| 1. |
- Braakhekke, Maarten C., et al.
(författare)
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The use of radiocarbon to constrain current and future soil organic matter turnover and transport in a temperate forest
- 2014
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Ingår i: Journal of Geophysical Research: Biogeosciences. - 2169-8953. ; 119:3, s. 372-391
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Tidskriftsartikel (refereegranskat)abstract
- We investigated the merits of radiocarbon measurements for estimating soil organic matter (SOM) turnover and vertical transport for a temperate deciduous forest in Germany. Eleven parameters, defining decomposition and transport in the soil carbon model SOMPROF, were estimated using a Bayesian approach based on organic carbon measurements and radiocarbon concentration of SOM and heterotrophic respiration. The addition of radiocarbon data had strong effects on the parameters, most importantly a reduction of the decomposition and production rate of the slowest SOM pool by an order of magnitude, and a similar reduction in advective SOM transport. The modified parameters further led to changes in the partitioning of SOM over the different model pools. The calibration results were subsequently used to perform transient soil carbon projections for the period 1901-2100. These simulations were run with parameter sets from calibrations both with and without radiocarbon. The results show an increase over time of topsoil carbon and a decrease in the subsoil, adding to a net gain overall. Near the end of the 21st century, total carbon stocks stabilize andfor the radiocarbon-constrained modelstart to decrease. However, the changes are small compared to the total stocks. The model results for the calibrations with and without radiocarbon are in general quite similar, but the latter shows notably higher heterotrophic respiration fluxes. Constraining the model with radiocarbon yielded only a small reduction of uncertainty for the total carbon stocks, while for the individual depth compartments, the uncertainty wasincreased. Key Points SOM turnover and transport was estimated using Bayesian calibration Radiocarbon data strongly improved constraint of turnover rate of slow pool Predictive simulation showed small increase of soil C stocks in 21st century
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| 2. |
- Rockström, Johan, et al.
(författare)
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Climate change : The necessary, the possible and the desirable Earth League climate statement on the implications for climate policy from the 5th IPCC Assessment
- 2014
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Ingår i: Earth’s Future. - 2328-4277. ; 2:12, s. 606-611
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Tidskriftsartikel (refereegranskat)abstract
- The development of human civilisations has occurred at a time of stable climate. This climate stability is now threatened by human activity. The rising global climate risk occurs at a decisive moment for world development. World nations are currently discussing a global development agenda consequent to the Millennium Development Goals (MDGs), which ends in 2015. It is increasingly possible to envisage a world where absolute poverty is largely eradicated within one generation and where ambitious goals on universal access and equal opportunities for dignified lives are adopted. These grand aspirations for a world population approaching or even exceeding nine billion in 2050 is threatened by substantial global environmental risks and by rising inequality. Research shows that development gains, in both rich and poor nations, can be undermined by social, economic and ecological problems caused by human-induced global environmental change. Climate risks, and associated changes in marine and terrestrial ecosystems that regulate the resilience of the climate system, are at the forefront of these global risks. We, as citizens with a strong engagement in Earth system science and socio-ecological dynamics, share the vision of a more equitable and prosperous future for the world, yet we also see threats to this future from shifts in climate and environmental processes. Without collaborative action now, our shared Earth system may not be able to sustainably support a large proportion of humanity in the decades ahead.
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| 3. |
- Silva Von Randow, Rita Cassia, et al.
(författare)
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Response of the river discharge in the Tocantins River Basin, Brazil, to environmental changes and the associated effects on the energy potential
- 2019
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Ingår i: Regional Environmental Change. - : Springer Science and Business Media LLC. - 1436-3798 .- 1436-378X. ; 19:1, s. 193-204
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Tidskriftsartikel (refereegranskat)abstract
- Climate change is expected to impact the hydrological regime worldwide, and land use and land cover change may alter the effects of the former in some cases. Secondary growth in deforested and abandoned areas is one of the main consequences of land use and cover changes in Amazonia. Among land uses, the effects of the secondary growth in water availability in large scale basins are not well understood. This work analyzes the potential effects of secondary growth under climate and land use change on water availability and hydropower in the Tocantins basin, in the Legal Amazon region of Brazil, using the MHD-INPE hydrological model driven by different climate scenarios and two future socioeconomic-based potential land use scenarios. The model projects decrease on discharge under climate change scenarios, which further cause the simulated hydropower energy potential to decrease significantly. When only deforestation scenarios are included, the effects of climate change are weakened, but when secondary growth is also considered, the effects of climate change are enhanced. Results suggest that different aspects of environmental change, such as secondary growth, may affect water production and the sectors depending on it.
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