Global warming experts recommend drastic measures to sa...(addressed before decisions to act can be...)

In addition to biological considerations, their framework includes social dimensions of the issue, such as cost and inherent value people place on the target species.

The authors argue that the most suitable scenario is when the risk of extinction of the target species is high in its historic range, but the risk to the community into which the species will be imported is low. It might also be appropriate when the likelihood of successful colonization is high, but the time and cost to perform the transplantation is low.

"Passively assisting coral reef migration may be acceptable, but transplanting polar bears to Antarctica, where they would likely drive native penguins to extinction, would not be acceptable," Parmesan said.

"Ultimately, the decision about whether to actively assist the movement of a species into new territories will rest on ethical and aesthetic grounds as much as on hard science," she said. "Conservation has never been an exact science, but preserving biodiversity in the face of climate change is likely to require a fundamental rethinking of what it means to 'preserve biodiversity.'"

'/>"/>