China
Africa
Explore chapters and articles related to this topic
Climate Change Overlays
Published in Gregory T. Haugan, The New Triple Constraints for Sustainable Projects, Programs, and Portfolios, 2016
The global sea level rose by about 400 feet during the several millennia that followed the end of the last ice age (approximately 21,000 years ago), and stabilized between 3,000 and 2,000 years ago.‡ It appears from various sea level indicators that global sea level did not change significantly from then until the late nineteenth century Satellite observations available since the early 1990s provide relatively accurate sea level data with nearly global coverage. Since 1993, sea level has been rising at an average rate of around 1/8 inch (3 mm) per year globally, and this rate is significantly higher than the average during the previous half century. It is important to qualify this figure—this is a global average and it may be much higher in some regions and much lower in others. There have been recent studies analyzing the regional impacts and it is suggested that these be researched if you are interested in any particular narrow geographic area. At the Chesapeake Bay, there is a subsidence phenomenon that adds another 0.12 inches (2.7 mm) per year to the sea level rise and the opposite is occurring in southeastern Alaska, where sea level is dropping about 10 mm per year due to the land rising after the retreat of the weight of the glaciers.*
Global Warming or Global Cooling: Challenges and Future Prospects
Published in Moonisa Aslam Dervash, Akhlaq Amin Wani, Climate Change Alleviation for Sustainable Progression, 2022
The last ice age began about 110, and ended 13 thousand years ago. Approximately 5-7 thousand years ago, the climate was somewhat warmer and wetter than it is now – the peak of the interglacial period (the so-called Holocene optimum) was passed. Probably, such conditions were favourable for ancient man and the development of civilisation, but now man has different economic conditions, different numbers and settlements on the planet, different life expectancy and standards. Therefore, it would be a mistake to think that a ‘similar’ warming of a couple of degrees will be a boon for our modern civilisation. Then, about 5 thousand years ago, the climate gradually cooled and became close to the modern one.
Landslide risk management in Norway
Published in Ken Ho, Suzanne Lacasse, Luciano Picarelli, Slope Safety Preparedness for Impact of Climate Change, 2017
B. Kalsnes, F. Nadim, R.L. Hermanns, H.O. Hygen, G. Petkovic, B.K. Dolva, H. Berg, D.O. Høgvold
During October and November 2000, southeast Norway experienced heavy rainfall with exceptionally long duration. The records from meteorological stations in the area show precipitation records up to 400% of normal values for the month of November. However, no single event with exceptionally high precipitation intensity was observed. Nevertheless, the accumulated precipitation resulted in severe slide activity in the region due to long time infiltration. Most of the slides were situated in the low lands of southeastern Norway. In this region, the terrain is characterized by flat open areas that are cut by steep river ravines. The terrain was formed from river and marine sediments after the last ice age. The ground consists mainly of a thin layer of soils of grain sizes varying from gravel to clay. The area is ideal for farming and comprises more than 60% of the farmland in Norway. The first slides occurred on 19 and 20 October 2000. The slide activity started again at the beginning of November and increased gradually until 20 November 2000 when 13 slides occurred within 1 day. After that peak, the slide activity continued until 21 December. Additional slides were released during the spring 2001, when slopes already weakened in autumn failed during the spring thaw. The plan area of the slides ranged from 5 to 80 m width and up to 150 m length. The volumes of the slides ranged from 5 to 20.000 m3. The majority of the slides occurred in silt and clay deposits. Most of the slides were slumps located at man-made fills and cuts. Only a few occurred in natural slopes and terrain. The release mechanism for the majority of the slides was evaluated to be infiltration from precipitation. In some cases the slides were directly caused by river bank or surface erosion, or by human activities such as excavation.
Sedimentary processes, stratigraphic sequences and middens: the link between archaeology and geoheritage—a case study from the Quaternary of the Broome region, Western Australia
Published in Australian Journal of Earth Sciences, 2019
Since the end of the last ice age, and the melting of glaciers globally 20000 years ago, there has been a rise in sea level to its approximately present position about 10000 years ago (Fairbridge, 1961, 1976). In the Broome region, the history of mean sea level (MSL) has been determined by sea-level indicators such as sediments, structures, and biota, and dated by radiocarbon (Semeniuk, 2008). For purposes of this paper, there is focus on three sediment formations:specific horizons in the beach sediments of the Cable Beach Sand to show the position of MSL (beach lamination and Donax), and high-water spring tide (Spirula and Sepia skeletons);the contact of the mangrove sediments with the mid–low tidal mud sediments to indicate MSL; andthe upper contact of mangrove sediments and salt-flat sediment to indicate mean high-water spring tide levels.
Measured end resistance of CFA and drilled displacement piles in San Francisco Area alluvial clay
Published in DFI Journal - The Journal of the Deep Foundations Institute, 2018
T. C. Siegel, T. J. Day, B. Turner, P. Faust
The subject load tests are all located in the San Francisco Bay Area which is recognised as part of Coastal Ranges geomorphic province. The Coastal Ranges are a series of alternating parallel mountain ranges and valleys trending from the southeast to the northwest along the coast of California that were formed when the Pacific Plate collided with the North American Continental Plate. During the last Ice age (Pleistocene epoch), the sea level was much lower than today, and the current San Francisco Bay Area was a series of broad valleys between the Coastal Ranges. At the beginning of the Holocene epoch, glaciers melted causing a rapid rise in sea level. The resulting influx of seawater through the Golden Gate filled the current San Francisco Bay. As inflow of sea water slowed, the rivers draining into the San Francisco Bay Area continued to deposit material derived from the Coastal Ranges. These youngest Holocene marine sediments continue to accumulate and are recognised as the Bay Muds. The clay that is the subject of this paper is Pleistocene alluvium deposited in the Coastal Range valleys outside the extent of the current San Francisco Bay before the end of the last Ice age. A detailed description of the geologic history of the San Francisco Bay Area is presented by Helley, Lajoie, Spangle and Blair (1979).