A large terrestrial carbon sink in north america implied by atmospheric and oceanic carbon dioxide data and models

Limiting the rise in global mean temperatures relies on reducing carbon dioxide (CO2) emissions and on the removal of CO2 by land carbon sinks. China is currently the single largest emitter of CO2, responsible for approximately 27 per cent (2.67petagrams of carbon per year) of global fossil fuel emissions in 20171. Understanding of Chinese land biosphere fluxes has been hampered by sparse data coverage2-4, which has resulted in a wide range of a posteriori estimates of flux. Here we present recently available data on the atmospheric mole fraction of CO2, measured from six sites across China during 2009 to 2016. Using these data, we estimate a mean Chinese land biosphere sink of -1.11±0.38petagrams of carbon per year during 2010 to 2016, equivalent to about 45 per cent of our estimate of annual Chinese anthropogenic emissions over that period. Our estimate reflects a previously underestimated land carbon sink over southwest China (Yunnan, Guizhou and Guangxi provinces) throughout the year, and over northeast China (especially Heilongjiang and Jilin provinces) during summer months. These provinces have established a pattern of rapid afforestation of progressively larger regions5,6, with provincial forest areas increasing by between 0.04 million and 0.44 million hectares per year over the past 10 to 15years. These large-scale changes reflect the expansion of fast-growing plantation forests that contribute to timber exports and the domestic production of paper7. Space-borne observations of vegetation greenness show a large increase with time over this study period, supporting the timing and increase in the land carbon sink over these afforestation regions.

Rhizosphere-induced changes of Pinus densiflora (S. and Z.) grown at elevated atmospheric temperature and carbon dioxide are presented based on experiments carried out in a two-compartment rhizobag system filled with forest soil in an environmentally controlled walk-in chamber with four treatment combinations: control (25°C, 500 μmol mol−1 CO2), T2 (30°C, 500 μmol mol−1 CO2), T3 (25°C, 800 μmol mol−1 CO2), and T4 (30°C, 800 μmol mol−1 CO2). Elevated temperature and atmospheric carbon dioxide resulted in higher concentration of sugars and dissolved organic carbon in soil solution, especially at the later period of plant growth. Soil solution pH from the rhizosphere became less acidic than the bulk soil regardless of treatment, while the electrical conductivity of soil solution from the rhizosphere was increased by elevated carbon dioxide treatment. Biolog EcoPlate™ data showed that the rhizosphere had higher average well color development, Shannon–Weaver index, and richness of carbon utilization compared with bulk soil, indicating that microbial activity in the rhizosphere was higher and more diverse than in bulk soil. Subsequent principal component analysis indicated separation of soil microbial community functional structures in the rhizosphere by treatment. The principal components extracted were correlated to plant-induced changes of substrate quality and quantity in the rhizosphere as plants' response to varying temperature and atmospheric carbon dioxide.

Changes in atmospheric carbon dioxide concentrations, climate, and land management influence the abundance and distribution of C3 and C4 plants, yet their impact on the global carbon cycle remains uncertain. Here, we use a parsimonious model of C3 and C4 plant distribution, based on optimality principles, combined with a simplified representation of the global carbon cycle, to assess how shifts in plant abundances driven by carbon dioxide and climate affect global gross primary production, land carbon isotope discrimination, and the isotopic composition of atmospheric carbon dioxide. We estimate that the proportion of C4 plants in total biomass declined from about 16% to 12% between 1982 and 2016, despite an increase in the abundance of C4 crops. This decline reflects the reduced competitive advantage of C4 photosynthesis in a carbon dioxide-enriched atmosphere. As a result, global gross primary production rose by approximately 16.5 ± 1.8 petagrams of carbon, and land carbon isotope discrimination increased by 0.017 ± 0.001‰ per year. Accounting for changes in C3 and C4 abundances reduces the difference between observed and modeled trends in atmospheric carbon isotope composition, but does not fully explain the observed decrease, pointing to additional, unaccounted drivers.

Atmospheric carbon dioxide has been increased and was reached approximately to 390 mg/L at December 2010 (Tans, 2011). Rising trend of carbon dioxide in past and present time may be an indicator capable of estimating the concentration of atmospheric carbon dioxide in the future. Cause for increase of atmospheric carbon dioxide was already investigated and became general knowledge for the civilized peoples who are watching TV, listening to radio, and reading newspapers. Anybody of the civilized peoples can anticipate that the atmospheric carbon dioxide is increased continuously until unknowable time in the future but not in the near future. Carbon dioxide is believed to be a major factor affecting global climate variation because increase of atmospheric carbon dioxide is proportional to variation trend of global average temperature (Cox et al., 2000). Atmospheric carbon dioxide is generated naturally from the eruption of volcano (Gerlach et al., 2002; Williams et al., 1992), decay of organic matters, respiration of animals, and cellular respiration of microorganisms (Raich and Schlesinger, 2002; Van Veen et al., 1991); meanwhile, artificially from combustion of fossil fuels, combustion of organic matters, and cement making-process (Worrell et al., 2001). Theoretically, the natural atmospheric carbon dioxide generated biologically from the decay of organic matter and the respirations of organisms has to be fixed biologically by land plants, aquatic plants, and photosynthetic microorganisms, by which cycle of atmospheric carbon dioxide may be nearly balanced (Grulke et al., 1990). All of the human-emitted carbon dioxide except the naturally balanced one may be incorporated newly into the pool of atmospheric greenhouse gases that are methane, water vapor, fluorocarbons, nitrous oxide, and carbon dioxide (Lashof and Ahuja, 1990). The airborne fraction of carbon dioxide that is the ratio of the increase in atmospheric carbon dioxide to the emitted carbon dioxide variation was typically about 45% over 5 years period (Keeling et al., 1995). Canadell at al (2007) reported that about 57% of human-emitted carbon dioxide was removed by the biosphere and oceans. These reports indicate that the airborne fraction of carbon dioxide is at least 43-45%, which may be the balance emitted by human activity. The land plants are the largest natural carbon dioxide sinker, which have been decreased globally by deforestation (Cramer et al., 2004). Especially, tropical and rainforests are being

Atmospheric transport models are used to constrain sources and sinks of carbon dioxide by requiring that the modeled spatial and temporal concentration patterns are consistent with the observations. Serious obstacles to this approach are the sparsity of sampling sites and the lack of temporal continuity among observations at different locations. A procedure is presented that attempts to extend the knowledge gained during a limited period of measurements beyond the period itself resulting in records containing measurement data and extrapolated and interpolated values. From limited measurements we can define trace gas climatologies that describe average seasonal cycles, trends, and changes in trends at individual sampling sites. A comparison of the site climatologies with a reference defined over a much longer period of time constitutes the framework used in the development of the data extension procedure. Two extension methods are described. The benchmark trend method uses a deseasonalized long‐term trend from a single site as a reference to individual site climatologies. The latitude reference method utilizes measurements from many sites in constructing a reference to the climatologies. Both methods are evaluated and the advantages and limitations of each are discussed. Data extension is not based on any atmospheric models but entirely on the data themselves. The methods described here are relatively straightforward and reproducible and result in extended records that are model independent. The cooperative air sampling network maintained by the National Oceanic and Atmospheric Administration Climate Monitoring and Diagnostics Laboratory in Boulder, Colorado, provides a test bed for the development of the data extension method; we intend to integrate and extend CO2 measurement records from other laboratories providing a globally consistent atmospheric CO2 database to the modeling community.

Grass attack

Effects of fuel and forest conservation on future levels of atmospheric carbon dioxide

’s (2012) conclusion that observed climate change is comparableto projections, and in some cases exceeds projections, allows further inferences ifwe can quantify changing climate forcings and compare those with projections.The largest climate forcing is caused by well-mixed long-lived greenhouse gases.Here we illustrate trends of these gases and their climate forcings, and we discussimplications. We focus on quantities that are accurately measured, and we includecomparison with fixed scenarios, which helps reduce common misimpressionsabout how climate forcings are changing.Annual fossil fuel CO

Effects of fuel and forest conservation on future levels of atmospheric carbon dioxide

There is an increasing concern over climate change and its environmental impacts. Effective greenhouse gases (GHG) monitoring and control strategies are of pivotal importance. Models such as STILT (Stochastic Time-Inverted Lagrangian Transport), statistical techniques, and experimental data analysis provide valuable tools for quantifying emissions and identifying greenhouse gas (GHG) tendencies. The Mediterranean basin is considered a global hotspot for air-quality and climate change: here, we combine experimental datasets of atmospheric methane (CH 4 ) and carbon dioxide (CO 2 ) with atmospheric transport models to present an atmospherically-based framework for monitoring GHG emissions. We applied methodologies, i.e., the Smoothed Minima (SM) and STILT, to extract background concentration data from the time series of atmospheric gases and identify measurements deemed representative of atmospheric background (GRD) levels. At the Lamezia Terme (Global Atmosphere Watch, GAW code: LMT), Capo Granitola (GAW code: CGR), and Lampedusa (GAW code: LMP) observation sites, GHG measurements were performed with specific calibration routines carried out using primary standards of calibration from the National Oceanic and Atmospheric Administration – Global Monitoring Laboratory (NOAA–GML), with secondary standards used to evaluate possible drifts and calibration factors stability. The first two are coastal stations and the third is an island station. At these sites, atmospheric CH 4 and CO 2 mole fractions can be evaluated at local and continental scales, in locations with specific Mediterranean climatic characteristics. This paper presents the variability of CH 4 and CO 2 in the central Mediterranean basin by analyzing hourly GHG concentrations over a 9-year period (2015–2023) for LMT, a 8-year period (2015–2022) for CGR, and a 19-year period (2006–2024) for CO 2 and 5-year period (2020–2024) for CH 4 at LMP. STILT provides 3-hourly results for methane and carbon dioxide concentrations that correlate well with surface measurements at LMT, CGR, and LMP. These analyses are aimed at relevant long-term datasets of GHG over southern Italy. This work would provide a useful contribution to comparing the observed concentrations of gases measured at three sites in the central Mediterranean with those predicted by models such as STILT. The results indicate good agreement between in situ measurements and modeling, and underline the importance of synergies between different institutions and methodologies. Compared to the CGR and LMP site, LMT has recorded higher levels of anthropogenic emissions in the area. Graphical Abstract Framework shows the variability of methane and carbon dioxide in the Mediterranean basin at three permanent World Meteorological Organization/Global Atmosphere Watch (WMO/GAW) stations in southern Italy: Lamezia Terme (GAW code: LMT), Capo Granitola (GAW code: CGR) and Lampedusa (GAW code: LMP). Accurate modeling of atmospheric transport is essential to address environmental concerns and to establish a quantitative link between observed gas distributions and surface emissions. In the present work, we used the Stochastic Time Inverted Lagrangian Transport (STILT) and the Smoothed Minima (SM) models. STILT simulates transport by following the time evolution of a particle ensemble, interpolating meteorological fields to the subgrid location of each particle. Both methods were used to extract background concentration data from the time series of atmospheric gases representative of the atmospheric background levels. The paper is an important contribution to the comparison between the observed and predicted by models concentrations of methane and carbon dioxide at three sites in the central Mediterranean. The STILT model datasets, validated at the three sites, show satisfactory results, with the exception of an overall underestimation in all comparisons (background and no-background). They demonstrate that the model can accurately estimate the CH 4 and CO 2 concentrations in the Mediterranean basin. Similar results are also obtained when comparing the SM and STILT background datasets. This last comparison indicates a good identification of the concentrations of the background gases by the models.

The increase in carbon dioxide in the atmosphere is one of the main causes of global warming. Remote sensing technology has become an important means of monitoring the distribution of carbon dioxide gas. By remotely monitoring the temporal and spatial distributions of atmospheric carbon dioxide, people can further deepen their understanding of the global carbon process. The GOSAT (Greenhouse Gases Observing SATellite) CO2 L4B concentration data from 2010 to 2015 were validated using local station atmospheric data. The spatial and temporal distributions of the carbon dioxide concentration and its variation characteristics were analyzed. Based on the total primary productivity data and human emissions of carbon dioxide data, the influencing factors of spatial variations in carbon dioxide were analyzed. The results show that: (1) The correlation coefficient between GOSATL4B data and ground-measured data is above 0.95, which indicates that the remotely acquired data have high precision and stability. (2) The spatial distribution characteristics of carbon dioxide at different atmospheric pressure heights are quite different. The variation in the long-term series mean of carbon dioxide concentration levels at 17 vertical heights was studied. The fluctuations in concentration changes at different height levels vary, and the closer to the surface, the greater the fluctuation is. The near-surface carbon dioxide concentration (975 hPa) has the largest fluctuation. When the atmospheric pressure is low (for example, 150 or 100 hPa), the high carbon dioxide concentration region is banded and concentrated near the equator. The trends in carbon dioxide concentration over land and sea surfaces are similar, and the common pattern is that the concentration of carbon dioxide has been increasing. (3) The near-surface carbon dioxide concentration (975 hPa) has clearly different spatial characteristics. There are four high-value centers across the globe: East Asia, western Europe, the US East Coast, and Central Africa. The concentration of carbon dioxide in the Northern Hemisphere near the ground is higher than that in the Southern Hemisphere. The fluctuation in the Southern Hemisphere is relatively small, and the trend is opposite that in the Northern Hemisphere. (4) The concentration of carbon dioxide showed a significant growth trend during the study period. By studying the change characteristics of the monthly global average at the 975 hPa level (approximately 300 m above sea level) from January 2010 to October 2015, it can be seen that the global CO2 concentration has been above 400 ppm for most of the year, and it is increasing each year. (5) Compared with the Southern Hemisphere, the cyclical changes in carbon dioxide concentration in the Northern Hemisphere are obvious and large, while the trend in the Southern Hemisphere is relatively stable, and the change is small. There are opposite trends in the cyclical changes in the carbon dioxide concentration in the Northern and Southern Hemispheres. When the carbon concentration in the Northern Hemisphere resides over the annual high-value area, the Southern Hemisphere has a low-value area of carbon dioxide concentration every year. In addition, the change in carbon dioxide concentration during the year is obvious with seasonal changes. This should be related to changes in vegetation phenology and different seasons in the Northern and Southern Hemispheres. (6) Four countries in East Asia (Korea, Mongolia, Japan and China) from 2010 to 2014 were selected to analyze the relationship between GPP (gross primary production) and near-surface carbon dioxide concentration. These two factors have a significant inverse correlation. When carbon dioxide is at a minimum, the GPP is at its peak, and when carbon dioxide reaches its peak, the GPP reaches a minimum. The above relationship fully indicates that terrestrial ecosystems play an important role as carbon sink contributors in the carbon cycle. (7) The relationship between atmospheric carbon dioxide and carbon dioxide data from human activities from the Global Atmospheric Research Emissions Database was analyzed. The former is significantly and positively correlated with carbon dioxide emissions caused by human activities, indicating that human activities are an important factor in the increase in carbon dioxide.

An investigation of carbon dioxide partial pressures in the atmosphere and surface ocean conducted as part of a cooperative study under the general sponsorship of the International Geophysical Year is summarized. Results are given for about 470 hours of air analyses and 200 individual surface ocean water measurements made from 1957 to 1959 between 60°N and 58°S. Over the Atlantic Ocean, the atmospheric carbon dioxide concentration is found to average 316 ppm by volume and to be quite uniform except for a minor increase toward the equator. The total carbon dioxide in the earth's atmosphere is estimated to be 2.41×1018g. In the equatorial region, the partial pressure of carbon dioxide appears to be higher in the surface water than in the atmosphere; in the higher latitudes it appears to be lower.

Identifying the sources and sinks of methane and carbon dioxide is important for understanding processes within the Earth's climate system. This paper attempts to use back trajectories to identify sources of atmospheric methane and carbon dioxide as measured by high resolution in situ gas analyzers during aircraft ascents and descents in Southern Australia. Results from the back trajectory analysis were confirmed by also performing a forward trajectory analysis on some of the data. The in situ aircraft measurements were part of a joint Japanese‐Australia field campaign in March and April 2007 near Adelaide, South Australia. The vertical profiles showed considerable variation in methane and carbon dioxide content above the planetary boundary layer. We used back trajectories based on an atmospheric transport model to derive the origin of the air masses which enabled speculation about sources of the gases. We were thus able to identify emission from the volcanoes on Réunion Island in the Indian Ocean and the seafloor hydrothermal activity in the Southeast Indian Ridge, confirming speculations published earlier by other research teams.

Annual CO2 emissions (in 1000 Mt) %

The heat of immersion of Zeolite (Molecular Sieve-13X) in water was experimentally found to increase with its degassing temperature and to have a maximum peak at about 300°C. The acidity of Zeolite measured by n-butylamine titration also showed a similar peak at 300°C. But the heat of immersion of Zeolite in benzene showed a definite value above 200°C. It was found that though physically absorbed water or structral water may be remove at lower degassing temperature, further desorption of water and surface changes occurred above 300°C.Magnesia showed a higher heat of immersion when ground in the atmospheres of dry air and carbon dioxide. The activation of the Magnesia surface was mainly caused by the distorted surface layer, i. e., the plastic flow of the surface. From the infra-red spectra, carbon dioxide was detected on the Magnesia surfaces which were ground in the atmosphere of carbon dioxide. In this case, the surface activation by grinding was caused by the formation of an electro-static field by the chemisorbed carbon dioxide, as well as by the distortion of the surface layer.