There are many benefits to using the metric system, namely that it eases the calculations and conversions dealing with measurements and it provides a universal standard to which most countries now adhere. The United States and a few other smaller nations are the only ones left that have not yet gone through complete metrification. However even with these holdouts, shouldn't the metric standard body start thinking about ways to further the boundaries and reach of the metric system? More specifically, the metric system is currently used to measure everything else but time (with the exception of the second), thus why not create a serious effort in metrifying time?
Time is different from other measurements in that we can only, for now, measure forward progression. We can certainly use temporal measurements for discussing past or future events. However, time is unique in that one can't go back and re-measure something after it has already happened. So maybe, this is at least one consideration in deciding whether to metrify time.
Another consideration for not metrifying time, is that our current system for measuring time is already a global standard (more or less). Almost all countries recognize the Gregorian calendar and, at least in official business, use that calendar for describing or scheduling events. However, there is also an argument that the current calendar uses as its basis, measurements that aren't scientifically grounded. In fact, it has Judeo-Christian origins, and while that may be fine for those that adhere to Judeo-Christian theologies, it can be argued that it is not sensitive to the backgrounds of the multitude of peoples who do not abide by those philosophies. Therefore, does it make sense to create a measurement of time that is based on something more common and more centric to all the peoples of the Earth? If that's the case, what would that basic standard be?
The other problem with metrifying time is that metrification assumes some decimal framework to the measurement. However, we have grown accustom to using time to succinctly measure the movements of the Earth relative to the sun or moon. That is what gives us approximately 86,400 seconds in a day, 28 days to a month, and 365 days to a year. These obviously are not inherently decimal in the sense that they are not cleanly divisible by ten.
As stated above, there is one metric temporal measurement and that is the second. In the metric system, a second is based on the exact frequency of the microwave spectral line emitted by atoms of cesium-133 at the temperature of zero Kelvin. More specifically, that ends up being the duration of 9,192,631,770 cycles of microwave light absorbed or emitted by the hyperfine transition of a cesium-133 atoms at zero Kelvin. But is that 'second' the same as the seconds we use do define our current minutes, hours, and days? Here we enter the complexity of apparent solar days versus mean solar days. An apparent solar day (which is exactly defined by how long it takes the earth to make one rotation around its axis) changes throughout the solar year from about minus 14 to about plus 16 of these metric seconds. The mean solar day is considered an approximate average and leaves the length of the day set at 24 of our current hours.
For humans, I would think, the measurement of a day is more crucial than the measurement of a second (at least so long as we live on Earth). So, shouldn't we shift our focus to metrifying the measurement of a day, rather than the second? For instance, can't we define a day as being the exact amount of time it takes the Earth to rotate on its axis during the summer solstice (actually more accurately defined as the northern solstice in which the sun is at its greatest distance from the northern hemisphere's equatorial plane (the Tropic of Cancer ) defined as 23° 26′ 22″ north of the actual equator)? And then from that point, we can divide the day into 10s. We can call this a metric day (maybe call it a mday?). A tenth of a day (a little under 2.5 current hours) could be called a deciday. A hundredth of a day (a little under 14.5 current minutes) could be called a centiday. This can go and on until we can redefine the metric second as 10-5 of a day which is approximately .864 of our current second. I don't think there is a metric prefix for 10-5, but maybe something like petoday would be close enough.
In any case, this allows us to have 10 day metric weeks, or a dekaday. Also, we could have 10 metric weeks equal a metric month, or a hectoday. But then, of course, this would mean we might end up defining a metric year (or a kiloday) as equalling 10 metric months... essentially 95 days short of three solar years. This of course is where the idea of metrifying time (in the context of Earth) starts falling apart. That is, unless, we decide to learn to accept that a metric year may consist of almost three seasonal cycles... and we rely on the calendar companies to keep track of where the seasons fall within our current calendar year.
In any case, something to think about. Maybe for fun, somebody can implement something like this and see how it works, and tweak it as needed. If executed, it could be called The Implementation of the Metric Era, i.e. T.I.M.E. So, we could start defining metric years as being AT or BT... that is After T.I.M.E. or Before T.I.M.E.. Amusing, probably uselsess, but interesting. Well, time to go.
