64 research outputs found
Climate change and increased risk for the insurance sector: A global perspective and an assessment for the Netherlands.
Climate change is projected to increase the frequency and severity of extreme weather events. As a consequence, economic losses caused by natural catastrophes could increase significantly. This will have considerable consequences for the insurance sector. On the one hand, increased risk from weather extremes requires assessing expected changes in damage and including adequate climate change projections in risk management. On the other hand, climate change can also bring new business opportunities for insurers. This paper gives an overview of the consequences of climate change for the insurance sector and discusses several strategies to cope with and adapt to increased risks. The particular focus is on the Dutch insurance sector, as the Netherlands is extremely vulnerable to climate change, especially with regard to extreme precipitation and flooding. Current risk sharing arrangements for weather risks are examined while potential new business opportunities, adaptation strategies, and public-private partnerships are identified. © The Author(s) 2009
Explosive volcanism on the ultraslow-spreading Gakkel ridge, Arctic Ocean
Author Posting. © Nature Publishing Group, 2008. This is the author's version of the work. It is posted here by permission of Nature Publishing Group for personal use, not for redistribution. The definitive version was published in Nature 453 (2008): 1236-1238, doi:10.1038/nature07075.Roughly 60% of the Earth’s outer surface is comprised of oceanic crust formed by volcanic
processes at mid-ocean ridges (MORs). Although only a small fraction of this vast volcanic
terrain has been visually surveyed and/or sampled, the available evidence suggests that
explosive eruptions are rare on MORs, particularly at depths below the critical point for
steam (3000 m). A pyroclastic deposit has never been observed on the seafloor below 3000
m, presumably because the volatile content of mid-ocean ridge basalts is generally too low
to produce the gas fractions required to fragment a magma at such high hydrostatic
pressure. We employed new deep submergence technologies during an International Polar
Year expedition to the Gakkel Ridge in the Arctic Basin at 85°E, to acquire the first-ever
photographic images of ‘zero-age’ volcanic terrain on this remote, ice-covered MOR. Our
imagery reveals that the axial valley at 4000 m water depth is blanketed with
unconsolidated pyroclastic deposits, including bubble wall fragments (limu o Pele),
covering a large area greater than 10 km2. At least 13.5 wt% CO2 is required to fragment
magma at these depths, which is ~10x greater than the highest values measured to-date in
a MOR basalt. These observations raise important questions regarding the accumulation
and discharge of magmatic volatiles at ultra-slow spreading rates on the Gakkel Ridge (6-
14 mm yr-1, full-rate), and demonstrate that large-scale pyroclastic activity is possible
along even the deepest portions of the global MOR volcanic system.This research was
funded by the National Aeronautics and Space Administration, the National Science Foundation,
and the Woods Hole Oceanographic Institution
Post-depositional fracturing and subsidence of pumice flow deposits: Lascar Volcano, Chile
Unconsolidated pyroclastic flow deposits of the
1993 eruption of Lascar Volcano, Chile, have, with time,
become increasingly dissected by a network of deeply
penetrating fractures. The fracture network comprises
orthogonal sets of decimeter-wide linear voids that form a
pseudo-polygonal grid visible on the deposit surface. In this
work, we combine shallow surface geophysical imaging
tools with remote sensing observations and direct field
measurements of the deposit to investigate these fractures
and their underlying causal mechanisms. Based on ground
penetrating radar images, the fractures are observed to have
propagated to depths of up to 10 m. In addition, orbiting radar interferometry shows that deposit subsidence of up to
1 cm/year occurred between 1993 and 1996 with continued
subsidence occurring at a slower rate thereafter. In situ
measurements show that 1 m below the surface, the 1993
deposits remain 5°C to 15°C hotter, 18 years after
emplacement, than adjacent deposits. Based on the observed
subsidence as well as estimated cooling rates, the fractures are
inferred to be the combined result of deaeration, thermal
contraction, and sedimentary compaction in the months to
years following deposition. Significant environmental factors,
including regional earthquakes in 1995 and 2007, accelerated
settling at punctuated moments in time. The spatially variable
fracture pattern relates to surface slope and lithofacies
variations as well as substrate lithology. Similar fractures
have been reported in other ignimbrites but are generally
exposed only in cross section and are often attributed to
formation by external forces. Here we suggest that such
interpretations should be invoked with caution, and deformation
including post-emplacement subsidence and fracturing of
loosely packed ash-rich deposits in the months to years postemplacement
is a process inherent in the settling of pyroclastic
material
Novel insights into the aetiology and pathophysiology of increased airway inflammation during COPD exacerbations
Airway inflammation increases during acute exacerbations of COPD. Extrinsic factors, such as airway infections, increased air pollution, and intrinsic factors, such as increased oxidative stress and altered immunity may contribute to this increase. The evidence for this and the potential mechanisms by which various aetiological agents increase inflammation during COPD exacerbations is reviewed. The pathophysiologic consequences of increased airway inflammation during COPD exacerbations are also discussed. This review aims to establish a cause and effect relationship between etiological factors of increased airway inflammation and COPD exacerbations based on recently published data. Although it can be speculated that reducing inflammation may prevent and/or treat COPD exacerbations, the existing anti-inflammatory treatments are modestly effective
Controls on explosive-effusive volcanic eruption styles
One of the biggest challenges in volcanic hazard assessment is to understand how and why eruptive style changes within the same eruptive period or even from one eruption to the next at a given volcano. This review evaluates the competing processes that lead to explosive and effusive eruptions of silicic magmas. Eruptive style depends on a set of feedbacks involving interrelated magmatic properties and processes. Foremost of these are magma viscosity, gas loss, and external properties such as conduit geometry. Ultimately, these parameters control the speed at which magmas ascend, decompress and outgas en route to the surface, and thus determine eruptive style and evolution
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