You may be interested to note that the 2020s started well before you think they did. Trump was impeached around a month or so ago, and it’s an excellent cultural benchmark to hang a decade around. Decades are different than centuries. Contemporaneously they start from zero to nine, not one to zero. Nobody has ever referred to, say, 1990, as part of the ‘80s, but people are having the same argument as they always do in this part of the century. So let’s get it over with, shall we?
There are two ways of counting decades, contemporaneous and cultural. Contemporaneous decades are the ones we live in at the moment. Right now we’re at the end of the 2010s. It began on January 1, 2010. All the popular culture publications said so. There were lots and lots of TV specials all over the World in December of 2009, and Time inc. had special issues of TIME and LIFE. Most weekly supplements of daily newspapers had articles reviewing the old decade; those of us who are too old to be teenagers remember that. We also remember that none of these things came out in December of 2010.
However, culturally, the decade DID end in December of 2010, December 17, to be exact, when a poor sap named Mohamed Bouazizi set himself on fire in Tunisia, sparking the Arab Spring, and a bunch of horrid wars and revolutions that are still going on. Also, a month prior, or thereabouts, The Republicans gave Obama his famous shellacking, poisoning American politics to this very day. So the ‘10s (pronounced “tens”) lasted from December 17, 2010, to December 18, 2019. A nice neat package. Not exactly ten years to the day, more like nine, but close enough.
The counter-argument is specious. “There was no zero AD.” True enough. But then again, there wasn’t a One AD, either. At the time, it was either “the consulship of Gaius Caesar and Lucius Aemilius Paullus” or AUC 754, the years since Romulus and Remus founded Rome. Even in Judea, It would have been 310 AG (Anno Graecorum, “Anno Mundi” wasn’t used by the Jews until after the year 1000). Dionysius Exiguus didn’t place the year One where it is until the year 525.
But getting back to Zero AD. Okay, there isn’t one, but there is a Zero CE (Common Era). The term dates back to 1615, when the great astronomer Johannes Kepler, in a work published that year, used the term “annus aerae nostrae vulgaris,” instead of “anno domini.” He continued to use the term, and in 1625, in his Rudolphine Tables, he adds a year zero to his calculations of the past in order to make them work accurately, Other scientists, most notably Jacques Cassini in the 1740s began to use it, and today, most non-English speaking countries use a year zero in their dating of ancient times.
So, while January 1, AD 2020 and January 1, 2020 CE are exactly the same, 1 BC and 1 BCE are not. As CE more and more replaces AD in the numbering of years, so must the year zero. Let’s hope the ‘twenties are better than how they began.