In preparation for next time...

The last post was unplanned, but it actually sets up the next topic nicely, as I will be looking at one of those theoretical (modeling!) studies that attempt to predict how biodiversity will fare in the future. I'll be looking at the big picture: global rather than just freshwater biodiversity, as much of the literature around the future impact of climate change on biodiversity is at this scale. In preparation, it's worth considering a few things about the relationship between climate change and biodiversity.

The Convention on Biological Diversity's website provides a nice overview of climate change and it's relationships with biodiversity; some key points are summarized in this paragraph. Cycles of climatic changes are a big part of life's evolutionary history, with periods of rapid climate change often driving migration, behavioral adaptation and evolution of new physical characteristics to survive. Key concerns for the current warming is that it's happening very quickly, will reach higher levels than seen in the last 1.8 million years and is happening alongside other anthropogenic pressures (such as pollution or hunting), all of which could result in far more extinction than in previous warming periods. The article uses the term biodiversity to mean 'all life', and hence suggests that biodiversity can impact climate change, as more photosynthesizing biota would remove CO₂ from the atmosphere, so slow climatic change. It's not clear to me that this relationship exists when you consider biodiversity to mean the diversity of life, as a carbon sink does not need to be species rich to be effective.

It's important to consider that extinctions of vulnerable species doesn't necessarily lead to a significant long-term loss of biota, just biodiversity. Climate change may may not reduce the biomass of the plant, just it's heterogeneity, and there may well be areas where new conditions drive the introduction or evolution of new species leading higher local biodiversity. All that is certain is that the planet's biotic communities will be altered (in content and distribution), and that many current species are likely to be lost.