This is very probably NOT what you wanted but it's something that I found interesting. In Guardians of the Galaxy #2, Mantis informs the recently-arrived-from-the-future Vance Astrovik that the current date is as follows: "By the Shi'Ar calendar, it is sixty-eight thousand, the cycle of Bright Wing. According to the Kree, it is four hundred and fifty-six Khen-Vell Sah. As the Skrull have it, it is Shift fifteen hundred and (something), and on Earth it is two thousand and eight, Christian calendar." Personally, those numbers seem a bit off to me, seeing as how the Skrulls had the oldest galactic empire while the Shi'Ar have the youngest.
Actually Don, this information is EXACTLY what I am looking for. I am working on something of a timeline project for the entirety of the MU, and how other races view the passage of time is of interest.
Which is one of two reasons why it isn't necessary to be annoyed/concerned by the Skulls having the "youngest" calendar, numerically, and the Shi'ar having the "oldest". [The other is that those calendars, judging by those numbers, have almost certainly been reset to zero multiple times ANYWAY.]
This much does make sense. There is no reason to believe that all the non-human calendars are equated to exactly one Earth year (although the Kree one does seem to do just that). Differences in planetray years and even numerical systems could accomodate this. For example, human math is based upon a base number 10, while Skrull math is based upon the base number 17, as per A 134.
And is is probable the Kree updated their calendar a few times. Even in human history there is much precedent to this. The Kree rcalender recalibration may have happened at least three times, to accomodate the original dates in Kree Years almost a million years ago, the the lesser dates mentioned in the Sentry article, then the completly different date in GOTG2 2.
Also, your mention of the Kree Calendar gives me an excuse to voice one of my pet peeves. The Marvel Handbook has not done a good job of clearing up various conflicting pieces of data that it itself has generated. Consider the date of first contact between the Skrulls and the Kree. The SKRULLS entry states that "approximately 10 million years ago, the Skrulls first ventured outside their native galaxy into the nearby Greater Magellanic Cloud and Milky Way Galaxy." The KREE entry states that "the Kree began their empire over a million years ago, within 100 years of the acquisition of interstellar technology from the then-benevolent race of Skrulls." The SUPREME INTELLIGENCE entry states that it "was originally devised by the Science Council of the Kree in the Kree Year 4538 (about 990,750 B.C.) for the purpose of creating a Cosmic Cube" and that "it was elected absolute ruler of the entire Kree Empire in the Kree Year 4791." The SENTRY entry states that "the Kree scientist Bronek developed the prototype Sentry in the Kree Year 1220 (approximately 80,000 years ago)." And the WATCHERS entry states that "Uatu resides in the Blue City on Earth's moon, an abandoned settlement with its own atmosphere built by the alien Kree several million years ago."
Given the contradictory information, I would probably figure the 10 million years ago statemt is incorrect, as the one million years ago reference seems to fit in better with the Kree Year statements (ie 990,750 B.C.). But then it does seem that chronology often has to deal with contradictions. For example, Egyptian ancient history is often off by as much as several centuries, given upon which soure is cited.
One final point. The Earth dates that wolframbane provided seem to be calculated using the idea that one Kree Year equals one Earth year. As far as I know, this has never been established and I hope that it never will be. It really bugs me when I read/watch a science fiction story in which the writer has assumed that planets in alien solar systems would take as long to orbit their stars as our Earth does around the Sun. Star Trek (which I love) is often guilty of this. While some periods of time are measured in "Earth-years," the majority are defined simply in terms of "years" and I can't recall any event being described in terms of a "non-Earth" year. In the absence of any information, we viewers can only assume that Earth and Vulcan and Kronos and Romulus (to name a few) all have years which are the same length. And that's just wrong.
Even Star Trek on occassion has introduced other methods of dating. Besides the infamous and confusing Stardates, there is also the Klingon Year, with the Earth year of 2373 coinciding with the year of Kahless 999. And then there is the Kryptonian year used in the Silver Age Superman comics, where 1.4 Earth years equal 1 Krypton Year, and Krypton exploded in Year 10,000.