Targeted and careful field research combined with rigorous laboratory analyses of samples can provide powerful insights into ancient climates. This type of research is essential if we are to distinguish climate change induced by human activities from that induced by natural processes. The field expeditions led by Dr. Natalia Rybczynski of the Canadian Museum of Natural History to Ellesmere Island, high in the Canadian Arctic, provide an excellent example of this approach.
Because of modern global warming, strata previously hidden beneath glacial ice have been recently exposed. These new exposures are readily identified on satellite images. Working in strata about 3.5 million years old (i.e., mid-Pliocene in age), Dr. Rybczynski’s research team uncovered a bone fragment less than the length of a human thumb. Laboratory analysis has revealed that naturally occurring proteins preserved in the bone are a perfect match for a camel. Further investigations yielded about 30 bone fragments that together comprise part of the limb bone of a camel (Fig. 20A).
Figure 20A: Camels Bones in the Arctic.
These fossils comprise part of a limb bone of a camel.
Fossils in nearby layers indicate that local vegetation would have resembled a northern (boreal) forest, in contrast to its stark modern landscape (Fig. 20B). The mid-Pliocene has been established as a warm interval, with average global temperatures estimated to be about 2–3ºC (4–5ºF) warmer than today. But these camel bones and plant fossils indicate that the average temperatures in the high Arctic at the time were about 14 to 22ºC warmer than today.
Figure 20B: Ellesmere Island in the Pliocene.
This portrayal of the habitat in Ellesmere Island in the high Arctic some 3.5 million years ago is based on fossils in nearby strata.
This find is about 1200 kilometers further north than any previous camel fossil discovery. The camels in the high Arctic must have endured months of continuous darkness during the winter. The researchers speculate that the camel evolved several features, including its hump, which stored fat, to cope with the darkness.
This research also highlights the sensitivity of the Arctic to climate change in the past, and may well be a harbinger for the changes in the Arctic that we will experience this century.