| 1. |
- Barcikowska, Monika J., et al.
(författare)
-
Euro-Atlantic winter storminess and precipitation extremes under 1.5 degrees C vs. 2 degrees C warming scenarios
- 2018
-
Ingår i: Earth System Dynamics. - : Copernicus GmbH. - 2190-4979 .- 2190-4987. ; 9:2, s. 679-699
-
Tidskriftsartikel (refereegranskat)abstract
- Severe winter storms in combination with precipitation extremes pose a serious threat to Europe. Located at the southeastern exit of the North Atlantic's storm track, European coastlines are directly exposed to impacts by high wind speeds, storm floods and coastal erosion. In this study we analyze potential changes in simulated winter storminess and extreme precipitation, which may occur under 1.5 or 2 degrees C warming scenarios. Here we focus on a first simulation suite of the atmospheric model CAM5 performed within the HAPPI project and evaluate how changes of the horizontal model resolution impact the results regarding atmospheric pressure, storm tracks, wind speed and precipitation extremes. The comparison of CAM5 simulations with different resolutions indicates that an increased horizontal resolution to 0.25 degrees not only refines regional-scale information but also improves large-scale atmospheric circulation features over the Euro-Atlantic region. The zonal bias in monthly pressure at mean sea level and wind fields, which is typically found in low-resolution models, is considerably reduced. This allows us to analyze potential changes in regional-to local-scale extreme wind speeds and precipitation in a more realistic way. Our analysis of the future response for the 2 degrees C warming scenario generally confirms previous model simulations suggesting a poleward shift and intensification of the meridional circulation in the Euro-Atlantic region. Additional analysis suggests that this shift occurs mainly after exceeding the 1.5 degrees C global warming level, when the midlatitude jet stream manifests a strengthening northeastward. At the same time, this northeastern shift of the storm tracks allows an intensification and northeastern expansion of the Azores high, leading to a tendency of less precipitation across the Bay of Biscay and North Sea. Regions impacted by the strengthening of the midlatitude jet, such as the northwestern coasts of the British Isles, Scandinavia and the Norwegian Sea, and over the North Atlantic east of Newfoundland, experience an increase in the mean as well as daily and sub-daily precipitation, wind extremes and storminess, suggesting an important influence of increasing storm activity in these regions in response to global warming.
|
|
| 2. |
- Barfuss, Wolfram, et al.
(författare)
-
Sustainable use of renewable resources in a stylized social-ecological network model under heterogeneous resource distribution
- 2017
-
Ingår i: Earth System Dynamics. - : Copernicus GmbH. - 2190-4979 .- 2190-4987. ; 8:2, s. 255-264
-
Tidskriftsartikel (refereegranskat)abstract
- Human societies depend on the resources ecosystems provide. Particularly since the last century, human activities have transformed the relationship between nature and society at a global scale. We study this coevolutionary relationship by utilizing a stylized model of private resource use and social learning on an adaptive network. The latter process is based on two social key dynamics beyond economic paradigms: boundedly rational imitation of resource use strategies and homophily in the formation of social network ties. The private and logistically growing resources are harvested with either a sustainable (small) or non-sustainable (large) effort. We show that these social processes can have a profound influence on the environmental state, such as determining whether the private renewable resources collapse from overuse or not. Additionally, we demonstrate that heterogeneously distributed regional resource capacities shift the critical social parameters where this resource extraction system collapses. We make these points to argue that, in more advanced coevolutionary models of the planetary social-ecological system, such socio-cultural phenomena as well as regional resource heterogeneities should receive attention in addition to the processes represented in established Earth system and integrated assessment models.
|
|
| 3. |
- Bayer, Anita D., et al.
(författare)
-
Uncertainties in the land-use flux resulting from land-use change reconstructions and gross land transitions
- 2017
-
Ingår i: Earth System Dynamics. - : Copernicus GmbH. - 2190-4979 .- 2190-4987. ; 8:1, s. 91-111
-
Tidskriftsartikel (refereegranskat)abstract
- Land-use and land-cover (LUC) changes are a key uncertainty when attributing changes in measured atmospheric CO2 concentration to its sinks and sources and must also be much better understood to determine the possibilities for land-based climate change mitigation, especially in the light of human demand on other land-based resources. On the spatial scale typically used in terrestrial ecosystem models (0.5 or 1°) changes in LUC over time periods of a few years or more can include bidirectional changes on the sub-grid level, such as the parallel expansion and abandonment of agricultural land (e.g. in shifting cultivation) or cropland-grassland conversion (and vice versa). These complex changes between classes within a grid cell have often been neglected in previous studies, and only net changes of land between natural vegetation cover, cropland and pastures accounted for, mainly because of a lack of reliable high-resolution historical information on gross land transitions, in combination with technical limitations within the models themselves. In the present study we applied a state-of-The-Art dynamic global vegetation model with a detailed representation of croplands and carbon-nitrogen dynamics to quantify the uncertainty in terrestrial ecosystem carbon stocks and fluxes arising from the choice between net and gross representations of LUC. We used three frequently applied global, one recent global and one recent European LUC datasets, two of which resolve gross land transitions, either in Europe or in certain tropical regions. When considering only net changes, land-use-Transition uncertainties (expressed as 1 standard deviation around decadal means of four models) in global carbon emissions from LUC (ELUC) are ±0.19, ±0.66 and ±0.47gCa1 in the 1980s, 1990s and 2000s, respectively, or between 14 and 39% LUC. Carbon stocks at the end of the 20th century vary by ±11 PgC for vegetation and ±37PgC for soil C due to the choice of LUC reconstruction, i.e. around 3% of the respective C pools. Accounting for sub-grid (gross) land conversions significantly increased the effect of LUC on global and European carbon stocks and fluxes, most noticeably enhancing global cumulative ELUC by 33PgC(1750-2014) and entailing a significant reduction in carbon stored in vegetation, although the effect on soil C stocks was limited. Simulations demonstrated that assessments of historical carbon stocks and fluxes are highly uncertain due to the choice of LUC reconstruction and that the consideration of different contrasting LUC reconstructions is needed to account for this uncertainty. The analysis of gross, in addition to net, land-use changes showed that the full complexity of gross land-use changes is required in order to accurately predict the magnitude of LUC change emissions. This introduces technical challenges to process-based models and relies on extensive information regarding historical land-use transitions.
|
|
| 4. |
- Botta, Nicola, 1961, et al.
(författare)
-
The impact of uncertainty on optimal emission policies
- 2018
-
Ingår i: Earth System Dynamics. - : Copernicus GmbH. - 2190-4979 .- 2190-4987. ; 9:2, s. 525-542
-
Tidskriftsartikel (refereegranskat)abstract
- We apply a computational framework for specifying and solving sequential decision problems to study the impact of three kinds of uncertainties on optimal emission policies in a stylized sequential emission problem. We find that uncertainties about the implementability of decisions on emission reductions (or increases) have a greater impact on optimal policies than uncertainties about the availability of effective emission reduction technologies and uncertainties about the implications of trespassing critical cumulated emission thresholds. The results show that uncertainties about the implementability of decisions on emission reductions (or increases) call for more precautionary policies. In other words, delaying emission reductions to the point in time when effective technologies will become available is suboptimal when these uncertainties are accounted for rigorously. By contrast, uncertainties about the implications of exceeding critical cumulated emission thresholds tend to make early emission reductions less rewarding.
|
|
| 5. |
- Braakhekke, Maarten C., et al.
(författare)
-
Nitrogen leaching from natural ecosystems under global change : A modelling study
- 2017
-
Ingår i: Earth System Dynamics. - : Copernicus GmbH. - 2190-4979 .- 2190-4987. ; 8:4, s. 1121-1139
-
Tidskriftsartikel (refereegranskat)abstract
- To study global nitrogen (N) leaching from natural ecosystems under changing N deposition, climate, and atmospheric CO2, we performed a factorial model experiment for the period 1901-2006 with the N-enabled global terrestrial ecosystem model LPJ-GUESS (Lund-Potsdam-Jena General Ecosystem Simulator). In eight global simulations, we used either the true transient time series of N deposition, climate, and atmospheric CO2 as input or kept combinations of these drivers constant at initial values. The results show that N deposition is globally the strongest driver of simulated N leaching, individually causing an increase of 88% by 1997-2006 relative to pre-industrial conditions. Climate change led globally to a 31%increase in N leaching, but the size and direction of change varied among global regions: Leaching generally increased in regions with high soil organic carbon storage and high initial N status, and decreased in regions with a positive trend in vegetation productivity or decreasing precipitation. Rising atmospheric CO2 generally caused decreased N leaching (33% globally), with strongest effects in regions with high productivity and N availability. All drivers combined resulted in a rise of N leaching by 73% with strongest increases in Europe, eastern North America and South-East Asia, where N deposition rates are highest. Decreases in N leaching were predicted for the Amazon and northern India. We further found that N loss by fire regionally is a large term in the N budget, associated with lower N leaching, particularly in semi-arid biomes. Predicted global N leaching from natural lands rose from 13.6 TgNyr-1 in 1901-1911 to 18.5 TgNyr-1 in 1997-2006, accounting for reductions of natural land cover. Ecosystem N status (quantified as the reduction of vegetation productivity due to N limitation) shows a similar positive temporal trend but large spatial variability. Interestingly, this variability is more strongly related to vegetation type than N input. Similarly, the relationship between N status and (relative) N leaching is highly variable due to confounding factors such as soil water fluxes, fire occurrence, and growing season length. Nevertheless, our results suggest that regions with very high N deposition rates are approaching a state of N saturation.
|
|
| 6. |
- Claremar, Björn, 1980-, et al.
(författare)
-
Ship Emissions and the use of current air cleaning technology : contributions to air pollution and acidification in the Baltic Sea
- 2017
-
Ingår i: Earth System Dynamics. - : Copernicus GmbH. - 2190-4979 .- 2190-4987. ; 8, s. 901-919
-
Tidskriftsartikel (refereegranskat)abstract
- The shipping sector is a significant contributor to emissions of air pollutants in marine and coastal regions.In order to achieve sustainable shipping, primarily through new regulations and techniques, greater knowledgeof dispersion and deposition of air pollutants is required. Regional model calculations of the dispersion andconcentration of sulfur, nitrogen, and particulate matter, as well as deposition of oxidized sulfur and nitrogenfrom the international maritime sector in the Baltic Sea and the North Sea, have been made for the years 2011to 2013. The contribution from shipping is highest along shipping lanes and near large ports for concentrationand dry deposition. Sulfur is the most important pollutant coupled to shipping. The contribution of both SO2concentration and dry deposition of sulfur represented up to 80% of the total in some regions. WHO guidelinesfor annual concentrations were not trespassed for any analysed pollutant, other than PM2:5 in the Netherlands,Belgium, and central Poland. However, due to the resolution of the numerical model, 50 km50 km, there maybe higher concentrations locally close to intense shipping lanes.Wet deposition is more spread and less sensitiveto model resolution. The contribution of wet deposition of sulfur and nitrogen from shipping was up to 30%of the total wet deposition. Comparison of simulated to measured concentration at two coastal stations close toshipping lanes showed some underestimations and missed maximums, probably due to resolution of the modeland underestimated ship emissions.A change in regulation for maximum sulfur content in maritime fuel, in 2015 from 1 to 0.1 %, decreasesthe atmospheric sulfur concentration and deposition significantly. However, due to costs related to refining, thecleaning of exhausts through scrubbers has become a possible economic solution. Open-loop scrubbers meet theair quality criteria but their consequences for the marine environment are largely unknown. The resulting potentialof future acidification in the Baltic Sea, both from atmospheric deposition and from scrubber water alongthe shipping lanes, based on different assumptions about sulfur content in fuel, scrubber usage, and increasedshipping density has been assessed. The increase in deposition for different shipping and scrubber scenariosdiffers for the basins in the Baltic Sea, with highest potential of acidification in the southern basins with hightraffic. The proportion of ocean-acidifying sulfur from ships increases when taking scrubber water into accountand the major reason for increasing acidifying nitrogen from ships is increasing ship traffic. Also, with the implementationof emission control for nitrogen, the effect of scrubbers on acidification is evident. This study alsogenerates a database of shipping and scrubber scenarios for atmospheric deposition and scrubber exhaust fromthe period 2011 to 2050.
|
|
| 7. |
- Di Baldassarre, Giuliano, et al.
(författare)
-
Drought and flood in the Anthropocene : Feedback mechanisms in reservoir operation
- 2017
-
Ingår i: Earth System Dynamics. - : Copernicus GmbH. - 2190-4979 .- 2190-4987. ; 8:1, s. 225-233
-
Tidskriftsartikel (refereegranskat)abstract
- Abstract. Over the last few decades, numerous studies have investigated human impacts on drought and flood events, while conversely other studies have explored human responses to hydrological extremes. Yet, there is still little understanding about the dynamics resulting from their interplay, i.e. both impacts and responses. Current quantitative methods therefore can fail to assess future risk dynamics and, as a result, while risk reduction strategies built on these methods often work in the short term, they tend to lead to unintended consequences in the long term. In this paper, we review the puzzles and dynamics resulting from the interplay of society and hydrological extremes, and describe an initial effort to model hydrological extremes in the Anthropocene. In particular, we first discuss the need for a novel approach to explicitly account for human interactions with both drought and flood events, and then present a stylized model simulating the reciprocal effects between hydrological extremes and changing reservoir operation rules. Lastly, we highlight the unprecedented opportunity offered by the current proliferation of big data to unravel the coevolution of hydrological extremes and society across scales and along gradients of social and hydrological conditions.
|
|
| 8. |
- Engström, Kerstin, et al.
(författare)
-
Assessing uncertainties in global cropland futures using a conditional probabilistic modelling framework
- 2016
-
Ingår i: Earth System Dynamics. - : Copernicus GmbH. - 2190-4979 .- 2190-4987. ; 7:4, s. 893-915
-
Tidskriftsartikel (refereegranskat)abstract
- We present a modelling framework to simulate probabilistic futures of global cropland areas that are conditional on the SSP (shared socio-economic pathway) scenarios. Simulations are based on the Parsimonious Land Use Model (PLUM) linked with the global dynamic vegetation model LPJ-GUESS (Lund-Potsdam-Jena General Ecosystem Simulator) using socio-economic data from the SSPs and climate data from the RCPs (representative concentration pathways). The simulated range of global cropland is 893-2380 Mha in 2100 (± 1 standard deviation), with the main uncertainties arising from differences in the socio-economic conditions prescribed by the SSP scenarios and the assumptions that underpin the translation of qualitative SSP storylines into quantitative model input parameters. Uncertainties in the assumptions for population growth, technological change and cropland degradation were found to be the most important for global cropland, while uncertainty in food consumption had less influence on the results. The uncertainties arising from climate variability and the differences between climate change scenarios do not strongly affect the range of global cropland futures. Some overlap occurred across all of the conditional probabilistic futures, except for those based on SSP3. We conclude that completely different socio-economic and climate change futures, although sharing low to medium population development, can result in very similar cropland areas on the aggregated global scale.
|
|
| 9. |
- Engström, Kerstin, et al.
(författare)
-
Impacts of climate mitigation strategies in the energy sector on global land use and carbon balance
- 2017
-
Ingår i: Earth System Dynamics. - : Copernicus GmbH. - 2190-4979 .- 2190-4987. ; 8:3, s. 773-799
-
Tidskriftsartikel (refereegranskat)abstract
- Reducing greenhouse gas emissions to limit damage to the global economy climate-change-induced and secure the livelihoods of future generations requires ambitious mitigation strategies. The introduction of a global carbon tax on fossil fuels is tested here as a mitigation strategy to reduce atmospheric CO2 concentrations and radiative forcing. Taxation of fossil fuels potentially leads to changed composition of energy sources, including a larger relative contribution from bioenergy. Further, the introduction of a mitigation strategy reduces climate-change-induced damage to the global economy, and thus can indirectly affect consumption patterns and investments in agricultural technologies and yield enhancement. Here we assess the implications of changes in bioenergy demand as well as the indirectly caused changes in consumption and crop yields for global and national cropland area and terrestrial biosphere carbon balance. We apply a novel integrated assessment modelling framework, combining three previously published models (a climate-economy model, a socio-economic land use model and an ecosystem model). We develop reference and mitigation scenarios based on the narratives and key elements of the shared socio-economic pathways (SSPs). Taking emissions from the land use sector into account, we find that the introduction of a global carbon tax on the fossil fuel sector is an effective mitigation strategy only for scenarios with low population development and strong sustainability criteria (SSP1 Taking the green road). For scenarios with high population growth, low technological development and bioenergy production the high demand for cropland causes the terrestrial biosphere to switch from being a carbon sink to a source by the end of the 21st century.
|
|
| 10. |
- Faranda, Davide, et al.
(författare)
-
Minimal dynamical systems model of the Northern Hemisphere jet stream via embedding of climate data
- 2019
-
Ingår i: Earth System Dynamics. - : Copernicus GmbH. - 2190-4979 .- 2190-4987. ; 10:3, s. 555-567
-
Tidskriftsartikel (refereegranskat)abstract
- We derive a minimal dynamical systems model for the Northern Hemisphere midlatitude jet dynamics by embedding atmospheric data and by investigating its properties (bifurcation structure, stability, local dimensions) for different atmospheric flow regimes. The derivation is a three-step process: first, we obtain a 1-D description of the midlatitude jet stream by computing the position of the jet at each longitude using ERA-Interim. Next, we use the embedding procedure to derive a map of the local jet position dynamics. Finally, we introduce the coupling and stochastic effects deriving from both atmospheric turbulence and topographic disturbances to the jet. We then analyze the dynamical properties of the model in different regimes: one that gives the closest representation of the properties extracted from real data; one featuring a stronger jet (strong coupling); one featuring a weaker jet (weak coupling); and one with modified topography. Our model, notwithstanding its simplicity, provides an instructive description of the dynamical properties of the atmospheric jet.
|
|
