Shipping is a big polluter so the freight giants are trying new cargo ships powered by wind or green methanol

• The International Maritime Organization is hoping to reduce shipping's greenhouse gas emissions.
• Two cargo ships have launched in the last five weeks that could help achieve that.
• Maersk launched a methanol-powered vessel last month, and Cargill announced a wind-powered one on Monday.

Shipping is an increasingly polluting industry, responsible for 3% of the world's greenhouse gases according to research from the European Union.

The UN's International Maritime Organization announced plans in 2020 to reduce the sector's emissions by 50% by 2050.

And two cargo ships that have launched in the last five weeks are set to help achieve that target.

Danish shipping giant Maersk originally planned to operate the world's first carbon-neutral liner vessel by 2030, but brought its target forward by seven years.

Its first ship fueled by green methanol began its maiden voyage on July 17 from South Korea to Denmark, The Maritime Executive first reported.

That's one of 25 methanol-powered ships ordered by Maersk, per New Scientist, marking a big push to decarbonize the shipping industry.

Maersk says that the vessels could help reach its target of a 50% reduction in its emissions per transported container by 2030 compared to 2020.

And on Monday, Cargill announced that a Mitsubishi wind-powered ship it has chartered has set sail for the first time.

The Pyxis Ocean was retrofitted with two WindWings, huge sails designed for cargo ships by BAR technologies, which Cargill says can reduce emissions by up to 30%.

"If international shipping is to achieve its ambition of reducing CO2 emissions, then innovation must come to the fore," said John Cooper, CEO of BAR technologies. "Wind is a near marginal cost-free fuel and the opportunity for reducing emissions, alongside significant efficiency gains in vessel operating costs, is substantial."

And Dr Simon Bullock, a shipping researcher at the University of Manchester, told the BBC: "Ultimately we do need zero-carbon fuels on all ships, but in the meantime, it is imperative to make every journey as efficient as possible."