How exceptional is the recent warm weather, with its record high temperatures around the world? As places as far apart as Japan, London and Madrid suffer their highest temperatures on record, and with wildfires and drought affecting large swathes of Ontario and Europe, coupled with floods and heavy rainfall in other places, can we expect this weather pattern to continue, or is it simply an unusual series of extreme weather events? If the climate is changing, as it seems to be, is this a part of a natural historical cycle of climate change, such as has been known throughout history? Or are we seeing something different now, and, if so, what might the future bring?
Last week, the Times spoke with Dr. Nathan Gillett, the Manager of the Canadian Centre for Climate Modelling and Analysis with Environment and Climate Change Canada. Dr. Gillett holds a PhD in atmospheric physics from the University of Oxford. After his doctorate, Nathan worked as a post-doc at the University of Victoria in Canada on the detection and attribution of climate change. His primary research interests are in detection and attribution of climate change, and the influence of stratospheric ozone depletion on climate.
I started by asking him if what we are seeing is different, or simply a part of a natural cycle of climate change. His answer was quite definite. “It is a real phenomenon that we’re observing: more heatwaves, more temperature records being broken more frequently, more heat extremes. That is something we expect and is consistent with the overall warming of the climate.”
How much of this increased warming can be attributed to human activity? “In terms of heatwaves, there are studies attributing that increase to increasing greenhouse gases”, according to Dr. Gillett. “There’s always some level of uncertainty when we make these assessments, but heatwaves are very strongly linked to human influence on climate.”
Given that, can we act to change the situation, or are we now beyond that? Can political policies, such as carbon taxes or cap and trade, make a significant difference to future trends? “Going forward into the future, the level of climate change that we expect to see in fifty or a hundred years will depend on the policies that we enact today, and the pathway of greenhouse gas emissions; whether those emissions are increasing globally, as they have up to now, or whether they level out or decline. And the policies of any individual country, like Canada, play into that. I should say that greenhouse gases are well-mixed globally, and it’s the global level of greenhouse gas emissions that are important in determining the climate’s response. Of course, each country has a part to play in how that evolves.”
I wondered whether there was anything that can be done on a local, or municipal level, that would have an impact, or is it a matter of national and international initiatives? Dr. Gillett did not discount the need for acting locally. “It takes action on multiple levels, so broad scale international decisions will influence how emissions will evolve, but the combined actions of a lot of individual people can also influence that in terms of lifestyle choices. In terms of responses to climate change, the one important thing is to mitigate the effects, which means reducing emissions.”
But change is happening, and Dr. Gillett feels it is vital that we learn to adapt as soon as possible to what is certainly coming. “That can happen at the municipal level. For example, Environment and Climate Change Canada is involved in a project on changing the building codes, so that they take into account how climate is going to change in the future.”
Finally, I asked him for his predictions, based on modelling, and assuming no change in emissions. This was the biggest shock. “We can expect continued warming, which is the biggest thing. If greenhouse gas emissions stay high, by the end of the century we can expect 5-6 degree warming, on average, over Canada. We would also expect reduced snowfall, reduced snow pack, and that will change stream flow. We’ve already seen a large reduction in the ice in the Arctic, and that is expected to continue to decline. We can expect, in this scenario, ice-free summers in the Arctic by the middle of the century.
“We can also expect more intense heavy rainfall events and increased sea levels. The rising sea level is a result of an overall warming which makes the water expand, as well as the melting of the glaciers and ice sheets, which are draining into the sea and increasing the sea level.
“Drought is also expected to change in some regions due to climate change. There’s more regional variation and uncertainty in that, but it comes from warmer temperatures which leads to a faster drying out of soil, and so on. Certainly, here in Canada we would expect to see less water stored in snow packs, so river flows would be lower by the end of the summer because that rain won’t be stored as long in the snow packs.”
This is the context in which we have to judge political policies and the actions of municipal, provincial and national governments as they balance budgets and the future of the planet.
Thanks to Jeff Goodman for arranging the interview.
