Maritime countries have been finalizing a plan Thursday to slash emissions from the shipping industry to net zero by about 2050 but experts warn the deal falls well short of what’s needed to prevent climate catastrophe. Negotiators at the meeting of the United Nations’ International Maritime Organization in London, seen as key to limit global warming to 1.5 degrees Celsius (2.7 degrees Fahrenheit) since pre-industrial times, are set to officially agree Friday for shipping emissions to reach net zero “by or around” 2050, rather than setting the date as a hard deadline. The draft plan also calls for shipping emissions...