Just like the aviation sector, cruising if often frowned upon by environmentalists, with criticism directed at mega-ships polluting the ocean.

Historically, there have been several big energy guzzlers riding the waves, but in the last few years, there’s been a seismic shift to a more sustainable way of sailing.

Various companies have set their own green goals in a global effort to cut carbon dioxide emissions from cruising by 40 per cent by 2030. So, when vessels do get the green light to travel again, once the coronavirus pandemic is brought under control, conscious cruising is set to be of increased interest.

Here are a few of the environmentally-focused cruise companies to seek out.

1. New kid on the block: Tradewind Voyages

This ambitious company aims to sail without engines for 70 per cent of the season. Golden Horizon is the largest square-rigged sailing ship in the world, offering guests in the 140 sea-view cabins the charm and romance of an historic ship, coupled with modern luxury. It will debut with an ex-UK programme from May 2021, before heading east, following the winds and tracking a course around the globe.

There will be no plastic straws or bottles of water onboard, and shampoo bottles will be biodegradable. There is also a commitment to use local produce, sustainably sourced wherever possible on menus.

With regards to on-board entertainment, the programme has a strong sustainability focus with natural world experts, such as Liz Bonnin and Kate Humble, hosting some of the itineraries.

How: A 15-day Best of Britain cruise with Liz Bonnin, visiting England, Northern Ireland, Ireland, the Isle of Man, the Channel Islands and the Isles of Scilly, starts from £2,699pp (two sharing). Departs May 29, 2021. Visit tradewind.tripsmiths.com or call 0808 239 1012.

2. River royalty: AmaWaterways

AmaKristina was the river cruise industry’s first ship to earn the prestigious Green Award certification – a quality mark for ships that demonstrate high safety and environmental standards. Now the company’s full fleet of 18 vessels has received the designation.

With an ongoing commitment to protecting and preserving the world’s rivers, AmaWaterways’ ships are designed with eco-friendly elements, such as LED lights; windows that reduce energy needs for heating and cooling; power locks to plug into a port’s power supply instead of running generators; solar heating systems; water treatment plants that use a membrane technology to provide microfiltration and recycling of all water used onboard.

How: A seven-night cruise on the Enchanting Rhine aboard AmaMora starts from £2,335 per person. Sailing down river from Basel to Amsterdam, the itinerary is more fuel efficient. Flights extra. Visit amawaterways.co.uk or call 0800 520 2250.

3. Wildlife bonanza: Ecoventura

A decision to visit the Galapagos Islands, an archipelago of specially adapted species who are a product of their pristine environment, brings with it a responsibility to travel with as light a footprint as possible.

Ecoventura lead the way in sustainable cruises to this Pacific paradise, 600 miles off the coast of Ecuador. Their luxury vessels, Origin and Theory, were built specifically to minimise environmental impacts; their design allows for reduced fuel consumption and greater speed.

The company supports the local community by buying 30% of its produce from the islands and sponsoring schemes, such as the construction of chicken coops to help boost livelihoods. They also donate use of a cabin on one of their yachts to support the work of organisations involved in caring for the Galapagos.

In a war against pernicious plastics, single-use straws and bottles have been banned, and guests can request to participate in beach clean-ups.

How: Abercrombie & Kent (abercrombiekent.co.uk; 01242 547 760) offer an eight-night Discover Galápagos trip from £4,050pp (two sharing). Includes flights, transfers and accommodation.

4. Expedition experts: Hurtigruten

Founded in 1893, this Norwegian company has the world’s largest fleet of expedition ships. Positioning themselves as sustainability champions, they introduced the world’s first hybrid battery-powered cruise ships, the MS Roald Amundsen and the MS Fridtjof Nansen. Both vessels were designed to reduce CO2 emissions by more than 20% compared to other cruise ships of the same size.

Additionally, the company is in the process of rebuilding existing ships in the fleet to run on a combination of large battery packs, liquefied natural gas (LNG) and biogas (LBG).

To celebrate their 125th anniversary, they banned all single-use-plastics and have also introduced plant-based meals in their on-board restaurants. Food is largely sourced from local suppliers to minimize transport emissions, and there is a commitment to reduce food waste by up to 30% in 2021.

Eager to preserve fragile wilderness destinations, they actively oppose mass tourism and offer year-round itineraries to distribute numbers sustainably.

How: A 14-day The Heart Of Greenland cruise around the western coast of Greenland and Disko Bay, onboard the MS Fridtjof Nansen, starts from £5,738pp, including meals and a range of excursions. Departs August 8, 2021. Visit hurtigruten.co.uk or call 020 3603 7112.