"DeltaDeltaDelta" wrote in message
...
Possibly they meant that the hydrogen can be obtained from liquid water,
but
leaves the engine in a gaseous state. Some of this will condense, but some
could also stay in the atmosphere and form clouds or drift into the higher
layers of the atmosphere.

Water vapor is already a byproduct of our current engine technologies. And
yes, it is a potential problem. But fuel cells are FAR more efficient than
combustion engines, without any of the other harmful emissions. Anyone
trying to argue that fuel cells won't be a net win is just plain crazy.

Pete