ABSTRACT: A study was carried out to determine the impact of climate change on natural forest ecosystems in Pakistan assuming a 0.3°C rise in temperature and a precipitation change of 0, +1 and -1% decade^-1 with 1990 as the base year. The current atmospheric CO₂ concentration of 350 ppmv was assumed to increase to 425 ppmv in 2020, 500 ppmv in 2050 and 575 ppmv in 2080. The BIOME3 model was used for computer simulation of 9 dominant plant types, or biomes. Of these, 3 biomes (alpine tundra, grassland/arid woodlands and deserts) showed a reduction in their area, and 5 biomes (cold conifer/mixed woodland, cold conifer/mixed forests, temperate conifer/mixed forests, warm conifer/mixed forests, and steppe/arid shrub lands) showed an increase in their area as a result of climate change. Enhanced CO₂ concentration in the atmosphere appeared to have a pronounced effect on the biomes' area. Net primary productivity exhibited an increase in all biomes and scenarios. However, there is a possibility of forest dieback occurring and of time lag before the dominant plant types have enough time to adjust to changed climate and migrate to new sites. In the intervening period, they would be vulnerable to environmental and socio-economic disturbances (e.g. erosion, deforestation, and land-use changes). Thus, the overall impact of climate change on the forest ecosystems of Pakistan could be negative. A number of adaptation strategies are proposed to cope with climate change impacts on forest ecosystems.

KEY WORDS: Biome · Forest · Ecosystem · Climate change · Dominant plant type · Net primary productivity · Adaptation

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Published in CR Vol. 12, No. 2-3 (1999) on August 27
ISSN: 0936-577X. Copyright © Inter-Research, Oldendorf/Luhe, 1999