March 26, 2011 — andyextance

Efforts to understand the biological impacts of climate change on a detailed local scale are “misguided”, and conservation research should be favoured instead, a small but influential group of scientists have suggested this week. “This focus diverts energies and research funds away from developing crucial adaptation and conservation measures,” wrote biologists Camille Parmesan and Michael Singer from University of Texas, Austin, and their colleagues. Parmesan was a lead author for the Third Assessment Report of the Intergovernmental Panel on Climate Change (IPCC), for which it won a Nobel Peace Prize jointly with Al Gore in 2007.

With a strong body of evidence showing that climate change is happening, the IPCC is now recommending scientists try and link its effects on plants and animals to human actions. “Biologists are now expected to shift away from detection towards attribution – that is assessing the extent to which observed biological changes are being driven by greenhouse-gas-induced climate change versus natural climate variability,” the team wrote.

Singer told Simple Climate that the consequences of human activity can be puzzled out on a global scale, though this is easier for climate effects than for biological impacts. However, the IPCC is encouraging ever more detailed attribution studies, something he feels is understandable but ill-judged. “From a basic research standpoint, once you’ve shown something at a large or rough scale, people then work at finer and finer detail,” he explained. “So, it seems the obvious ‘next step’ for the new IPCC assessment would be this kind of trajectory. Folk who work with modelling seem particularly attracted to this question. Folk who work with natural biological systems are more leery of it, because of feasibility, not interest.”

An impossible target?

Writing in new journal Nature Climate Change on Sunday, the scientists note that successfully attributing effects to greenhouse gases becomes dramatically less likely as you look at shorter timespans and smaller regions. The paper is based on the scientists’ opinion – invited by the journal’s editor – rather than new research. However, Parmesan had previously looked at attributing effects on the global scale for hundreds of wild species. That study found 57 percent had responded strongly to regional climate changes, through their range boundaries moving and events happening in spring getting earlier.

One problem is that even species living close together can respond very differently, which is in part due to a complex interplay between climate change and other human influences like habitat destruction, land-use change and pollution. “Effects of climate change are everywhere, but they act on top of all these other stresses faced by wild species,” says Parmesan. “What we need to do now is to focus on extensive field experiments and observations that try to understand how multiple factors interact with a changing climate to directly affect these species.”

Yet even when biological impacts can be linked strongly to climate events, it remains difficult to link those events to human actions. For example, the Monteverde golden toad went extinct following an extremely warm and dry period in 1986 and 1987, but that event could not be attributed with high confidence to human-induced climate change. Political concerns, largely the desire to win over people reluctant to accept that human actions are having negative consequences through climate change, drive the IPCC’s demands for such links to be established. But Singer, Parmesan and colleagues feel establishing these links is unnecessary. “From the perspective of a wild plant or animal, a changing climate is a changing climate, irrespective of its cause,” wrote the scientists.

“At a local scale global change influences the probability of events,” Singer explained. “Climate warming renders more likely the summer heatwaves that have plagued Europe and Russia in recent years and the weather events that preceded the demise of the Golden Toad.” Modellers can ask, and have been asking, what effect global climate change has on the probability of such events. However trying to take the detail down to the level of individual species is likely futile, and distracts researchers from trying to maintain the world’s biodiversity, Singer said. “To try to ask what was in fact the relative contribution of natural global climate change and anthropogenic global climate change to the extinction of the toad is probably not a question that can be answered,” he suggested. “In any case, it doesn’t help the poor toad or help us to conserve other species that currently risk the same fate.”

Europe and intertidal invertebrates off California7.

Some of this diversity stems fro