The distance from Shenzhen to Long Beach is some 300 times the distance from Long Beach to Pasadena, depending on where exactly in Pasadena and which route you take. The CO2 emissions factor for a truck is some 10-100x that of a container ship. The exact ratio depends on what kind of truck, and what scope of emissions are being included. The more one accounts for, the more it will favor the boat. But overall, the emissions from the oceanic leg of the trip are probably anywhere from 1-3x those of the truck.