You might even be tempted to assume that humanity has little future to look forward to. But such gloominess is misplaced.

你可能不知不觉地认为人类的未来没什么好期待的。但们也不应该很绝望。

It's usually depicting sadness or irritability or gloominess.

通常描绘的是悲伤、阴郁的情绪。

So despite the gloominess of many topics,   we want to approach them with informed and well researched optimism – not brushing  humanity's very real challenges aside, but also not falling into the trap of pessimism.

所以尽管许多话题都很阴郁，们仍然希望以有根据且经过深入研究的乐观态度来面对们——既不忽视人类面临的真正挑战，也不陷入悲观的陷阱。