[saltcured]

I think that the difference in perspectives is seeing pessimism/optimism as just a mood valance. In a sense, it takes some pessimism to even perceive that problems exist. Purified optimism would see every kind of evidence as good and interesting and every possible outcome as rosy.

These are spectra, and neither extreme is "correct" and rooted in objective reality. Pessimism/optimism can be decoupled from other axes like ignorance/knowledge, acceptance/denial, awareness/delusion, etc. Assuming "climate change is happening" as fact, someone might exhibit climate change denial for any number of reasons. These are just illustrative sketches, not an effort to build some taxonomy of beliefs:

Ignorance: someone may be unable to comprehend the complicated climate system concepts, statistical concepts, nor noisy data.

Cynical pessimism: someone may believe it is happening and unavoidable, but they want to minimize their own inconvenience or discomfort prior to the end game.

Blind optimism: someone may just harbor a profound faith that things will work out in the end; to them, the people trying to address climate change seem like toxic pessimists who harbor delusions of grandeur!