Learn about Climate Change: Frequently Asked Questions
How do you respond to people who talk about uncertainty and trusting the models?
Reflections from Kimberley's Coordinator, Ingrid Liepa
Whenever you are talking about the future, there is always uncertainty. That said, climate scientists from around the world are in agreement that the earth is warming and that the warming is linked with rising concentrations of greenhouse gases in the atmosphere (ref: National Academies of Science, G-8 declaration, etc). The various global climate circulation models (GCMs) that have been developed around the world concur on the overall warming trend; where they differ is on how much warming and how fast. The common thread is that we are likely to see more extreme weather events and more variability in our weather patterns.
Thus, as a prudent risk management exercise, it is useful to work with the upper and lower ranges in the box plots developed by PCIC as part of its future climate projections to start asking “what if” questions around natural/built/human elements in the community that are already experiencing sensitivity and/or vulnerability to climate changes experienced in the last few decades, as these are likely to become more significant in the coming decades.
The GCMs run various scenarios based on different assumptions around future levels of greenhouse gas emissions (eg. A1, A2, B1, B2, etc). There is not much difference in the impacts on temperature and precipitation of different scenarios until after the 2050s because the current warming trajectory is already “locked in” due to the amount of time that carbon cycles in the atmosphere. One must look to the 2080s to start seeing the appreciably distinctive consequences of different GHG emission scenarios. (Note from Trevor Murdock of PCIC: Agreed but actually the changes will be more dramatic than the 2050s projections by the 2080s EVEN with significant GHG reductions – they will just be that much larger again without the reduction.)
A helpful approach, therefore, is to focus on changes forecast for the 2050s with the understanding that without significant GHG management, the changes will be more dramatic by the 2080s.
What do you say to people who want to know how that translates into an impact?
I would refer them to the CBT’s work with PCIC in 2006/07 which translates predicted changes in precipitation and temperature into a series of potential impacts in the Columbia Basin. Some impacts are easier to predict because they are simpler and closer to the source in the chain of causation. For example, if summers become hotter and there is less rain fall, the prospects for drought conditions increase, as do the risks of wildfire. More challenging and complex is predicting how an entire forest ecosystem might respond to changing climate.
How do you respond to climate deniers?
It is likely that a project will encounter community stakeholders who are skeptical about climate change and/or its causes. Some of them will disagree entirely with the proposition that climate change is occurring, others will agree that it is occurring and disagree with the current scientific consensus that greenhouse gas emissions are a significant factor driving warming.
For those who believe that climate change is not occurring, there is frequently also a significant underlying mistrust of the establishment, e.g. governments and authority. They believe that people are being duped into a big climate change hoax and want to remove the wool from our eyes so that we don’t end up making costly decisions that have no benefits. Don’t think that you are going to change their views by arguing with them – for the most part they will not be interested in listening. In general, give them an opportunity to make their statements, thank them for their comments, and move on. If they persist, remind them (and the rest of the audience if it’s a public event) about the IPCC, National Academies of Science and G-8 positions on climate change, and move on.
For those who agree that the climate is warming and believe that it is happening for reasons other than greenhouse gas emissions, eg. solar activity, the adaptation project is an easier sell because its focus is addressing and planning for the impacts of climate change regardless of cause. The anti-AGW folks (AGW = anthropogenic global warming) may take issue with the modeling because greenhouse gas emission levels are a key factor/variable.
Kimberley’s report addresses the core project assumptions around climate science and the role of greenhouse gas emissions in climate change, emphasizing that given the widespread scientific agreement on a changing climate, it would not be prudent to ignore potential impacts and adaptation on a local level.
See Learn About Climate Change:Useful Material for a powerpoint presentation on scientific consensus.