> This one year, or the year previous, is not evidence that the ecosystem of the planet is going to collapse in 10 years.

Global warming writ large has been going on for a lot longer than a couple of years, and ocean temperature tipping points have been an anticipated consequence. An anomaly of this size warrants alarm. If not proof of imminent ecosystem collapse, it seems foolish to 'wait and see'. Though I take your point that defeatism is worse, but I doubt OP is defeatist.

> rhetoric that we're all gonna die by 2030

That's an even more sensationalist spin than what the OP wrote