Alien Terraforming: The Ultimate Clue to Advanced Civilizations?

Could greenhouse gases lead us to aliens? In an effort to search for life in space, researchers have identified greenhouse gases that may indicate that advanced alien civilizations are actively terraforming remote planets.
The study focused on unusual, potent gases such as fluorinated methane and ethane, which, if detected, could serve as technosignatures of sophisticated interstellar engineering. Astronomers using space telescopes such as the James Webb in search of intelligent life, could detect these gases on distant planets to look for evidence of alien civilizations, according to UCR astrobiologist and lead study author Edward Schwieterman.
For us, these gases are bad because we don't want to increase heat. But they would be good for a civilization that might want to stop an impending Ice Age or terraform an otherwise uninhabitable planet in its system, as humans have proposed for Mars