Gigatons Of Carbon Research Articles

Enhanced Carbon Flux Response to Atmospheric Aridity and Water Storage Deficit During the 2015–2016 El Niño Compromised Carbon Balance Recovery in Tropical South America

AbstractDuring the 2015–2016 El Niño, the Amazon basin released almost one gigaton of carbon (GtC) into the atmosphere due to extreme temperatures and drought. The link between the drought impact and recovery of the total carbon pools and its biogeochemical drivers is still unknown. With satellite‐constrained net carbon exchange and its component fluxes including gross primary production and fire emissions, we show that the total carbon loss caused by the 2015–2016 El Niño had not recovered by the end of 2018. Forest ecosystems over the Northeastern (NE) Amazon suffered a cumulative total carbon loss of ∼0.6 GtC through December 2018, driven primarily by a suppression of photosynthesis whereas southeastern savannah carbon loss was driven in part by fire. We attribute the slow recovery to the unexpected large carbon loss caused by the severe atmospheric aridity coupled with a water storage deficit during drought. We show the attenuation of carbon uptake is three times higher than expected from the pre‐drought sensitivity to atmospheric aridity and ground water supply. Our study fills an important knowledge gap in our understanding of the unexpectedly enhanced response of carbon fluxes to atmospheric aridity and water storage deficit and its impact on regional post‐drought recovery as a function of the vegetation types and climate perturbations. Our results suggest that the disproportionate impact of water supply and demand could compromise resiliency of the Amazonian carbon balance to future increases in extreme events.

Peatland wetness as an indicator of fire occurrence in forest and land fires (FLFs)

Background: Peatland ecosystems play an important role in the hydrological cycle and carbon cycling. In Indonesia, peatlands store about 28.6 gigatonnes of carbon which is equivalent to 10 years of global fossil fuel emissions. Peatlands act as a water storage during wet seasons and slowly release water during dry seasons to maintain river discharges and hydrological balance. However, climate change induced prolong drought has increased peatland dryness in recent decades which elevate the risks of unwanted peatland fires. During El Nino-induced drought in 2015, over 2.6 million hectares of forest and land burned, emitting 0.81–1.4 gigatonnes of greenhouse gases. The extreme fires damaged biodiversity, degraded water quality and displaced thousands of locals. This study aimed to analyze peatland wetness as an indicator of fire occurrences in forest and land fires (FLFs) in Riau, Indonesia by examining the relationship between degree of peatland wetness derived from satellite imagery and hotspots data. Methods: Peatland wetness was estimated from microwave backscattering coefficients at several RadarSat synthetic aperture radar (SAR) wavelengths and cross validated with water table depth measurements from 120 monitoring wells. Hotspots data between 2015-2020 were obtained from NASA's MODIS active fire product. Finding: Preliminary results showed significant negative correlations between peatland wetness and numbers of hotspots in peatlands, with more hotspots occurring in drier peatlands compared to wetter ones. This implies that maintaining peatland hydrological functions through continuoussaturation is pivotal to prevent severe peatland wildfires under future climate change. Conclusion: Conservation efforts to restore hydrological balance in degraded peatlands through re-wetting strategies are recommended. Further research utilizing machine learning algorithms to produce high-resolution peatland wetness maps can improve fire risk monitoring in peatlands. Novelty/Originality of this Study: This study introduces the novel concept of utilizing peatland wetness as a key indicator for predicting and mitigating forest and land fires in Indonesia, particularly in Riau Province. By combining peatland moisture and temperature data, the research establishes threshold values to better predict fire risks and guide timely mitigation efforts, thereby enhancing the efficiency and effectiveness of FLF response activities.

Weaker regional carbon uptake albeit with stronger seasonal amplitude in northern mid-latitudes estimated by higher resolution GEOS-Chem model

Terrestrial ecosystem in the Northern Hemisphere is characterized by a substantial carbon sink in recent decades. However, the carbon sink inferred from atmospheric CO2 data is usually larger than process- and inventory-based estimates, resulting in carbon release or near-neutral carbon exchange in the tropics. The atmospheric approach is known to be uncertain due to systematic biases of coarse atmospheric transport model simulation. Compared to a coarse-resolution inverse estimate at 4° × 5° using GEOS-Chem in the integrated region of N. America, E. Asia, and Europe from 2015 to 2018, the annual carbon sink estimate at a native high-resolution of 0.5° × 0.625° is reduced from −3.0±0.08 gigatons of carbon per year (GtC yr−1) to −2.15±0.08 GtC yr−1 due to prominent more carbon release during the non-growing seasons. The major reductions concentrate in the mid-latitudes (20°N–45°N), where the mean land carbon sinks in China and the USA are reduced from 0.64±0.03 and 0.35±0.02 GtC yr−1 to 0.14±0.03 and 0.15±0.02 GtC yr−1, respectively. The coarse-resolution GEOS-Chem tends to trap both the release and uptake signal within the planetary boundary layer, resulting in weaker estimates of biosphere seasonal strength. Since the strong fossil fuel emissions are persistently released from the surface, the trapped signal leads to the stronger estimates of annual carbon uptakes. These results suggest that high-resolution inversion with accurate vertical and meridional transport is urgently needed in targeting national carbon neutrality.

Changes in land use and management led to a decline in Eastern Europe’s terrestrial carbon sink

Land-based mitigation is essential in reducing net carbon emissions. Yet, the attribution of carbon fluxes remains highly uncertain, in particular for the forest-rich region of Eastern Europe (incl. Western Russia). Here we integrate various data sources to show that Eastern Europe accounted for an above-ground biomass carbon sink of ~0.41 gigatons of carbon per year over the period 2010–2019, that is 78% of the entire European carbon sink. We find that this carbon sink is declining, mainly driven by changes in land use and land management, but also by increasing natural disturbances. Based on a random forest model, we show that land use and management changes are main drivers of the declining carbon sink in Eastern Europe, although soil moisture variability is also important. Specifically, the saturation effect of tree regrowth in abandoned agricultural areas, combined with increasing wood harvest removals, particularly in European Russia, contributed to the decrease in the Eastern European carbon sink.

Calling time on the imperial lawn and the imperative for greenhouse gas mitigation

Non-technical summaryAs green spaces, lawns are often thought to capture carbon from the atmosphere. However, once mowing, fertlising and irrigation are taken into account, we show that they become carbon sources, at least in the long run. Converting unused urban and rural lawn and grassland to treescapes can make a substantial contribution to reducing greenhouse gas emissions and increasing carbon absorption from the atmosphere. However, it is imperative for governing bodies to put in place appropriate policies and incentives in order to achieve this.Technical summaryMown grass or lawn is a ubiquitous form of vegetation in human-dominated landscapes and it is often claimed to perform an ecosystem service by sequestering soil carbon. If lawn maintenance is included, however, we show that lawns become net carbon emitters. We estimate that globally, if one-third of mown grass in cities was returned to treescapes, 310–1630 million tonnes of carbon could be absorbed from the atmosphere, and up to 43 tonnes of carbon equivalent per hectare of emissions could be avoided over a two-decade time span. We therefore propose that local and central governments introduce policies to incentivise and/or regulate the conversion of underutilised grass into treescapes.Social media summaryIf unused lawns were planted with trees, a gigaton of carbon could be removed from the atmosphere over two decades.

Biobased plastic: A plausible solution toward carbon neutrality in plastic industry?

Biobased plastic exhibits unique benefits for achieving carbon neutrality, a key step toward reducing atmospheric greenhouse gases, due to its stability, high carbon content, and origin of carbon by photosynthesis. Herein we evaluate the role and potential of biobased plastic as an alternative carbon reservoir which is completely artificial, since most plastic polymers are synthetic and massively produced after the 1950 s. Model simulation indicates that plastic, under usage, burial, and littering, forms a growing carbon reservoir, sinking 6.82 gigatons of carbon (GtC) in 2020. Plastic-formed carbon is estimated to stack up to 19.4–23.2 GtC in 2060 under various production scenarios. However, only 18–40% of carbon stored in plastic is biobased carbon, equivalent to approximately 31–48 gigatons of carbon dioxide. Without any low carbon energy upgrade, carbon neutrality is difficult to achieve even with 90% biobased plastic substitution and 50% recycling ratio. Because extra GHG emissions are generated as a result of increasingly using incineration as a post-treatment strategy in response to increasing waste generation, the annual net GHG emission continues to rebound after the bio-based plastic substitution and plastic recycling approach their upper limits. Additional strategies are therefore needed to achieve complete carbon neutrality.

The other side of tropical forest drought: do shallow water table regions of Amazonia act as large-scale hydrological refugia from drought?

Tropical forest function is of global significance to climate change responses, and critically determined by water availability patterns. Groundwater is tightly related to soil water through the water table depth (WT), but historically neglected in ecological studies. Shallow WT forests (WT < 5 m) are underrepresented in forest research networks and absent in eddy flux measurements, although they represent c. 50% of the Amazon and are expected to respond differently to global-change-related droughts. We review WT patterns and consequences for plants, emerging results, and advance a conceptual model integrating environment and trait distributions to predict climate change effects. Shallow WT forests have a distinct species composition, with more resource-acquisitive and hydrologically vulnerable trees, shorter canopies and lower biomass than deep WT forests. During 'normal' climatic years, shallow WT forests have higher mortality and lower productivity than deep WT forests, but during moderate droughts mortality is buffered and productivity increases. However, during severe drought, shallow WT forests may be more sensitive due to shallow roots and drought-intolerant traits. Our evidence supports the hypothesis of neglected shallow WT forests being resilient to moderate drought, challenging the prevailing view of widespread negative effects of climate change on Amazonian forests that ignores WT gradients, but predicts they could collapse under very strong droughts.

We need biosphere stewardship that protects carbon sinks and builds resilience

Earth’s biosphere, its extraordinary and complex web of species and ecosystems on land and in the oceans, drives the life-sustaining cycles of water and other materials that enable all life on Earth to thrive. The biosphere is also a principal driver of immense negative feedback loops in the Earth system that stabilize atmospheric CO2 concentrations and thereby global climate—including carbon sequestration by vegetation, soils, and the oceans. As such, Earth’s ecosystems have played a central role in keeping our planet’s climate system unusually stable throughout the last 11,700 years (i.e., the inter-glacial Holocene). During this epoch, global mean temperatures have oscillated only about 1 °C around the pre-industrial average, providing the unique conditions that allowed human civilizations to flourish. Today, ocean and land ecosystems remove around 50% of anthropogenic CO2 emissions from the atmosphere each year (1), an extraordinary biophysical feat, given that these emissions have risen from approximately 4 gigatonnes of carbon (GtC) per year in 1960 to around 11 GtC per year today. Put another way, half our “climate debt” is removed, for free, by the biosphere every year—a vast subsidy to the world economy. Safeguarding the biosphere from further degradation or collapse is an existential challenge for humanity. There are important steps we can take to contain the damage. Image credit: Shutterstock/Kritskiy-ua. The recent Working Group 1 report of the sixth assessment of the Intergovernmental Panel on Climate Change (IPCC) confirmed this major nature contribution to climate stability, estimating the cumulative carbon sequestration by land and oceans to be 56% of all human-caused emissions between 1850 and 2019 (2). All major global climate models whose simulations give us hope of meeting the target of the Paris Climate Agreement—to keep warming well below 2 °C—take the continued provision of this gigantic biosphere endowment for granted, merely … [↵][1]1To whom correspondence may be addressed. Email: johan.rockstrom{at}pik-potsdam.de. [1]: #xref-corresp-1-1

GAMBUT LESTARI : AWARENESS SOLUTIONS FOR THE CRISIS OF PEATLAND

Peatland reserves one-third of the world's carbon storage. In 1 year it is evaluated that the peatland absorbs and contains 22.5 - 43.5 gigatonnes of carbon, which is proportionate to the outflows of 17-33 billion cars. Looking back on 2015, more than 50% or 2 million hectares of peatlands were burned down causing 220 trillion rupiah loss, victims suffering from respiratory diseases, disconnection of transportation networks and threats to biodiversity. The aim of this paper is to know the strategies used to increase awareness of peatlands and these discoveries appearing the sort of data and information that required prioritization to educate and advance such awareness. The method used for this paper is divided into two for the project planning and data collection instrument. For the data collection instrument, we used the data from third parties. The project planning that we conclude are including gambutlestari.com, pilot, share information, training &amp; education, signing the petition, and donation. Our project planning is encouraging the participation of people to increase the preventive action towards peatlands damage and indirectly fixed the peatlands damage that previously happened. In conclusion, it is a developed system to create the discussion for an educational training program. Hence, each party can embrace in communicating and advancing awareness on the peatland issue. Achieving our goal to be able to increase awareness of peatlands in Indonesia, we provide a one-stop service called “Push-Sustainable Peatlands” which can be accessed easily by everyone.

Sustainable Forest Management and Avoiding Pandemic Crisis

Forests are a unique gift from nature to man. They are the most biologically-diverse ecosystem on land and home of more than 75% of terrestrial species of animals, birds, plants and insects. They store about 296 Giga ton of carbon and counter climate change. They conserve soil, fix nitrogen and add organic matter to improve soil fertility. Forested watersheds and wetlands supply 75% of fresh water. They clean air and water, provide critical wildlife habitat, and make the planet a healthier place to live. Deforestation, climate change, poaching of wildlife, capturing them and their illegal world trade are worrisome. Due to the consumption and exposure of meat from the "wet market" or unnatural reproduction of animals, their deadly viruses are spreading in humans by spreading global epidemics. In the years 2003 to 2019, three global epidemics were encountered. The Covid-19 epidemic has disturbed the entire world. To avoid global epidemics in the future, sustainable forest management and allowing wildlife to live in the forests is absolutely necessary for public welfare.

The value of habitats of conservation importance to climate change mitigation in the UK

The twin pressures of climate change and biodiversity loss mean that it is imperative to manage land in ways that benefit carbon storage and biodiversity conservation. We focus on a set of UK habitats of recognised conservation value, first quantifying the carbon stored in the vegetation and top 30 cm of soil in these areas. We estimate that these areas store 0.55 gigatonnes of carbon in vegetation and soil to a depth of 30 cm, approximately 30% of the UK terrestrial carbon store to a similar depth, on 20% of the land area. Most of these high carbon, high conservation value habitats are in upland areas, with particularly notable extents and mass of carbon in Scotland. In their current condition, we estimate these areas to exert a net sequestration effect of more than 8 million tonnes of CO2 equivalents per year. Furthermore, restoration of these habitats from their current, generally poor condition could result in an extra 6–7 million tonnes of CO2 equivalents per year, in the context of the UK's total emissions of 455.9 million tonnes CO2eq in 2017. Restoration of degraded bogs would avoid significant annual emissions (currently negating significant sequestration by woodlands and coastal habitats) and should be a particular priority.

Analysis of the Simulation Results of Three Carbon Dioxide (CO2) Cycle Models

The CO2 (carbon dioxide) circulation models referred by the IPCC (Intergovernmental Panel on Climate Change) show that the increase of atmospheric CO2 by 240 GtC (Gigatonnes of carbon) from 1750 to 2011 is totally anthropogenic in nature, which corresponds to the permille value of about -12.5‰, but the observed value is only -8.3‰. The author’s improved 1DAOBM-3 CO2 circulation model shows that the anthropogenic CO2 amount in 2011 is only 73 GtC, satisfying the observed atmospheric permille values from 1750 to 2017. The CO2 circulation between the ocean and the atmosphere has increased the amount of atmospheric CO2 by natural CO2 197 GtC from the ocean, and this explains why the net uptake rate is only 1.9 GtC yr-1. Together with the anthropogenic amount of 73 GtC, the total increase is 270 GtC by 2017, corresponding to the observed atmospheric CO2 concentration. The simulations for 1000 GtC emissions by 2100 have been carried out by three models, including 1DAOBM-3, Bern2.5CC, and the mean model of 15 circulation models (called Joos 2013). The residence time of 1DAOBM-3 is 16 years for anthropogenic CO2 impulse, the same as for the radiocarbon decay time. The decay time of 1DAOBM-3 for the impulse function is about 600 years meaning the residence time of about 150 years only. These values are much shorter than the residence times of two other models, which show that 25±9‰ of any anthropogenic CO2 is still found in the atmosphere after 1,000 years. The reasons have been analyzed. The advantage of 1DAOBM-3 over the other models is that its results are in line with the oceanic and atmospheric observations from 1750 to 2017 but the future simulations include uncertainties due to ocean and biosphere uptake rate models.

Large influence of soil moisture on long-term terrestrial carbon uptake.

The terrestrial biosphere absorbs about 25% of anthropogenic CO2 emissions, yet the rate of land carbon uptake remains highly uncertain, leading to uncertainties in climate projections1,2. Understanding the factors that are limiting or driving land carbon storage is therefore important for improved climate predictions. One potential limiting factor for land carbon uptake is soil moisture, which can reduce gross primary production due to ecosystem water stress3,4, cause vegetation mortality5, and further exacerbate climate extremes due to land-atmosphere feedbacks6. Previous work has explored the impact of soil moisture availability on past carbon flux variability3,7,8. However, the magnitude of the effect of soil moisture variability and trends on the long-term carbon sink and the mechanisms responsible for associated carbon losses remain uncertain. Here we use four global land-atmosphere models9, and find that soil moisture variability and trends induce large CO2 sources (~2–3 GtC/year) throughout the twenty-first century; on the order of the land carbon sink itself1. Subseasonal and interannual soil moisture variability generates a CO2 source as a result of the nonlinear response of photosynthesis and net ecosystem exchange to soil water availability and the increased temperature and vapour pressure deficit caused by land-atmosphere interactions. Soil moisture variability reduces the present land carbon sink while soil moisture variability and its drying trend reduce it in the future. Our results emphasize that the capacity of continents to act as a future carbon sink critically depends on the nonlinear response of carbon fluxes to soil moisture and on land-atmosphere interactions. This suggests that with the drying trend and increase in soil moisture variability projected in several regions, the current carbon uptake rate may not be sustained past mid-century and could result in an accelerated atmospheric CO2 growth rate.

Response to Comment on "Contrasting carbon cycle responses of the tropical continents to the 2015-2016 El Niño".

Chevallier showed a column CO2 ([Formula: see text]) anomaly of ±0.5 parts per million forced by a uniform net biosphere exchange (NBE) anomaly of 2.5 gigatonnes of carbon over the tropical continents within a year, so he claimed that the inferred NBE uncertainties should be larger than presented in Liu et al We show that a much concentrated NBE anomaly led to much larger [Formula: see text] perturbations.

Contrasting carbon cycle responses of the tropical continents to the 2015-2016 El Niño.

The 2015-2016 El Niño led to historically high temperatures and low precipitation over the tropics, while the growth rate of atmospheric carbon dioxide (CO2) was the largest on record. Here we quantify the response of tropical net biosphere exchange, gross primary production, biomass burning, and respiration to these climate anomalies by assimilating column CO2, solar-induced chlorophyll fluorescence, and carbon monoxide observations from multiple satellites. Relative to the 2011 La Niña, the pantropical biosphere released 2.5 ± 0.34 gigatons more carbon into the atmosphere in 2015, consisting of approximately even contributions from three tropical continents but dominated by diverse carbon exchange processes. The heterogeneity of the carbon-exchange processes indicated here challenges previous studies that suggested that a single dominant process determines carbon cycle interannual variability.

Meeting that 1.5°C goal could be a pipe dream

The Paris Agreement aspires to limit global warming to 15°C above pre-industrial levels. Climate scientists had estimated that this means we can emit no more than 70 gigatonnes of carbon (GtC) after 2015. At current emission rates, we will pass this threshold by 2022. Now, a study is claiming that we can emit 200 GtC--nearly three times as much, pushing the deadline back to 2035. Here, Le Page finds out whether the team of Joeri Rogelj at the International Institute for Applied Systems Analysis in Australia is right.

Probability of emergence of novel temperature regimes at different levels of cumulative carbon emissions

The United Nations Paris Agreement creates new urgency and importance for understanding the emergence of climate impacts at different levels of cumulative carbon emissions. Using observations and climate models, we quantify the probability that different areas of the globe will experience permanent separation from the historical temperature regime, as a function of both time and cumulative emissions. We find that, in addition to a ~50% probability that global warming will exceed 2°C, cumulative emissions of 1000 gigatons of carbon (GtC) are likely to cause large areas of the tropics to transition to a new climate regime in which the annual temperature is never less than four standard deviations above the baseline mean. Although limiting cumulative emissions to 750 GtC substantially reduces these risks, the likelihood that some regions will still permanently experience extremely high annual temperatures suggests a critical role for adaptation, even if the Paris Agreement's mitigation targets are met.

The economic impact of biochar use in Central Europe

ABSTRACT Over the last two decades, it has been repeatedly stated that biochar might sequester gigatons of carbon from the atmosphere, reduce greenhouse gases, reverse soil degradation, etc. Most of the submitted environmental, societal, and ethical arguments originated in laboratories and were based on pot experiments, small-scale field trials, and mathematical models. Huge amounts of public money were subsequently invested worldwide into efforts to achieve the outlined ambitious goals. In reality, however, the rise of biochar has failed to materialize anywhere. Doubts have therefore been raised about the feasibility of the vision for biochar. This article assesses the first results obtained from a commercial scale project in Central Europe. The success seems to be dependent on reduction of the biochar price.

Critical insolation-CO2 relation for diagnosing past and future glacial inception

The past rapid growth of Northern Hemisphere continental ice sheets, which terminated warm and stable climate periods, is generally attributed to reduced summer insolation in boreal latitudes. Yet such summer insolation is near to its minimum at present, and there are no signs of a new ice age. This challenges our understanding of the mechanisms driving glacial cycles and our ability to predict the next glacial inception. Here we propose a critical functional relationship between boreal summer insolation and global carbon dioxide (CO2) concentration, which explains the beginning of the past eight glacial cycles and might anticipate future periods of glacial inception. Using an ensemble of simulations generated by an Earth system model of intermediate complexity constrained by palaeoclimatic data, we suggest that glacial inception was narrowly missed before the beginning of the Industrial Revolution. The missed inception can be accounted for by the combined effect of relatively high late-Holocene CO2 concentrations and the low orbital eccentricity of the Earth. Additionally, our analysis suggests that even in the absence of human perturbations no substantial build-up of ice sheets would occur within the next several thousand years and that the current interglacial would probably last for another 50,000 years. However, moderate anthropogenic cumulative CO2 emissions of 1,000 to 1,500 gigatonnes of carbon will postpone the next glacial inception by at least 100,000 years. Our simulations demonstrate that under natural conditions alone the Earth system would be expected to remain in the present delicately balanced interglacial climate state, steering clear of both large-scale glaciation of the Northern Hemisphere and its complete deglaciation, for an unusually long time.

Critical insolation-CO2 relation for diagnosing past and future glacial inception.

The past rapid growth of Northern Hemisphere continental ice sheets, which terminated warm and stable climate periods, is generally attributed to reduced summer insolation in boreal latitudes. Yet such summer insolation is near to its minimum at present, and there are no signs of a new ice age. This challenges our understanding of the mechanisms driving glacial cycles and our ability to predict the next glacial inception. Here we propose a critical functional relationship between boreal summer insolation and global carbon dioxide (CO2) concentration, which explains the beginning of the past eight glacial cycles and might anticipate future periods of glacial inception. Using an ensemble of simulations generated by an Earth system model of intermediate complexity constrained by palaeoclimatic data, we suggest that glacial inception was narrowly missed before the beginning of the Industrial Revolution. The missed inception can be accounted for by the combined effect of relatively high late-Holocene CO2 concentrations and the low orbital eccentricity of the Earth. Additionally, our analysis suggests that even in the absence of human perturbations no substantial build-up of ice sheets would occur within the next several thousand years and that the current interglacial would probably last for another 50,000 years. However, moderate anthropogenic cumulative CO2 emissions of 1,000 to 1,500 gigatonnes of carbon will postpone the next glacial inception by at least 100,000 years. Our simulations demonstrate that under natural conditions alone the Earth system would be expected to remain in the present delicately balanced interglacial climate state, steering clear of both large-scale glaciation of the Northern Hemisphere and its complete deglaciation, for an unusually long time.