Net Land Research Articles

Propulsion-gear-based characterisation of artisanal fisheries in the Malindi-Ungwana Bay, Kenya and its use for fisheries management

In Kenya, like other tropical countries, coastal artisanal fishery is multispecies, multigear and multifleet in nature with many management challenges. The Malindi-Ungwana Bay in particular, supports both the artisanal fishery and the semi-industrial bottom trawl shrimp fishery presenting a management challenge. Recent stock assessment surveys have identified catch composition of the semi-industrial bottom trawl fishery in the bay but artisanal catches remain barely described. This study describes, the artisanal fish catch composition (total number of species caught, sizes and trophic levels), and catch-per-unit-effort (CPUE) for each of the most popular propulsion-gear categories used in the bay. We make a case that the use of specific propulsion-gear categories can be dynamically managed to encourage the recovery of selected fish groups and thus support fisheries management. A total of 4 269 finfish belonging to 177 species and 66 families were sampled by the 5 most popular propulsion-gear categories between 2009 and 2011. The total number of species caught was highest for canoe-gillnet, mashua-gillnet and foot-seine net, and lowest for foot-handline and mashua-handline. Significant differences in catch composition existed between the different propulsion-gear categories. The CPUE was not significantly different between propulsion-gear, although this was on the average highest for canoe-gillnet and mashua-gillnet, and lowest for the foot-handline. The highest trophic level of 4.0 was recorded for mashua-gillnet and the lowest 3.4 and 3.2 for canoe-gillnet and foot-seine net respectively. The use of specific combinations of propulsion-gear categories, give an alternative approach in management recommendation of the coastal artisanal fisheries in the tropics, from the traditional gear-based management initiative. This study, singled out the mashua-gillnet, canoe-gillnet and foot-seine net as suitable units for monitoring the artisanal fisheries in Malindi-Ungwana Bay since mashua-gillnet lands the highest mean trophic level and largest sized individuals, and canoe-gillnet and foot-seine net land the highest number of species caught and smallest sized individuals.

Exploiting provisions of land economic productivity without degrading its natural capital

Motivated by the United Nations target of achieving zero net land degradation by 2030 and the Rio + 20 United Nations' “future we want” resolution, which aims to achieve a green economy, this study was conducted with an objective of identifying strategies for achieving sustainable use of lands at a global and a regional level. Using econometric approaches, we observed that achievement of zero net degradation is possible, even in developing regions, if land users are provided with good market access and secure land rights and if institutions are strengthened to regulate land use. Such achievement is possible, even in densely populated and severely impoverished areas. The probability of achieving zero net land degradation is greater in drylands – especially among communities with pastoral and other livestock-based livelihoods.

Land use changes from EU biofuel use: a sensitivity analysis

This paper employs the general equilibrium model MAGNET to assess the effects of the European Commission’s proposals for the revision of the Renewable Energy Directive (RED) on land use changes in the European Union and worldwide. The focus of the paper is to evaluate the sensitivity of the land use changes to different assumptions on the blending mix between ethanol and biodiesel for meeting the 5 % blending target of first generation biofuels, on the intensification level of agricultural production and on the available agricultural land. The results suggest that net land use changes (LUC) in the EU due to the revised RED are limited and are more sensitive to the share of ethanol and biodiesel in meeting the blending target compared to different assumptions on the availability of land and of yields that can be achieved when substituting land with other production factors. LUC in the rest of the world stem from increased EU imports of feedstock and of biofuels. LUC is especially sensitive to the substitution between land and fertilizer in regions with extensive agricultural production systems. In regions trading vegetable oil and oilseeds with the EU, and in regions producing ethanol, LUC is influenced by the share of ethanol in the biofuel mix used in the EU.

Operationalizing Zero Net Land Degradation: The next stage in international efforts to combat desertification?

At the United Nations Conference on Sustainable Development (Rio+20) in June 2012, governments adopted “The Future We Want” outcome document, which recognized (in paragraph 206) “the need for urgent action to reverse land degradation. In view of this we will strive to achieve a land-degradation neutral world … .” This paragraph sets a goal of maintaining a world where the total amount of degraded land remains constant, and that would secure the currently available productive land for the use of present and future generations.This article examines the challenges of operationalizing this concept of Zero Net Land Degradation (ZNLD) and its global derivative, a land degradation neutral world (LDNW).First, the concept and need for ZNLD is introduced and explained. Then we look at the expectations from ZNLD/LDNW targets within the context of promoting the recognition of land degradation as a global threat and contributing to global food security. Next we elaborate the challenges in making ZNLD operational, including: scoping (determining the spatial scale and the selected domain for which land degradation neutrality is to be achieved); mapping (classifying the lands by their current use and state of their productivity); prescribing (prescribing management practices relevant to each of the land classes); applying the selected land management (for either reducing degradation, restoring productivity, or increasing resilience); and monitoring management and its outcome.We then examine the enabling environment necessary to capture ZNLD opportunities and address the technical challenges facing the operationalization of ZNLD. The article concludes with recommendations for the way forward: first, recognize existing projects suitable for ZNLD testing and establish new pilot projects at the local community or landscape scales; and the second, seek recognition and support for achieving ZNLD at the global scale through the United Nations system.

The implications of environmental trading mechanisms on a future Zero Net Land Degradation protocol

Despite many important success stories around the planet, there is general disappointment at the overall impact of the United Nations Convention to Combat Desertification (hereinafter: UNCCD) during its first 20 years, with soil degradation still a challenge for land managers throughout much of the world's drylands. Calls for a new protocol under the UNCCD that will ensure “Zero Net Land Degradation” (ZNLD) have gained momentum since the tacit endorsement of the concept at the 2012 Rio + 20 summit. There is great conceptual appeal to a framework that implicitly allows for development by balancing associated soil fertility loss with commensurate gains resulting from restoration activities. Trading programs which seek to reach “zero net” degradation of other natural resources have been in place for many years now internationally and offer an important basis for assessing the practical and theoretical problems that are likely to arise under a ZNLD framework. This article summarizes the relevant experiences garnered in “offsetting” regulatory schemes in the areas of wetland preservation, biodiversity, forestry, greenhouse gas emissions mitigation, real estate zoning, and conventional air pollution control. While many of these initiatives take place in environments with completely different climatic conditions, they offer important lessons for ZNLD advocates. Pitfalls in offset programs are identified in the areas of: reliability of trades; clear quantifiable units of measure; equivalence given land heterogeneity; and delayed benefits. The article contains a series of recommendations for land degradation offsets based on this diverse international experience. Proven implementation strategies should inform any future ZNLD policies as part of national and regional regulatory programs to combat desertification and arid land soil degradation.

Terminology as a key uncertainty in net land use and land cover change carbon flux estimates

Abstract. Reasons for the large uncertainty in land use and land cover change (LULCC) emissions go beyond recognized issues related to the available data on land cover change and the fact that model simulations rely on a simplified and incomplete description of the complexity of biological and LULCC processes. The large range across published LULCC emission estimates is also fundamentally driven by the fact that the net LULCC flux is defined and calculated in different ways across models. We introduce a conceptual framework that allows us to compare the different types of models and simulation setups used to derive land use fluxes. We find that published studies are based on at least nine different definitions of the net LULCC flux. Many multi-model syntheses lack a clear agreement on definition. Our analysis reveals three key processes that are accounted for in different ways: the land use feedback, the loss of additional sink capacity, and legacy (regrowth and decomposition) fluxes. We show that these terminological differences, alone, explain differences between published net LULCC flux estimates that are of the same order as the published estimates themselves. This has consequences for quantifications of the residual terrestrial sink: the spread in estimates caused by terminological differences is conveyed to those of the residual sink. Furthermore, the application of inconsistent definitions of net LULCC flux and residual sink has led to double-counting of fluxes in the past. While the decision to use a specific definition of the net LULCC flux will depend on the scientific application and potential political considerations, our analysis shows that the uncertainty of the net LULCC flux can be substantially reduced when the existing terminological confusion is resolved.

Achieving Zero Net Land Degradation: Challenges and opportunities

Land degradation is extensive, covering approximately 23% of the globe's terrestrial area, increasing at an annual rate of 5–10 million ha, and affecting about 1.5 billion people globally. Such detrimental processes call for urgent and comprehensive action to halt land degradation. In this paper, we assess the causes and extent of land degradation around the world, followed by an outline of the various challenges in implementing a global Zero Net Land Degradation (ZNLD) policy. The concept of ZNLD proposes a scheme under which the extent of global degraded lands will decrease or at least, remain stable. To enable this type of scenario, the rate of global land degradation should not exceed that of land restoration. Restoration efforts should include not only croplands, rangelands, and woodlands, but also natural and semi-natural lands that do not generate direct economic revenues. The United Nations Convention to Combat Desertification (UNCCD) envisages achieving this target by 2030. Despite being seemingly ambitious, the target of ZNLD could be achieved if degraded lands are restored to a considerable extent and, at the same time, land-degrading management practices are replaced with ones that conserve soils. To enable effective implementation of these steps, it is necessary to formulate a ZNLD Protocol aimed at managing assessment actions and maintaining of supportive policies and regulations. Restoration projects could be financed through payments for improving ecosystem services, as well as other economic mechanisms. Achieving the target of land degradation neutrality would decrease the environmental footprint of agriculture, while supporting food security and sustaining human wellbeing.

Reckoning perverse outcomes of resource conservation policies using the Ecological Footprint

Spatially expanding economies threaten the status of basic natural resources. In particular, wildlife habitats rarely benefit. Apart from protected areas, political-economic decision-making is ill-prepared to accommodate wildlife habitats with standard valuation methods. In some cases habitat loss is an inadvertent outcome of resource conservation policies intended to lower resource consumption.We recognize the term resource conservation as multifaceted, with a range of meanings from protecting wildlife habitats to efficiently allocating and using materials and energy. Resource conservation policies that spur economic benefits may produce unwanted outcomes. This is partly because linkages between economic and conservation goals seem tangential. Moreover, relevant information is imperfect and predictive tools are limited. This is particularly true for land converting impacts, which are often addressed after the fact, not during policy formulation, and can lead to successive resource degradation.We argue for the need to calculate the positive and negative land converting impacts from resource conservation policies that may expand the economy. Using the Ecological Footprint (EF) approach, we tested for potentially perverse outcomes of an existing resource conservation policy. In doing so, we conceptually mapped linkages among economic sectors to their cumulative effects of converting land. We assume an inverse relationship between economic expansion and land conservation.A New York State energy efficiency incentive program was tested using recent data from all tracked economic sectors. The economic data were converted in a series of steps from dollar values to energy units, to carbon dioxide emissions, and ultimately expressed in hectares of net land conversion. A policy scenario was compared to a reference scenario (no resource conservation policy), and the results anticipate a net gain in conserving land (0.6% reduced conversion). We interpret this as a potentially proportional offset favoring wildlife habitat retention. Two sensitivity analyses demonstrated that the policy’s impact on conserving land depended on both the affected economy’s scale (tripling reduces the estimated benefit to 0.2%), and the level of economic expansion that followed (doubling leads to a net loss of wildlands).This novel use of the EF approach may serve as a model for a more general approach to assessing a broader class of policies. It may also hold promise toward developing tools that can better examine well-intentioned resource conservation policies with uncertain outcomes. Our hope is that work like this can lead to better sets of tools for examining critical ecological–economic linkages for improved policy design.

Land-taking processes: An interpretive study concerning an Italian region

Land take is a process of significant relevance in the countries of European Union (EU).Land take is the “Change of the amount of agriculture, forest and other semi-natural and natural land taken by urban and other artificial land development” (European Environment Agency, 2013a).In 2011, the European Commission (EC) put in evidence that an important milestone for the EU should be to reach the goal of no net land take by 2050, and to take under strict control the impact on landtaking processes of the EU policies in the new Structural Funds programming period (2014–2020) (Communication of the EC to the European Parliament COM(2011) 571 of 20.9.2011).In this paper we analyze the Sardinian land-taking process as related to factors which are identified as relevant variables in several studies concerning land take, such as area size, accessibility, proximity to regional and local cities and small settlements, natural risk, proximity to nature conservation areas.

Geographical and seasonal variability of the global “practical” wind resources

This paper provides global and seasonal estimates of the “practical” wind power obtained with a 3-D numerical model (GATOR-GCMOM) that dynamically calculates the instantaneous wind power of a modern 5 MW wind turbine at 100-m hub height at each time step. “Practical” wind power is defined as that delivered from wind turbines in high-wind locations (year-average 100-m wind speed ≥ 7 m/s) over land and near-shore, excluding both polar regions, mountainous, and conflicting land use areas, and including transmission, distribution, and wind farm array losses. We found that seasonal variations in the global practical wind resources are significant. The highest net land plus near-shore capacity factors globally are found during December–January–February and the lowest during June–July–August. The capacity factors in the transitional seasons (March–April–May and September–October–November) are rather similar to one another in terms of geographical patterns and frequency distributions. The yearly-average distributions of capacity factors, whether in terms of geographic patterns or frequency distributions, differ from those in all four seasons, although they are closest to the transitional seasons. Regional practical wind resources are sensitive to seasons and to thresholds in year-average wind speed and bathymetry, but are more than enough to supply local electricity demand in all regions except Japan.

A joint atmosphere‐ocean inversion for the estimation of seasonal carbon sources and sinks

We have estimated global surface fluxes of carbon dioxide for the period 1992–1996 using an inverse approach that sequentially considers four constraints: (1) atmospheric CO2, (2) ocean interior DIC (dissolved inorganic carbon) interpreted through an ocean interior inversion and surface ocean pCO2 (partial pressure of CO2), (3) annual prior fluxes for selected land regions, and (4) atmospheric model selection based on vertical transport skill. Estimated fluxes are monthly resolved for each of the 22 Transcom regions over land and ocean. The ocean constraint is particularly valuable, as it does not only add prior information about air‐sea fluxes to the inversion problem but also preserves the regional variance‐covariance structure from the underlying ocean interior inversion. It allows to constrain annual oceanic uptake of 1.8 PgCyr−1 to within 0.2 PgCyr−1, which implies a net annual land uptake of 1.3 (±0.3) PgCyr−1. Furthermore, it leads to a pronounced asymmetry in the seasonal pattern of global land uptake, which was not seen in previous atmosphere‐only inversions. Tropical land is consistently estimated to be a source of carbon, though the source magnitude is reduced as more constraints are applied. With all four constraints, the inversion suggests a net tropical source of 1.1 (±0.9) PgCyr−1, which is comparable to global estimates of deforestation rates in tropical forests and therefore implies an annually balanced tropical land biosphere flux. This balance is not found, however, at the regional level: For the Amazonian region and after accounting for deforestation, we find a biospheric source of 0.6 (±0.5) PgCyr−1. This is at the upper range of estimates from bottom‐up methods, which tend to identify the region as a sink.

Diurnal variation in stored energy flux in São Paulo city, Brazil

This work describes the diurnal variation in energy flux storage in the city of São Paulo, Brazil. Monthly average hourly values for the storage of energy flux were estimated using the energy balance residual and parameterisation methods. The energy balance residual method used in situ observations of net all-wave radiation and turbulent fluxes of sensible and latent heat. The anthropogenic heat flux and horizontal net heat advection were not considered. The parameterisation method, based on the objective hysteresis model, used net all-wave radiation and land use information inferred from a 1-km radius area centred at the main observational site. Using the residual balance method, the maximum diurnal evolution in monthly average hourly values of energy flux storage occurred approximately 2h earlier than the net all-wave radiation. Using the parameterisation method to estimate energy flux storage, the daytime integrated values correspondedto approximately 51% of the net all-wave radiation and daily values to approximately 27%. The diurnal evolution in urban heat island intensity, based on monthly average values, reached a maximum intensity of 3.3°C and a minimum of, did not show a correlation with the energy flux storage during the time period considered in this work.

Towards a more objective evaluation of modelled land-carbon trends using atmospheric CO<sub>2</sub> and satellite-based vegetation activity observations

Abstract. Terrestrial ecosystem models used for Earth system modelling show a significant divergence in future patterns of ecosystem processes, in particular the net land–atmosphere carbon exchanges, despite a seemingly common behaviour for the contemporary period. An in-depth evaluation of these models is hence of high importance to better understand the reasons for this disagreement. Here, we develop an extension for existing benchmarking systems by making use of the complementary information contained in the observational records of atmospheric CO2 and remotely sensed vegetation activity to provide a novel set of diagnostics of ecosystem responses to climate variability in the last 30 yr at different temporal and spatial scales. The selection of observational characteristics (traits) specifically considers the robustness of information given that the uncertainty of both data and evaluation methodology is largely unknown or difficult to quantify. Based on these considerations, we introduce a baseline benchmark – a minimum test that any model has to pass – to provide a more objective, quantitative evaluation framework. The benchmarking strategy can be used for any land surface model, either driven by observed meteorology or coupled to a climate model. We apply this framework to evaluate the offline version of the MPI Earth System Model's land surface scheme JSBACH. We demonstrate that the complementary use of atmospheric CO2 and satellite-based vegetation activity data allows pinpointing of specific model deficiencies that would not be possible by the sole use of atmospheric CO2 observations.

Recent decadal growth of the Atchafalaya River Delta complex: Effects of variable riverine sediment input and vegetation succession

The Mississippi River Delta Plain has experienced substantial wetland loss from subsidence, erosion, and sea level rise, threatening coastal communities and the ecosystems that support them. The Atchafalaya River, the largest distributary of the Mississippi River, has one of the few prograding delta features along the ~200-km deltaic coastline. Understanding changes in the Atchafalaya River Delta complex (ARDC) development has critical implications for future prediction and management strategy for the Mississippi River Delta Plain. This study was organized to answer two major questions: (1) how did development of the ARDC respond to fluctuation in riverine sediment supply over the period 1989–2010, and (2) has vegetation succession helped stabilize subaerial land? The study quantified annual total suspended sediment yields to the two ARDC subdeltas—Atchafalaya River subdelta (ARSD) and Wax Lake outlet subdelta (WLSD)—classified delta land cover using satellite imagery over ~5-year intervals into three classes: barren land, vegetation, and open water and investigated the relationship of delta land change with sediment yield and vegetation succession. Over the entire 21-year study period, we found a net land gain of 59km2, with the ARSD accounting for 58% of this gain and WLSD 42%. Sediment yield to the subdeltas decreased from an average annual of 38megatonnes (MT) for ARSD and 18 MT for WLSD during 1989–1995 to an average annual of 24MT for ARSD and 17MT for WLSD during 2004–2010, corresponding to the decrease in riverine suspended sediment concentration. Concurrently, total land growth rate decreased from 2.4km2y−1 to 1.6km2y−1 for ARSD and 3.2km2y−1 to 0.6km2y−1 for WLSD. However, the ARDC had a net land loss of 2.1km2 during 1999–2004 because of tropical system effects in conjunction with the lack of large river floods (defined as discharge>13,800m3s−1). On average, more than 60% of newly vegetated land remained vegetated in subsequent years, and when compared with barren areas, vegetated land was less likely (7.3% vs. 32%) to be converted to water, indicating vegetative stabilization effect. However, during the period without a major flood, vegetation buffering against tropical system erosion was limited. This indicates that over the period 1989 to 2010 land growth of the ARDC was dictated by large flood events.

The carbon budget of South Asia

Abstract. The source and sinks of carbon dioxide (CO2) and methane (CH4) due to anthropogenic and natural biospheric activities were estimated for the South Asian region (Bangladesh, Bhutan, India, Nepal, Pakistan and Sri Lanka). Flux estimates were based on top-down methods that use inversions of atmospheric data, and bottom-up methods that use field observations, satellite data, and terrestrial ecosystem models. Based on atmospheric CO2 inversions, the net biospheric CO2 flux in South Asia (equivalent to the Net Biome Productivity, NBP) was a sink, estimated at −104 ± 150 Tg C yr−1 during 2007–2008. Based on the bottom-up approach, the net biospheric CO2 flux is estimated to be −191 ± 193 Tg C yr−1 during the period of 2000–2009. This last net flux results from the following flux components: (1) the Net Ecosystem Productivity, NEP (net primary production minus heterotrophic respiration) of −220 ± 186 Tg C yr−1 (2) the annual net carbon flux from land-use change of −14 ± 50 Tg C yr−1, which resulted from a sink of −16 Tg C yr−1 due to the establishment of tree plantations and wood harvest, and a source of 2 Tg C yr−1 due to the expansion of croplands; (3) the riverine export flux from terrestrial ecosystems to the coastal oceans of +42.9 Tg C yr−1; and (4) the net CO2 emission due to biomass burning of +44.1 ± 13.7 Tg C yr−1. Including the emissions from the combustion of fossil fuels of 444 Tg C yr−1 for the 2000s, we estimate a net CO2 land–atmosphere flux of 297 Tg C yr−1. In addition to CO2, a fraction of the sequestered carbon in terrestrial ecosystems is released to the atmosphere as CH4. Based on bottom-up and top-down estimates, and chemistry-transport modeling, we estimate that 37 ± 3.7 Tg C yr−1 were released to atmosphere from South Asia during the 2000s. Taking all CO2 and CH4 fluxes together, our best estimate of the net land–atmosphere CO2-equivalent flux is a net source of 334 Tg C yr−1 for the South Asian region during the 2000s. If CH4 emissions are weighted by radiative forcing of molecular CH4, the total CO2-equivalent flux increases to 1148 Tg C yr−1 suggesting there is great potential of reducing CH4 emissions for stabilizing greenhouse gases concentrations.

Agricultural trade and virtual land use: The case of China's crop trade

Trade liberalization has greatly accelerated the volume of traded agricultural products in past decades. As land resources become more limited in some countries, international trade plays an important role in compensating for land scarcity in these countries. This paper aims to measure and locate the virtual land use hidden in China's imports and exports, for both primary crops and processed products, from 1986 to 2009. The results show that as China's crop imports had grown greatly during the last decade, the net virtual land trade hidden in international trade had increased from −4.42Mha in 1986 to 28.90Mha in 2009. The main category of virtual land imports had changed from cereals to oil crops, which accounted for 82.2% of the total virtual land imports in 2009. Over the two decades the main source of virtual land imports had changed from North America to both South America and North America. International trade could also lower demand for land resources at the global level: our results showed that China's crop trade was contributing to global land savings by 3.27Mha on annual average during 1986–2009. Economic development, and associated dietary changes and policy shifts were linked to the change of China's virtual land trade pattern. To make land use more sustainable at the global level, both importing and exporting countries of virtual land should consider ecological and socio-economic impacts of these trade flows in their policies.

A model-based constraint on CO<sub>2</sub> fertilisation

Abstract. We derive a constraint on the strength of CO2 fertilisation of the terrestrial biosphere through a "top-down" approach, calibrating Earth system model parameters constrained by the post-industrial increase of atmospheric CO2 concentration. We derive a probabilistic prediction for the globally averaged strength of CO2 fertilisation in nature, for the period 1850 to 2000 AD, implicitly net of other limiting factors such as nutrient availability. The approach yields an estimate that is independent of CO2 enrichment experiments. To achieve this, an essential requirement was the incorporation of a land use change (LUC) scheme into the GENIE Earth system model. Using output from a 671-member ensemble of transient GENIE simulations, we build an emulator of the change in atmospheric CO2 concentration change since the preindustrial period. We use this emulator to sample the 28-dimensional input parameter space. A Bayesian calibration of the emulator output suggests that the increase in gross primary productivity (GPP) in response to a doubling of CO2 from preindustrial values is very likely (90% confidence) to exceed 20%, with a most likely value of 40–60%. It is important to note that we do not represent all of the possible contributing mechanisms to the terrestrial sink. The missing processes are subsumed into our calibration of CO2 fertilisation, which therefore represents the combined effect of CO2 fertilisation and additional missing processes. If the missing processes are a net sink then our estimate represents an upper bound. We derive calibrated estimates of carbon fluxes that are consistent with existing estimates. The present-day land–atmosphere flux (1990–2000) is estimated at −0.7 GTC yr−1 (likely, 66% confidence, in the range 0.4 to −1.7 GTC yr−1). The present-day ocean–atmosphere flux (1990–2000) is estimated to be −2.3 GTC yr−1 (likely in the range −1.8 to −2.7 GTC yr−1). We estimate cumulative net land emissions over the post-industrial period (land use change emissions net of the CO2 fertilisation and climate sinks) to be 66 GTC, likely to lie in the range 0 to 128 GTC.

The carbon balance of South America: a review of the status, decadal trends and main determinants

Abstract. We summarise the contemporary carbon budget of South America and relate it to its dominant controls: population and economic growth, changes in land use practices and a changing atmospheric environment and climate. Component flux estimate methods we consider sufficiently reliable for this purpose encompass fossil fuel emission inventories, biometric analysis of old-growth rainforests, estimation of carbon release associated with deforestation based on remote sensing and inventories, and agricultural export data. Alternative methods for the estimation of the continental-scale net land to atmosphere CO2 flux, such as atmospheric transport inverse modelling and terrestrial biosphere model predictions, are, we find, hampered by the data paucity, and improved parameterisation and validation exercises are required before reliable estimates can be obtained. From our analysis of available data, we suggest that South America was a net source to the atmosphere during the 1980s (~ 0.3–0.4 Pg C a−1) and close to neutral (~ 0.1 Pg C a−1) in the 1990s. During the latter period, carbon uptake in old-growth forests nearly compensated for the carbon release associated with fossil fuel burning and deforestation. Annual mean precipitation over tropical South America as inferred from Amazon River discharge shows a long-term upward trend. Although, over the last decade dry seasons have tended to be drier, with the years 2005 and 2010 in particular experiencing strong droughts. On the other hand, precipitation during the wet seasons also shows an increasing trend. Air temperatures have also increased slightly. Also with increases in atmospheric CO2 concentrations, it is currently unclear what effect these climate changes are having on the forest carbon balance of the region. Current indications are that the forests of the Amazon Basin have acted as a substantial long-term carbon sink, but with the most recent measurements suggesting that this sink may be weakening. Economic development of the tropical regions of the continent is advancing steadily, with exports of agricultural products being an important driver and witnessing a strong upturn over the last decade.

An estimate of the terrestrial carbon budget of Russia using inventory-based, eddy covariance and inversion methods

Abstract. We determine the net land to atmosphere flux of carbon in Russia, including Ukraine, Belarus and Kazakhstan, using inventory-based, eddy covariance, and inversion methods. Our high boundary estimate is −342 Tg C yr−1 from the eddy covariance method, and this is close to the upper bounds of the inventory-based Land Ecosystem Assessment and inverse models estimates. A lower boundary estimate is provided at −1350 Tg C yr−1 from the inversion models. The average of the three methods is −613.5 Tg C yr−1. The methane emission is estimated separately at 41.4 Tg C yr−1. These three methods agree well within their respective error bounds. There is thus good consistency between bottom-up and top-down methods. The forests of Russia primarily cause the net atmosphere to land flux (−692 Tg C yr−1 from the LEA. It remains however remarkable that the three methods provide such close estimates (−615, −662, −554 Tg C yr–1) for net biome production (NBP), given the inherent uncertainties in all of the approaches. The lack of recent forest inventories, the few eddy covariance sites and associated uncertainty with upscaling and undersampling of concentrations for the inversions are among the prime causes of the uncertainty. The dynamic global vegetation models (DGVMs) suggest a much lower uptake at −91 Tg C yr−1, and we argue that this is caused by a high estimate of heterotrophic respiration compared to other methods.

Did 1933 new deal legislation contribute to farm real estate values: A regional analysis

The proportion of land values generated by farm program payments and farm returns are examined using an extended income capitalization model. The extended income capitalization model addresses the identification issue introduced by the counter-cyclical nature of farm program payments and farm returns. Procedures are presented that allow the estimation of agriculture land value shares without requiring explicit knowledge or assumptions with respect to the net land rental shares of farm returns or farm program payments. Results from the panel recursive or triangular-structure simultaneous equation model applied to 48 states in the U.S. for the period 1938–2010 indicate on average 24–29.2 percent and 76–70.8 percent of the agricultural land values can be identified with farm program payments and farm returns, respectively. Spatially, at the resource regional level the contribution of farm program payments was as low as 20.5 percent in the Eastern Upland region compared to a high of 69 percent in the Mississippi Seaboard region.