Impact of a possible future global hydrogen economy on Arctic stratospheric ozone loss

The potential role of molecular hydrogen (H2) as a future alternative energy carrier has generated widespread interest. The possible amount of additional hydrogen emission into the atmosphere in a hydrogen-based economy depends on future hydrogen production and leakage rates throughout the complete process chain. However, the expected emissions are highly uncertain. Based on the current literature an upper limit is estimated. Additional hydrogen emissions yield enhanced water vapor concentrations in the stratosphere which will have an impact on stratospheric temperatures and on polar ozone loss. Both stratospheric water vapor and ozone are important drivers of climate change. The potential environmental risks are described and assessed to be low compared to the environmental benefits.