SHARE

November/December 2011 | by Lee Narraway

Understanding Global Warming

My camera is focused on the exquisite remains of a tree. It is a metre tall, twisted and silvered with stubby branches reaching out in all directions. Five million years ago, this tree lived and thrived in the High Arctic. It is one of many fossils from Ellesmere Island, Nunavut that are stored here in the archives of the Canadian Museum of Nature.

At 196,236 square kilometres, Ellesmere Island is the tenth largest in the world, the most northerly point in Canada, and has fewer than 150 permanent residents. This stark and magnificent land of mountains, ice caps, permafrost and glaciers is one of the coldest and driest places on Earth. The annual precipitation of only 6 cm equals that of the Sahara desert. Temperatures range from minus 38° C in winter to 9° C in summer. Still, a fragile ecosystem survives on this vast polar desert and despite its sparse vegetation; the tundra is able to support a small population of musk oxen, wolves, Peary caribou, Arctic hare, fox, weasels and lemmings. Polar bears roam the coastline and migratory birds visit during the brief summers.

Fifty million years ago, Ellesmere Island was totally different and the proof lies in its fossils. In 1975, American palaeontologists Mary Dawson and Robert West found the fossil remains of primitive alligator, fish, turtle and mammals on Ellesmere Island. Their discovery proved that millions of years ago, the climate of the far North had been warm. This breakthrough was recognized as one of the greatest contributions to vertebrate palaeontology of the last century.

Fossil records verify that during the Eocene period, 50 to 55 million years ago, there was no permanent polar ice on Ellesmere Island. Instead, a lush rainforest dominated by dawn redwood trees and tropical vegetation flourished near Strathcona Fiord. This fertile ecosystem survived despite being shrouded in darkness for six months of the year. The forest thrived on rich flood plains that teemed with a diverse variety of life, including alligators, tapir, giant tortoises, primates, snakes, lizards and the hippo-like Coryphodon, all nourished by the abundant rainfall and mild climate. Over many millennia, the Earth began to cool.

During the Pliocene period of three to five million years ago, shortly before Earth plunged into an ice age, a lake existed on Ellesmere Island amid a boreal forest setting of larch, dwarf birch and northern white cedar. Wetland mosses, herbs and patches of grass surrounded it. The area was home to fish, frogs, molluscs, birds, tiny deer, primitive black bear, three-toed horse, rabbit, badger, shrews and small beaver.

In 1961, John Fyles of the Canadian Geological Survey discovered what is now known as the Beaver Pond site near Strathcona Fiord and in 1988, he found the first fossil there, that of a beaver. Ongoing field research began in 1992 with teams led by Canadian palaeontologist Dick Harington and Natalia Rybczynski, palaeontologist with the Canadian Museum of Nature.

Fossils are often preserved through a process known as permineralization. This occurs when solutions rich in minerals fill in the porous tissues of organic material such as bone or wood. Although heavier, the fossil now retains the original shape of the organism. But this site has yielded organic material, including trees, leaves, cones, plants and mosses that have been preserved in peat deposits, thus they are “mummified” rather than fossilized.

The Beaver Pond site on Ellesmere Island is unique. There are no other recorded fossil bones from the Pliocene period anywhere else in the High Arctic regions of the world. Many believe this is one of the most important fossil archives on the planet. Tests on its organic material indicate that average annual temperatures during the Pliocene period were 11-16° C warmer than today in summer and 18 to 19° C warmer in winter. Climate models have confirmed that during the Pliocene era, the Earth itself was two to three degrees warmer than now and predict the temperature of the planet will again rise to that level over the next 100 years. Therefore, data from this site provides both a fossil archive of the actual conditions in the High Arctic under those temperatures and a benchmark to measure the pace and impact of current climate change.

But… these irreplaceable fossil records are under threat. Ellesmere Island fossil forests are preserved as coal seams and, unfortunately, the Strathcona Fiord region, with the most fossils and the most coal, has been licensed for exploration and future mining.

When this information became public in 2010, an outpouring of protest letters from scientists around the world helped convince the Nunavut Impact Review Board to demand that the project be modified or abandoned due to the “high likelihood of unacceptable adverse impacts to wildlife and fossil beds” in the region. However, the final decision still remains in the hands of the Department of Indian and Northern Affairs.

The fossils of Ellesmere Island provide a window into a warm Arctic world that has disappeared. The information they retain plays an ever-important role in our understanding of global warming and its future effect on the planet.