I believe that's a VERY SMART and RESPONSIBLE question to ask.
Unfortunately, answers are not very clear or understandable in common English.
Results from Google will get you too many different angles that lead to debatable arguments that will end up to no conclusions anyways.
People still struggle to understand, fail or simply don't care while they're comfortably watching Netflix on their couches and driving their polluting, clean air burner vehicles.
The truth is that it's our lifestyle that is toxic to us and our planet.
We already have solutions, ingenuity, will and working technologies to stop this.
FCEL is certainly one of them
The reversal has already started around the planet, we just need time now.