7 / 40
7
Medium
Low
No change
Low
Medium
High
High
0.25 0.5 1 2 4
NO
3
-N mg/L
Insufficient data for analyses
or region not included in study
Decreased levels
Increased levels
Insufficient data for analysis
or region not included in study
MARCH 2002
PHILIPPEREKACEWICZ
1991-2000
Global Average Nitrate Levels
Concentrations at Major River Mouths
Changes Between
1976-1990 and 1991-2000
Source: United Nations EnvironmentProgramme (UNEP) - Global Environment Monitoring System (GEMS) Water Programme
2001; National Water Research Institute Environment Canada, Ontario, 2001.
UNEP
Figure 2:
Increases in nitrate and dissolved phosphate levels between 1976-1990 and 1991-2000 in some of the major
watersheds in the World show particular high changes in Asia.
0.1 0.2 0.3 0.4 0.5
PO
4
-P mg/L
Medium
Low
No change
Low
Medium
High
High
Decreased levels
Increased levels
Insufficient data for analyses
or region not included in study
Insufficient data for analysis
or region not included in study
MARCH2002
PHILIPPEREKACEWICZ
1991-2000
Global Dissolved Phosphate Levels
Concentrations at Major River Mouths
Changes Between
1976-1990 and 1991-2000
Source: United Nations EnvironmentProgramme (UNEP) - Global Environment Monitoring System (GEMS) Water Programme
2001; National Water Research Institute Environment Canada, Ontario, 2001.
UNEP
household water, food, fisheries, jobs and cultural tradi-
tions. Changes in the catchments and the rivers could be
detrimental not only to individuals, but also to nations
and welfare of several billion people in the region (Lu et
al, 2003; Viviroli et al., 2003). Currently, both natural
and human driven disasters are common throughout
the region, including floods, land slides, earthquakes
and glacial outbursts (Gerrard and Gardner, 2002; Yong
and Yiqian, 2003). Problems are currently being exacer-
bated by climate change which speeds up meltdown of
high altitude glaciers at unprecedented rates.
To the last part of the 20th century, the topography of the
region largely functioned as natural protection to large-
scale development, thereby providing unique gradients
from largely untrammeled areas with only minimal im-
pacts from pastoralism and subsistence type agriculture,
to some of the most densely populated regions of this
planet, thus preserving the precious water resources
in the catchments. However, development of the infra-
structure network in recent years has greatly increased
the access of industry to forest products, minerals, hydro
power, oil and gas. Environmental pressures and threats
include nuclear waste, toxic tailings from industry, pol-
lution, sand storms, deforestation, overgrazing and
erosion from increases in domestic animals, reduction
in nomadism, unsustainable agricultural practices and
loss of seasonal pastures and natural flood-buffers.
Growing populations result in intensified land use prac-
tices along road corridors, increased water consumption
and increased vulnerability to climate change. This has
resulted in increases in both nitrate and dissolved phos-
phate levels in the rivers across the last decades (Fig. 2).
While numerous water and participatory programs have
been developed and some successfully directed towards
individual and local issues, there are currently few, if any
assessments of the large-scale long-term changes of hu-
man settlement and resource exploitation in the region.
Such major long-term changes may play a major role
for the functioning of ecosystems and their services to
people and should of particular interest for policy mak-
ing as they may exhibit trans-boundary patterns. Such