In case you missed it, the National Snow and Ice Data Center (NSIDC) announced last week that Arctic sea ice had reached its annual winter maximum, and that was the lowest on record for the third year in a row. This is bad news, but we knew it was coming.

Over the years, I’ve found it necessary to remind people that the theory of human-caused climate change was a predictive one. We knew the temperature would rise decades before the rise was statistically significant. We knew that sea levels would rise too, and that ice would melt. We also knew that melting arctic ice would increase the amount of heat that the ocean absorbed, and lead to faster warming, and faster melting.

The reason we knew was that at its most basic, the physics of global warming is pretty simple. It’s physically impossible to add this much CO₂ to the atmosphere without increasing the planet’s temperature. It’s physically impossible to increase the planet’s temperature without causing ice to melt and sea levels to rise. It’s also physically impossible to increase the planet’s temperature without causing changes to ecosystems around the globe.

Of course, not every year will break records. We will almost certainly have a year in which the winter maximum of arctic sea ice will be higher than the year before, but it will not recover to the point it was at a decade or two before. For all its chaos and irregularity, the warming of our planet is a bit like reeling in a fish. The fish is swimming all over the place, but for every turn of the reel, it gets a bit closer to the fisherman.

We might get a cold year now and then, but when you look at where we’ve been, there’s no question. The planet is warming, and it’s not going to stop. The only question is what we’re going to do about it.