The range in expected growth of CO2 from shipping until 2050 is shown in Figure 1 (Transport & Environment). The wide range indicates the level of uncertainty in the projection, however, the trend is always upwards. As ratified by Paris agreement, this trend must be reversed for shipping to become carbon neutral by the year 2040 if the rise in global temperatures is to be kept below 1.5C (see Figure 2, Transport & Environment).