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History Matters: Carbon Emissions in Context

Posted on 6 July 2011 by Stephan Lewandowsky

A short piece for the general audience of RTR radio, Perth, Australia.
(listen to the original audio podcast)

We often hear that our CO2 emissions are such a tiny fraction of the world’s total, around 1.5%, that there is no need for us to take action. If we are only responsible for such a small proportion, why should we bother with a carbon tax?

Is there any validity to this argument?

Not really. In fact, not at all.

And to understand why, we need to understand the basics of carbon emissions. The key to understanding what is happening with carbon in the atmosphere is your bathtub at home—because the atmosphere is just a bathtub that are currently filling with extra CO2, in the same way that you fill your bathtub by turning on the tap.

Suppose you’ve been drawing water into your bathtub for 5 minutes and it’s close to full. All of a sudden your neighbour shows up and empties a bucket of water into the tub.

Who bears the greatest responsibility for the water in your tub? Your tap that ran for 5 minutes or your neighbour’s one bucket?

Obviously, it’s you, and not your neighbour, despite the fact that for the last few seconds, his bucket made a much bigger splash than your tap.

The same applies to carbon emissions: If we want to assign responsibility for global warming, we must look at the sum total of emissions across the last few hundred years. What matters isn’t just what we emit today, but what we have emitted for hundreds of years.

Because the atmosphere is a bathtub for CO2.

And guess what, if we compare emissions among the roughly 200 countries in the world, then we find that all but 14 of them have pumped less carbon into the atmosphere than Australia. Yes, we are the 14th-largest historical emitter in the world. We therefore shoulder greater responsibility for global warming than more than 90% of the countries in the world.

The 21 million of us shoulder a greater responsibility for global warming than any one of the lesser emitters whose combined population exceeds 3 billion people.

So of course we need to live up to that global responsibility by cutting emissions. We wouldn’t want to be a free-riding global dole bludger, after all.

This is the text of a 3-minute climatecast that initially aired on Perth’s RTR-FM 92.1. All our climatecasts are now available also as a regular podcast in the iTunes store  — just search for “Climate Podcasts from the University of Western Australia” in the iTunes store. Alternatively, you can subscribe to the stream via feedburner.

A more extended version of this particular climatecast, with the data analysis on which this post is based can be found at Shaping Tomorrows World. Note: this post was initially (accidentally) posted on SkS on June 8 but only aired on RTR today on July 6.

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Comments 1 to 12:

  1. This seems to me to be a moral piece rather than a scientific piece, and if this is the case, it is disapointing to see such a piece on a site that prides itself in dispasionate scientific discussion on the subject of AGW. I also take exception to the seemingly insistent use of the word carbon when referring to CO2.
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  2. Muzz, this piece speaks to the tragedy of the commons. In that sense, it *is* a moral piece, even if a large part of the moral is self-interest. And don't forget that CO2 isn't the only greenhouse gas humans emit: there's methane and CFCs as well, which both contain carbon. Of course, there are some others that don't contain carbon (such as ozone), but they play a relatively minor role compared to the carbon-based ones.
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  3. Muzz, this is just a brief radio piece which puts some climate statistics out in an easily understood manner. If only other statistics could be presented so quickly and neatly.
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  4. The bathtub analogy is portrayed in an excellent graphic on the National Geographic website:
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    [DB] Fixed URL.

  5. Muzz, go to the journals if you want pure science. This site never was strictly about science. Look at the site's subtitle. This is about how and why people look at the science and say, "I don't believe it." If the subject were the wing size of albino drosophila melanogaster in the northwest region of Costa Rica, this wouldn't be an issue. Instead, the site deals with one of the more high-consequence situations humans have had to deal with in a while. Understanding why and how people either misunderstand, abuse, reject, or otherwise don't accept the conclusions that are drawn from the broad range of findings is critical in helping both short- and long-term mitigation efforts. Why mitigate? That's a moral/ethical issue. This site obviously does not shy away from defending the need to mitigate. And, by the way, people on this site pride themselves in the relatively dispassionate discussion of the science. Relative to many climate-related sites, the language used here is much less motivated by the need to convince at any cost and much more motivated by the need to explain and explore. But if your implication is that the posters here are politically disconnected, passionless, objective science robots, think again. The passion is expressed in the willingness to persistently take on any sort of argument for "it's not happening," "it's not us," or "it's not bad." The use of 'carbon' indicates that a poster thinks about GW from the point of view of mitigation.
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  6. I understand where Muzz is coming from. I sort of thought the same thing when I read it. I think the bathtub analogy could've been used a little better. It isn't the fact that the bucket (anthropogenic CO2) was the most recent addition that makes it a concern or the fact that it is a small percentage of water in the tub overall. It is the fact that the water already in the tub (nature's CO2) is accounted for by nature. So maybe you could add to the analogy that the tub faucet is constantly running but that the tub drain is also draining at the same rate that the faucet is running. So if left alone, the tub will never overflow. But if you start adding buckets of water into the tub, then eventually you will overflow.
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  7. Eliminating the use of carbon fuels should be the goal of any country's effort to stop manmade global warming. Thus, Australia should spend 100% of its "global warming" money in the search for new energy sources that will eliminate the need for carbon energy. If not 100% then what about 50%? Ironically, this isn't happening and will never happen, will it? It's intuitively obvious that taxing the use of carbon fuels is the way to go... especially when there's no alternative full time energy available... Right? WRONG! Money should never be spent on any CO2 reduction scheme unless and until taxpayers are informed of the quantifiable benefit that would result. Ironically, this isn't happening and will never happen, will it? As a taxpayer, a person of modest means, why should you be OK with this?
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  8. daisym @7 Isn't mitigating the effect of sea level rise, ice cap melt, extreme weather events, agricultural losses and population displacement a good enough swag of benefits fow you?
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  9. Quite the opposite of being a 'moral' piece, the assignment of responsibility is a core issue of this pollution problem. President Bush derailed the American response with his false escape argument about America's unfair share. The Chinese grabbed the angle, and used it at the Bangkok Conference in 2004 to claim the old western imperialist nations were responsible for 90% of all the pollution to date. Proper share is a stumbling block that derails the mitigation approach. The result isn't someone else throwing a bucket of water in the tub - it's everyone throwing a bucket of water in the tub.
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  10. daisym wrote : "Money should never be spent on any CO2 reduction scheme unless and until taxpayers are informed of the quantifiable benefit that would result. Ironically, this isn't happening and will never happen, will it?" With regard to Australia, you could do worse than start here for further information : Carbon Pollution Reduction Scheme
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  11. Daisym, you don't really want a number, do you? There are plenty of numbers out there. I suspect that you'll argue with the basis of whatever number you get--argue to the point of convincing yourself that it's not accurate enough. But this is not about getting what you pay for. It's about paying for what you already have. This is a problem that extends beyond the average lifespan of an individual human. That makes it fair game for middle-class denial. After all, why should you personally pay for something that will primarily benefit future generations, living long after you're ashes or in a box in the ground? Why? If your morality is based on social justice and general human welfare, the answer is obvious. However, if your morality (or perhaps ethics in this case) is based on contracts and market responsibility, then you are now confronted with two problems. One, your current quality of life is largely based on over a century's worth of cheap fossil fuel use. All of the debt that can be paid for this use (setting aside the quite serious post-colonial reparations argument) is and has been paid, excepting one critical externalized cost. Aerosol pollution is an externalized cost that is being and has been paid for through regulation and the resulting market mechanics, and you'll probably agree that life is better without lead, SO2, and mercury raining down on us, even if we can't place an accurate number on the benefits. CO2 is the external cost that has not been paid for, has never been paid for. We've been cranking it out for the last century, and no one has taken responsibility for it. Ultimately, you'd have to agree, the responsibility lies with us to clean up the mess our irresponsible ancestors left us. They've given us wonderful things, but there's a skeleton in the closet--and it's beginning to move, and it has a baseball bat in its grip. That leads us to number 2: if you decide to pass on the responsibility, then you become irresponsible. If you decide to continue with business as usual, refusing to recognize the CO2 external cost, then you are buying something without fully paying for it. Basically, the modern world has had a free lunch for a century, and you're now being asked to pay for it. And now you want the same free lunch and want to make my grandchildren pay for it? Nope. And the longer the check remains unpaid, the more expensive it gets.
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  12. To me, the conceptual problem is that we draw the bathtub around just the atmosphere. In reality, the bathtub contains the atmosphere, the ocean (OA anyone?), and the plants. Very little CO2 is coming out of this tub and human emissions of CO2 are by far the main input to the bathtub. Something has to overflow.
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