# Temperature percentages

Tonight, Jon Snow talked of an estimated six per cent rise in temperatures during our children’s lifetimes. While I think he was using 0°C as his frame of reference, I find this phenomenally confusing and mathematically incorrect.

From a purist perspective, he should have used zero kelvin as his base, meaning that the six per cent increase would actually be more like 0.4%. (Incidentally, in Fahrenheit the rise is more like three per cent.) But in reality, for something that has no real concept of a minimum in everyday life, changes shouldn’t be expressed in percentage terms. If the average global temperature was set to rise from 0.1°C to 1.0°C, would we refer to a 900% increase? Odder still, would a reduction in the global temperature from -5°C to -10°C constitute a doubling in the temperature?

As an aside, while researching whether per cent takes a space in the middle, the Google search:

percent per cent

yielded the following calculation result:

1 percent per U.S. cent = 1 U.S. Dollar-1