Mid Sweden University

The requirement for vernalization, a need for prolonged cold to trigger flowering, aligns reproductive development with favorable spring conditions. In Arabidopsis thaliana vernalization depends on the cold-induced epigenetic silencing of the floral repressor locus FLC. Extensive natural variation in vernalization response is associated with A. thaliana accessions collected from different geographical regions. Here, we analyse natural variation for vernalization temperature requirement in accessions, including those from the northern limit of the A. thaliana range. Vernalization required temperatures above 0°C and was still relatively effective at 14°C in all the accessions. The different accessions had characteristic vernalization temperature profiles. One Northern Swedish accession showed maximum vernalization at 8°C, both at the level of flowering time and FLC chromatin silencing. Historical temperature records predicted all accessions would vernalize in autumn in N. Sweden, a prediction we validated in field transplantation experiments. The vernalization response of the different accessions was monitored over three intervals in the field and found to match that when the average field temperature was given as a constant condition. The vernalization temperature range of 0–14°C meant all accessions fully vernalized before snowfall in N. Sweden. These findings have important implications for understanding the molecular basis of adaptation and for predicting the consequences of climate change on flowering time.

Brazil is home to the largest tracts of tropical vegetation in the world, harbouring high levels of biodiversity and carbon. Several biomass maps have been produced for Brazil, using different approaches and methods, and for different purposes. These maps have been used to estimate historic, recent, and future carbon emissions from land use change (LUC). It can be difficult to determine which map to use for what purpose. The implications of using an unsuitable map can be significant, since the maps have large differences, both in terms of total carbon storage and its spatial distribution. This paper presents comparisons of Brazil's new ‘official’ carbon map; that is, the map used in the third national communication to the UNFCCC in 2016, with the former official map, and four carbon maps from the scientific literature. General strengths and weaknesses of the different maps are identified, including their suitability for different types of studies. No carbon map was found suitable for studies concerned with existing land use/cover (LULC) and LUC outside of existing forests, partly because they do not represent the current LULC sufficiently well, and partly because they generally overestimate carbon values for agricultural land. A new map of aboveground carbon is presented, which was created based on data from existing maps and an up-to-date LULC map. This new map reflects current LULC, has high accuracy and resolution (50 m), and a national coverage. It can be a useful alternative for scientific studies and policy initiatives concerned with existing LULC and LUC outside of existing forests, especially at local scales when high resolution is necessary, and/or outside the Amazon biome. We identify five ongoing climate policy initiatives in Brazil that can benefit from using this map.

Using wood as a building material affects the carbon balance through several mechanisms. This paper describes a modelling approach that integrates a wood product substitution model, a global partial equilibrium model, a regional forest model and a stand-level model. Three different scenarios were compared with a business-as-usual scenario over a 23-year period (2008-2030). Two scenarios assumed an additional one million apartment flats per year will be built of wood instead of non-wood materials by 2030. These scenarios had little effect on markets and forest management and reduced annual carbon emissions by 0.2-0.5% of the total 1990 European GHG emissions. However, the scenarios are associated with high specific CO₂ emission reductions per unit of wood used. The third scenario, an extreme assumption that all European countries will consume 1-m³ sawn wood per capita by 2030, had large effects on carbon emission, volumes and trade flows. The price changes of this scenario, however, also affected forest management in ways that greatly deviated from the partial equilibrium model projections. Our results suggest that increased wood construction will have a minor impact on forest management and forest carbon stocks. To analyse larger perturbations on the demand side, a market equilibrium model seems crucial. However, for that analytical system to work properly, the market and forest regional models must be better synchronized than here, in particular regarding assumptions on timber supply behaviour. Also, bioenergy as a commodity in market and forest models needs to be considered to study new market developments; those modules are currently missing

Power-to-gas allows conversion of surplus electricity to methane when CO2 is available, which becomes an important technology for carbon capture, utilization and sequestration, as well as for increasing the flexibility of electricity production from renewable energy resources such as wind and solar energy. H2/CO2 biomethanation is a potentially promising alternative to the conversion of H2/CO2 to methane without limitation of variable hydrogen production. To identify mixed culture-based metabolic pathways of H2/CO2 under the mesophilic (35 °C) and thermophilic (55 °C) conditions, two specific inhibitors, 2-bromoethane sulfonate (BES) and vancomycin were employed in this experimental study. The combination of hydrogenotrophic and homoacetogenesis-acetoclastic methanogenesis makes up the pathway for the mesophilic cultivated microbial consortia. 16S rRNA gene analysis indicates that abundant Bacteria, Methanobacterium and Methanosaeta play important role in the conversion. Further analysis shows close collaboration between microorganisms by the formation of microbial clustering and the production of humic acids. The detailed metabolic mechanisms further confirm a diverse biomethanation network under the mesophilic condition. While under the thermophilic condition, the H2/CO2 biomethanation is fully dominated by the direct hydrogenotrophic methanogenesis mainly with Methanothermobacter, which is straightforward but more efficient. 

We present a novel, global 30 arc seconds (similar to 1 km at the equator) population projection dataset covering each year from 2010 to 2100 that is consistent with both country level population and gridded urban fractions from the Coupled Model Intercomparison Project 6 (CMIP6). While IPCC population projections until 2100 are available at country level for Socio-Economic Pathways (SSPs), land cover (including the urban fraction) is only available for Representative Concentration Pathways (RCPs). To perform simulations of e.g., future supply and demand for agricultural products, fine scale projections of population density are needed for combinations of SSPs and RCPs. Therefore, we generated a 30 arc seconds dataset consistent with both SSPs and RCPs within the framework of the IPCC. This data set is useful in applications where spatially explicit projections of aspects of global change are investigated at a fine spatial scale. For example, if a link function between night-time lights and population density is found based on current satellite images and recent population density data, a projection of night-time light lights can be generated by using this link function with our projected population density. Such a projection can for example be used to evaluate the potential for future light pollution. 

Here we analyse the radiative forcing implications of forest fertilization and biomass substitution, with explicit consideration of the temporal patterns of greenhouse gas (GHG) emissions to and removals from the atmosphere (net emissions). We model and compare the production and use of biomass from a hectare of fertilized and non-fertilized forest land in northern Sweden. We calculate the annual net emissions of CO ₂, N ₂O and CH ₄ for each system, over a 225-year period with 1-year time steps. We calculate the annual atmospheric concentration decay of each of these emissions, and calculate the resulting annual changes in instantaneous and cumulative radiative forcing. We find that forest fertilization can significantly increase biomass production, which increases the potential for material and energy substitution. The average carbon stock in tree biomass, forest soils and wood products all increase when fertilization is used. The additional GHG emissions due to fertilizer production and application are small compared to increases in substitution benefits and carbon stock. The radiative forcing of the 2 stands is identical for the first 15 years, followed by 2 years during which the fertilized stand produces slightly more radiative forcing. After year 18 the instantaneous and cumulative radiative forcing are consistently lower for the fertilized forest system. Both stands result in long-term negative radiative forcing, or cooling of the earth system. By the end of the 225-year simulation period, the cumulative radiative forcing reduction of the fertilized stand is over twice that of the non-fertilized stand. This suggests that forest fertilization and biomass substitution are effective options for climate change mitigation, as climate change is a long term issue. © 2011 Springer Science+Business Media B.V.

This is an evaluation of Jämtland County’s ability to achieve its climate targets to reduce greenhouse gas (GHG) emissions with 10% annually, and to become fossil fuel free 2030. There is a risk that the target to become fossil fuel-free, relying primarily on outtake of forest biomass, contradicts with the target in the UN Paris Agreement to keep the global temperature increase below 1.5°C. Neither the GHG emissions reduction target, nor the target to become fossil fuel free, takes forest carbon content into account. To reach the target to become fossil fuel free, forest harvest volumes may need to be increased. This can result in lower short-term net climate benefits than if fossil fuels are substituted to a less extent, and harvest volumes are kept at lower levels. Lower harvest volumes contribute to higher net climate benefits, and in the short term this effect is greater the lower the harvest level. In any case, forest production should be optimized towards products that give high substitution effects from the replacement of other materials. 

To be able to reach the short-term reductions of GHG emissions, efforts should be made to decrease regional energy demand and general consumption. The transition to new technologies is slow, and is unlikely to contribute to short-term reductions. By the end of 2023, according to the county strategy, the GHG emissions should be max 73% of the emissions by the end of 2019. This is a historically huge reduction. The potential to increase uptake of carbon dioxide in forests should be considered as a complement to the other climate targets.  

Assessments of social/welfare risks have to be weighed against the risks of increased temperatures, which is challenging, but needs to be done. The complexity of differences in short-term and long-term carbon balance effects makes risk assessments of climate mitigation strategies difficult. Compromises will be required between risks with different time horizons. To rely on techno-optimistic visions increase the risks that the emission reduction target will not be reached. From some perspectives, it is positive to spread techno-optimistic future visions, but there is a risk that we will keep on increasing consumption if we believe that problems with increased atmospheric concentrations of GHG can be solved by continuous consumption of ‘sustainable’ products. A simple 2% rule of thumb is that 2 kg of CO2eq is emitted for each 100 SEK consumed. 

This study presents a regional model showing the balance of carbon dioxide and methane fluxes in the Swedish county Jämtland, applying a Global Warming Potential 20-year time horizon (GWP20) to meet the Paris agreement horizon and regional policy goals. The results clearly show the necessity to take both anthropogenic and non-anthropogenic emissions into consideration in analyses to be able to make proper priorities in future action strategies. The total annual impact from Jämtland calculated as carbon dioxide equivalents (CO_2eq) is an uptake of 2.4 Mton (19 ton per capita). Jämtland shows large annual uptakes in forests (12.7 Mton CO₂), but also large emissions of methane (80 kton corresponding to 6.7 Mton CO_2eq), mainly from lakes, mires and ruminants. Anthropogenic carbon Greenhous gas emissions are dominated by transportation, working machines and consumption (mainly imported indirect emissions).

As a complement to GWP also the Absolute Global Temperature Change Potential (AGTP) as degree K response, is presented per sector and total for Jämtland County, for yearly emissions (as a pulse) and continuous emissions over 200 years. A yearly pulse from Jämtland gives a temperature response of about 0 K after 10 years and about −4 μK (cooling effect) after about 50 years). Using both GWP and AGTP as indicators improves the possibilities to find ways how to optimize regional climate policies to reduce global warming until a specific year.

Strategies and action plans should be developed focusing on the following:

- Reduced regional transportation and consumption activity.

- Increased (prioritized) use of renewable fuels for working machines in forestry and agriculture, as well as for heavy trucks.

- Evaluate the potential to reduce emissions of methane from wetlands and mires.

- Increase/optimize carbon dioxide assimilation in forests.

Carbon dioxide (CO2), as one of the major anthropogenic greenhouse gases, is widely acknowledged to contribute to global warming and climate change. Historically, the major focus on the role of the aquatic environment in the carbon cycle has been on the atmosphere-ocean exchange. More recent findings suggest the importance of freshwater (lakes, rivers and streams) as a source for atmospheric CO2. The freshwater contribution is, however, poorly understood, mainly due to a paucity of data, especially from running waters.

To address this issue, eddy covariance (EC) measurements in a large boreal river in Northern Sweden (Indalsälven), are being made as part of a two-year long continual study of the carbon dioxide emissions between the air and water. This is one of the first known studies of its kind where EC measurements are conducted in a river setting. Continual data acquisition began in April 2018, monitoring a variety of general meteorological parameters, turbulent emissions of carbon dioxide, latent, and sensible heat, together with water-side measurements of CO2. The aim of the study is to investigate the temporal control on river carbon dioxide emissions covering timescales from hours to seasons.

This paper describes the ongoing work, and reports on the present status of the project. The primary focus lies on data that indicates a dependence of carbon dioxide flux on wind-speed. Wind speed demonstrates a positive correlation with the measured emissions, with the highest emissions measured corresponding to the directions where the upwind distance to land was greatest, indicating that the wind-generated turbulence has a strong influence on the carbon dioxide emissions over a boreal river.