Boreal and subarctic peatlands comprise a carbon pool of 455 Pg that has accumulated during the postglacial period at an average net rate of 0.096 Pg/yr (1 Pg = 1015g). Using Clymo's (1984) model, the current rate is estimated at 0.076 Pg/yr. Longterm drainage of these peatlands is estimated to be causing the oxidation to CO2 of a little more than 0.0085 Pg/yr, with conbustion of fuel peat adding °0.026 Pg/yr. Emissions of CH4 are estimated to release ° 0.046 Pg of carbon annually. Uncertainties beset estimates of both stocks and fluxes, particularly with regard to Soviet peatlands. The influence of water table alterations upon fluxes of both CO2 and CH4 is in great need of investigation over a wide range of peatland environments, especially in regions where permafrost melting, thermokarst erosion, and the development of thaw lakes are likely results of climatic warming. The role of fire in the carbon cycle of peatlands also deserves increased attention. Finally, satellite—monitoring of the abundance of open water in the peatlands of the West Siberian Plain and the Hudson/James Bay Lowland is suggested as a likely method of detecting early effects of climatic warming upon boreal and subarctic peatlands.

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Northern Peatlands: Role in the Carbon Cycle and Probable Responses to Climatic Warming.

Climate change due to greenhouse gas emissions is predicted to raise the mean global temperature by 1.0–3.5°C in the next 50–100 years. The direct and indirect effects of this potential increase in temperature on terrestrial ecosystems and ecosystem processes are likely to be complex and highly varied in time and space. The Global Change and Terrestrial Ecosystems core project of the International Geosphere-Biosphere Programme has recently launched a Network of Ecosystem Warming Studies, the goals of which are to integrate and foster research on ecosystem-level effects of rising temperature. In this paper, we use meta-analysis to synthesize data on the response of soil respiration, net N mineralization, and aboveground plant productivity to experimental ecosystem warming at 32 research sites representing four broadly defined biomes, including high (latitude or altitude) tundra, low tundra, grassland, and forest. Warming methods included electrical heat-resistance ground cables, greenhouses, vented and unvented field chambers, overhead infrared lamps, and passive night-time warming. Although results from individual sites showed considerable variation in response to warming, results from the meta-analysis showed that, across all sites and years, 2–9 years of experimental warming in the range 0.3–6.0°C significantly increased soil respiration rates by 20% (with a 95% confidence interval of 18–22%), net N mineralization rates by 46% (with a 95% confidence interval of 30–64%), and plant productivity by 19% (with a 95% confidence interval of 15–23%). The response of soil respiration to warming was generally larger in forested ecosystems compared to low tundra and grassland ecosystems, and the response of plant productivity was generally larger in low tundra ecosystems than in forest and grassland ecosystems. With the exception of aboveground plant productivity, which showed a greater positive response to warming in colder ecosystems, the magnitude of the response of these three processes to experimental warming was not generally significantly related to the geographic, climatic, or environmental variables evaluated in this analysis. This underscores the need to understand the relative importance of specific factors (such as temperature, moisture, site quality, vegetation type, successional status, land-use history, etc.) at different spatial and temporal scales, and suggests that we should be cautious in "scaling up" responses from the plot and site level to the landscape and biome level. Overall, ecosystem-warming experiments are shown to provide valuable insights on the response of terrestrial ecosystems to elevated temperature.

/pdf/a-meta-analysis-of-the-response-of-soil-respiration-net-4y6fejl9qw.pdf

A meta-analysis of the response of soil respiration, net nitrogen mineralization, and aboveground plant growth to experimental ecosystem warming

The recent warming in the Arctic is affecting a broad spectrum of physical, ecological, and human/cultural systems that may be irreversible on century time scales and have the potential to cause rapid changes in the earth system. The response of the carbon cycle of the Arctic to changes in climate is a major issue of global concern, yet there has not been a comprehensive review of the status of the contemporary carbon cycle of the Arctic and its response to climate change. This review is designed to clarify key uncertainties and vulnerabilities in the response of the carbon cycle of the Arctic to ongoing climatic change. While it is clear that there are substantial stocks of carbon in the Arctic, there are also significant uncertainties associated with the magnitude of organic matter stocks contained in permafrost and the storage of methane hydrates beneath both subterranean and submerged permafrost of the Arctic. In the context of the global carbon cycle, this review demonstrates that the Arctic plays an important role in the global dynamics of both CO2 and CH4. Studies suggest that the Arctic has been a sink for atmospheric CO2 of between 0 and 0.8 Pg C/yr in recent decades, which is between 0% and 25% of the global net land/ocean flux during the 1990s. The Arctic is a substantial source of CH4 to the atmosphere (between 32 and 112 Tg CH4/yr), primarily because of the large area of wetlands throughout the region. Analyses to date indicate that the sensitivity of the carbon cycle of the Arctic during the remainder of the 21st century is highly uncertain. To improve the capability to assess the sensitivity of the carbon cycle of the Arctic to projected climate change, we recommend that (1) integrated regional studies be conducted to link observations of carbon dynamics to the processes that are likely to influence those dynamics, and (2) the understanding gained from these integrated studies be incorporated into both uncoupled and fully coupled carbon-climate modeling efforts. (Less)

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Sensitivity of the carbon cycle in the Arctic to climate change

The geographic and seasonal emission distributions of the major sources and sinks of atmospheric methane were compiled using methane flux measurements and energy and agricultural statistics in conjunction with global digital data bases of land surface characteristics and anthropogenic activities. Chemical destruction of methane in the atmosphere was calculated using three-dimensional OH fields every 5 days taken from Spivakovsky et al. (1990a, b). The signatures of each of the sources and sinks in the atmosphere were simulated using a global three-dimensional tracer transport model. Candidate methane budget scenarios were constructed according to mass balance of methane and its carbon isotopes. The verisimilitude of the scenarios was tested by their ability to reproduce the meridional gradient and seasonal variations of methane observed in the atmosphere. Constraints imposed by all the atmospheric observations are satisfied simultaneously by several budget scenarios. A preferred budget comprises annual destruction rates of 450 Tg by OH oxidation and 10 Tg by soil absorption and annual emissions of 80 Tg from fossil sources, 80 Tg from domestic animals, and 35 Tg from wetlands and tundra poleward of 50°N. Emissions from landfills, tropical swamps, rice fields, biomass burning, and termites total 295 Tg; however, the individual contributions of these terms cannot be determined uniquely because of the lack of measurements of direct fluxes and of atmospheric methane variations in regions where these sources are concentrated.

/pdf/three-dimensional-model-synthesis-of-the-global-methane-lwoiox228k.pdf

Three‐dimensional model synthesis of the global methane cycle

Review and assessment of methane emissions from wetlands

Northern (>40°N) wetlands have been suggested as the largest natural source of methane (CH4) to the troposphere. To refine our estimates of source strengths from this region and to investigate climatic controls on the process, fluxes were measured from a variety of Minnesota peatlands during May, June, and August 1986. Sites included forested and unforested ombrotrophic bogs and minerotrophic fens in and near the U.S. Department of Agriculture Marcell Experimental Forest and the Red Lake peatlands. Late spring and summer fluxes ranged from 11 to 866 mg CH4 m−2 d−1, averaging 207 mg CH4 m−2 d−1 overall. At Marcell Forest, forested bogs and fen sites had lower fluxes (averages of 77 ± 21 mg CH4 m−2 d−1 and 142 ± 19 mg CH4 m−2 d−1) than open bogs (average of 294 ± 30 mg CH4 m−2 d−1). In the Red Lake peatland, circumneutral fens, with standing water above the peat surface, produced more methane than acid bog sites in which the water table was beneath the moss surface (325 ± 31 and 102 ± 13 mg CH4 m−2 d−1, respectively). Peat temperature was an important control. Methane flux increased in response to increasing soil temperature. For example, the open bog in the Marcell Forest with the highest CH4 flux exhibited a 74-fold increase in flux over a three-fold increase in temperature. We estimate that the methane flux from all peatlands north of 40° may be on the order of 70 to 90 Tg/yr though estimates of this sort are plagued by uncertainties in the areal extent of peatlands, length of the CH4 producing season, and the spatial and temporal variability of the flux.

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Methane flux from Minnesota Peatlands

Energy productivity indicates the efficiency of energy use in production. Investment in energy efficient solutions, technologies and practices lead to increased energy productivity. It is often used as a suitable measure to compare the results of economic, energy and climate policies. In 2006, the Republic of Serbia became a member of the Energy Community, thus taking on the obligation to accept the energy acquis of the European Union. By this move, it also accepted the obligation to increase the use of renewables, its final energy consumption and energy services' efficiency. Energy productivity in Serbia has increased by 66.94%, in the period from 2000 to 2019. This growth was primarily driven by the national GDP high growth rate, but not by the reduction of energy consumption. Given the still extremely high Serbian energy intensity levels compared to the European and world average, the aim of this paper is to examine the expected future trends of this indicator. The inverse function econometric model best describes the energy productivity trend in Serbia. The paper concludes that its trend will most likely continue to move upwards, primarily because no significant changes in the Serbian economic and energy policy are expected and because, at least according to official statistics, the country's economy has not been largely affected by the global coronavirus pandemic COVID-19. Since the energy productivity improvement determines the competitiveness and performance of the economy, it is extremely important for Serbia to apply energy efficient technologies, and to implement its further structural changes.

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Modelling the trend of energy productivity in the Serbian economy

The aim of this paper is to explore the motives of Serbian farmers for introducing innovations from the aspect of Rogers' main attributes of innovations. The outcomes of the applied method of binary logistic regression show that these agricultural producers are not so much driven by personal motives in introducing innovations, especially not by their observability and compatibility with farmers' adopted values. The findings also point out that there are impulses and desires of Serbian farmers for introducing innovations, but that the still unfavourable and uncertain market environment hinders them. Since there is no economic progress without innovations and technological progress, the state should provide them with a favourable environment by actively investing in appropriate legal, financial, rural, corporate, educational, and research infrastructure. In addition, it is necessary for farmers to adopt the principles of market orientation and entrepreneurial activities that would help them to increase their productivity, innovations and competitiveness.

Motives for the introduction of agricultural innovations in Serbia with particular accent on beekeepers: The application of logistic regression

The purpose of this article is to analyse the trend of global gold price yields and volatility with the aim of making effective financial decisions about investments in this precious metal, by applying and comparing the results of ARCH and GARCH competing models, using the lowest values of the chosen information criteria. ARCH and GARCH models are intended for the time series' analysis, with the observed instability of the conditional variance. Gold usually has the function of a safe haven, also serving as a warrantor of monetary stability, especially in times of crisis. On the example of 1,151 daily observations on the gold global price and yield rates, the E-GARCH model was applied, the results of which suggest investors to be cautious in their decision-making since the impact of negative shocks (losses) on yield volatility has a strong long-memory effect, making this investments highly risky, especially in bad economic circumstances.

Modelling the volatility of the global gold price by applying the ARCH/GARCH models

Innovations, as the applications of new ideas, solutions and technological practices that improve goods, services and business processes, are the most important driver of economic progress. They lead to greater productivity and efficiency, and therefore to better economic results. The purpose of this article is to examine the state, interrelation and the impact of innovative activities on the economic growth of Serbia. The paper first uses standard multiple regression and concludes that in the period from 2004 to 2020, the number of registered patents did not contribute, while the gross expenditures for research and development (GERD) contributed positively and significantly to the growth of the Serbian GDP. Therefore, it can be said that Serbia is facing a kind of innovation paradox, since the growth of allocations coexists with a dramatic decrease in the number of registered patents. Its second part is based on the construction of the corresponding Vector autoregressive VAR(1) model that traces the causal relationship between GERD and the economic growth of Serbia in the period from 1997 to 2020. It follows that while GERD does not cause GDP in the Granger sense, the GDP causes GERD allocations for innovative activities in Serbia. The scientific research work in Serbia is not efficient and effective enough because it draws funds from the GDP, but does not meet expectations and does not produce tangible results, especially in the expected number of registered patents. Therefore, it is necessary to build an appropriate incentive environment that would stimulate more adequately and value new innovative ventures.

https://ae.ef.unibl.org/index.php/ae/article/download/433/398

L. Madzar

Papers

Methane flux from Minnesota Peatlands

Modelling the trend of energy productivity in the Serbian economy

Motives for the introduction of agricultural innovations in Serbia with particular accent on beekeepers: The application of logistic regression

Modelling the volatility of the global gold price by applying the ARCH/GARCH models

The innovation paradox in the serbian economy: the granger causality approach