Under the 2015 Paris climate agreement, the world committed to limit global temperature increase to well below 2°C, and to pursue efforts to hold the rise to 1.5°C.
To meet these targets global emissions need to fall rapidly. In models of possible future emissions that limit warming to 1.5°C emissions peak before 2020 and then start declining.
By the middle of the century net emissions reach zero, with any remaining emissions balanced by technologies that extract carbon from the atmosphere — a point known as ‘carbon neutrality’.
Negotiations to deliver an inital climate strategy for the sector start at the London-based Internatonal Maritime Organisation’s HQ on 26 June, with a plan due in 2018. Here’s why they are so important.
Shipping currently produces about 2.3% of global emissions.
Current plans to cut emissions 2 under the Paris Agreement do not apply to international shipping, and, unlike the aviation industry, the shipping industry has not yet agreed any sector-wide deal to stop its greenhouse gas emissions increasing.
The IMO expects to release in 2018 an initial plan to cut greenhouse gas emissions and to agree a final strategy by 2023.
It introduced minimum energy-efficiency standards for new ships in 2013.
Analysis suggests the industry will continue increasing its greenhouse gas emissions until at least the middle of the century.
According to one set of projections by the International Maritime Organization (IMO) — which assume ship efficiency will increase by 40% and the industry makes some progress in switching to cleaner forms of power — shipping emissions are due to increase by 21–48% between 2015 and 2030, an increase over that period from 800 million tons of carbon dioxide to 970–1,200 million tons.
Any projected growth in shipping emissions puts the industry at odds with other sectors and countries that plan to reduce emissions.
The IMO’s projections mean that shipping, in terms of its greenhouse gas emissions, could be compared unfavourably with Donald Trump.
Even if President Trump’s plans to scrap clean energy rules are successful, US emissions are expected to remain constant through to 2030 at around 3% below 2012 emissions.
Over the same period, the shipping industry is projected to emit up to 48% more.
1.5°C in jeopardy?
As global emissions fall, shipping, like other sectors, would need to cut its emissions rapidly to avoid producing a growing share of global emissions.
If it doesn’t, growth in shipping emissions will put pressure on the Paris Agreement and could make the 1.5°C target unachievable.
To cut emissions at the same rate as other sectors and meet the 1.5°C target, the shipping industry should halve its emissions by 2035 and be carbon neutral by 2045, according to one model of possible future emissions.
Shipping emissions in 2030 should not exceed 498 million tons of carbon dioxide to meet these targets.
But the IMO’s projections suggest the industry may produce 970–1,200 million tons of carbon dioxide in 2030, 95–141% higher than this limit (or between two and two and a half 8 times greater).
While forthcoming projections are expected to show slightly slower emissions growth, shipping would threaten the Paris Agreement unless its emissions begin to fall from 2020 and reach zero in the 2040s.
Put it another way. By 2050, shipping could have burnt a sixth of the global 1.5°C carbon budget
For a 66% chance of limiting warming to 1.5°C, the world’s total emissions of carbon dioxide from 2015 should not exceed 243 billion tons.
With shipping emissions rising while other sectors’ emissions are falling, the sector is set to produce a growing share of global emissions.
According to the IMO projections the industry may produce 39 billion tons of carbon dioxide between 2015 and 2050 in a scenario where global emissions are otherwise tightly limited.
If this happens, shipping would, alone, consume 16% of the global carbon budget for 1.5°C by 2050. Other sectors would have to cut their emissions faster and further to accommodate rising emissions from shipping.
● Global carbon dioxide emissions must start falling rapidly by 2020 to meet the Paris Agreement.
● Shipping industry emissions are expected to continue increasing past this date — projections suggest they could grow by 21–48% from 2015 to 2030.
● This would mean international shipping emissions in 2030 would be on course to be twice the level compatible with the Paris Agreement’s aim of limiting warming to 1.5°C.
● Shipping emissions threaten to make the Paris Agreement unachievable. By 2050 the sector could burn 16% of the world’s total remaining carbon budget for a 1.5°C goal.
● The shipping industry plans to establish a strategy to cut emissions but so far has not committed to the radical change that would be needed to meet the Paris Agreement.