An analogy is a powerful tool in science communication. Here are two of my favourites to do with climate change.
The first is of my own creation (although it isn’t too original) and came about after I had presented to high school students a few times. As anyone taking high school physics learns pretty quickly, when using the formula F=ma, to find the net acceleration (the actual, observable result) you must always use the net force. If three people are pushing a box three different directions, you can’t just take one person into account. You have to look at all of them to see which way the box will move, and how fast.
Similarly, to analyze observed climate change, you can’t just take one forcing into account. You can’t only look at greenhouse gases and expect that they will track perfectly with the global temperature. You have to look at what the sun is doing, what aerosol levels are doing, where the ENSO cycle is. Climate is influenced by a combination of factors, and it will never track perfectly with any one. But if only one is changing significantly, and the others are staying pretty much steady, it’s obvious which way the box is going to move.
I found the second analogy in David Archer’s book Global Warming: Understanding the Forecast. I’m only two pages in and already I found something that I want to share here!
[The energy budget/climate equilibrium] is analogous to a sink with water flowing in from a faucet. The faucet fills the sink at some constant rate, while outflow down the drain depends on the water level in the sink. The sink fills up until water drains out as fast as it comes in.
It is possible to change the average temperature of the Earth by altering the energy flow either coming in or going out. In our sink, one way to raise the water level is to turn up the faucet and wait a few minutes. The water will rise until it finds a new equilibrium water depth. We can also alter the water level by partly constricting the drain. Egg shells and orange peels work well for this purpose. If the drain is partly obstructed, the equilibrium water level will rise.”
Brilliant, no? I think that Greg Craven had a similar analogy (the “bathtub”) in his book.
What are your favourite analogies – of your own creation or that you heard elsewhere? Share them in the comments below.