Terraforming is quite simply the process of taking an alien world and making it's climate and surface conditions mimic those of Earth so that humans can live there without needing hostile encounter gear or pressurized atmosphere suits. Following the Resource Wars, the Earth was left in terrible condition. Forests were burnt, deserts were expanding at a rapid pace, the oceans were hot and acidic, and the temperature was steadily rising, the sea was rising, and there were radioactive craters across the face of the planet. Earth looked more like an alien world than the cradle of humanity.
Technology that was being developed for Mars and Venus were conscripted into repairing Earth's biosphere, with the intent of retro-terraforming the planet. At the point of the O2 depletion event, it looked like the atmosphere would only be viable for a few more decades before collapsing into a nitro-carbon cloud around the planet, forcing the survivors to live permanently inside sealed cities and arcologies.
The Tower Initiative
An Atmospheric Processing Tower looks very similar to a nuclear cooling tower. Rather than being a thin shell around a heat exchanger, the APT is both much larger and more complex. Ambient air is drawn in through the base of the tower via electric fans. This air passes through chemical filters and scrubbers that clean particulate matter and fix a certain amount of the carbon into large algeal tanks. Rather than being filled with wondrous arcanotech devices, it is a mile tall algae farm. The inside is a maze of clear tubes filled with water and algae. The cleaned air is pumped through the system where it is again filtered and metabolized by the vast amount of algae inside. The end product is clean air with improved oxygen levels, heat, and water. The shape of the tower pushes the heat up and out of the structure to keep the algae from cooking itself, and there are condenser towers inside the main tower that keep the insides of the structure dry. The mile tall towers are typically built up near a large depression so that the condensate water has a place to go. By the Cosmic Era, the towers are still running, and the holding ponds have become lakes, rivers, and in the case of the Atlantic Federation's Victoria arcoplex, with no fewer than 6 such towers, Lake Victoria is more commonly called the Victoria Sea.
The Towers are aging, and some are starting to show systems failures, but this is considered acceptable. Under the Utopia Initiative, global forests and green zones have seen a spectacular resurgence
Air dams are a relatively uncommon sight, and were the replacement for wind turbine farms. The Air dam is a large wall like structure, but rather than being solid it is made of hundreds or even thousands of vertical turbines. Old wind turbines retained the shape of windmills, a technology over a thousand years old. The new turbine is a tall cylinder that the air spins. The turbine itself is at the top or bottom of the cylinder and generates electricity the same way as previous turbines. Placed in large banks across high wind areas, these structures generate a large amount of power for a relatively small investment. The original air dams were built upwind from major cities to clean the air coming in and generate power for said city. These were largely found in second world nations lacking arcanotech for building true megastructures. The lost cost and high efficiency of these systems say their spread through out the world. Modern arcologies and geofronts all have smaller more compact versions of air dams for their ventilation needs.
Ionizer Array - air dams are ionized structures, cleaning the air that passes through them. As they are power generators themselves, this is generally a free action for the dam, and requires only a very small amount of the power generated.
Ozone Generator - the bottom section of an air dam is an intake system for an Oxygen generator plant. The facility uses a cold plasma technique to fix oxygen out of the air and to dry and condense it down into ozone and other pure oxygen molecules. These are packaged in canisters and distributed as needed. This gas is used in aerosol seeding of the ozone layer via aerospace craft, and replenishing the air tanks of transatmospheric craft and stations.
The concept of sequestration was simple, dig a really deep hole, bury the bad stuff, and move on. The only thing that has changed is the depth of the hole being dug. The Sequestration Well is a megastructure that is dug down into the earth. Once the geofront is complete, mining shafts sink down into the earth. Once those reach maximum depth, the drilling equipment is lowered into the shaft, and the actual digging starts. The well shaft, once dug, can extend as much as 20,000 meters beneath the surface of the Earth. At this depth, the temperature is well above 350C, causing many mundane materials to lose strength and performance due to heat. The Sequestration Well is internally cooled, and made of thermoablative materials, allowing it to keep running.
The first round of Terminal Boreholes were used to sequester toxic and nuclear waste materials that couldn't be reprocessed and that no one wanted to risk breaking up in a rocket or magnetic launch. At such high temperatures and pressures, the materials are effectively destroyed by the embrace of the earth. It is worth noting that these wells are not dug straight down. Rather, once the shaft mining is complete, a Drill Head is established, usually in the 3-5 km range. At this depth, humans in suits can inspect the facility and make repairs. The drills and line are then extended at an angle down and away from the main shaft. A single Drill Head can support dozens or even hundreds of sequestration boreholes. The average borehole is just 12 inches across, while the Drill Head room is large enough for a few thousand meters of pipe, drill engines and pumping systems, and a cooling system to be operating.
The boreholes are now more commonly used for tapping into thermal pockets to access geothermal energy and the deep drilling cores are used in scientific research for ultra-deep mining technology.
Also know as the Big Freeze, these are large arcanotech devices that were engineered from normal arcanotech heat sinks. The normal heat sink absorbs heat and pumps it 'elsewhere'. Scientists aren't really sure where, or even when this heat is going. In the operation of dimensional reactors, it is considered moot as the heat and electricity are also coming from elsewhere. The Endothermic Reactor is similar to an Atmospheric Processing Tower, but it sucks in enough heat to dramatically cool everything around it.
The majority of Endothermic reactors are found at the polar regions. The units run, and the drop in temperature encourages the spread of pack ice. This has lowered sea levels to previous safe levels, and stabilized the atmosphere. The poles are cold, and the equator is hot, instead of everything running at overheat. Other locations include high mountainous zones that have been ice depleted, where the large machines have spurred the recovery of glaciers, and even in some places, full glaciation has been restored, such as in Greenland.
The Atlantic Federation is planning on making a mobile version of the Big Freeze so that it can be dropped into Venus' atmosphere, where they can run and start cooling the planet enough that other terraforming gear can be dropped into place. It isn't uncommon for close solar habitats to have large heat shields hooked to endothermic reactors, allowing them to survive in truly hellish environments.
The oceanic filter is a very large, very low tech structure. It is a porous wall of synthetic stone placed in high flow areas. This does alter the flow of the water, being as these filters are tens of miles long. The structure of the synthetic stone causes it to leach heavy metals and contaminants out of sea water, as well as decreasing the carbon acidity of the water. After time, the filter needs to be changes, and this generally involves a ship lifting out the fouled sections and dropping fresh stone panels into place. The fouled panels are ground up and the contaminants are run through an incinerator. The valuable heavy metals are recovered and the rest is fed through an air plant like an air dam and clean air is belched out.
The Devil's Due
Nothing in the Cosmic Era is free, humanity is callous, and everything arcanotech touches is tainted. These are simple facts. The terraforming structures have done a splendid job of repairing the damage mankind did to the planet. But there was another fact at play that most denizens of the CE don't take into account, 90% of the global population was gone. The population contraction saw the world go from over 10 billion people down to just over 1 billion people in the span of a century. The biosphere would have corrected itself as the most industrialized countries were the hardest hit, and thus the prime offenders were the worst punished. Life in sub-Saharan Africa just got a little harder. Life in the central United States got Sub-Saharan Africa hard.
The megastructures were expensive. Their construction and operation did bankrupt nations. Hundreds, and in some cases, thousands of workers died in the construction process. The air processors turned the land around them into swamps and lakes, where strange things team in the water. People who live near the water have strange illnesses but certainly none of that is due to the strange machinery at work. With the impetus towards environmental domain, people have been crammed into relatively tiny amounts of space, and under unnatural conditions. There is plenty of room for mankind to relax and spread back out across the planet, but more and more people are moving to the arcologies, the geofronts, and in ever increasing numbers, into space.
Where the terrible things live