SFU professor Rolf Mathewes and researcher Bruce Archibald, among others, have gained critical insights into climate change while investigating 50 million-year old palm beetle fossils.
In establishing the existence of palm beetles during this period, the team was able to hypothesize as to the existence of palm plants — the beetles’ food source — even without fossil evidence of the palm plants themselves. Mathewes summarized, “Finding [the beetles] basically proved that there had to be palms, even though we did not have the fossils.”
Furthermore, their existence proves that during a period of global warming in the geological past, there were mild, frost-free winters in North America.
Mathewes explained, “To give you some background, palms are very important climate indicators. We are particularly interested in the climate of this period called the greenhouse earth, which was the warmest period since the extinction of the dinosaurs in the last 65 million years. This was around 50 to 53 million years ago.”
He continued, “In the Eocene greenhouse world, the whole world was very warm and almost tropical everywhere, except for some of the upland areas.” Because the palms cannot survive in regions with significant frost days, the existence of palm beetles in North America indicates moderate temperatures.
The team investigated fossils from a number of sites in central British Columbia, in an area called the Okanagan Highlands. In the Okanagan Highlands, fossil lake deposits formed during a period of mountain building and volcanism that preserved plants, flowers, and insects, among other things. “The fossil record is wonderful,” Mathewes said.
Mathewes has been making fossil collections for over 30 years. Archibald discovered beetles called bruchines in these collections; it was in these collections that he found a set of beetles of a certain family called palm beetles, which feed only on the seeds of palm trees.
Archibald researched and found one specimen at first, and thought there must be more. He “found three sites, possibly a fourth, that have these palm bruchine, which span about over a 1,000 kilometres of latitude from northern Washington to Smithers in the center of BC, and everywhere in between,” Mathewes said.
Looking at climate change clues in the distant past, the team hopes to provide greater insight into the future as the world increasingly experiences the effects of global warming.
