmania. The researchers noted that their estimate did not include root systems and may have underestimated the forest’s true carbon storage.

The researchers still do not know how many other giant trees remain hidden in Taiwan’s mountains. However, the combination of LiDAR mapping, citizen science, and field verification gives them a way to search terrain that would otherwise be nearly impossible to survey systematically.

Austin Burgess is a writer and researcher with a background in sales, marketing, and data analytics. He holds an MBA, a Bachelor of Science in Business Administration, and a data analytics certification. His work focuses on breaking scientific developments, with an emphasis on emerging biology, cognitive neuroscience, and archaeological discoveries.

In recent years, forests have emerged as pivotal players in global climate mitigation efforts, representing one of the most promising nature-based climate solutions available today. These ecosystems sequester approximately 31% of anthropogenic carbon dioxide emissions annually, providing a critical buffer against the accelerating pace of climate change. However, the reliability of forest carbon credit systems—mechanisms designed to monetize and incentivize carbon sequestration efforts—has come under intense scrutiny. A groundbreaking study published in the journal Biological Diversity unveils deep-rooted methodological flaws that cast profound doubt on the environmental integrity of current carbon credit frameworks, signaling a crisis of confidence across global carbon markets.

The rigorous analysis, spearheaded by environmental scientists from Yangtze University and Beijing Normal University, meticulously dissects the complex architecture of forest carbon credit systems and identifies four principal structural weaknesses that collectively undermine their trustworthiness. Foremost among these is the use of subjective assessments of additionality, a core concept requiring that credited emissions reductions would not have occurred in the absence of the project. Present carbon credit models predominantly rely on static historical baselines to calculate additionality, yet only an alarming 6% of REDD+ credits—credits allocated under the United Nations’ Reducing Emissions from Deforestation and Forest Degradation program—provide robust empirical evidence to substantiate genuine additional carbon mitigation.

Beyond the critical challenge of additionality, the permanence of carbon sequestration—signifying the long-term retention of carbon stock in forest biomass—is grossly overestimated by current standards. This overestimation is particularly precarious in light of escalating ecological disturbances linked to climate change including wildfires, prolonged droughts, pestilence outbreaks, and inadvertent carbon leakage where forest degradation shifts to unmonitored regions. The failure to appropriately incorporate these growing risks into permanence calculations means that many credited projects likely exaggerate their true contribution to climate mitigation, presenting an illusory picture of impact.

The study further reveals that leakage accounting—the assessment and adjustment for project-driven emissions displacement—is critically underdeveloped. Prevailing methodologies apply a modest average leakage deduction of only 7%, a figure that starkly contrasts with empirical findings suggesting leakage rates ranging from 10% to a staggering 70%. Such systemic under-accounting inflates the perceived net climate benefits of these forest projects, enabling an artificially optimistic valuation of carbon credits within international markets and undermining carbon trading integrity.

Compounding these shortcomings are the conspicuous omissions of biophysical impacts such as albedo and evapotranspiration effects in carbon accounting. Forest ecosystems substantially influence Earth’s energy balance through their reflectance properties and water cycling functions. Neglecting these elements obscures the true net climate impact, as alterations in surface albedo can significantly offset the cooling benefits gained from carbon sequestration, thereby diluting the overall effectiveness of forest-based interventions in climate regulation.

The collective failure to address these intertwined issues has deep ramifications not only for the credibility of carbon markets but also for biodiversity conservation and community well-being, which are often marginalized in project implementation. Insufficient local community involvement and opaque benefit-sharing arrangements risk alienating indigenous stakeholders, raising social equity concerns, and jeopardizing the sustainability and durability of mitigation efforts.

In response to these multifaceted challenges, the research team advocates for a transformative overhaul of forest carbon credit systems through a data-driven, science-based, and integrative accounting framework. Central to this reform is the replacement of static baselines with dynamic monitoring systems that leverage high-frequency remote sensing technologies alongside advanced machine learning algorithms. This approach enables objective, continuous, and quantitative assessments of additionality, dramatically enhancing transparency and scientific rigor in credit issuance.

Addressing permanence requires the establishment of a comprehensive three-tier risk management architecture comprised of prevention, buffering, and insurance mechanisms. This tiered system proactively mitigates disturbances by integrating biodiversity conservation as a mandatory compliance criterion rather than considering it a supplemental benefit, thus embedding ecosystem resilience at the heart of carbon project governance.

Transparency and standardization are equally emphasized through the call for stringent Monitoring, Reporting, and Verification (MRV) protocols. The use of cutting-edge technologies such as Light Detection and Ranging (LiDAR) and environmental DNA (eDNA) is prescribed to ensure precise biomass and biodiversity assessments. Additionally, mandatory disclosure of datasets and verification methodologies aims to foster independent third-party audits, enhancing accountability and stakeholder confidence in carbon accounting practices.

Sociopolitical dimensions are also addressed, with the framework highlighting the critical necessity of formalized community governance structures and the institutionalization of Free, Prior, and Informed Consent (FPIC) procedures. These mandates ensure that forest-dependent communities retain decision-making power and equitable access to the socioeconomic benefits derived from carbon sequestration projects, thereby reinforcing local stewardship and long-term project viability.

While the introduction of these rigorous standards is expected to contract the overall volume of carbon credits issued—reflecting a more conservative and realistic accounting of mitigation gains—the resultant credits will embody higher integrity and trustworthiness. This qualitative transformation is paramount for forest carbon credits to evolve from contested commodities susceptible to skepticism into robust and reliable assets underpinning credible global climate governance.

The implications of this research are profound. By embedding scientific rigor and standardized risk management, forest carbon credits can realize their full potential as durable climate mitigation tools while simultaneously safeguarding biodiversity and respecting community rights. This paradigm shift promises to restore confidence among stakeholders, catalyze more effective climate finance mechanisms, and advance global efforts to stabilize the Earth’s climate system.

Ultimately, this work underscores a crucial message: nature-based climate solutions like forests must be governed by scientifically sound and socially just frameworks. Only through such commitment to transparency, accuracy, and inclusivity can these natural assets deliver genuine and lasting contributions to the fight against climate change.

Subject of Research: Not applicable
Article Title: Restoring Trust: Rebuilding the Forest Carbon Credit System Through Scientific Rigor
News Publication Date: June 17, 2026
Web References: http://dx.doi.org/10.1002/bod2.70026
References: Chen, Xiaoqian, and Shaokun Li. 2026. “Restoring Trust: Rebuilding the Forest Carbon Credit System Through Scientific Rigor,” Biological Diversity: 1–5.
Image Credits: Xiaoqian Chen, and Shaokun Li
Keywords: Environmental sciences, Carbon emissions, Biodiversity conservation, Climate change mitigation, Risk management, Deforestation, Community ecology, Albedo, Resource policy, Environmental economics, Sustainable development, Land use, Climate change adaptation, Forestry, Carbon, Environmental policy, Environmental impact assessments, Environmental management, Remote sensing, Forest ecosystems