Unique Opportunities for Climate Change Research
Text and image by Professor Jon Woodhead Many scientists are currently engaged in the study of our changing climate. While increasingly sophisticated models are being developed to predict how rising global temperatures will impact terrestrial ecosystems, one important aspect – precipitation – is actually very difficult to model and considerable uncertainties remain in future projections. Palaeoclimatology – the study of past climates – offers an alternative means of approaching the problem. By looking at records of past climate variation we can see how the planet previously responded to temperature changes and this may help to predict any future response. Cave deposits such as stalagmites, stalactites and flowstones, which scientists collectively term ‘speleothems’, are an important archive of past climate change. They are particularly important in this regard because they can be reliably dated by radiometric methods and depend upon water availability to form and thuscan provide us with robust records of past precipitation variations through time. The key period of geological time identified by scientists of most relevance to the future climate debate is the Pliocene epoch ranging from 2.6 to 5.3 million years ago. This is the last time the Earth saw temperatures like those expected in coming centuries and it is hoped that the Pliocene can provide some clues as to what we might expect as our planet warms. In this regard the Nullarbor caves form a unique and invaluable resource since almost all of them contain speleothems formed during the Pliocene epoch while these are exceptionally rare elsewhere in the world. We have only just started to explore the wealth of paleo-climatic information preserved in Nullarbor speleothems, but they may well prove invaluable in helping to define future precipitation trends under a warming climate. It would be a tragic irony if we were to destroy this unique scientific resource in a push to build a ‘Green’ Energy Hub.