Modeling the future, looking to the past

Glaciers worldwide have been shrinking over the last century. The McCarty Glacier has almost completely disappeared since 1909. Prepared by Robert Rohde for Global Art Warming.

Most scientists agree that abrupt climate change is occurring [1]. We can observe such changes taking place as ocean and land temperatures rise each year, and glaciers around the world rapidly melt. These observations have led many people to wonder what the affects of today's changing climate will have on future generations?

What is being done

Presently, concerned citizens around the world are working to reduce the impacts of abrupt climate change by decreasing the amount of greenhouse gases, such as carbon dioxide, in the atmosphere. To compliment this approach, scientists are furthering our understanding of climate change by studying its impacts in the present and trying to predict those that will occur in the future.

So how do scientists begin to study what might happen in the future? Part of the answer lies in something called scientific modeling. Scientific modeling helps us predict what is most likely to occur in the future. We can plug information from many different sources into a mathematical model, which can incorporate large amounts of data and help us make predictions on future outcomes. Scientific modeling using computers was first employed in the 1960s, and has grown by leaps and bounds with the technology available today.

The Complex Climate

Dr. Andrew Weaver from the University of Victoria

Modeling in some fields of science can be relatively straightforward; unfortunately, modeling climate change is not so simple. Climate is defined by the long-term weather patterns of an area and involves complex interactions between the atmosphere, biosphere, ocean, and ice-covered surfaces of the planet. Each modeling system is different depending on the information that is used, but when you run the scenario many times you end up with an average answer that allows you to simulate the past and predict future climates [2, 3].

Dr. Andrew Weaver, a climatologist at the University of Victoria , is passionate about understanding how climate change will affect the world that we live in. Dr. Weaver and his team have developed one of the most sophisticated climate modeling facilities on the planet, the Earth System Climate Model, which is now used by researchers across the globe. By incorporating information on how ocean and land plants absorb atmospheric carbon, Dr. Weaver is able to investigate how changes in the carbon cycle have interacted with climatic changes over the last 650,000 years [4].

Work in progress

Although Dr. Weaver's climatic models have been very successful, they are still a work in progress. One key component that is missing from the carbon cycle model is permafrost, soil frozen solid for more than two years. In Canada , permafrost accounts for more than half the landmass, mainly in the Arctic. Across the planet, this massive layer acts as a frozen carbon reserve and scientists are still working on how to incorporate permafrost into the global carbon budget[4].

Extent of permafrost in the Northern Hemisphere. Scientists are still not able to incorporate permafrost into most climate models even though it is a huge carbon sink in the northern hemisphere. Prepared by cartographer Hugo Ahlenius, UNEP/GRID-Arendal [6], with source data from Brown et.al. 1997[7].

Looking to the past for future answers

One of the areas that Dr. Weaver is currently working on is how past climate changes are linked to the larger global carbon cycle. Gases in the environment are exchanged between the oceans, the living organisms, and the atmosphere continuously. Understanding these exchanges in the past will aide scientists in determining how increases in present levels of gases will affect the climate in the future. By studying how and why environmental and atmospheric changes in the past happened, we can start to understand how the future may look [4].

The more information we can put into the models that we use the better the results will be at predicting what may occur in the future. The work that Dr. Weaver and his team are doing will aide us as we adapt to the changes that will likely occur as the climate continues to change as a result of our past, present and future actions.

In November 2007 Dr. Weaver was also appointed to British Columbia's Climate Action Team [5]. A group that will examine how Canada will reduce its greenhouse gas emissions and become carbon neutral over the next decade. For more information on Dr. Andrew Weaver visit his website at climate.uvic.ca/people/weaver/.

Scientific modelling lesson plan

1. Oreskes, N., The Scientific Consensus on Climate Change. Science, 2004. 306 (5702): p. 1686.

2. Weaver, A.J. and F.W. Zwiers, Uncertainty in climate change. Nature, 2000. 407 : p. 571-572.

3. Zwiers, F.W. and A.J. Weaver, The Causes of 20th Century Warming. Science, 2000. 290 (5499): p. 2081-2083.

4. Back to the future. 2007, The Ring.

5.B.C.'s Climate Action Team unveiled by premier. 2007, Times Colonist.

6. Ahlenius, H., Permafrost extent in the Northern Hemisphere. 2007, United Nations Environmental Programme / GRID-Arendal.

7. Brown, J., Ferrians, O.J.J., Heginbottom, J.A. and Melnikov, E.S.International Permafrost Association Circum-Arctic Map of Permafrost and Ground Ice Conditions, Scale 1:10,000,000. 1997. U.S. Geological Survey.