and “extreme”, which can roughly be interpreted as the most positive and the most
negative projections of P and T changes among the herein analysed GCM-RCMESs. Both “mild” and “extreme” scenarios were further analysed in order to define
possible positive and negative climate change impacts on components of the
environment in the Biebrza Valley, as well as for the socio-economic aspects of
wetland management. Due to the reported and widely-discussed uncertainty of
GCMs and RCMs (e.g. Anagnostopoulos et al. 2010; Kundzewicz and Stakhiv
2010; Wilby 2005, 2010), the authors of this paper state that the results presented
herein on prospective climate change (including hypothetical “mild” and “extreme”
scenarios) should not be considered as forecasts, but as a scientifically and
statistically-based background for the analysis of possible, climate-induced impacts
on environmental and socio-economic aspects of the Biebrza Valley.
The “mild” scenario (Fig. 14.3c, d) was derived in order to represent the most
positive prospective climate change for the contemporary environment of the
Biebrza Valley. The temporal variability in air temperature and precipitation provided in this scenario entails the sustainability of riparian ecosystems. The lowest
possible increase in the air temperature during winter months (November–March)
will sustain snow accumulation, which – along with an increased winter sum of
precipitation – would underpin respectable spring flooding. Hence, nutrient removal
from the floodplain, as one of the main ecosystem services of riparian wetlands
(Maltby 2009), will also be sustained. Satisfactory and regular spring flooding would
also entail appropriate fish spawning (e.g. in the case of the European pike Esox
lucius whose spawning season occurs in March–April) and provide suitable conditions for migratory wetland birds such as geese (Anserinae), ducks (Anatinae), ruffs
(Philomachus pugnax) and various waders (Scolopacidae and Tringinae). For the
remaining part of the average year in the “mild” scenario of climate change, the air
temperature will remain slightly higher than the average for contemporary conditions. Precipitation volumes and rainfall temporal distributions defined in this
scenario assume a significant increase in the cold part of the year and a slight
decrease in the summer. Though, in this way, the possibility of sizeable summer
floods is likely to be reduced. Thus, the stakeholders’ pressure on ecosystems by
demanding intensive drainage will also be lowered. However, as none of the
information on the temporal distribution of precipitation could have been derived
from the analysed GCM-RCM ensembles, it is fairly possible that summer flooding
in the Biebrza Valley in the “mild” scenario can still be an important management
challenge in 2070–2100, if the observed increasing trend in maximum daily precipitation (Fig. 14.2c) persisted.
The “Extreme” scenario (see Fig. 14.3 c, d) was established to represent the most
challenging conditions for the environment and management of the Biebrza Valley.
It assumes the highest increase in the average monthly temperature among the
entire set of GCM-RCM projections analysed, which is 4.1
C in the scale of the
average year in the period 2070–2100. The most significant increase in air temperature (up to 5.2
C) was projected for the winter (December–March) and for the
peak of summer (July) (Fig. 14.3c). A more polarised temporal distribution of the
average monthly sums of precipitation was assumed in the “extreme” scenario.
14 Climate-Induced Challenges for Wetlands: Revealing. . .
219
negative projections of P and T changes among the herein analysed GCM-RCMESs. Both “mild” and “extreme” scenarios were further analysed in order to define
possible positive and negative climate change impacts on components of the
environment in the Biebrza Valley, as well as for the socio-economic aspects of
wetland management. Due to the reported and widely-discussed uncertainty of
GCMs and RCMs (e.g. Anagnostopoulos et al. 2010; Kundzewicz and Stakhiv
2010; Wilby 2005, 2010), the authors of this paper state that the results presented
herein on prospective climate change (including hypothetical “mild” and “extreme”
scenarios) should not be considered as forecasts, but as a scientifically and
statistically-based background for the analysis of possible, climate-induced impacts
on environmental and socio-economic aspects of the Biebrza Valley.
The “mild” scenario (Fig. 14.3c, d) was derived in order to represent the most
positive prospective climate change for the contemporary environment of the
Biebrza Valley. The temporal variability in air temperature and precipitation provided in this scenario entails the sustainability of riparian ecosystems. The lowest
possible increase in the air temperature during winter months (November–March)
will sustain snow accumulation, which – along with an increased winter sum of
precipitation – would underpin respectable spring flooding. Hence, nutrient removal
from the floodplain, as one of the main ecosystem services of riparian wetlands
(Maltby 2009), will also be sustained. Satisfactory and regular spring flooding would
also entail appropriate fish spawning (e.g. in the case of the European pike Esox
lucius whose spawning season occurs in March–April) and provide suitable conditions for migratory wetland birds such as geese (Anserinae), ducks (Anatinae), ruffs
(Philomachus pugnax) and various waders (Scolopacidae and Tringinae). For the
remaining part of the average year in the “mild” scenario of climate change, the air
temperature will remain slightly higher than the average for contemporary conditions. Precipitation volumes and rainfall temporal distributions defined in this
scenario assume a significant increase in the cold part of the year and a slight
decrease in the summer. Though, in this way, the possibility of sizeable summer
floods is likely to be reduced. Thus, the stakeholders’ pressure on ecosystems by
demanding intensive drainage will also be lowered. However, as none of the
information on the temporal distribution of precipitation could have been derived
from the analysed GCM-RCM ensembles, it is fairly possible that summer flooding
in the Biebrza Valley in the “mild” scenario can still be an important management
challenge in 2070–2100, if the observed increasing trend in maximum daily precipitation (Fig. 14.2c) persisted.
The “Extreme” scenario (see Fig. 14.3 c, d) was established to represent the most
challenging conditions for the environment and management of the Biebrza Valley.
It assumes the highest increase in the average monthly temperature among the
entire set of GCM-RCM projections analysed, which is 4.1
C in the scale of the
average year in the period 2070–2100. The most significant increase in air temperature (up to 5.2
C) was projected for the winter (December–March) and for the
peak of summer (July) (Fig. 14.3c). A more polarised temporal distribution of the
average monthly sums of precipitation was assumed in the “extreme” scenario.
14 Climate-Induced Challenges for Wetlands: Revealing. . .
219