An urbanization bomb? Population growth and social disorder in cities

For the first time in history, the majority of the world population now lives in cities. Global urbanization will continue at high speed; the world's urban population is projected to increase by more than 3 billion people between 2010 and 2050. Some of this increase will be the result of high urban fertility rates and reclassification of rural land into urban areas, but a significant portion of future urbanization will be caused by rural-to-urban migration. This migration is expected to be particularly prevalent in countries and regions most affected by the changing climate. While urban populations generally enjoy a higher quality of life, many cities in the developing world have large slums with populations that are largely excluded from access to resources, jobs, and public services. In the environmental security literature, great rural resource scarcity, causing rural to urban migration, is seen as an important source of violent conflict. This study investigates how population growth affects patterns of public unrest in urban centers within the context of crucial intervening factors like democracy, poverty, economic shocks. It utilizes a newly collected event dataset of urban social disturbance covering 55 major cities in Asia and Sub-Saharan Africa since 1960. The empirical analysis provides little support for the notion that high and increasing urban population pressure leads to a higher risk or frequency of social disorder. Instead, we find that urban disorder is primarily associated with a lack of consistent political institutions, economic shocks, and ongoing civil conflict.     

Metallic mineral deposits in the Nordic countries

The Nordic countries, including Greenland, have a long tradition in mining. Documented mining dates back to the 8th century AD. Today this region is the most important metallic mining district of the European Union. Metals are produced from active mines in all countries except Iceland and related industries are thriving in all countries.
Important ore deposit types include： volcanogenic massive sulphide deposits （Cu, Zn, Pb, Au, Ag）, orogenic gold deposits （Au）, layered intrusions （Ni, PGE, Ti±V）, intrusive hosted Cu-Au, apatite-Fe deposits, Cr- and anorthosite hosted Ti deposits. Besides these well- documented deposits, new kinds of deposits are being explored, e.g., iron oxide-copper-gold （IOCG）, shale-hosted Ni-Zn-Cu and different types of uranium deposits.     

The recession of the Inland Ice margin during the Holocene climatic optimum in the Jakobshavn Isfjord area of West Greenland

Recent subsurface mapping of parts of the Greenland Inland Ice margin in the region of Jakobshavn Isbræ indicates that the fjord system in the period of at least 2700–4700 calendar yr B.P. was more ice free than at present, and that the front of the glacier was at least 15 km behind the present position. The ¹⁴C-dating of subfossils brought to the present ice margin fit with the climatic records from ice cores and confirm the favourable conditions for Greenland's first settlers, the Sarqaq people, who arrived in the region about 400 yr ago to find hunting grounds 10–20% larger than the present.     

Heavy minerals in stream sediments,Southwest Norway

As part of a regional prospecting programme, 600 panned stream sediment concentrates from 1000 km² have been examined for scheelite (CaWO₄) using ultraviolet light. The mineralogical compositions of the heavy mineral concentrates were determined and related to bedrock geology. The results of the investigation are presented on maps showing the distribution of scheelite, magnetite, and ilmenite. Follow-up work resulted in the discovery of nine new tungsten occurrences. Magnetite dominates in areas of acid rocks, and ilmenite in areas of basic rocks. The areal distribution of hornblende and hypersthene reflects the metamorphic grades.     

Oxygen isotope and palaeotemperature records from six Greenland ice‐core stations: Camp Century,Dye‐3, GRIP,GISP2, Renland and NorthGRIP

Oxygen isotope variations spanning the last glacial cycle and the Holocene derived from ice‐core records for six sites in Greenland (Camp Century, Dye‐3, GRIP, GISP2, Renland and NorthGRIP) show strong similarities. This suggests that the dominant influence on oxygen isotope variations reflected in the ice‐sheet records was regional climatic change. Differences in detail between the records probably reflect the effects of basal deformation in the ice as well as geographical gradients in atmospheric isotope ratios. Palaeotemperature estimates have been obtained from the records using three approaches: (i) inferences based on the measured relationship between mean annual δ¹⁸O of snow and of mean annual surface temperature over Greenland; (ii) modelled inversion of the borehole temperature profile constrained either by the dated isotopic profile, or (iii) by using Monte Carlo simulation techniques. The third of these approaches was adopted to reconstruct Holocene temperature variations for the Dye 3 and GRIP temperature profiles, which yields remarkably compatible results. A new record of Holocene isotope variations obtained from the NorthGRIP ice‐core matches the GRIP short‐term isotope record, and also shows similar long‐term trends to the Dye‐3 and GRIP inverted temperature data. The NorthGRIP isotope record reflects: (i) a generally stronger isotopic signal than is found in the GRIP record; (ii) several short‐lived temperature fluctuations during the first 1500 yr of the Holocene; (iii) a marked cold event at ca. 8.2 ka (the ‘8.2 ka event’); (iv) optimum temperatures for the Holocene between ca. 8.6 and 4.3 ka, a signal that is 0.6‰ stronger than for the GRIP profile; (v) a clear signal for the Little Ice Age; and (vi) a clear signal of climate warming during the last century. These data suggest that the NorthGRIP stable isotope record responded in a sensitive manner to temperature fluctuations during the Holocene. Copyright © 2001 John Wiley & Sons, Ltd.     

Structural changes in the FeAl2O4–FeCr2O4 solid solution series and their consequences on natural Cr-bearing spinels

The influence of Al–Cr substitution on the spinel structure was studied in synthetic single crystals belonging to the FeCr₂O₄–FeAl₂O₄ series produced by flux growth at 1,000–1,300 °C in controlled atmosphere. Samples were characterized by single-crystal X-ray diffraction, electron microprobe analyses and Mössbauer spectroscopy. Crystals of sufficient size and quality for single-crystal X-ray diffraction were obtained in the ranges Chr_0–0.45 and Chr_70–100 but not for intermediate compositions, possibly due to a reduced stability in this range. The increase in chromite component leads to an increase in the cell edge from 8.1534 (6) to 8.3672 (1) Å and a decrease in the u parameter from 0.2645 (2) to 0.2628 (1). Chemical analyses show that Fe²⁺ is very close to 1 apfu (0.994–1.007), Al is in the range 0.0793–1.981 apfu, Cr between 0 and 1.925 apfu. In some cases, Fe³⁺ is present in amounts up to 0.031 apfu. Spinels with intermediate Cr content (Chr component between 40 and 60) are strongly zoned with Cr-rich cores and Cr-poor rims. Mössbauer analyses on powdered spinels of the runs from which single crystal has been used for X-ray structural data show values of Fe³⁺/Fe_tot consistently larger than that calculated by EMPA on single crystals, presumably due to chemical variation between single crystals from the same runs. The synthesis runs ended at a temperature of 1,000 °C, but it is possible that cation ordering continued in the Cr-poor samples towards lower temperatures, possibly down to 700 °C.     

Aggregatstabilitetsanalyse

Madsen, Henrik, 1975: Aggregatstabilitetsanalyse. Geografisk Tidsskrift 74: 70–78. København, juni 1, 1975.

A method to describe the stability and size distribution of soil aggregates by dry sifting. The profit and disadvantages of the method are discussed. A methematical adaption is given and further the influence of humus on the soil aggregates is discussed, as well as the possibility of the method for giving significant values in relation to soil erosion.     

Stratigraphic gaps at northern South China Sea margin reflect changes in Pacific deepwater inflow at glacial Termination Ⅱ

To constrain short-term changes of climate and oceanography in the northern South China Sea(SCS)over interglacial marine isotope stage(MIS)5.5,we studied planktic and benthic 18O records of seven marine sediment cores with a time resolution of70–700 yr.Using 6–8 tie points the planktic records were tuned to the U/Th chronology of speleothem 18O records in China and Europe.The last occurrence of pink Globigerinoides ruber marks the top of Heinrich stadial 11(HS-11)near 128.4 ka.HS-11 matches a 2300-yr long positive 18O excursion by 1.5/0.8‰both in planktic and benthic 18O records.Hence half of the planktic 18O signal was linked to increased upwelling of18O-and12C-enriched deep waters in the southwestern SCS.The increase was possibly linked to a strengthened inflow of Pacific deep waters through the Bashi Strait,that form a boundary current along the northern slope of the SCS,building a major sediment drift.At its lower margin near 2300–2400 m water depth(w.d.)Parasound records reveal a belt of modern erosion.At the end of glacial termination 2,stratigraphic gaps deleted HS-11 in core MD05-2904 and subsequent peak MIS 5.5 at ODP Site 1144.Likewise hiatuses probably earmarked all preceding glacial terminations at Site 1144 back to 650 ka.Accordingly,boundary current erosion then shifted~300 m upslope to~2040–2060 m w.d.These vertical shifts imply a rise in boundary current buoyancy,that in turn may be linked to transient events of North Pacific deepwater formation similar to that traced in SCS and North Pacific paleoceanographic records over glacial termination 1.