50% in 30 years isn't near enough but it's better than nothing.
When I think about things like this, I can kind of understand why people are attracted to the idea of "smaller is better." People who believe in small government, Bill McKibben's views on regional projects, etc. With things like shipbuilding, developing power stations, exploration projects, etc., theres often so much money and planning involved that things literally take decades to develop, which makes it very difficult to suddenly change course. Contracts, loans, hiring and training personnel, and so on all factor into the decision making process. The bigger a project, the more sunk costs seem less like a fallacy and more like a justification for embracing a project's inertia.
Might be better than a good start. Some of those ships produce more pollution than all the cars in California. They use heavy fuel oil that nobody else can use (although that started to change in 2014 from that article). HFO is terrible shit from my experience. The interesting thing from that article is that they are pushing for LNG. You probably know this but a big source of the terrible LA basin pollution has always been shipping. All those container ships off Long Beach dumping soot and untreated smoke into the air. It's too early but I remember seeing that they now force the ships to use ground power to turn off the generators etc onboard which has helped with the soot and sulphur. So there is a bit of movement, small that it is. Next up will (should) be the concrete industry.