Warning: contains spoilers for Superman: Son of Kal-El #1!
The new Superman has barely begun his tenure, but he already knows what fight will define him as a superhero. Jonathan Kent, the son of Kal-El, officially takes over for the Man of Steel in Superman: Son of Kal-El #1, written by Tom Taylor with art by John Timms and colors by Gabe Eltaeb. He may be young and inexperienced compared to his father, but his greatest fight lies ahead - and he knows just how difficult the battle will become.
Jonathan Kent is a relatively new addition to the Superman mythos, appearing six years ago in Convergence: Superman #2. Over the years, he's become a hero with all the powers and abilities of Clark Kent, minus some considerable experience. Nevertheless, he wants to follow in his father's footsteps and become a hero for the rest of humanity, and stand for "Truth, justice, and a better world" in his own words.
In Superman: Son of Kal-El #1, Jonathan Kent, officially adopting the Superman name, flies into California during a massive wildfire. Firefighters attempt to evacuate civilians, but the heat is so intense that the tires begin to melt. Superman swoops in and, alongside the firefighters, beats back the blaze long enough for civilians to be saved. "Firefighters said this is a once-in-a-hundred-year-fire," Superman muses as he flies through the flames. "Seems like we have those every year now." He admits to himself that the area has had a decade of record-high temperatures. It's clear that the ever-increasing threat of climate change weighs quite heavily on Superman.
Though the fire is started by a metahuman teenager who can't control their pyrokinetic powers, Superman understands that the entire area was a tinderbox to begin with (and the military attacking the metahuman certainly didn't help matters either). The climate change narrative continues into the future - namely DC's Future State events. In Future State: Superman/Wonder Woman #2, Superman reveals that the Earth came dangerously close to being destroyed by humanity's own willful blindness towards climate change. Thanks to Superman's enhanced senses, he felt every degree of warmth and every minute change in the planet's atmosphere. Earth was nearing the point of no return, and surprisingly, Superman couldn't stop it. He mentions that it was humanity who changed their ways in their most desperate hour and eventually brought about a utopia.
It's important to note that the stories told in Future State were a series of potential scenarios; the future of Superman and the DC universe is not set in stone. Still, the threat of climate change is quite real and Superman knows how difficult it will be to combat it; Batman's son Damien Wayne tells Jonathan it's not a problem one can simply defeat with a punch. While Jonathan lacks Clark Kent's experience, this new Superman is like his father in at least one respect: he will never give up on Earth or its inhabitants.