Nitrate in major rivers
Considering the data for all the rivers at the continental level, there has been little change in nitrate (NO3-N) concentrations between the two decades under comparison. Changes in the median value were not statistically significant. European rivers showed the highest nitrate loads transported to the marine environment. Comparing data from the two decades, North American and European rivers have remained fairly stable, while major river basins i...
17 May 2005 - by Philippe Rekacewicz, UNEP/GRID-Arendal
Sea level rise and assessment of the state of the marine environment
A significant sea level rise is one of the major anticipated consequences of climate change. This will cause some low-lying coastal areas to become completely submerged, while others will increasingly face short-lived high-water levels. These anticipated changes could have a major impact on the lives of coastal populations. The small island developing states (SIDS) will be especially vulnerable to the effects of sea level rise, and to changes in ...
01 Oct 2009 - by Philippe Rekacewicz
Nitrate levels: concentrations at river mouths
Nutrients are essential to life. In aquatic systems, nitrogen and phosphorus are the two nutrients that most commonly control the growth of aquatic plants, algae and bacteria. Nitrogen and phosphorus are considered to be the primary drivers of eutrophication of aquatic ecosystems, where increased nutrient concentrations lead to increased primary productivity. Some systems are naturally eutrophic, whereas others have become eutrophic as a result o...
26 Jan 2009 - by Philippe Rekacewicz
Human actions leading to coastal degradation
Physical alteration and the destruction of habitats are now considered one of the most significant threats to coastal areas. Half of the world’s wetlands, and even more of its mangrove forests, have been lost over the past century to physical alterations, the major causes being accelerating social and economic development and poor-planning (UNEP, 2002).
There are currently about one billion people living in coastal urban areas. It is estimated t...
26 Jan 2009 - by Philippe Rekacewicz (Le Monde diplomatique), February 2006
Coastal populations and shoreline degradation
Unsurprisingly, the coastal areas with the greatest population densities are also those with the most shoreline degradation.
The areas surrounding the Black Sea, the Mediterranean and southern Asia have the highest proportion of altered land, while the coastal zones of the Arctic, northeast Pacific, south Pacific, West and Central Africa, East Africa, the Red Sea/Gulf of Aden, and Kuwait have the highest proportions of least modified land.
01 Oct 2009 - by Phillippe Rekacewicz, February 2006
Industrial areas and seasonal zones of oxygen depleted waters
This graphic illustrates the strong link between areas with high densities of industrial activity and zones of seasonally oxygen-depleted waters.
There is a strong link between areas with high densities of industrial activity and zones of seasonal oxygen-depleted waters. In recent years there has been an increasing focus on treating and reducing municipal and industrial waste, and on reducing nitrogen levels in agricultural runoff. However, less...
26 Jan 2009 - by Phillipe Rekacewicz, (Le Monde diplomatique) February 2008