Trade has not been slowing down. The rate at which it has been increasing (YoY change) has been slowing down. There actually is a difference, but the author is to stupid to know that, or thinks that most of the readers are to stupid to know that. 

Granted, for a few countries, at the end of this year, trade did, actually, slow down. Given that things seem to be turning around now, it seems likely that for the US, at least, and probably Germany and one or two other major players, things will start turning around