Sovereign - Environment: Up until the last years of the 41st Millennium, Sovereign was a temperate, bountiful world. Her oceans teemed with life and her seemingly endless plains produced a vast bounty. The seasons were consistently mild and ideal for agriculture.The water was pure and pollution had been kept to a manageable level in spite of thousands of standard years of Human habitation. If there was a major challenge for Humanity, it had not been discovered since the colony world had been established.When the Exterminatus action was executed in 809.M41, all of the planet's native life was completely purged. Sovereign became a barren wasteland.Though the planet's astronomical coordinates are unchanged, its atmosphere and environmental characteristics have been transformed. Massive planetary strikes from orbiting warships and the release of devastating virus bombs destroyed the world.As firestorms swept across its surface, the explosions and toxins transformed every living thing into little more than ash. Huge quantities of carbon dioxide, along with many complex organic substances, were released into the atmosphere. Smoke filled the sky and the heat of the flames transformed Sovereign's weather patterns.Over the intervening years, the planet's recovery has been negligible. Most of the changes induced by the Exterminatus have not yet abated. The atmosphere remains heavily clogged with ash and toxins. Little light can reach the world's surface through these dense clouds.The world's weather patterns remain unstable and massive fronts of hot or cooler air still occasionally sweep across the planet. Where they clash, savage storms erupt, stirring more debris into the planet's upper atmosphere.Without any life, there is little potential for the atmosphere to quickly change. There is currently too little remaining free oxygen in the atmosphere to safely support Human life -- though with the atmospheric pollutants, a rebreather would be necessary even if there were enough.The concentrations of water vapour and carbon dioxide in the air leave it feeling sticky, as well. An increase in surface temperature, due to all of the atmospheric changes and the massive release of heat during the global conflagration, has only intensified this unpleasantness. Most of Sovereign's temperate regions were once a comfortable twenty-four degrees during the day throughout most of the year.Now, those same locales average a daily temperature of more than thirty-three degrees centigrade. There are no known surviving native species of plant or animal upon Sovereign's surface, in its skies, or under its seas.While it is possible that some might yet dwell deep beneath the planet's surface or at the very bottom of its oceans, any such creatures have not yet made an impact on the world's environs. Without some sort of biological processes involved, cleansing the world's atmosphere and restoring its soils to a useful status could take millions of Terran years.Alternatively, some group might attempt to accelerate this process through a combination of technological and biological means. At this time, there are no Imperial forces within the Jericho Reach that have access to the necessary resources to restore the world to a habitable status.In order for the world to become fit for resettlement, substantial resources would have to be spent to seed the world with organisms that could be used to first restore the atmosphere to a sustainable level. Then, organisms more suited for long-term settlement could be introduced.Such a process would require at least a few thousand standard years if it were monitored closely, though Human settlers could be reintroduced much sooner if they were provided ample supplies and survival gear.The conundrum, of course, is that Sovereign is far from the front of the Achilus Crusade, and it is no longer a desirable habitat for colonisation.Unless other valuable resources were discovered, there is little motivation for Human forces to restore the world to habitability -- as numerous other, more suitable worlds could be claimed and exploited during the thousands of years it would take to complete the restoration.As things stand, it is much more likely that a group opposed to the Imperium would begin such a restoration long before Imperial forces decided to devote the necessary assets to such a project.