Climate change and conservation

Evidence about the extinction of megafauna, such as the giant sloth,
can be used to challenge climate-species fatalism

If the planet is already locked into significant climate change, as is widely recognised, then what is the point of conservation? In the past, the earth has undergone considerable changes that have been accompanied by species extinctions and so aren’t contemporary conservation efforts just wasting resources by attempting to preserve species that are maladapted to the present climate?

The above statement is an example of what I like to call ‘climate-species fatalism’, which argues that human efforts will be unable to overcome the pressures placed on endangered species by climate change therefore rendering conservation pointless. While economists may be notorious for holding controversial opinions, I’m just trying to provoke a response here and don’t actually believe this. Although climate-species fatalism may appeal to politicians looking for an excuse to avoid action, I would argue that evidence from past extinction events implies that, even in the present context, conservation can still prove effective.

The wave of late Pleistocene megafauna extinctions is a good case in point. 50 ka BP the planet was home to over 150 genera of megafauna (animals >44kg) but by 10 ka BP at least 97 of these had become extinct. The causes of this significant extinction event are debated and there is a rich academic literature that attempts to solve the megafauna mystery. Was it the arrival of trigger-happy human populations who hunted easy-to-catch larger species to extinction or are shifts in climate to blame? While proof of the latter of these causes would support the position of climate-species fatalists, Barnosky et al (2004) have undertaken a comprehensive summary and analysis of a range of studies that indicates that both factors were significant. Observing that the global wave of extinctions occurred in a pattern of regional pulses, the authors assess both paleoecological evidence about major regional climate shifts and archaeological evidence about the date of human population arrival to suggest that regional extinctions peaked when both adverse human and climatic pressures were present.

These findings have present day relevance as they imply that, even as unavoidable climate change places increased pressure on species, addressing anthropogenic impacts that are adversely affecting threatened species can mitigate extinction risks.

So if conservation remains important, what sort of policies should conservationists be pushing for? I have previously discussed the development of integrated environment-economy models and believe that they can offer an insight here. In particular, Lenzen et al (2012) have developed a particular economic-environment model that analyses the impact of trade on global biodiversity. By evaluating the species impact of supply chains and combining this with an analysis of international trade patterns, the authors have been able to show how the impacts that consumers have on biodiversity often extend well beyond national borders. For example, the study finds that UK imports threaten 285 species abroad owing to the high volumes of environmentally harmful crops such as tea, coffee and palm oil demanded by UK consumers.

This shows that a national approach to conservation, which focuses exclusively on domestic biodiversity impacts, will be inadequate to preserve global biodiversity. Lenzen et al (2012) emphasise that their findings show how local biodiversity threats are driven by global trade systems and argue that this international dimension demands similarly international conservation policies. For example they argue that policies to address production practices with damaging impacts on local biodiversity should acknowledge the role of international traders and consumers as well as local producers themselves. This gives support to initiatives such as the Roundatable for Sustainable Palm Oil which seeks to increase the sustainability of palm oil production through engagement with stakeholders across the commodity’s geographically dispersed supply chain.

    

While climate-species fatalism is challenged by historical evidence I fear that, unless further conservation efforts are made at an international level, conservation policy will be inadequate to mitigate the extinction threats posed by climate change and the climate-species fatalists will be proved right.