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CO2 in the air is like water in a bathtub (Var. I) Featured

Think of CO2 in the atmosphere as water in a bathtub. If you partly open the drain and run the tap at the same rate, the water level stays level. If you open the tap a bit more, the water level rises until it overflows.

As long as we keeping pouring CO2 into the air faster than nature drains it out, the CO2 level rises and the planet warms. Even a small imbalance, over time, makes a big difference.

Notes:  Whether it's plumbing or climate, even a small imbalance over time can have large consequences.  (When a CB editor recently left on vacation, unaware of a slow drip from his water heater, he returned two weeks later to a fully flooded basement!  :))  

Though humans add only a small amount "extra" CO2 to the natural carbon cycle, it's enough to tip the balance and, over time, cause the earth to heat up.   Imagine a plumber  saying, "Don't worry; enjoy your sabbatical!   It's just one drop every few minutes!"

There are many variations to this classic climate metaphor, which was coined to clarify the distinction between the rate of annual  emissions (the open tap), and the total concentration of CO2 in the air.   For other variations, click on the tag  "CO2 emissions" (in Advanced Search).

The challenge with this one is to phrase it succinclty.    Though everybody knows what happens when you open the bathtub tap too far, the metaphor itself can get rather convoluted.   (For a cartoon parody of getting tangled up in this extended metaphor, see Marc Roberts, cartoonist.)

Bite Source: various sources, including National Geographic

Image Source: here

4 votes

Bite Details

Submitted by
Tom Smerling
Com (2)
byMarc Hudson

September 18, 2011

This is one where everyone who ever takes baths SHOULD be able to understand it. The curmudgeon in me wonders if this sort of 'basic knowledge',which kids USED to learn when mucking about, is harder to come by for the "facebook generation" (Insert rant about how kids today don't know anything...).
byBrian Ettling

October 22, 2011

Really liked this analogy ever since I saw it in National Geographic a couple of years ago. Who has not been very annoyed with an overflowing bathtub, sink or toilet getting the bathroom floor soaking wet? Hopefully, all of us will find a way to resolve climate change so we will not have to deal with a planetary overflowing carbon bathtub. Thanks for posting this.

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