Hi Allan my friend,
The task of thinking 200,000 years ahead is an arduously difficult exercise, and a certain impossibility, isn't it. Yet you asked. And it would be in the fit of curious mind that we providentialy possess, to speculate about the future of our species.
I am going to indulge in some guess work, and with little sense of any responsibilty whatsoever, now and hereforth.
I get a feeling that we will be divided into three sub species.........
1) Homo sapiens technus
2) Homo sapiens tradius
The first will have two races, namely 'urbanis' and 'noahsis'.
Technuses will be the advanced human beings who would take the path of using technological developement as their core idealogy. The race 'urbanis' will be terrestrial, and 'noahsis' will be living in islands or in mega-super ships or super oceanliners, surrounded by all sides with water.
The Earth will no longer be called Earth - the rock; rather, it would meta morphise into a term called Warth. a combo of watery earth. The ices sheets would have melted long ago. The Earth which is the terrestrial part would be 1/6th of what it is today, 5/6th being covered by or under water. Homos will be staying in higher grounds where the mega polises remain.
Desertification will happen. There will not be any large vegetation anywhere except under water. Except grasses no other plants will grow. The temperature above the land mass will be 45-55 deg. celsius. Winds will be hot during day time and cool in the night. There will be no nations. The billions will have been reduced to millions, after reaching a peak of 50 billion humans. This would take place after a minimum of ten to twenty world wars. Including nuclear wars.
The sub-species technus will be using and moving around in aero-bikes, They will live in sky scrapers completely insulated from outside weather systems, like depicted in Flash Gorden stories. The insulation will make the towns look like a city or towns inside a bubble. Lets call them bublites. The bubblites will be self sufficient towns or cities affiliated to other megapolises. Of course the aero-bikes wil be used to travel from one bubble to another, but special ducts will also be there between and inter-bubble having mass transporter machines. All people will have wired systems that will take solar energy and it will charge the mobile phones, laptops, fans etc which can be carried on their back-packs. They will rule the air. And they will be ruled by a woman.
Technus has another race that calls itself Noahsis. The Noahites, oririginating from the word naav, which means boat from the Indo-European language, will be the masters of the vast oceans. They will be th eboat people. But their boats are lik ecities of their cousins bubblites. The boats are as big as a few square Kilometeres. These may be populated by over one lakh people each. They are also self sufficient except for some agricultural produce. These mega ships or ocean-liners wil be protected by battle ships. They also have submarines which will take the few who occupies it down to the abysses. Noahites visits the bubblites after going through an acclimatisation process at the port of entry.
The rich will be staying in water, in large mega barge kind of ships. People will stay in large mega liners, on rent to the ship-owners. Fishes will be primary diet........ they will all turn meganin or black,
The most interesting people are the tradis, which means the traditionalists. They are the rebels, they have defied the human genetic inclination, and has resisted any modern way of life in terms of lifestyle. They believes that only the earth is the ultimate saviour. Humans therfore should be loyal to Earth and not Warth.
This sub-species will veer itself away from the techno-homos, and form cities protecetd by a transparent sheath -dome over head with wallled cities inside it. All kinds of agriculture will be produced inside the walls. They will trade with the bublites and noahites ony for perishable products like vegetables and fruits. And will not keep any formal communications with them. They will arm themselves with nuclear weapons, and have mined inside the earth, where many factories will produce all useful materials needed by those men. They choose agriculture as ther primary source of occupation. But they too are good in their sciences. They too have space crafts. Here, man will rule.
These three sub-species will rule over, but there would be other smaller groups which will occupy the deserts, here and there. They will turn nomadic.
In general, man would have colonised the Moon and planet Mars. Mars will be cooler than Earth. Each of these groups will be fighting to have space in the moon and mars, some may go exploring to Titan, and Venus.
All tribes will be exterminated by the ground dwelling semi urbanites (tradis) and urbanites (bublites). All large animals will be extinct. There will be no birds except vestiges of vultures and perhaps crows. Insects will all go subterrean. Micro-organisms will be totally fumigated and remain outside the cities. Flowers will be like gold. Cloned milking animals will be there in all the worlds.
Nuclear missiles will still remain facing the bubble cities and the walled cities. The military will now be called spacetary. Military generals each affilitaed to the three kinds will overlook any military manouveres from the respective space stations, each protected by their own missile systems like in the star wars program. Internet will be wireless controlled by the space-military, and the cities.
The smarter, ground dwellers will have flat footed horse hooved feet, and the bubblesites will have feets similar to the shapes as today but no nails nor hair will grow,.......... lungs and nose will grow, eyes will be larger, brain again larger, their will be professional women who will give birth, men will have no say on child birth,........ the woman will rule.
In the walled city the men will continue to rule, and birth will take place, in family sytems, but all children will work on communal systems, slaves will be in fashion, who will do all the labour,
...... Warthians will be the first to have laser weapons and go to battle on the moon.
Fantasies may turn into reality who knows.................
edit: I think i had overshot my limit..... wrong calculations. The fictionothesis above, is thought for the year 20,000 A.D.; The likely scenario 10 times over and above this period is simply unimaginable, at least for me. Probably, humans may have abandoned the 3rd planet!... who knows??.