Not because of the sentiment. Climate change presents a real danger to humanity, and it’ll hit the humans who live near oceans first. Los Angeles, where Eric Garcetti is mayor, has a population of over 10 million people, a quarter of California’s humans, and the busiest port in the United States. Sea level rise and pollution matter there.
And it’s not weird because Garcetti was wrong about the politics. President Trump has, as you’ve no doubt read, expressed doubt in the reality of climate change (he’s wrongabout that) and threatened to withdraw the United States from the Paris Agreement (he could, but it wouldn’t be simple) signed by 200 countries in 2015.