Unlike the Noah Flood, which is an artificial flood designed to fill the oceans of a planet, a fire flood is a controlled runaway greenhouse effect.
Some planets can contain high amounts of natural occurring toxins, like formaldehyde or dioxins.
Pollution can occur on many terraformed planets under the form of invasive species, deadly diseases (mutant viruses or bacteria) or by high amount of toxic chemicals. At some point, the Fire Flood remains the most efficient way of cleanup.
In order to produce a fire flood, global temperature must be raised above water boiling point. This can be done by adding Greenhouse Gases or by removing Anti Greenhouse Technology. As temperature rises above 100 C even at the poles, water starts to boil and accumulates in the atmosphere, further increasing the greenhouse effect. Temperature rises even more. Wet heat is the best weapon to kill microorganisms and is also effective in destroying many chemical compounds.
The planet will be left to boil until even in the deepest oceans temperature reaches values above 100 C. Under high pressures, water boiling point increases up to a few hundred degrees, until both gasses and liquids become hyperfluids. At that point, we can be sure that all life went extinct and majority of toxins are neutralized.
During the fire flood, the planet becomes a new Venus. The atmosphere is hot and extremely corrosive.
After this, we need to decrease the temperature. The most feasible technology requires the use of Micro Helium Balloons. The planet is cooled again and terraforming starts.
It is important to note that, if the planet was terraformed before, all oxygen might react with exposed carbon stored on the seabed. The result could be a planetary scale fire, which will further increase temperature.
The fire flood technology is the last solution in case of large scale pollution. It is a radical, extreme engineering solution that can save a planet that has no other choices. It also is the last and most extreme solution to biological weapons.
The costs of such an intervention are huge. First of all, if the planet is inhabited, we need to relocate the entire population. However, in case of a deadly disease, everything is far more complicated. Every human extracted from the planet needs to be tested, to be placed in quarantine, to take huge amounts of medical drugs in order to make sure no microbes survived and to stay a for many years on another planet, until the fire flood ends.
The biggest costs will be related to relocation of the local population during the fire flood. This can result in violation of many human rights (see below).
In case of a disease Edit
If the planet is already inhabited, the entire population must be relocated for a lengthy period of time. However, this works as long as the cause of a fire flood is not something like a virus or a bacteria.
In case of a disease (virus or bacteria), the planet automatically will be under embargo. Nobody wants to contaminate the whole cosmos with a germ. All trade will stop and the planet will be isolated. Trying to cure a contaminated planet will be a hard task.
It is clear that local population will not survive a fire flood on the planet. The only solution is to relocate them. But, doing so will automatically include the risk of carrying the disease with them. There is a tight balance between the risk of contaminating other planets and the risk of producing a genocide. From the most radical to the most humanitarian, these are the solutions:
Contamination solution: People from the planet will try to leave and will carry the disease with them. As this happens, they will contaminate other worlds. Also, terrorists will try to pick samples and contaminate other worlds. If a strict embargo is not put in place, the whole Universe is at risk.
Radical solution: Leave the entire population on the planet to die during the fire flood. This is clearly an act off genocide. We might see such radical measures if the group trying to start a fire flood is in fact trying to colonize the planet for itself.
Abandon Solution: Many terraformed planets need maintenance and an embargo will damage the economy. As this happens, inhabitants will not have the power to maintain their ecosystems. If no external force tries to do something, the planet will be in the end lost.
Partially radical solution: Test the entire population for any sign of infection. Those who are positive or who are not sick, but entered in contact with the disease, will be left on the planet and will die. Those who are negative, will be sent to a quarantine station, where they will be further tested, to make sure they are negative. if all tests pass well, they will be moved to another planet until their home planet is cleaned. Again, all those found positive or suspected to be positive during quarantine, will be sent back to their home planet, to death.
Extended quarantine solution: Test the entire population for signs of infection or passive contamination. All those found to be positive or suspected to passive carry the germ, will be sent to a sacrificed planet, where they can stay. That planet will be placed under quarantine. All those who present no risk, will stay on a non-contaminated planet until their home planet finishes the fire blood phase.
Quarantine and castration solution: This solution implies that all people found to be negative to the infection will be sent to another planet. Those found positive or passive carriers will be sent to a sacrificed planet or an orbital station and castrated, to avoid contamination of further generations.
A variation of this solution is that all positive and passive carriers will be left on the planet, but castrated. The fire flood will not occur during their lifetimes. However, those found negative will in most cases also not survive that long. Their children might not be interested in returning to the planet of their parents.
Medical solution: It might be possible that the disease can be cured. If so, then the whole population can be saved. By constantly vaccinating the population for many years, it could be possible to fight against the disease until the risk of contamination is very low. At that point, local population can be relocated for the fire flood to occur. If there are antibiotics that can fight the disease efficiently, then all those found to be positive or passive carriers will use medicine for a lengthy period of time, until al germs are considered dead. However, a vaccine cannot be prepared for all germs and not all germs can definitively be cured with antibiotics.
Humanitarian solution: People that are tested to be negative can leave the planet. However, people found to be positive or passive carriers, will be left on the plane or moved to an alternative orbital station, if they wish. As long as there will be people on the planet not willing to be relocated, a fire flood cannot occur.
In the end Edit
In a Soviet sci-fi novel, humans took all precautions not to contaminate the space and the newly terraformed worlds inside the Solar System and beyond with germs from Earth. And since people have lived for centuries without diseases, their bodies are less adapted to this risk. At some point it was concluded that a single flu virus could kill 90% of the population. So, in year 2450, they put the Earth under a strict embargo.
After many years, in 3100, humans noticed that the Earth is the only place in the Universe under quarantine. So, they tried to find a solution. They tried to extract the remaining population of Earth, about 200 million people. Everyone was tested for high-risk diseases. Those found negative, had to suffer a long quarantine for further testing. And after that, those still found negative, had to take almost lethal doses of medical drugs against viruses, bacteria, parasites and fungi.
Finally, those who have past the test were tested for genetic diseases and had genetic manipulation done to repair their DNA. And even so, all found to suffer of psychological disorders were not accepted.
All found positive, all who could not endure the medical tests and all who suffered from psychological disorders were moved to an orbital station where they were castrated and allowed to live the rest of their lives. However, a suicide attack made the station explode. All debris were caught and sent into the Sun, to prevent any germ from falling back to Earth.
Those who passed all tests, about 30% of the population, were resettled back to Earth when the fire flood ended. Survivals returned to the planet, which has become like a new garden of Eden. The Galactic Federation, which founded the fire flood and resettlement program, expected survivals to be respectful for all their work. However, one of the survival, at the resettlement ceremony, said: You isolated us for half a millennia, then you invaded our homeland and killed two thirds of us. How could we be thankful to this? These worlds show just how complicated a fire flood event could be in case of an inhabited planet.