Global warming is the process of the Earth's average temperature rising. Global warming, particular that caused by the actions of humans, has been a recurring theme in various Teenage Mutant Ninja Turtles continuities. These stories are inspired by the real-life global warming occurring on the Earth today.
According to Rock of Ages, the Earth was populated by humans hundreds of millions of years ago when the planet's continents were united as Pangaea. The humans were poor stewards of their planet, causing a cataclysmic episode of global warming that wiped out their civilization and caused the Permian–Triassic extinction event. The discovery that they were actually humans from Earth's distant past raised the specter that the exact same thing was going to happen on the modern Earth all over again in the near future.
In The Blue Hole, Glurin reveals how Utrom scientists have predicted a catastrophic realignment of the North Atlantic Current and the possibility of a new ice age if the temperature of the water in that current is allowed to rise by even just a few degrees higher (rising because of the effects of global warming). Glurin and Donatello are out in the Sargasso Sea to inspect a data collector that has stopped reporting back, leading into that story's main plot.
Dark Shadows reveals that the Utroms finally decided to make public first contact with the people of Earth because Utrom scientists had detected an imminent cataclysm that would severely alter the Earth's axis, destabilize its tectonic plates, and cause runaway global warming. The Utroms offer to evacuate all people who wish to leave the planet and disaster behind, and the vast majority of the Earth's human population takes up the offer, leaving behind too few remaining people to maintain civilization let alone prepare for the disaster itself. This is shown to have happened in other future stories like the end of Day in the Life, where an elderly Raphael is shown living on a building rooftop amidst the flooded ruins of what used to be New York City.
Silent Night and Swan Song strongly suggest that the Earth's civilization eventually starts recovering from this disaster within a century, as major cities (including New York and Tōkyō) have been restored or rebuilt.
Various Palladium TMNT RPG resource books, like After the Bomb and Road Hogs, involve a future Earth that has been devastated both by nuclear war and by global warming, wiping out most of the human population and leaving behind a population of mostly mutant animals with a minority of surviving humans. The map of the world's coastline has been heavily altered by these events.
The episode Shredder's Mom includes Shredder and Krang using a satellite to speed up the process. In Too Hot to Handle, professor Filo Sopho tries to make the Earth collide with the Sun. Even if the warming in these episodes are created using different machines, Shredder's Mom already includes a conference about the topic, planned even without Shredder and Krang striking.
- Most TMNT stories involving global warming as a major plot device have been written by Stephen Murphy (often under his pen name Dean Clarrain), who has also written more officially licensed TMNT stories than any other author; his stories usually involve an cautionary environmental moral. Various other stories involving global warming have been written by Dan Berger, though more as a story setting and less from a moral perspective.