21st century

The 21st century was, as Jack Harkness cryptically said, "when everything changes". (TV: Everything Changes) Earth was a very tempting target for invasion; by this century, half of the species from Earth to the Verlixix Spiral Cluster had plans to invade. (TV: Enemy of the Bane)
According to some accounts, the early 21st century was when the whole human race on Earth learned that extraterrestrial life existed. (TV: The Christmas Invasion) While in the past alien incursions were generally covered up or dismissed as hoaxes, (TV: Remembrance of the Daleks, World War Three, PROSE: Who Killed Kennedy) the early 21st century saw frequent large-scale attacks on Earth which couldn't be covered up, such as the Battle of Canary Wharf, (TV: Doomsday) the March of the Adipose, (TV: Partners in Crime) the Dalek Invasion of Earth, (TV: The Stolen Earth) the 456 incident, (TV: Children of Earth: Day Five) and the Year of the Slow Invasion. (TV: The Power of Three)
This century saw many organisations - such as UNIT, (TV: The Zygon Invasion) ICIS, (AUDIO: The Coup) Torchwood Three, (TV: Everything Changes) Torchwood One, (AUDIO: New Girl) MIAOW, (PROSE: Enter Wildthyme) the Forge, (PROSE: Project: Valhalla) PROBE, (HOMEVID: When to Die) the Department, (TV: The Eclipse of the Korven) and UNISYC (PROSE: Alien Bodies) - defend the Earth against alien attacks. Indeed, the Shift once remarked, "one can barely materialise on the planet without being fought over by five different covert paramilitary organisations". (PROSE: Head of State) However, the century also saw a number of independent alien defenders, such as the Bannerman Road gang, (TV: Revenge of the Slitheen) the Torchwood team, (TV: Dead of Night) the Coal Hill defenders, (TV: Brave-ish Heart) the Ghost, (TV: The Return of Doctor Mysterio) Erimem & friends, (PROSE: The Last Pharaoh) Lucy Wilson and Hobo Kostinen, (PROSE: Avatars of the Intelligence) and the K9 Unit. (TV: Regeneration)
Ashildr, a 9th centuryIn the television story The Woman Who Lived, which is set in the year 1651, Ashildr mentions having had 800 years of adventure. Viking girl who was rendered effectively immortal when she was brought back to life by the Twelfth Doctor through a self-repairing Mire repair kit, (TV: The Girl Who Died) was known to have lived on Earth up to at least the early part of the 21st century, by which point she was the Mayor of the trap street. (TV: Face the Raven) She would ultimately live all the way to the end of the universe. (TV: Hell Bent) Jack Harkness, another immortal, as well as an occasional time traveller, lived through the 21st century three separate times. (AUDIO: The Torchwood Archive)
, having been stranded in Paris and robbed of his TARDIS by the Thirteenth Doctor in 1943, was forced to live on Earth through the remainder of the 20th century and the first two decades of the 21st before he was ultimately banished to the Kasaavin realm in early 2020. (TV: Spyfall)
The First Doctor once described the early 21st century as "[a] time of epicurean excess, a time of simmering global strife, a time of hamburgers the size of your head and thick shakes as big as your arm, of imaginary medical complaints and stress-related lives, of panic and terror, of genetic modification and salads with more calories than a chocolate bar". (PROSE: The Mother Road)
This century was a period of great technological advancement, but also great political, economic, and ecological turmoil. The T-Mat (TV: The Seeds of Death) and the weather-controlling Gravitron (TV: The Moonbase) were developed in the middle part of this century, and the first excursions outside the Solar system occurred towards the century's end. (TV: The Waters of Mars)
Space travel increased dramatically. Many more missions were undertaken by NASA, the Russian Federal Space Agency, and European Space Agency (later the Eurozone Space Agency (AUDIO: The Feast of Axos)). All-German teams achieved ten lunar missions by 2050. Australia, Spain, and (possibly) the Philippines all got involved in space travel. The Branson Inheritance (TV: The Waters of Mars) and Ironclad Industries (who bought the British Rocket Group) were two private space organisations. (AUDIO: The Feast of Axos) In 2071, India's space agency collaborated with Britain in clearing space junk out of Earth orbit. (AUDIO: Scavenger) This new space race ended when T-Mat was invented, causing rockets to be seen as obsolete. This was shown to be an error when the Ice Warriors seized control of T-Mat Control (TV: The Seeds of Death) in 2086. (PROSE: Transit)
The nations of Europe began to unify more under the Eurozone in the early decades of this century, (PROSE: Trading Futures) though one account had the United Kingdom attempting to leave the European Union around 2018, in an ongoing affair known as Brexit. (PROSE: Lucy Wilson & the Bledoe Cadets)
For forty years after 2019, Earth suffered through climate change (including both extreme storms and a 22+ weeks without rain), ozone degradation, the "Great Cataclysm", and "the oil apocalypse". Millions of refugees streamed out of North Africa and the Baltics. In 2059, it was believed mankind came close to extinction. (TV: The Waters of Mars, Aeolian, AUDIO: Hothouse) People in the future would remember Earth's ecosystem collapsed during this century. (AUDIO: Davros) The Eleventh Doctor once referred to the dangerously corrosive acid rain of the mid-21st century. (COMIC: Strange Loops)
In 2049, a dragon-like creature hatched out of the Moon, laying an egg that became the new Moon. (TV: Kill the Moon)
:In a negated timeline, most people knew and accepted alien life by the 2050s, (TV: The Mad Woman in the Attic) although given events early in the century, odds are this fact remains in the restored timeline.
Earth's first off-world colony, Bowie Base One, was both established on Mars and lost in the late 2050s. (TV: The Waters of Mars) It would later establish a permanent base. (PROSE: Home)
Some accounts suggested that the Doctor's first encounter with the Daleks, the Thal-Dalek battle and the Dalek Empire's first exploration into space travel all took place in the mid-2060s. (PROSE: Stingray Attacked!, Peaceful Thals Ambushed! et alt.)
The Thousand Day War between the United Nations and Mars was fought between 2086 and 2088, following the T-Mat attack. Over 45,000 UN soldiers were killed and Paris was bombarded in an act of terror, but the weakened Ice Warriors were defeated. Most of the Warriors left Mars for a new planet and humans started to colonise it en masse. (PROSE: Transit, GodEngine, Legacy)
Earth sent its first lightspeed ship to Proxima Centauri, under the command of Susie Fontana Brooke. (TV: The Waters of Mars)
Various nations had political changes during this century: Italy suffered civil war and China split into North China and South China in the early 21st century, (PROSE: Trading Futures) Britain become the dictatorship of New Britain for part of the mid-21st century, and the United States fell. (PROSE: Christmas on a Rational Planet)
By century's end, there was a massive 'breakout' of human colonists to other worlds despite the experimental nature of warp drives, the extortionate cost levied by corporations, the health risks, and the control corporations would have on the new worlds. Popular views held that this was to escape overpopulation, environmental collapse, or alien invasions. Some historians would suggest the main cause was that many humans lived in relative poverty while being well aware of the high-end luxury of the wealthy, and the colonies were a way to escape the trap. (PROSE: Prelude Deceit)
At some point during this century, on an Istanbul rooftop, the Ninth Doctor fought two Sontarans in a sword fight. Sally Sparrow, who had become "some sort of spy", saved the Doctor from one of them, and gave him her Christmas homework from 2005, which would help him when the TARDIS would later hop forward in time twenty years without the Doctor. Sally told the Doctor to keep the essay with him at all times. (PROSE: What I Did on My Christmas Holidays by Sally Sparrow)
Using gold as currency fell out of favour in the late 21st century. (AUDIO: The Evil One)
== Behind the scenes ==
=== Real world production history ===
The Doctor Who television series was revived beginning in 2005, ending a hiatus lasting 16 years.
=== Invalid sources ===
The Discontinuity Guide claimed that the Daleks, following the defeat of the 22nd century Dalek invasion, completed their time travel program, which they had began with Theodore Maxtible, and waged a successful invasion of Earth in the late 21st century, whilst they themselves came from no later than the 23rd century, long before the Draconian Gambit. When their work was undone by the Third Doctor, the Daleks pursued the First Doctor in an attempt to neutralise his "future intervention".BBC.co.uk 'Discontinuity Guide' article on Dalek History: Part One in the original series of Doctor Who It is further noted that, since the Fourth Doctor inadvertently changed Dalek history so that Davros survived, this event would have occurred vastly differently if it happened at all in the new timeline.BBC.co.uk 'Discontinuity Guide' article on Dalek History: Part Two in the original series of Doctor Who
Giving no precise date for the Cyberman attack on the Wheel, The Discontinuity Guide placed it to anywhere following the 2070 Moonbase attack to the early 22nd century. This was followed eventually by the expedition to Telos.BBC.co.uk 'Discontinuity Guide' article on Cyber History in the original series of Doctor Who
== Footnotes ==