Not quite the same, though.
In the case of Pascal's Wager, if there's no God but you were religious, there's a cost. Pascal argues that the cost is worth it based on the potential outcomes, but even he acknowledges that there would be a cost.
OTOH, if we take climate change seriously, there are all sorts of benefits. Even without considering the potential for future climate change and all of its effects, we can acknowledge that:
- reducing air pollution is a net positive. There are lots of non-climate-change reasons to do this.
- reducing the urban heat island effect in cities is a net positive. We already have people dying in heat waves.
- reducing our vulnerability to flooding is also a net positive. It's not like severe floods don't already happen.
- etc., etc.
If we did the things that we need to do to properly respond to climate change, we would win even if climate change weren't real. The only question is how much we win by. And by the same token, if we don't do those things, we lose no matter what. The only question is how bad a loss we'd suffer.
... so with climate change, one course of action dominates without Pascal-style pondering of just how good or bad each of the outcomes might be.