Here’s a rule of thumb - the federal reserve has a target inflation rate that they try to meet, and that is usually around 2%. Therefore, if you want to do a quick party trick you can do the mental math that things have roughly doubled in price since the 90s. Recent covid related inflation, upcoming tariff related inflation, and 1970s inflation break the trend, but typically the value of money halves every 30-35 years.
A nice rule of thumb is that the doubling time for anything growing by a specific percentage is roughly 70 divided by that percentage. So inflation of 2% annually means something will be twice as expensive every 35 years. A 2% increase in energy use means we will use twice as much energy in 35 years. And those fossil fuel deposits (or other raw materials of choice) that are going to last a couple of hundred years “at current rate of use” will be used up twice as fast at 2% increased use every year in a mere 35 years and four times as fast in 70 years at which point those “hundreds of years” of reserves are probably almost gone.
Here’s a rule of thumb - the federal reserve has a target inflation rate that they try to meet, and that is usually around 2%. Therefore, if you want to do a quick party trick you can do the mental math that things have roughly doubled in price since the 90s. Recent covid related inflation, upcoming tariff related inflation, and 1970s inflation break the trend, but typically the value of money halves every 30-35 years.
A nice rule of thumb is that the doubling time for anything growing by a specific percentage is roughly 70 divided by that percentage. So inflation of 2% annually means something will be twice as expensive every 35 years. A 2% increase in energy use means we will use twice as much energy in 35 years. And those fossil fuel deposits (or other raw materials of choice) that are going to last a couple of hundred years “at current rate of use” will be used up twice as fast at 2% increased use every year in a mere 35 years and four times as fast in 70 years at which point those “hundreds of years” of reserves are probably almost gone.
If you want to get real nerdy about it this works because the natural logarithm of 2 is ~0.69
(1+i)^n = 2
n log (1+i) = log 2
n = log 2 / log (1+i)
For small numbers, log(1+x) ≈ x
n ≈ log 2/i
log 2 ≈ 0.69
n ≈ 0.69 / i
n ≈ 69/100i
Which is pretty close to 70/100i which is the approximation.
that is pretty nerdy, but I appreciate the thorough explanation
The 4chan/greentext community is so wise