Climate Change Scenario Workshop

January 9, 2001
Hosted by Prairie Adaptation Research Collaborative

Objective

To provide an informal workshop setting for PARC-supported researchers to discuss the availability, characteristics and use of climate change scenarios with the PARC Research Coordinators and with Dr. Elaine Barrow, the Science PI on the Canadian Climate Impacts Scenarios (CCIS) Project.

Workshop Agenda

Discussion of PARC programs and activities - Dr. Dave Sauchyn

Canadian Climate Impacts Scenarios Project - Dr. Elaine Barrow
Background: An overview of the different scenario construction methods available and the advantages and disadvantages of each
Description of the Canadian Climate Impacts Scenarios Project
Scenario Use: What you can and can't do with the CCIS Project climate change scenarios
Down scaling: An Introduction

Summary of Open Discussion among the Participants and Workshop Presenters

What is the state of the art of regional climate models?

A new run is just about to begin for all of Canada. The original run was for Western Canada and an Eastern Canadian run is being debated. It was decided to do a run for all of Canada with coarse resolution; this run will begin soon and it will take at least a year before the data will be available, after which the results would have to be processed.

Is there no confidence in previous work done for Western Canada?

There may be a lack of confidence due to problems with boundary conditions and climate simulation at finer scales. The boundary conditions for RCMs are derived from GCMs. For useful results, it is best to wait until the regional climate model results are available for all of Canada.

How are maximum rainfall events modelled?

By comparing GCM output to known maximum rainfall to develop a threshold to define the wet-day and dry-day boundaries used in the GCMs. Changes in the mode and intensity of rainfall are more important than just changes in amount. For the six ecoregions in Saskatchewan, we have general ideas about impacts, but we could use more detailed information.

Will the models predict impacts more precisely?

You will get reasonable results only at the resolution of the GCM grid. This is the best model available at the moment in terms of spatial resolution.

What are the hydrologists doing in terms of studying climate change impacts?

PARC is supporting two projects. One deals with ground water and involves researchers from SRC, Sask Water and the GSC. The other project is a study of climate change impacts on glacier and snowmelt runoff from the eastern slopes of the Rocky Mountains. This project involves scientists from the GSC in Ottawa and the NHRI in Saskatoon. To our knowledge, no one is considering the climate impacts on prairie streams. This is an obvious gap in the impacts and adaptations research agenda.

Are the PARC Research Coordinators identifying the best approach to I & A research? How do we consider climate extremes if they cannot be identified in a GCM?

PARC does not endorse a specific approach to I & A research. We leave that to the discretion of the researchers based on their expertise. The purpose of today's workshop and our present discussion is to share our experiences with various approaches: climate modelling, historical scenarios, spatial scenarios, RCMs, and so on.
There is no simple answer to the question of best approach to I & A research, or even the best GCM experiment, because the approach depends very much on the objectives of a particular study and the questions that are being asked, and the social or biophysical systems under consideration.
Over time, confidence in the results of climate models will improve. Currently, however, all GCM model and experiments produce equally probable scenarios and thus we need to use experiments that produce a range of scenarios from the least change to the most extreme forecasts.
There are limited resources for research and a very large range of options and factors to consider. What is the best use of our resources given the amount of uncertainty about climate change?
Our modelling of climate change is improving but there is still a great deal of uncertainty about the degree and rate of climate change. The best approach at present is to consider the range of climate change and impact scenarios and the options for adaptation to this range. Then as our ability to forecast future climate and our confidence in modelling improves, the range of plausible scenarios and degree of uncertainty should decrease, limiting the scope of necessary adaptation.

Why don't we just look at historical records?

Although historical records contain valuable information, they do not necessarily tell us what will happen in the future. Climate forcing in the past did not include human-induced changes in the atmospheric concentration of green house gases. It is important to balance the use of relevant historical information with modelling techniques that predict future climate.
Sometimes we seem to get preoccupied with climate change rather than adaptation to climate.
Yes, by improving our adaptation to climate and climate variability, we minimise our vulnerability to climate change. A positive product of a focus on climate change is the attention being given to links between climate and the need to adapt. PARC funded only those research projects that address adaptation to some extent.
We surely cannot be expected to apply all 25 GCM experiments. Can we use Elaine Barrow as a resource for advice on which models and to use?
Examine the range of model outputs. Choose the experiments that forecast the minimum change, maximum change, and somewhere in-between. Since GCMs and experiments are equally valid, apply the range of outputs to evaluate the potential range of impacts. If necessary, contact Elaine but she has limited time for consultation.

Take-home message

Variability is characteristic of natural systems and science; understanding it is the nature of our work. We should use all of the resources and methods available to measure and model this variability and identify appropriate human responses.