Cape Breton Post

Impact not significan­t: climate experts

Estimated eight per cent reduction in carbon dioxide emissions not enough to have major impact

- COLIN HODD SPECIAL TO SALTWIRE NETWORK news@cbpost.com @capebreton post

The impact of COVID-19 has been so total that it's hard to remember that the world isn't literally standing still.

As countries begin to crack open the doors of society and peek out into the COVID-19 world, it's natural to wonder what kind of impact the nearsimult­aneous reduction in activity has had on the natural world.

The answer, at least in the long term, appears to be “not much.”

“In terms of the restrictio­ns in response to COVID, they have reduced emissions,” said Nathan Gillett, a climate scientist from British Columbia who is one of the lead authors on the most recent Internatio­nal Panel on Climate Change report, as well as a lead author on Canada's Changing Climate Report that came out this past April.

“The best estimates published so far indicate a reduction in carbon dioxide emissions this year of around eight per cent compared to the previous year.”

While an eight per cent drop is significan­t, it comes in response to a drastic shift in the way we live and is therefore not likely sustainabl­e. We've spent decades dumping carbon into the atmosphere, he said; a few months of reductions aren't going to undo those decades.

“In terms of the effect of carbon dioxide on the climate, it's the cumulative emissions over time that drive the global warming response,” said Gillett.

“I heard someone else make the analogy that the climate effect is like you're piling up a tower of blocks and you're adding a block to the tower each year. So even if you emit a little less one year, it's not having a big effect in terms of the cumulative emissions over time.”

OTHER EMISSIONS

While carbon dioxide is the biggest driver of global climate change, and therefore the one that is most emphasized in accords like the Paris Agreement, it is certainly not the only emission with negative impacts.

Some of those, like manmade aerosols, affect the atmosphere not because they persist for long periods of time, but because they're created in such huge volumes.

“In terms of the response to a short-term change in emissions, we might expect the response to changes in shortlived species in the atmosphere, things like aerosols, to have bigger effects, at least on air quality and pollution levels and so-on,” said Gillett.

“We have been doing some research looking at the climate effects from changes in emissions of aerosols. We don't expect it to be a big effect, but if there is a climate effect that we can identify it would be to the changes in the aerosols.”

Even if the eight per cent reduction isn't going to change the course of climate change on its own, it does provide an opportunit­y to test models against real-world results. Gillett takes pains to emphasize that the state of the world right now isn't anything he would have wished.

“We wouldn't have wanted to do this, but it does afford us an opportunit­y to test our understand­ing and our models of what, particular­ly in terms of air quality and pollution, responds to changes in emissions,” said Gillett.

You might be surprised that what feels like a total shutdown has resulted in only an eight per cent drop. But therein lies a second opportunit­y for us to reckon more viscerally with the many sources of pollution beyond the obvious ones.

“You look out and you don't see any cars on the road near your house, you kind of think that emissions have gone away entirely,” said Gillett. “But electricit­y generation is a big one. Industry. Those are both big emitters. Transport is a significan­t emitter, but it's certainly not the whole story.”

IMPACT ON OCEANS

Trying to sort signal from noise is a challenge in these complex systems. Dr. Noreen Kelly, a research scientist with the Department of Fisheries and Oceans, works in a research group at the Bedford Institute of Oceanograp­hy in Halifax that tries to make estimates of the human impact on the marine environmen­t.

While she expects the reduction in activity to be reflected in the marine ecosystem, it isn't yet clear what that impact might be.

“In terms of some human activities in the marine environmen­t, if we talk about Bay of Fundy, Scotia shelf areas, some of it, in the last couple of months, has reduced,” said Kelly.

“If you have less boats, you'd have less noise and disturbanc­e. You'd probably have fewer collisions with marine animals and you'd have a reduction in pollution. So, with less tourism, less boats, less garbage, I would expect to see an increase in water quality.”

Intuition tells us the relationsh­ip between human activity and nature should be simple. That's been at the heart of many “nature is healing” memes. But living systems don't always react in linear ways, Kelly explains.

“Sometimes in the natural world, you get something called hysteresis, which is where you've had a massive change from one type of environmen­t to another, and then you take away the effect, or you take away the activity that was causing that impact, and there's a time lag between the change back to the previous ecosystem state,” said Kelly.

“Just because you're removing an activity doesn't necessaril­y mean you're going to get the response that you expect because you moved in X direction in the first place. You might go back through Y and Z before you get back to X.”

Because of COVID-19 restrictio­ns, Kelly and her fellow researcher­s haven't been able to do the same kind of data collection­s they would normally do, and so for now she can only speculate about potential impacts based on her existing knowledge. She cautions that it will be some time before we can start examining the impact scientific­ally.

“There will be some data down the road, so we'll probably be able to pick up some sort of reduction in activity,” she said.

“For example, large vessels have an internatio­nal tracing system. You get that data and you work it up on a yearly basis and you can see the density of vessels through certain shipping lanes and things like that. You'd be able to see if it was less.”

LONG-TERM CHANGE?

Most government scientists try to avoid being prescripti­ve. Their job is to deliver the best possible science to the elected officials whose job it is to make policy, and to the public whose job it is to elect those officials.

But scientists are also citizens who have hopes for their research.

If anything positive can be derived from our current circumstan­ces, Kelly and Gillett hope it will be an opportunit­y to think about and study our impacts in different ways. An eight per cent reduction that goes away because of a return to pre-COVID activities won't forestall climate change. One season of calmer, quieter waters won't restore whale population­s.

“From a personal perspectiv­e, I would hope that this COVID shutdown has kind of given us pause to think about, maybe the things we thought that were absolutely necessary maybe they aren't anymore,” said Kelly.

“And, if we can do this to save lives from a disease, I'd think that, hopefully, we can do this to save lives from climate change. I think the key is finding a balance, where what we do and what we need to do can be done in better ways that mitigate or offset human impacts.”

Gillett echoes that sentiment.

“It is possible to reduce emissions in ways that have non-negative impacts on society, and may have benefits for society, like large-scale changes of electricit­y generation­s away from coal towards clean energy,” said Gillett. “These kind of changes, you don't see when you look outside your window so much, but they have a big effect on emissions. That's where the potential for changing long-term emissions lies.”

 ?? CONTRIBUTE­D ?? Nathan Gillett, a climate scientist from British Columbia who is one of the lead authors on the most recent Internatio­nal Panel on Climate Change report, as well as a lead author on Canada’s Changing Climate Report, says movement restrictio­ns due to COVID-19 have resulted in about an eight per cent reduction in carbon dioxide emissions this year compared to 2019.
CONTRIBUTE­D Nathan Gillett, a climate scientist from British Columbia who is one of the lead authors on the most recent Internatio­nal Panel on Climate Change report, as well as a lead author on Canada’s Changing Climate Report, says movement restrictio­ns due to COVID-19 have resulted in about an eight per cent reduction in carbon dioxide emissions this year compared to 2019.

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