Dealing with uncertainty: Reflections on the role of projecting regional climate change

Over the past three decades, CSIRO has led the provision of national climate change projections for Australia. Amongst a broader range of products, National Statements on Australia’s future climate were released in 1992, 1996, 2001, 2007 and 2015 (the last two in collaboration with BoM).  These projections have been widely cited and used in Australian adaptation work.  Penny Whetton had a leading role in the production of these products since 1992 and led the research team in CSIRO responsible for these projections from 1999 to 2014. 

Climate projection work lies at the interface between climate modelling and the research and management of climate impacts. Traditionally it is viewed by both those fields as a service role, whereas in actual fact it generates a range of unique scientific and ethical challenges which are often under-appreciated. This presentation will be a reflection on her experience in this role, with a focus, in particular, on those difficult challenges that needed to be addressed and on the guiding principles applied. 

The issues typically included finding a balance between competing approaches and objectives.  For example, is this task primarily about the research perspective of improving knowledge of how regional climate will change, or is about providing detailed projection data sets for use in applications (knowledge versus data)?  Should scientific effort go into generating the most appropriate high resolution simulations of regional climate, or should the effort go more into assessment of all existing high resolution and course resolution modelling data and other lines of evidence?  Should broad ranges of uncertainty be presented to users, or do the projection providers have a responsibility to identify and focus on the most likely changes, and how should they do that?  Is there a difference between ‘scenarios’ and ‘projections’, and do providers and users understand the difference?  What is the role of national projections versus state by state projection products?

It is intended that the exploration of these questions, and a range of related ones, will be valuable to current providers, users and funders of regional climate projections.