by Rolf Schuttenhelm, cross-posted from Bits of Science
The results of studies that try to quantify the effects of climate change on biodiversity loss — which include damage to the micro scale level of subspecies and genetic variation — are perhaps most shocking.
When, however, you focus on the response to climate change at the macro level, the ecosystem level, you get a better understanding of what is one of the major drivers of that biodiversity loss: forced migrations. And even here, the numbers may be larger than one would expect, as a new assessment by NASA and Caltech published in the journal Climatic Change shows that by 2100 some 40 percent of “major ecological community types” – that is biomes like forest, grassland, tundra – will have switched to a different such state.
According to the same study most of the land on Earth that is not currently desert or under an icecap will undergo at least a 30 percent change in vegetation cover.
Ecological damage is the real climate problem
Based on IPCC temperature projections for 2100 [which are probably on the conservative side] of 2-4 degrees Celsius warming scientists of NASA’s Jet Propulsion Laboratory and the California Institute of Technology ran special computer models to calculate the most probable ecosystem responses across the planet. This average temperature rise is of similar magnitude to the warming that occurred between the Last Glacial Maximum and the onset of the (milder) Holocene – with the big exception that the current warming is happening about 100 times faster – and for ecology that makes a huge difference, the authors stress.