Here is the briefing room scene again:
[Briefing room]
(A large picture of their guest in on a screen)
KIRK: Name, Khan, as we know him today. (Spock changes the picture) Name, Khan Noonien Singh.
SPOCK: From 1992 through 1996, absolute ruler of more than a quarter of your world. From Asia through the Middle East.
MCCOY: The last of the tyrants to be overthrown.
SCOTT: I must confess, gentlemen. I've always held a sneaking admiration for this one.
KIRK: He was the best of the tyrants and the most dangerous. They were supermen, in a sense. Stronger, braver, certainly more ambitious, more daring.
SPOCK: Gentlemen, this romanticism about a ruthless dictator is
KIRK: Mister Spock, we humans have a streak of barbarism in us. Appalling, but there, nevertheless.
SCOTT: There were no massacres under his rule.
SPOCK: And as little freedom.
MCCOY: No wars until he was attacked.
So Khan ruled a large region, approximately a quarter of earth (or more likely a quarter of the land area of Earth).
Earth has a surface area of about 510,072,000 square kilometers or 196,940,000 square miles, and a land area of about 148,940,000 square kilometers or 57,510,000 square miles, which is 0.292017 of the total surface area. So if Khan ruled a quarter of the total surface area of Earth he would have ruled almost all of the land area. Thus Khan probably ruled a quarter of the land area of Earth and thus an area of about 37,2350,000 square kilometers or about 14,377,500 square miles.
https://en.wikipedia.org/wiki/Earth
So Khan's realm would have been somewhat larger than the British Empire at its height about 1920, when the British Empire had an area of 35,500,000 square kilometers or 13,710,000 square miles.
https://en.wikipedia.org/wiki/List_of_largest_empires
Asia covers an area of 44,579,000 square kilometres (17,212,000 sq mi), about 30% of Earth's total land area and 8.7% of the Earth's total surface area.
https://en.wikipedia.org/wiki/Asia
Size of Africa:
At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of
Earth's total surface area and 20% of its land area.
[4]
https://en.wikipedia.org/wiki/Africa
Khan's state could have been entirely within Asia. But since Spock said:
From Asia through the Middle East.
I deduce that Khan's realm probably included African regions that count as part of the Middle East, thus making Khan's share of Asia somewhat smaller.
The
Middle East is a
transcontinental region which includes
Western Asia (although generally excluding the
Caucasus) and all of
Egypt (which is mostly in
North Africa). The term has come into wider usage as a replacement of the term
Near East (as opposed to the
Far East) beginning in the early 20th century. The broader concept of the "
Greater Middle East" (or
Middle East and North Africa) also adds the
Maghreb,
Sudan,
Djibouti,
Somalia,
Afghanistan,
Pakistan, and sometimes even
Central Asia and
Transcaucasia into the region. The term "Middle East" has led to some confusion over its changing definitions.
So Khan's realm almost certainly included Egypt, and might have included some or all of Libya, Tunisia, Algeria, Morocco, Sudan, Djibouti, & Somalia, and possibly parts of other African countries. So possible maps of Khan's realm could vary a lot in how much of Asia and Africa, and which regions of those continents, are included, though Khan would probably always rule more of Asia than Africa.
Spock said;
SPOCK: From 1992 through 1996, absolute ruler of more than a quarter of your world. From Asia through the Middle East.
Earlier, Spock said:
SPOCK: There is that possibility, Captain. His age would be correct. In 1993, a group of these young supermen did seize power simultaneously in over forty nations.
KIRK: Well, they were hardly supermen. They were aggressive, arrogant. They began to battle among themselves.
SPOCK: Because the scientists overlooked one fact. Superior ability breeds superior ambition.
KIRK: Interesting, if true. They created a group of Alexanders, Napoleons.
Note that groups of young supermen took power in over forty nations in 1993, the year after Khan gained power in his realm in 1992. I don't know where those supermen were in the spectrum between enemies of Khan and followers of Khan, but apparently the countries they ruled remained independent of Khan's state. Khan's realm was not one of those over forty nations, but was separate from them.
At the present time (2020) there are 54 nations in Africa
https://en.wikipedia.org/wiki/List_of_sovereign_states_and_dependent_territories_in_Africa
There are 48 countries in Asia, 45 countries in Europe, 23 countries in North America, 12 countries in South America, and 14 countries in Oceania/Australia.
https://simple.wikipedia.org/wiki/List_of_countries_by_continents
I imagine that the Supermen may have taken over countries in someor all of the continents of Africa, Asia, Oceania/Australia, Europe, and North and South America, and there may have also been countries ruled by ordinary humans in some or all of those continents.
Khan apparently was not aggressive during his rule from 1992 to 1996:
MCCOY: No wars until he was attacked.
Khan may have been attacked by other supermen ruling other countries and/or by normal humans, but since Khan was:
MCCOY: The last of the tyrants to be overthrown.
Khan must have been overthrown by ordinary humans during what Spock called:
SPOCK: There was the war to end tyranny. Many considered that a noble effort.
The Eugenics Wars happened in the 1990s in the calendar used in "Space Seed":
SPOCK: No such vessel listed. Records of that period are fragmentary, however. The mid=1990s was the era of your last so-called World War.
MCCOY: The Eugenics Wars.
And the Eugencis Wars were also Earth's last world War in the history sources used by Spock.
How bloody did a war have to be for Spock to consider it a world war?
In "Bread and Circuses" Spock listed some world wars which happened on Earth before Earth became peaceful.
MERIK: There's been no war here for over four hundred years, Jim. Could, let's say, your land of that same era make that same boast? I think you can see why they don't want to have their stability contaminated by dangerous ideas of other ways and other places.
SPOCK: Interesting, and given a conservative empire, quite understandable.
MCCOY: Are you out of your head?
SPOCK: I said I understood it, Doctor. I find the checks and balances of this civilisation quite illuminating.
MCCOY: Next he'll be telling us he prefers it over Earth history.
SPOCK: They do seem to have escaped the carnage of your first three world wars, Doctor.
MCCOY: They have slavery, gladiatorial games, despotism.
SPOCK: Situations quite familiar to the six million who died in your first world war, the eleven million who died in your second, the thirty seven million who died in your third. Shall I go on?
So a war with as "few" as six million dead can count as a world war in Earth's history according to Spock..
In
Star trek: First Contact Picard's
Enterprise travels back in time to:
DATA: April fourth, two thousand sixty-three.
Which is:
DATA: According to our astrometric readings we're in the mid twenty-first century. From the radioactive isotopes in the atmosphere I would estimate we have arrived approximately ten years after the Third World War.
RIKER: Makes sense. Most of the major cities have been destroyed. There are few governments left. Six hundred million dead. No resistance.
So the Third World War in the list used in the era of TNG happened about 2053 in the calendar used in the era of First Contact. And it had one hundred times as many people killed as in Spock's First World War, so it certainly counted as one of the world wars on the list that Spock used. There was no way that Spock would omit a war which killed 600,000,000 people and left most major cities destroyed from his list of Earth's world wars.
Since Spock mentioned:
the carnage of your first three world wars,
.
and:
the thirty seven million who died in your third. Shall I go on?
Spock's list of Earth's world wars probably includes a fourth world war and possibly more.
Since the 600,000,000 killed in First Contact's third world war were over 16 times as numerous as the 37,000,000 killed in Spock's third world war, Earth history must list different numbers of world wars in the era of TOS and the era of TNG. At least one war on the TOS era list must have been dropped from the TNG era list, making the fourth or later world war in the TOS era list the Third World War in the TNG era list.
The importance of making first contact is explained to Cochrane in First Contact:
RIKER: It is one of the pivotal moments in human history, Doctor. You get to make first contact with an alien race, and after you do, everything begins to change.
LAFORGE: Your theories on warp drive allow fleets of starships to be built and mankind to start exploring the Galaxy.
TROI: It unites humanity in a way no one ever thought possible when they realise they're not alone in the universe. Poverty, disease, war. They'll all be gone within the next fifty years.
So there will be peace on Earth after some time before 2113 in the First Contact calendar. There could be a number of wars after First Contact, but probably none of them will be bad enough to count as world wars.
In the TNG episode "Up the Long Ladder":
DATA: In the early twenty-second century, Earth was recovering from World War Three. A major philosopher of the period was Liam Dieghan, founder of the Neo-Transcendentalists, who advocated a return to a simpler life in which one lived in harmony with nature, and learned under her gentle tutelage.
So apparently Earth was not devastated by a fourth world war in the history used by Data, which indicates that none of the wars happening after the Third World War of First Contact were anywhere near as devastating as that one. Unless there was a really big world war after First Contact, but the list of world wars used in the second season of TNG listed a world war after the one on First Contact as the third one, thus making three separate lists listing different Earth World wars.
So when did the Eugenics wars happen in relation to the Third World War of First Contact?
Spock described the Eugenics Wars as:
SPOCK: No such vessel listed. Records of that period are fragmentary, however. The mid=1990s was the era of your last so-called World War.
So the Eugenics Wars must either be identical with the Third World War of First Contact or else have happened after First Contact.
Spock says:
SPOCK: Your Earth was on the verge of a dark ages. Whole populations were being bombed out of existence. A group of criminals could have been dealt with far more efficiently than wasting one of their most advanced spaceships.
That is certainly consistent with most major cities being destroyed and 600,000,000 dead. So the Eugenics Wars, Earth's last world war, are probably identical with the Third World War of First Contact.
But the Eugenics Wars are said to have happened in the 1990s in the calendar used in "Space seed", while the Third World war of First Contact happened about 2053 in the calendar used in First Contact. How can that be? Obviously different Earth calendars counting the years from different times must be used in the eras of TOS and First Contact.
Since there is no proof that either the "Space Seed" calendar or the First Contact calendar uses
Anno Domini dating, there is no way to know whether the war in "Space Seed" and in First Contact happens before AD 1996 or after AD 2053.
So why do members of Kirk's crew have some admiration for Khan while Picard compares him to Hitler in some way, probably in the disastrous results of Khan's actions?
It may be a change in attitudes several generations later. And in my opinion it may be due to Khan "pushing the button" in the war in which he was overthrown. Khan's radar may have detected hundreds of missiles with atomic warheads headed for his cities and Khan may have launched a strike with tens or hundreds of nuclear warheads in retaliation.
And possibly members of Starfleet in Picard's era think that such actions are more horrifying than Starfleet members in Kirk's era did, when Starfleet had a General Order 24.