Isotopes unlock weather mysteries

November 2, 2007

By Kirk Sibbald

The keys to the future are records from the past in the world of climate change, and some U of S researchers are hoping to unlock such mysteries through their work at the Saskatchewan Isotope Laboratory (SIL).

The SIL was established in 2000 and expanded to its current form in 2002,  said Chris Holmden, SIL co-director and professor in Geological Sciences whose work led to the creation of the lab. Since that time, researchers have been collecting isotopes from various sites in more than 80 countries, uncovering information about past climate variations in the hope of forecasting future trends.

Isotopes are defined by the Oxford Canadian Dictionary as “two or more forms of an element differing from each other in nuclear but not chemical properties,” although SIL co-director and professor Bill Patterson described them more simply as “fingerprints from the past.” He said his research team study isotopes by examining core samples taken from relatively undisturbed sites like bat caves or lake bottoms. They can date climate change by studying the core samples and other materials that include guano, rocks, clams, trees and fish ear bones.

Ultimately, Holmden and Patterson said one of their primary goals is to reconstruct the world’s climate over the last 10,000 years. They are currently researching climate in some of the world’s most sensitive meteorological areas, such as Western Canada, Western Europe, Iceland, Antarctica and the Eastern United States.

“Then we branch out from there,” said Patterson. “By developing these records, we are looking at the real details of past climate and establishing whether there are enough patterns there to infer what climate will be like in the future.”

In certain locations, the team has already developed some projections, one of which is the amount of lake-effect snow – snow produced when cold, arctic winds move across expanses of warmer lake water – in New York. Patterson said after observing that the amount of lake-effect snow in this area increased 300 per cent in the last century, his team used isotope records to predict that the increase would continue for at least 50 years. So far, their projections are right on, as another snowfall record was set only two years ago.

This year, the SIL team also collected trees from Labrador, and will be comparing the tree ring records to past precipitation data in order to forecast future trends in this region. While Patterson admits climate prediction is still an inexact science, they may be able to provide reasonable predictions of climate variations decades in advance.

“For example, we can say based on what has happened in the last 300 or 400 years, we expect this to happen in the next 50 years. So we can frame the question and hint at an answer, but it will be a long time before we understand the climate system completely,” he said.

Although working in the politically charged realm of climate change has inherent pressures, Patterson said he enjoys studying an issue that evokes such passionate responses from so many.

“It is the only thing that affects everybody and everything. Climate affects every living thing on Earth, it affects every inanimate object on Earth with weathering rates, so it is all related.”

As to whether or not the Earth’s current warming trend is directly related to human activity, both Patterson and Holmden believe the jury is still out.

On one hand, Holmden pointed to an ice age during the late Ordovician Period nearly 430 million years ago where CO2 levels were 12 to 16 times higher than they are today. That kind of data, he said, tends to discredit one pervasive theory that says increased human production of CO2 is causing global warming.

Patterson added that although some blame humans for the fact glaciers are melting, nearly all alpine glaciers on Earth completely disappeared about 6,000 years ago during another documented warming trend.

“What is happening now isn’t weird or abnormal by any means. It’s just weird for us because we are used to seeing them and now they’re going away,” he said.

In support of human activity affecting climate change, Patterson and Holmden noted there is a body of research that suggests farmers may have been the first culprits in the warming trend we are currently experiencing. Cereal crops, which became increasingly important in the Middle East, Northern Syria, and Europe about 8,000 years ago, contributed to the Earth’s CO2 level. Increased methane from rice production and livestock may have also played a role, they said.

But regardless of where one’s political or personal convictions lie, Holmden and Patterson both agree there is considerable research remaining to be done before anyone can draw definite conclusions.

“Having said all that, we don’t know how responsible we (humans) are for climate change,” said Patterson. “The dishonest or naïve person would say ‘Yes, we’re entirely responsible,’ or ‘No, we’re not responsible.’ But the real answer is we don’t know.”

The SIL received a significant monetary boost earlier this month in the form of a $300,000 donation from Talisman Energy and its CEO, Jim Buckee. Holmden said the money is earmarked for student support and bursaries, something essential in helping the lab attract top quality researchers in an increasingly competitive academic area.