A fossil bed near Cache Creek once leased by the province to mine for cat litter is one of a series of sites across British Columbia now helping generate crucial evidence of how the world’s climate changed 50 million years ago.
The McAbee site, remnant of an ancient lake bed in which a vast array of insects and plants were fossilized, was finally protected by the province in 2012 after a decade of wrangling and resistance to pleas from scientists regarding its importance.
Monday a high-profile paper published in the Proceedings of the National Academy of Sciences confirmed the site’s global scientific value.
Bruce Archibald, one of the paper’s authors along with fellow Simon Fraser University scientist Rolf Mathewes, likens his initial encounter with the richness of the McAbee site with the feelings of amazement that a 16th-century explorer setting foot on a new continent must have experienced: “A whole new world filled with marvels spread out.”
Insect fossils collected from the McAbee site were compared to those found at three other sites, to establish the range of temperature-sensitive plant species upon which the beetles depended.
“We use fossil beetles to act as substitute thermometers to estimate winter temperatures 50 million years ago across this region,” Archibald says.
The research provides a clearer picture of climate during a distant past when the landscape was home to exotic carnivores the size of a small pickup truck, predatory birds as big as modern bears, whales with legs and rhino-like creatures that were the largest mammals ever to walk the earth.
Scientists believe the global warming that occurred during the Eocene epoch, about 56-to-34 million years ago, characterized by rising levels of atmospheric methane and carbon dioxide, can serve as a climate analog that sheds light on processes now occurring that are further amplified and accelerated by greenhouse gases produced by human activity.
“We see a forest community preserved in a temperate upland of a world which had elevated atmospheric greenhouse gases and globally warmer climates, some of the very conditions that we might expect to see in climates that we will be surely encountering in our near future and further,” Archibald says. “Understanding the interplay between climate and natural communities as we experience climate change may well help to forearm us for challenges to come.”
Indeed, even as the paper was published, the New York Times was reporting that two sets of scientists have now independently confirmed that the collapse of large parts of the West Antarctica ice sheet is underway and is almost certainly unstoppable, and that a long-term sea level rise of three metres is probably inevitable (see story on page B3).
The ancient epoch being laid bare in B.C. is of particular interest because while global climate warmed rapidly during the early part of the Eocene to one of the warmest episodes in the fossil record — tropical and semitropical forests covered the planet’s continents from the North to the South poles — it later cooled rapidly, triggering rapid expansion of the Antarctic ice sheets.
On a more sobering note, the end of the Eocene around 34 million years ago was marked by a mass extinction of global life forms, beginning with aquatic and marine species.
Scientists from SFU, the University of Victoria and other leading institutions in Canada, the U.S. and Australia have been tracking evidence of these changes in the fossil record with increasing scrutiny.
Archibald and Mathewes, both of SFU, Geoffrey Morse of the University of San Diego and David Greenwood of Brandon University and the University of South Australia say they have devised a new way of examining this ancient climate change by studying a species of palm beetle.
In effect, they say they’ve found a method of “hindcasting” winter temperatures in the interior of B.C. and Washington 50 million years ago by using the fossilized palm beetles as “proxy thermometers.”
The beetles, the scientists say, were dependent upon a species of frost-intolerant palm trees that indicate the temperature range of warm winters extending northward through the Canadian uplands.
Nine specimens were gathered at sites extending from Driftwood Canyon Provincial Park near Smithers to Republic, Wash., just south of Grand Forks. The McAbee site and one at Quilchena near Merritt furnished other specimens.
These beetle specimens collected from sites separated by about 1,200 kilometres of driving provide what the authors call “robust support” for the ancient presence of palm forests around what’s now Merritt and Cache Creek.
And they will add profoundly to the understanding of the climate change and its implications for the present.
“Elevated carbon dioxide combined with globally warm temperatures in the Eocene make its climate ideal for understanding modern global warming and its biotic consequences,” the paper says.
Archibald brings the picture closer to home.
“We (already) see the dramatic effects of warming winters — even a small amount — across B.C. with the mountain pine beetle infestations that have so severely impacted forests and the communities that depend upon them throughout the province,” he says.
“Looking deeply into the fossil record to times of similar climates in order to better understand these issues is of great, direct importance to people right across B.C. and beyond.”