Application of a Dynamic Global Vegetation Model

Today’s post will look at the future impacts of Climate Change on the earths ecosystems from predictions from dynamic global vegetation models (DGVMs). A paper by Gonzalez et al. (2010) attempts to model future changes in global biomes by comparing observed changes in 20th century climate with modelled predictions of 21st century vegetation changes. Three global climate models (GCMs) were used in cooperation with the MC1 DGVM.

Results from the projected climate data (Figure 2) and projected vegetation changes (Figure 3) are shown. The GCMs project widespread temperature increase and precipitation changes by 2100. This includes global average temperature increases of 2.4-4 degrees. Average precipitation increases at rates of 0.03-0.04 mm, but becomes increasingly spatially variable. The model also predicts that wildfire frequency will increase in around 1/3 of the global area.

Results from global vegetation modelling follows observed patterns of global biomes. MC1 projections show potential extensive changes under 2071-2100 scenarios. Temperate mixed forest shows the highest areas of potential change, with desert showing the lowest. Gonzalez et al. (2010) believe between one-tenth and one-half of the earths biomes may be highly to very highly vulnerable to change.

Vegetation projections suggest potential latitudinal biome shifts of up to 400 km. Temperate mixed forest shows high vulnerability due to projected loss of coniferous species leading to conversion to temperate broadleaf forest. Tropical ecosystems show low vulnerability to change due to their high temperature tolerance combined with projections of increased precipitation around the equator (Malhi et al. 2008). MC1 data is congruent with data from other DGVMs which agree on shift of boreal forest into tundra at high latitudes and some forest lost in the Amazon.

As for effects, a large proportion of the world’s population live in areas in high vulnerability of potential biome changes. Biome change may alter ecosystem services, such as wood for timber, grass species preferred for grazing and water retention capacity of watersheds for human consumption.