Nothing new under the Sun: ‘Mountain Avens’ (Dryas octopetala L., Rosaceae), a small arctic-alpine evergreen shrub that gives its name to a period of very fast climate change known as the ‘Younger Dryas Event’. It is estimated, from annually-banded Greenland ice-cores, that the annual-mean temperature at the end of this dramatic period increased by as much as 10°C in 10 years.

Where climate change is concerned, context and history are everything. This is why anybody daring to comment on the possible effects of current climate change on the distribution and ecology of living organisms must read a brilliant new review published recently in the scientific journal, Progress in Physical Geography [see: G. M. MacDonald et al.: ‘Impacts of climate change on species, populations and communities: palaeobiogeographical insights and frontiers’, Progress in Physical Geography 32(2) (2008), pp. 139 - 172: DOI: 10.1177/0309133308094081. An Abstract and .PDF are available at Sage Journals Online]. This review is by some of the world’s leading authorities on palaeobiogeography, the study of the distribution of organisms through geological time.

The authors’ conclusions are seminal. I quote [see: pp.164-165]:

“ A pervasive message is that the climate has been dynamic at many different timescales and that biota have responded in a similarly dynamic fashion. The climate variations have included not only long-term millennial changes in mean conditions, but also much shorter-term shifts, and changes in variability. The assumption of stationarity is a short-term illusion in terms of both climate and the impacted biota. The shifts in climate have also impacted disturbance regimes such as fire and this has had a sharp impact on populations and landscapes. Finally, some shifts in climate may have been gradual, but events such as the YDE [‘Younger Dryas Event’] or the MCA [‘Medieval Climate Anomaly’] and the LIA [‘Little Ice Age’] were much more rapid. Responses to climate change have included changes in geographical distributions, shifts in community composition and extinction. Species which are extant today have in the past been organized into communities that have no modern counterparts. Regional bio-diversity has seen marked changes in response to shifts in climate. In addition to these ecological responses, which are expected in the case of large-scale habitat changes and climate warming, there is also evidence that species have responded with genotypic and phenotypic shifts in the face of Quaternary climatic change. Such evolutionary responses should also be anticipated in the future.”

Now That Is Fast!

“Onset and termination of the Younger Dryas Event ... were abrupt, occurring within a few decades in many regions. The magnitude of the YDE is well characterized for many regions, providing case studies in ecological response to abrupt climate change....

Records from Europe and eastern North America and other regions indicate that ecological responses to the rapid changes of the YDE were also rapid, occurring within decades.”

Indeed, it is estimated, from annually-banded Greenland ice-cores, that the annual-mean temperature at the end of this period increased by as much as 10°C in 10 years.

Now that is fast! What would The Guardian, The Independent, and The New York Times have said?

The idea that our current climate is changing faster than ever before is nonsense. Full stop.

So, do read this most authoritative review of climate change and the response of species in the past. It puts our minuscule present in much clearer perspective.

Coffee.