After reading most of the comments here, and re reading the short stories on civ site, I tried to make a time line doing some nods of the best ideas and some great games around. Hope you enjoy it, here we go
2020 - Scientists discover a terran planet in the Alpha Centauri system
2030 - A UN project called Unity, mobilizes many nations to launch the first extra solar mission
2040 - Riots arise on many countries in protest to the small number of colonists "chosen", influence of great corporations, and the great cost of investment.
2050 - USS Unity leaves to a mission to Alpha Centauri, many of the great minds of the generation left Earth on the project, many economies around the world collapse due the end of the enterprise, and lots of unemployment and unused infrastructure cause many riots and competition between old enemies. On India an specialist in cryogenics, Amar Thakur spends all his economies earned on Unity work and buys a military bunker on New Delhi
2051 - Pakistan and India start a skirmish on their border rising from old conflicts, the conflict escalates quickly with the Indian leader launching a nuclear missile, the Pakistan forces detect the attack and retaliate, the event further known as 9 minutes War left most of the area around the great cities on the both countries destroyed.
2052 - Smoke and nuclear fallout start to cause most of the northern hemisphere temperatures to drop, international commerce decrease with must countries turning their economies internally to repair most of the difficulties
2053 - Nuclear winter take places on the northern hemisphere, coal and oil prices rises to new records. Southern hemisphere nations rise their economies from the food commerce since they are the few remaining arable land
2060 - Oil reserves end, most of the Arab countries economies collapse, intercontinental commerce stops due lack of fuel.
2062 - Arabian countries launch an invasion on the northern and eastern countries, Eastern Europe and the left of India and Pakistan territories, are invaded.
2063 - Most of Europe and Asia countries are locked in conflict trying to defend or invade territories, most of the European countries around Russia form an alliance to protect against the invaders, great areas are polluted due the high usage of coal, temperatures start to rise
2065 - An accelerated green house effect starts to rise temperatures globally, ice caps start to melt at an alarming rate.
2068 - Floods and extreme meteorological events ravage most of the Earth, coastal cities are most affected, some insular nations are threatened to disappear.
2070 - Most countries are now isolated states, living from internal economy. Many borders are changed due war and floods. A new dark age falls on Earth, disease and famine are global.
2075 - Temperatures keeping rising, desertification spreads. Northern hemisphere is warm again.
2080 - Scientist discovery a way to create stable nuclear fusion, the new source of energy starts to help many nations to recover
2085 - Most South American nations unite under a great economic and political block called Brasilia, due to little side effects suffered from the global warming and wars, their water and food reserves let they have great global influence, the UN Peace corps are now under their leadership and they start a project to recover land and stop wars on Europe and Asia
2090 - Indonesia and other insular nations around the Pacific, uses the new fusion energy to power projects of water desalinization and hydroponic plantations, now that most of their territories are flooded
2100 - Most of the wars on Europe and Asia are quelled, France starts a project to revitalize their urban centers
2110 - Population start to return to Indian territory, a cult is formed around a religious figure supposedly found in New Delhi alive after all this years on the nuclear fallout
2120 - China enters in a new isolationist policy, with heavy militarization on their borders, and state propriety companies, bureaucrats are the new leaders
2130 - Indonesia, Australia and other Pacific nations creates an economic block called Polystralia, their success on hydroponics make them the number 1 exporter of food, high immigration from damaged areas make the population on the area grow
2140 - Other states on South Asia starts to collapse due high prices from imported food and water from Polystralia. Laos, Cambodia, Korea and others pledge alliance to China, they create a Pan Asian Cooperation treatise
2150 - Russia starts to use most of the now fertile Siberian region to became self sustained, their quality of life increases, and most of their govern is militarized, they start to invest in a space program to look for new resources from Moon and asteroids.
2155 - Spain, Portugal and Italy ask France to help them to revitalize their cities after the success of its program. Paris is the most cultured center on Western Europe, investing in tourism, archeology, renovation and arts
2160 - Neighbor countries on the intent to gather resources starts to stage military units on Russian borders. On a preemptive strike, most of the other Eastern Europe nations create an alliance and invade Russian territory, after humiliating defeats most of the Eastern Eurasian cities turn loyalty and join the now called Slavic Federation, with bigger resources from the many former countries they found the first permanent colony on Moon
2170 - Franco-Iberia is created and develops many cultural and scientific progress, the intellectual elite and aristocrats migrates in great numbers to the new country their money finances most of the projects
2180 - Even with the resources from the moon colony of Khrabrost the Slavic Federation needs more resources to their space program
2185 - After developing new boreholes technologies and quelling most of tribal and ethnic conflicts most of Africa countries unite and became the top seller of natural resources, great ecological damage spreads on the continent.
2190 - American Reclamation Company develops a terraforming technology that allows most of flooded areas to be recovered, many countries contract the services, and the company makes fortunes. After recovery most of the flooded areas on eastern USA and the offering of many new jobs, most of Mexico and Caribbean Nations migrates to those regions in search of jobs
2192 - Slavic Federation creates small colonies on most of the bodies of the solar system, they create the first colony on the most distant body of the solar system beyond the Kuiper Belt, a small asteroid where an array of deep space telescopes identifies many extra terrestrial planets, long range space travel technology improves
2194 - Scientist alert that the rising temperatures will not stop, and the greenhouse effect may turn Earth on a Venus like planet
2195 - Brasilia starts a secret project and redirects most of their resources to the industrial centers of São Paulo and Rio de Janeiro. They send military platoons to Sahara, Amazon, the few remaining glaciers on the center of Antarctic continent and irradiated areas in Karachi for survival
2200 - Pan African Union starts to finance many other countries and companies natural resources needs
2205 - Franco Iberia starts to build the Cannon, a collection of work of arts and history of the Western Civilization
2210 - Brasilia launches Aguia, the first seeding colony.
2211- Slavic Federation launches their Seeding Colony
2212 - Small countries and conglomerates rush to buy small versions of Aguia, most of them financed by PAU resources
2214 - PAC launches their Seeding Colony
2216 - Franco Iberia finishes the Cannon and launches their Seeding Colony
2217 - ARC launches their private Seeding Colony
2218 - Kavithan Protectorate launches their Seeding Colony
2219 - PAU launches their Seeding Colony financed by the money earned by the resource sells to the other countries
2220 - Scientist start to talk about Inflection Point, a theory that the resources left on Earth cant support the number of habitants or big constructions anymore
2225 - Polystralia launches their Seeding Colony
2250 - Temperatures keep raising, resources keep diminishing, future on Earth is uncertain