This week, crucial decisions at the International Maritime Organisation in London could undermine the central goals of the global climate deal agreed in Paris last December.
The Paris Agreement makes it impossible for any country or any sector to say climate change isn't their problem. It has created unprecedented momentum for all sectors in all countries to take action and be part of the solution.
The shipping industry plays a fundamental role in boosting global trade and prosperity. Maritime leaders have rightly recognised the need to invest in more energy-efficient vessels and to apply measures like slow-steaming. But to ensure a level playing field, collective action is urgently needed across the sector.
Because maritime carbon pollution happens beyond national boundaries, emissions from shipping did not get a specific reference in the final text agreed at the Paris climate conference. That is why the industry will be gathering at the International Maritime Organisation (IMO) in London from 18th-22nd April with the aim of agreeing a plan for the sector to manage its emissions.
Failure to get an agreement could put the integrity of the Paris Agreement - and the safety of us all - at risk.
The IMO, predicts emissions from shipping may rise by 50-250% by 2050 from 2012 levels. That would take the shipping sector from a carbon footprint the size of Germany, at 3% of global emissions, to one nearly the size of the entire EU.
We need robust sustainability regulations for shipping that are internationally recognised and respected. This will ensure shipping plays its part in the global transition to carbon neutrality.
It is now a year since the Marshall Islands called for measures to help the shipping sector to reduce its emissions. That proposal gained support but countries agreed to wait and see what the climate summit agreed.
In fact, the level of ambition agreed in Paris went far beyond what many had expected, with 195 governments signing up to a global goal of reaching 'net zero' emissions in the second half of the century.
Now the Marshall Islands have resubmitted their plan for the shipping industry to manage its pollution whilst maintaining a thriving maritime sector. They are joined by France, Germany, Morocco, the Solomon Islands and Belgium but the UK's position remains unclear.
These countries are supported by ever louder calls from ship owners and builders calling for a plan for the shipping industry to manage its pollution within a strategy to ensure a thriving industry of opportunity.
In February, the International Chamber of Shipping called for the shipping sector to put forward its own 'intended nationally determined contribution', following the national climate plans that countries announced ahead of the COP21 climate summit.
The Sustainable Shipping Initiative, backed by Maersk, Cargill and China Navigation Company, launched a sustainability roadmap last month, and has called for more focused, urgent action to be adopted.
So why is the UK prevaricating?
Last November Amber Rudd's leaked letter to Patrick McLoughlin showed the Department of Energy & Climate Change's frustration that McLoughlin's Department of Transport was dragging its feet in meeting the UK's clean energy targets.
In the Labour Party we are absolutely united in our belief that shipping must define its 'fair share' of tackling climate change, and develop an emissions reduction plan for the sector. In the words of the Sustainable Shipping Initiative, this is "the minimum" that countries must agree in London this week.
The new IMO Secretary-General, Kitack Lim, has called tackling climate change "a top priority for IMO". It must be a top priority for the UK's Department of Transport as well.
Barry Gardiner MP is Labour's shadow climate change minister and Richard Burden MP is Labour's shadow transport minister.