| 21. |
- Soto Gómez, Agnes Jane, et al.
(författare)
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Spatial Distribution of Disasters Caused by Natural Hazards in the Samala River Catchment, Guatemala
- 2015
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Ingår i: Geografiska Annaler. Series A, Physical Geography. - : Informa UK Limited. - 0435-3676 .- 1468-0459. ; 97:1, s. 181-196
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Tidskriftsartikel (refereegranskat)abstract
- Understanding the conditions of the locations where disasters are reported and applying that knowledge to disaster risk reduction actions is essential and especially needed on the local scale. This study assessed how important the physical configuration is as cause of disasters by studying the links between the locations where disasters have been reported and the physical attributes of those locations. The Samala River catchment in Guatemala was used as a case study because it is a relatively small but complex area exposed to multiple natural hazards. Disasters of hydro-meteorological origin were addressed for the study because they are the most frequent type of disasters reported in the area. The method proposed in this work classified the study area into geomorphological units that were used to analyze where disasters were reported, the physical conditions of the particular locations of disaster reports, and to what degree disasters are spatially linked to slope and temporally to precipitation. We found that analyzing the study area based on the geomorphological configuration was useful and allowed analyses on comparatively homogeneous zones and to hypothesize on the particular geomorphological processes related to the occurrences of disasters. For steep geomorphological units we found a clear spatial relationship between the number of disasters reported and the slope of the locations, with higher frequency of disasters in the less sloping areas of the unit. The need to consider social factors for understanding this relationship was emphasized. As expected there was a very strong temporal relationship between disaster occurrence and wetness, as estimated from the antecedent rainfall, with high risk for disaster at high wetness. The applied methodological approach provides a tool for disaster research on physically complex areas, which is common to active tectonic and volcanic regions.
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| 22. |
- Sugden, David E., et al.
(författare)
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Plucking enhanced beneath ice sheet margins : evidence from the Grampian Mountains, Scotland
- 2019
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Ingår i: Geografiska Annaler. Series A, Physical Geography. - : Informa UK Limited. - 0435-3676 .- 1468-0459. ; 101:1, s. 34-44
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Tidskriftsartikel (refereegranskat)abstract
- Concentrations of boulders are a common feature of landscapes modified by former mid-latitude ice sheets. In many cases, the origin of the boulders can be traced in the up-ice direction to a cliff only tens to hundreds of metres distant. The implication is that a pulse of plucking and short boulder transport occurred beneath thin ice at the end of the last glacial cycle. Here we use a case study in granite bedrock in the Dee Valley, Scotland, to constrain theory and explore the factors involved in such a late phase of plucking. Plucking is influenced by ice velocity, hydrology, effective ice pressure, the extent of subglacial cavities and bedrock characteristics. The balance between these factors favours block removal beneath thin ice near a glacier margin. At Ripe Hill in the Dee Valley, a mean exposure age of 14.2 ka on blocks supports the view that the boulder train formed at the end of ice sheet glaciation. The late pulse of plucking was further enhanced by ice flowing obliquely across vertical joints and by fluctuations in sub-marginal meltwater conditions. An implication of the study is that there is the potential for a wave of ice-marginal plucking to sweep across a landscape as an ice sheet retreats.
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| 23. |
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| 24. |
- Wang, F., et al.
(författare)
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Global and regional climate responses to national-committed emission reductions under the Paris agreement
- 2018
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Ingår i: Geografiska Annaler Series a-Physical Geography. - : Informa UK Limited. - 0435-3676 .- 1468-0459. ; 100:3, s. 240-253
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Tidskriftsartikel (refereegranskat)abstract
- To stabilize global mean temperature change within the range of 1.5-2.0 degrees C in accordance with the Paris Agreement, countries worldwide submitted their Intended Nationally Determined Contributions with their proposed emission reductions. However, it remains unclear what the resulting climate change in terms of temperature and precipitation would be in response to the Intended Nationally Determined Contribution emission efforts. This study quantifies the global and regional temperature and precipitation changes in response to the updated Intended Nationally Determined Contribution scenarios, using simulations of 14 Fifth Coupled Climate Model Intercomparison Project models. Our results show that Intended Nationally Determined Contribution emissions would lead to a global mean warming of 1.4 degrees C (1.3-1.7 degrees C) in 2030 and 3.2 degrees C (2.6-4.3 degrees C) in 2100, above the preindustrial level (the 1850-1900 average). Spatially, the Arctic is projected to have the largest warming, 2.5 and 3 times the global average for 2030 and 2100, respectively, with strongest positive trends at 70-85 degrees N over Asia, Europe and North America (6.5-9.0 degrees C). The excessive warming under Intended Nationally Determined Contribution scenarios is substantially above the 1.5 degrees C or 2.0 degrees C long-term stabilization level. Global mean precipitation is projected to be similar to preindustrial levels in 2030, and an increase of 6% (4-9%) by 2100 compared with the preindustrial level. Regional precipitation changes will be heterogeneous, with significant increases over the equatorial Pacific (about +120%) and strong decreases over the Mediterranean, North Africa and Central America (-15% - -30%). These results clearly show that it is necessary to adjust and strengthen national mitigation efforts on current Intended Nationally Determined Contributions to meet the long-term temperature target.
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