I believe you’re correct to point out that conservation biologists are not suddenly placing all their chips on climate change as the number one threat.

But generally speaking, current environmental debates both in the blogosphere and in mainstream media center around climate change politics and policy. I well understand that this reflects the topicality of climate change in the news–from Copenhagen to George Will to recent congressional hearings and proposed legislation.

Still, I wonder if Brendan has put his finger on something larger, a whole-scale shift in the way ecologists and environmentalists view threats to ecosystems and biodiversity. Of course this is not quantifiable. (Time for a survey?)

So while there may be, as Brendan admits, “only a handful of cases where climate change policy has negatively influenced biodiversity,” what’s more notable to me is how the media and many environmentalists have taken to viewing big, longstanding ecological issues, as I wrote here (www.collide-a-scape.com/2009/04/23/the-killer-macguffin/), “through a climate change lens.”

Lastly, Brendan, I doubt you’ll get much traction with your cost-benefit argument. In fact, it’ll probably only reinforce the whacky idea advanced by some, that you’re an “embryonic Lomborg.”

While a good conservationist will hedge their bets, they should generally be looking to save, for instance, the greatest number of species per dollar. And from the consumer’s perspective, a dollar spent on a hybrid vehicle may not be spent on a year’s supply of shade grown coffee.

The verdict on habitat loss vs. climate may not be in, but judging from these and other comments I’ve read — that alone is news to people.

As for Mike Lemonick’s comment: I do think these types of mental exercises are important. Battling climate change and saving biodiversity may not always be achieved via the same means and I think it is quite clear that they are often in conflict with one another. No doubt the conflicts will become more serious in the future and folks who care about biodiversity must think carefully about how they want to craft their policies and spend their dollars.

I stand behind the central point of the Slate essay, but I’ll add a bit of nuance to the discussion here. We can all agree that in terms of extinctions, the effects climate change and habitat loss are of the same order of magnitude (i.e. factor of 10). But after taking a close look at worldwide estimates for species loss, my money is still on habitat loss.

The two Con Bio papers that Zimmer cites deserve to be included in the debate, but they are hardly any more definitive than the analyses I mentioned in the Slate piece. For instance, in their discussion, Malcolm et al write, “The deforestation average [extinction rate] was 0.24%, which was more than twice as great as our overall SAR-based [climate] average of 0.11%. Under certain scenarios, however, the estimates associated with climate change exceeded those with deforestation.” The scenarios they describe in which climate change beats out habitat loss are, frankly, far-fetched.

The Sekercioglu et al (2008) paper is a nice look at how climate is going to force many bird species up mountains — and sometimes mountains don’t go high enough. But its not the “last word” on the bird extinction story, and the authors even write in the abstract “our climate-induced extinction estimates are broadly similar to those of bird species at risk from other factors, but these estimates largely involve different sets of species.” I also know from speaking with Jetz that he’s not about to temper his own findings, which fall strongly in favor of habitat loss as the biggest extinction culprit.

So where does this leave us? Eager for more data, certainly. But it should also be a reminder that “old school” conservation strategies still matter in a very big way, which is something I think many folks (and eco-conscious companies) have forgotten with all the talk of carbon offsets. Yes, we may need to tweak our land protection schemes to take into account shifting biomes, and we may want to keep north-south corridors intact for climate-related migration. But you can still burnish your environmental credibility by saving a chunk of land.

Just like has happened in the US over the last century.

Also, you might have heard the FAA is now releasing aircraft bird-strike information. Over the last five years, flight hours have been, at best, flat.

But reported bird strikes are way up. Why might that be?

http://southernfriedscience.com/2009/04/21/5-things-worse-for-the-planet-than-global-warming/

See. Problems are one and the same. Reducing habitat loss can be justified from multiple angles.

C.

However, I understand his frustration. Science & conservation funding IS a zero-sum game – there’s only so much money to go around. And habitat destruction frequently has relatively simple & cheap solutions (parks, conservation easements) compared to climate change (overhaul world economy).