Carbonbalance of Norway
The mean annual uptake of carbon in terrestrial ecosystems in Norway between 1990 and 2008 was 6.0±0.9 Tg C, which equalled 40% of Norway’s mean annual greenhouse gas (GHG) emissions for the same period (Figure 2A). The summed riverine transport of OC and DIC was almost 25% of the terrestrialcarbon uptake, or 1.0±0.1 and 0.3 (0.1-0.8) Tg C yr -1 , respectively. It is important to note that the net change in the terrestrialcarbon pool size is not simply found by reducing the terrestrialcarbon uptake with the riverine OC export. Links between terrestrialcarbon sequestration and lateral aquaticcarbon transport may be conceptually clear, but methodologically it is not straightforward to incorporate estimates of lateral aquaticcarbon transport in terrestrialcarbon accumulation estimates at a regional scale. We will return to this issue in the discussion. Evasion of CO 2 from surface waters was 1.7 (0.6 – 4.0) Tg C yr -1 , which includes CO 2 from in-lake processing of OC, from autotrophic and heterotrophic respiration on land and from weathering processes. The largest terrestrialcarbon uptake was in forest biomass (4.9±0.4 Tg C yr -1 ), followed by forest soils (1.1±0.2 Tg C yr -1 ). Carbon uptake in peatlands and carbon losses from agricultural areas almost balanced each other (0.3±0.2 and - 0.4±0.8 Tg C yr -1 , respectively). Mountains and lakes were the smallest carbon sinks (<0.1 Tg C yr -1 ).
emissions. When Fe(III) and SO 2− 4 are abundant in anaero- bic environments they provide preferential terminal electron acceptors for microbial metabolism and thus limit methano- genesis via competitive exclusion (Achtnich et al., 1995). However, high rates of sulfate reduction coupled with Fe re- duction can also lead to the accumulation of metal sulfide minerals, e.g. pyrite and AVS (Johnston et al., 2014). Un- der permanently saturated and low oxygen conditions, metal sulfides will steadily accumulate and remain relatively be- nign. However, if the saturated state of remediated sites can- not be maintained, AVS may react with oxygen, resulting in the undesirable production of acidity and low pH conditions. Therefore, the remediation of wetlands for carbon storage should involve careful site selection to both limit CH 4 pro-
The Fifth Assessment Report (AR5) of the Intergovernmen- tal Panel on Climate Change (IPCC) acknowledges the trans- port of carbon (C) across the inland water network as a key component of the global C cycle (Ciais et al., 2013), involv- ing a significant lateral C transfer along the flow path and stimulating vertical C fluxes in the form of greenhouse gases. However, Earth system models (ESMs) of the climate system and biogeochemical cycles used for the IPCC 5th Assess- ment currently omit lateral C transfers and simulate only lo- cal vertical exchange of C between atmosphere, vegetation and soils from photosynthesis, respiration and fires (Reg- nier et al., 2013). This is a major knowledge gap because recent evidence, from multiple disciplines, has highlighted that anthropogenic disturbances likely increase the lateral C transfers along hillslopes of upland catchments and through streams and rivers (Battin et al., 2009; Cole et al., 2007; Reg- nier et al., 2013). This perturbation may significantly reduce the estimated carbon stored in terrestrial vegetation and soils (Regnier et al., 2013) and increase the C evasion from inland waters to the atmosphere. Thus, it is suggested that lateral carbon transfers induce a positive feedback on the coupled carbon cycle–climate system, enhancing atmospheric CO 2
Consumption of DOC by heterotrophic bacteria is one of the largest fluxes of C in most aquatic ecosystems (Cole, 1999). Transfer of C from the recalcitrant pool to one of the metabolic gates is possible through the process of photo-oxidation (Granéli et al., 1996), which can be further used in algal photosynthesis. Photolysis breaks down complex compounds to the molecules of low molecular weight making them more prone to bacterial utilisation (Stewart & Wetzel, 1982; Geller, 1986; Kieber et al., 1989; Wetzel et al., 1995; Bertilsson & Tranvik, 1998; Cole, 1999), and leading to the formation of DOC, which is more efficiently incorporated into bacterial biomass (Lindell et al., 1995; Amon & Benner, 1996). It has been suggested (Wetzel, 1995; Hessen, 1998) that large pools of recalcitrant terrestrial DOC in aquatic ecosystems have a stabilising effect on ecosystem dynamics by reducing fluctuations of consumer biomass through stable supply of low-quality food from the bacterial-based food chain, which may not allow rapid population growth, but can assist consumers’ survival. Although additional input of DOC to lake or river may be thought to increase productivities of trophic levels as a result of utilisation of the labile C fraction, modelling suggests that the outcome may be more complex, as optical inhibition of photosynthesis due to chromatic dissolved organic material (CDOM) may exceed the enrichment effects of DOC (Jones et al., 2012). This has been observed in the field, where increasing coloured DOC in boreal lakes apparently reduced photosynthesis of benthic algae leading to a decline in total primary production (Ask et al., 2009). Secondary production was also decreased as a result. Jones (1992) reviews photo-inhibition by humic substances of primary production in lakes. Coloured DOC and nutrients can be equally important in regulating primary production (Carpenter et al., 1998).
The NASA Catchment-CN model (Koster et al., 2014) is a hybrid of two existing models: the NASA Catchment model (Koster et al., 2000) and the NCAR Community Land Model version 4 (CLM4) (Oleson et al., 2010). The hybrid utilizes the code from the Catchment model that performs water and energy budget calculations. The carbon and nitrogen dynam- ics from CLM4 provides to the hybrid all of the carbon reser- voir and carbon flux calculations as well as photosynthesis- based estimates of canopy conductance for use in the Catch- ment model’s energy balance equations. Unlike most land surface models, the surface element for Catchment-CN is the hydrological catchment (with a typical spatial dimension of about 20 km); model equations further provide a separation of each catchment into three separate dynamic hydrological regimes, each with its own set of energy balance calculations. There are 19 available plant functional types (PFTs) (Ta- ble S1 in the Supplement), and up to four PFTs are allowed in each of three static sub-areas loosely tied to the three hydro- logical regimes. The model used a 10 min time step for the energy and water balance calculations and a 90 min time step for the carbon calculations. This model’s ability to capture the observed sensitivity of phenological variables to mois- ture variations was demonstrated in Koster et al. (2014).
zoguchi et al., 2009; Takahashi et al., 1999) and ecosystem modeling (Chen et al., 2007; Fan et al., 2012; Randall et al., 1996; Randerson et al., 1997; Sellers et al., 1986, 1996). The top-down method uses atmospheric mole fraction data to derive the CO 2 sink/source information. As one of the im- portant “top-down” approaches, atmospheric inverse model- ing has been well developed and widely applied (Baker et al., 2006; Chevallier and O’Dell, 2013; Deng et al., 2007; Gurney et al., 2003; Gurney et al., 2004), and has shown to be particularly successful in estimating regional carbon flux for regions rich in atmospheric CO 2 observations like North America and Europe (Broquet et al., 2013; Deng et al., 2007; Peters et al., 2007, 2010; Peylin et al., 2005, 2013; Rivier et al., 2011, 2010). However, estimating Asian CO 2 surface fluxes with inverse modeling remains challenging, and the inverted Asian CO 2 fluxes still exhibit a large un- certainty partly because of a lack of surface CO 2 observa- tions. For example, in the TransCom3 annual mean con- trol inversion, Gurney et al. (2003) used a set of 17 mod- els to estimate the carbonfluxes and obtained different re- sults for the Asian biospheric CO 2 budget, ranging from a large CO 2 source of +1.00 ± 0.61 Pg C yr − 1 to a large sink of − 1.50 ± 0.67 Pg C yr − 1 for the year 1992–1996. In the REC- CAP (REgional Carbon Cycle Assessment and Processes) project, Piao et al. (2012) presented the carbonbalance of terrestrial ecosystems in East Asia from eight inversions dur- ing the period 1990–2009. The results from these eight in- version models also show disagreement. Six models esti- mate a net CO 2 uptake with the highest net carbon sink of − 0.997 Pg C yr − 1 , while two models show a net CO 2 source with the largest net carbon emission of +0.416 Pg C yr − 1 in East Asia. The important role of the sparse observational net- work was demonstrated by Maki et al. (2010), who reported a large Asian land sink of −1.17 ± 0.50 Pg C yr − 1 or much smaller sink of −0.65 ± 0.49 Pg C yr − 1 over the Asian region depending on which set of observations was included in the same inversion system. This situation suggests that a more accurate estimate of the surface CO 2 flux is urgently required in Asia, and the ability to base it on as much observational data as possible is key.
geoland/ Carbon will deliver an improved scientific understanding of natural terrestrialcarbonfluxes, in support of the implementation of the Kyoto protocol. More specifically, we envision building a global full carbon accounting modelling system, treating in particular the impact of weather and climate variability on ecosystem fluxes and carbon stocks. The observatory will deliver a unique tool to evaluate the inter- annual variability of the terrestrialcarbon cycle at global and regional scales. Since the same assimilation method will be applied to the whole globe, although with ecosystem-specific parameterisations, the products will serve as a basis for comparing the carbonbalance of one region with another. The users will be 1) international organisations in charge of assessing the carbonbalance (e.g. IGBP, IGOS, IPCC), 2) the scientific community itself (global carbon cycle studies, ecology, meteorology, hydrology), 3) decision makers involved in CO 2 emission control or reduction policies (e.g. carbon sequestration). The verification
Most of the carbon that is added to the soil through litter depo- sition each year (177 g C m 2 yr 1 ) is respired (166 g C m 2 yr 1 ; Table 3 ). When compared to other Arctic sites the estimated aver- age long-term respiration rate at TBL is in the upper range of res- piration measurements made by Elberling (2007) in East Greenland (Zackenberg) and Svalbard (103, 152 and 176 g C m 2 yr 1 for moist Cassiope heath, dry Dryas heath and Salix snow beds, respectively). It is also slightly higher than respiration during July to October in the Zackenberg area (148 g C m 2 yr 1 ; Christiansen et al., 2012 ). This implies that, even though our rough estimate of soil respiration relies heavily on the uncertain estimate of the max- imum active-layer carbon-age, it is at least reasonably correct. That we have used an integrative approach to establish the respiration rate – instead of relying on short term direct measurements of soil respiration – also circumvents any issues with inter and intra annual variability in soil respiration, and it accounts also for any losses of carbon through methane emissions, which can be consid- erable especially in wetter soils ( Mastepanov et al., 2013 ; Geng et al., 2019 ).
The ESF programme steps, and tend to focus on partitioning the soil carbon pool into different sub- pools. These models are generally very good at reproducing, for example, geo- climatic influences on soil carbon distribution, but are less good at describing fine resolution details such as the carbonfluxes at individual sites. On the other hand, the models used by the flux measuring community tend to be short time-step models describing instantaneous soil CO 2 efflux. These models explain most of the daily and annual variation of the CO 2 efflux at particular sites but cannot explain differences between sites and do not attempt to describe long-term carbon dynamics. We hope to bring together these different modelling communities, to bridge the gap in our modelling efforts, and to facilitate the development of a new generation of soil carbonbalance models – ones that can describe fluxes well at the individual site level as well as longer-term trends in soil organic carbon across many sites. The programme will bring together scientists to find ways of reducing uncertainties associated with stock change and flux estimates at site, national and A multidisciplinary programme
2.1. Model Description
2.1.1. Terrestrial Ecosystem Model
[ 6 ] The Terrestrial Ecosystem Model (TEM) is a process‐
based model that uses spatially referenced information on atmospheric chemistry, climate, elevation, soils, and land cover to estimate monthly carbon, nitrogen, and water fluxes and pool sizes in terrestrial ecosystems. The TEM is well‐ documented and has been used to examine patterns of ter- restrial C dynamics across the globe, including how they are influenced by multiple factors such as CO 2 fertilization, climate change, food crop and biofuels production, pastures, wildfire and ozone pollution [e.g., Melillo et al., 1993, 2009; Tian et al., 1998, 2003; McGuire et al., 2001, 2004; Felzer et al., 2004, 2005, 2007; Euskirchen et al., 2006; Zhuang et al., 2006; Balshi et al., 2007, 2009; Sokolov et al., 2008; Galford et al., 2011]. For this study, we used a version of TEM that has been modified from Felzer et al.  to include the influence of permafrost dynamics [Euskirchen et al., 2006], atmospheric nitrogen deposition, nitrogen fixa- tion, and the leaching of carbon and nitrogen (dissolved organic carbon, dissolved organic nitrogen, nitrate) to neighboring river networks on terrestrialcarbon dynamics. To simulate the effects of nitrogen deposition, NH X and NO Y from prescribed atmospheric sources are added to the appropriate available nitrogen pool (ammonium or nitrate) within TEM for potential uptake by microbes and vegeta- tion. Dissolved organic carbon (DOC) and nitrogen (DON) are assumed to be produced by the incomplete decomposition of soil organic matter (SOM). In addition to atmospheric in- puts, nitrate is produced from simulated nitrification in grassland, shrubland and tropical forest ecosystems. Nitrogen fixation is simulated based on the algorithms of Cleveland et al.  adapted to a monthly resolution with the nitro- gen added to either the vegetation structural nitrogen pool or the soil organic nitrogen pool based on the ecosystem par- titioning described by Cleveland et al. . Leaching losses of DOC, DON and nitrate are associated with water yield from the ecosystem. The TEM is calibrated to site‐ specific field data [McGuire et al., 1995; Clein et al., 2002] and extrapolated across the study area based on spatially explicit time series data.
to their fossil-fuel alternatives, will have a CN value of 0. Negative carbon neutrality would imply that the bioenergy strategy is more CO 2 intensive than the fos-
sil alternative. The carbon neutrality of the reference system is the highest while those of the other options are close to 0.93; reCecting the higher fossil-fuel in- put that is required to collect and process additional sugarcane biomass.
ily from practices that reduce the amount of organic carbon in the soil, e.g., fallow or intensive tillage. After the lithosphere and oceans, soil organic matter represents the earth’s third largest pool of carbon (C), greater than the C pools in the atmosphere and biosphere . An increasing amount (presently ~12 percent, see Wood et al. ) of the world’s land area is used for food production. The CAST Task Force reports that modified agricultur- al practices could help reduce agricultural CO 2 emissions. The United Nations Food and Agriculture Submission
Forest management strategy may affect the global carbon stock, biodiversity and global carbon cycle. It is necessary to understand how different management practices can aid in greenhouse gas reduction efforts instead of monetary benefits. Developing countries are required to produce robust estimates of forest carbon stocks for successful implementation of climate change mitigation policies related to Reducing Emissions from Deforestation and Degradation (REDD). Thus, community forest of Nepal has greater potentiality to gain monetary benefits through carbon credits from REDD + mechanism. The study found some evidence to select the best management practices for community forestry and helps to participate in the reducing emission from deforestation and degradation and enhancement of carbon stock (REDD+) mechanism. The study focused on description of the global terrestrialcarbon stocks, status of carbon in forest and shrub land of Nepal and relationship between carbon stock and biodiversity. Position of Nepal in global carbon stock is comparatively better than many others nation in the world. As Nepal is rich in biodiversity and there is positive linkage between biodiversity and carbon stock, Nepal can be benefitted through carbon market.
The Bali Action Plan included all the essentials of forest improvement i.e. reducing deforestation, conservation and sustainable management and enhancement of forest car- bon stocks. Whether forests act as reservoirs, sinks for car- bon from the atmosphere, or sources of GHGs depends on several factors such as the age of the forest, the manage- ment regime, other biotic and abiotic disturbances (e.g. insect pests, forest fires, etc.) and human-induced defores- tation. Planting forests (afforestation and reforestation) clearly provides an opportunity to sequester carbon in vegetation and soils. However, it takes decades to restore carbon stocks that have been lost as a result of land-use changes. The reduction of deforestation and enhancement of forest carbon stocks are the two sides of the same coin, where one cannot do without the other. Both are equally important.
In this study, we present a first integration of water and car- bon fluxes in African ecosystems. Within a rainfall gra- dient between 320–1150 mm the data showed a strong de- pendency of carbonfluxes on water relations. In particu- lar, the strong correlation between maximum canopy pho- tosynthetic capacity and mean annual rainfall revealed valu- able insights in ecosystem functioning in semi-arid environ- ments. However, we could only speculate about the eco- physiological mechanisms underlying our observations, even though we matched theoretical predictions based on global eco-physiological knowledge. We suggest that more ground- based measurements should be combined with modelling ap- proaches and remote sensing. By showing that f APAR pro-
Abstract. The Mackenzie Shelf in the southeastern Beaufort Sea is a region that has experienced large changes in the past several decades as warming, sea-ice loss, and increased river discharge have altered carbon cycling. Upwelling and down- welling events are common on the shelf, caused by strong, fluctuating along-shore winds, resulting in cross-shelf Ek- man transport, and an alternating estuarine and anti-estuarine circulation. Downwelling carries dissolved inorganic carbon (DIC) and other remineralization products off the shelf and into the deep basin for possible long-term storage in the world’s oceans. Upwelling carries DIC and nutrient-rich wa- ters from the Pacific-origin upper halocline layer (UHL) onto the shelf. Profiles of DIC and total alkalinity (TA) taken in August and September of 2014 are used to investigate the cycling of carbon on the Mackenzie Shelf. The along-shore transport of water and the cross-shelf transport of DIC are quantified using velocity field output from a simulation of the Arctic and Northern Hemisphere Atlantic (ANHA4) config- uration of the Nucleus of European Modelling of the Ocean (NEMO) framework. A strong upwelling event prior to sam- pling on the Mackenzie Shelf took place, bringing CO 2 -
Emission coefficients for e.g.: quantity of carbon released per km driven, are based on a variety of sources (SSB, 2005, 2009, 2012a).
In addition to the vector of household expenditures, several other datasets need to be com- bined to allow for the estimation of the indirect emissions. The vector of import coefficients used to split between consumption of Norwegian and non-Norwegian goods and services is estimated using symmetric input-output tables (IOT) for Norway (SSB, 2012b). IOT are available for 59 products times 59 activities organized by the so-called Classification of Products by Activity (EC, 2002). The share of import for each product is calculated as the quantity of imported input to supply a product divided by the total input necessary to supply the product.
switch from a source to a net sink of carbon ten years after restoration started. However, this faster switch suggested by Bain et al. (2011) may be due to this hypothesis considering non-gaseous carbonfluxes, unlike Joosten et al. (2006).
Samaritani et al. (2011) studied net ecosystem CO 2 exchange (NEE) on a cutover bog in the Jura Mountains, Switzerland over one growing season on sites where cutting had stopped 29, 42 and 51 years previously. No active restoration work had occurred, but Sphagnum cover had re-established naturally (Samaritani et al., 2011). Through both measurements and modelling, Samaritani et al. (2011) found that the 29-year site was a net source of CO 2 -C (40 g CO 2 -C m -2 ), whereas both the 42- and 51-year sites were net sinks, with respective average uptake rates of 222 and 209 g CO 2 -C m -2 . These findings by Samaritani et al. (2011) support the hypothesis of Joosten et al. (2006), in that the post-cutting sites followed a similar pattern to the graph shown in Figure 2.3; a net source followed by a net sink. From a study on a peatland over one year prior and three years post restoration in Québec, Canada where drainage ditches had been blocked and Sphagnum fragments had been introduced to speed up re-vegetation, Waddington et al. (2010) hypothesised that it would take 6-10 years from restoration for the site to become a net carbon sink, which is similar to the hypothesis presented by Bain et al. (2011). A maximum of 10 years to become a net carbon sink (Waddington et al., 2010) is a much shorter timescale than observed by Samaritani et al. (2011);
Table 4. Coefficients of variation (standard deviation relative to the mean, expressed in %) for sediment yield, carbon (C) and nitrogen (N) concentrations, and carbon to nitrogen (C:N) mass ratios averaged across years for each catchment, and averaged across catchments for each water year within the Kings River Experimental Watershed. Archive samples from 2006 were not available for sampling (indicated by no data or nd)
Reduced impact logging (RIL) is assumed as a logging practice that will be adopted for “sustainable manage- ment of forests” element of the REDD+ scheme. As RIL was able to significantly reduce wood wastes in the fo- rests (WPW), wood wastes at sawmills (SWS), and logging damages, carbonfluxes in short-lived wood com- ponents can be reduced and therefore reduce emissions when inflow fluxes are smaller than outflow fluxes. By being able to reduce damages, more sawnwood production can be achieved from the same amount of harvested timber. Because sawnwood has longer half-life time carbon, more carbon storage can be achieved as shown in Figure 6. Cumulative fluxes in sawnwood under RIL and CVL increased to 608.4 and 378.7 TgC in 2050 from 44.8 and 29.1 TgC in 2015, respectively. After 35 years, cumulative fluxes under RIL were 229.7 TgC higher than that in CVL. In addition, RIL was able to reduce fluxes in short-lived wood components at 100.6 TgC (Figure 6, Table 4). Not only RIL could retain more carbon in standing forests , but it can also increase sawnwood product and carbonfluxes in sawnwood.