This week I met a great group of climate activists and had a few hours of really good, thought-provoking discussions. We talked over the challenges of communicating climate science, how few people really seem to grasp the seriousness of the climate crisis, and how hard it is for ordinary people to picture the relentless build-up of CO2 in the atmosphere. One concern that came up is that some people may mis-perceive CO2 as similar to "air pollution," where emissions impact on those immediately downwind, for a short time, and can be relieved almost immediately by stopping the emissions. Close down the factory, and local air quality improves right away.
CO2 is not like that. CO2 does not settle out of the air, as particulate ("smoke") pollution gradually does, nor is it washed from the air by rain showers, as particulates are. We need to think of CO2 as "dissolving" in the atmosphere the way salt dissolves in water, milk dissolves in coffee, or gin dissolves in tonic water: once it is mixed in, there is no practical way to get it back out again.
So here's my new analogy to help picture the true nature of the CO2 problem: cutting greenhouse gas emissions is a bit like getting people to recycle. The problem of recycling is that we throw away far too much stuff, and landfills keep filling up. Nobody wants a new landfill near their home, so our best plan is to adopt the "Three Rs"--reduce, reuse, and recycle. That means to buy less stuff, choose products with less packaging, don't use things once and toss them, and when we do have unwanted items, try to separate materials for recycling so they don't end up in the landfill.
As long as the economy keeps growing, people keep buying more new things, and companies keep adding ever bulkier packaging for protection in transit, and to deter shoplifting, our waste stream keeps expanding. The rate the dump fills up depends on how much we are throwing away each year. The more we recycle, the longer we have before the dump is full and must be closed, and a new one located (after much squabbling.) Around here, new landfill sites are simply not being accepted.
The movement to promote recycling has been a long slog. Some people get the message and take on their individual responsibility out of personal concern, but many people either don't understand or just can't be bothered to separate their trash. They keep tossing paper, cans and bottles careless in the garbage bin. At some point, cities find that the one way to influence most people to get serious about recycling is to impose a cost on garbage pickup. This is what Toronto has done over the past couple of years: they provide each house a large blue bin for recycling, and a smaller grey bin for garbage; they charge extra for bag tags for overflow trash, and give people a break if they accept a smaller grey bin. Businesses must pay per bag for trash pickup, as well. Here in Toronto there is a third stream: a smaller green bin, picked up every week, for wet organic garbage and food waste. By keeping the wet and smelly matter separate, both the recycling and the grey bin can stay dry and odour-free so they can be picked up on alternate weeks. Toronto's program isn't perfect--there are problems with plastic in the wet garbage, apartment buildings don't yet have full access to these programs--but we are at least moving in the right direction.
Residents have to take on a bit of extra work of separating food scraps, recyclables, and those stubborn remaining "other" items that can only go in the actual trash. The modest cost imposed on extra bags or on having a larger grey bin provide the incentive to go to this small extra effort. People are now doing their bit, and blue bins are brimming with material ready to go to recycling and thus staying out of landfill.
Now think of the atmosphere as our landscape. We have been using it as a CO2 dump, but since CO2 is invisible, there has been no "NIMBY" resistance to the dumping. There is no one point where the atmosphere is going to be "full" and CO2 can't be dumped any more; rather, the longer we go on adding CO2, the more it will keep building up and the greater the impact on climate and the greater the severity of every kind of impact and risk we incur.
In trying to picture what's happening with CO2, it's important to realize that CO2 is more like landfill garbage than like factory smoke: it doesn't "go away" as soon as we get around to stopping emissions. It has been piling up higher and higher in the "CO2 dump", and even when we all attain zero emission perfection, the pile will still be standing there, stinking things up by overdriving the greenhouse effect.
CO2 hangs around in the atmosphere for hundreds to thousands of years before it will ever move on - by dissolving in the ocean, mainly. Even there it poses a further threat, since it becomes carbonic acid, lowering the pH of the ocean and harming sea life.
When we stop burning coal, the smoke will clear in a few days, but the CO2 left behind will just sit there in the air, going around and around the earth, year after year after year, trapping infrared heat and sending a bit extra back downward to heat things up here at the surface. The dump will just keep stinking. We can't cover it over and plant a golf course on top of the CO2 dump, either. We're going to be stuck with this for centuries.
Imposing a modest cost on throwing away trash has been effective in getting people to change their behaviour and adopt good recycling habits. Right now there is no cost at all for emitting CO2. It's free, so nobody goes to any trouble to emit less, except the idealistic few who understand the crisis and care deeply enough to change their habits. Like recycling, carbon reductions will only take hold across the board if there is a price signal. Once we show people they can save money by emitting less carbon, there are plenty of opportunities to make serious reductions. Since coal is very CO2-intensive for a given amount of power generated, an imposed carbon emission price - whether a carbon 'tax' or a tradeable 'permit' worth real money - will tip the scales away from coal and toward carbon-free power generation. There are plenty of alternatives waiting in the wings; wind power is already becoming competitive with most other forms of generation apart from existing, very dirty coal power.
When we finally make up our minds to begin to slow the buildup of CO2, we will need to stand tough against the dirty coal lobby, who have been tossing around terms like 'clean coal' rather casually. We certainly must not "grandfather" existing coal plants to be exempt from any carbon cost, as happened in the "New Source Review" shenanigans around power plant emission reductions. We don't yet know how feasible or affordable it is to capture the CO2 from a coal plant and bury it underground. People worry about what so much CO2 will do to groundwater and whether it may escape. One pilot plant in Germany set up to do this has not yet been able to overcome these concerns to get permission to begin pumping the CO2 underground, so it is still just dumping it into the air--carbon capture and spillage? Even when capturing the CO2 from coal, this does not in itself address the many other negatives of coal: sulphur, mercury, particulates, smog, and all the harm done by coal mining. It's really Orwellian to talk about coal as "clean."
So remember, CO2 is building up in our atmosphere's "airfill" just as every item we throw away ends up in a landfill, and whatever CO2 we emit is going to sit there for ages and ages. It won't blow 'away' or get washed out in the next rain the way smoke will. CO2 disperses and gets mixed evenly through the whole atmosphere. It continues to pump up the greenhouse effect even after it is spread out everywhere. Smoke can "disperse" and eventually we can see a blue sky again, but CO2 is not 'going away' even though we can't see it.
The whole atmosphere is one big airfill, and slowing our emissions will only slow the rate that the pile keeps growing. We don't have any easy way to take CO2 out of the atmosphere on the kind of scale we're now dumping it in. As long as we keep emitting, the pile is only going to keep growing. Planting trees or preserving rain forests will help a little, but can't absorb the kind of quantities we've dumped over the years. Some of the excess CO2 will gradually seep down from the air to the ocean, but that's actually driving a huge additional problem: acidification. It's a bit like leaching from a landfill into the ground water.
People weren't thrilled about having to pay for bag tags for excess garbage, but we've all adjusted to it and taken up using the blue bin. I also believe the world can cope with having a price on carbon emissions. It will not "destroy" the economy, it will simply channel it toward the many, many lower-carbon options we already have, as well as spurring the development and improvement of new ones.
To motivate the community to accept such a price signal, it would help for people to be able to picture that our one shared 'airfill' is getting dangerously full, and even though technically CO2 is odorless, the airfill is really getting damned stinky.