The demise of the Aral Sea – an environmental disaster

The shrinkage of the Aral Sea ranks as one of the world's greatest man-made environmental disasters. While there is some hope for a separated northern part, the main sea is doomed     

The flooding of New Orleans

With its man-made defences, New Orleans is at best only a marginally stable city, and it was destined to suffer as more powerful natural processes evolved. The aftermath of the August 2005 hurricane was the disaster that had been waiting to happen.     

Unloading joints and rockfalls in Norway's fiordlands

When overburden is removed by erosion, rock relaxes towards the surface and develops new fractures. These are then the focus of slope failures that are common and sometimes disastrous in Norway's mountain regions.     

Weathering rates of sandstone in a semi-arid environment (Hunter Valley,Australia)

The rate of sandstone weathering in the semi-arid climate of the Hunter Valley, New South Wales, Australia has been estimated from observations of gravestone weathering in the area. The gravestone data points to two distinct stages in the weathering process. The first stage covering the first century of exposure is characterised by a relatively low recession rate of 0.5 mm/100 years. This is followed by a second stage in which the rate of weathering increases sharply to ca 2.5 mm/100 years. The non-linear nature of the weathering trends over time suggests that during the first century of exposure, structural changes took place within the sandstone material, which lay the foundation for accelerated weathering after further exposure. Laboratory trials were also conducted to identify the effectiveness of different weathering processes in the decay of sandstone in this region. Of the four processes examined, only the freeze–thaw cycle produced a significant degree of mass loss and is therefore most likely a strong contributor to the weathering of sandstone in this region.