Table 5. Observed trends in climate and projected climate scenarios for six of the seven basins studied. The Nile, which runs through 10 countries, was not included because of insufficient data.

Table 5A. Indicators of climate change trends.
River basin Observed temperature trends Observed precipitation trends Observed snow and glacier dynamics
Amudarya Upper catchment (Tajikistan): temperature increases of 0.7–1.2°C in the valleys, 0.1–0.7°C at high altitudes

Lower catchment (Turkmenistan): small increase of about 0.5°C
Seasonal redistribution of precipitation, mostly an increase at higher altitudes, increase in extremes at lower altitudes
Change in type of precipitation (hard vs. liquid)
Glacier degradation: 14% decrease from 1957 to 1980§
Snow stock: 35% increase on average at altitudes up to 2000 m, 35% decrease at altitudes of 2000–3500 m (not in all regions)
 
Elbe (German part) 1.1°C increase in temperature during the last 50 yr| 46 mm decrease in summer precipitation, 50 mm increase in winter precipitation during the last 50 yr|
No observations
 
Guadiana Average maximum temperatures stable in the upper basin
Average temperatures increased by 1.8°C from 1950–1975 to 1975–2002
7% decrease in the last two decades over the period 1950–2002 in the upper basin Not applicable
Orange South Africa: average temperature increase of 0.2°C during 1990s# Namibia: increase of 1.15°C between 1950 and 2000†† Botswana: increasing trend of about 1°C over period 1900–1990‡‡
South Africa, Botswana: no overall trend††,‡‡ Namibia: extremely high variation in rainfall in excess of 30% across country, rising to 70% in southern areas†† Snow is common in the Lesotho portion of the basin, but data not accessible
Rhine 1°C temperature increase during the last century§§ During the 20th century, winter precipitation has increased by about 10–20%. No significant trend in summer precipitation detected§§ Switzerland: since 1850 the surface covered by glaciers has decreased from 1800 to 1300 km². The volume has decreased from 107 to 74 km³||
Tisza Temperature increase of about 1°C during the last 50 yr¶¶ Upward trend in precipitation in Ukrainian part
Downward trend in precipitation in Hungarian part##
No glacier environments in the basin
 
 
Table 5B. Projected climate scenarios for these basins.
River basin Change in temperature Change in precipitation
Amudarya Upper catchment: increase of 1.8–2.9°C by 2050 Lower catchment‡: increase of 1–2°C by 2030
Increase in temperature extremes.
Both an increase (3%–26%) and a decrease (3%–5%) are projected by different models by 2050
Change in distribution of precipitation.
 
Elbe (German part)
Increase of 1.5°C by 2051–2055 compared with 1961–1990 (model STAR)| Small decrease of 5.6 mm according to model STAR by 2051–2055 compared with 1961–1990|
 
Guadiana Worst case scenario: increase of 1–2°C in winter and 4–5°C in summer by 2070†††
Worst case scenario: decrease up to 0.25 mm/d in winter and 0.5 mm/d in summer by 2070†††
 
Orange South Africa: average increase of 2.5–3°C over north-central parts by 2050§§§ Namibia: 2–6°C above 1961–1990 mean by 2100†† Lesotho: 1.2–4.4°C increase by 2075‡‡‡ Botswana: 1–3°C increase by 2050‡‡
South Africa, Lesotho, Botswana: Different models project increases up to 5%–10% and decreases up to 10%–25%.§§§,‡‡‡,‡‡
Namibia: decrease of up to 200 mm/yr less than current average††
 
Rhine Increase of 1.0–2.0°C by 2050||| Increase of about 14% in winter precipitation by 2050, depending on temperature increase|||
 
Tisza Increase of 0.7–2.5°C by 2050¶¶¶ Increase of up to 30% in the Carpathians
Decrease of ~10%–30% in the spring period in Hungary and Ukraine by 2050¶¶¶
Republic of Tajikistan (2002)
MNPT (1999)
§Dukhovny (2002)
|Hattermann et al., (2006)
Martínez-Santos et al. (2004)
#Department of Environmental Affairs and Tourism (1999)
††Tarr (2002)
‡‡MWTCB (2001)
§§Klein Tank (2004)
||Maisch et al. (1997)
¶¶IPCC (2007)
##Jolonkai and Pataki (2005)
†††MMA (2005)
‡‡‡Ministry of Natural Resources (2000)
§§§Turpie et al. (2002)
|||Hurk et al. (2006)
¶¶¶MPI (2006)