By Stephen Nellis

CUPERTINO, California Apple on Tuesday said that three of its Apple Watch models will come in what it calls carbon-neutral versions sporting a new green logo on their boxes, and the biggest change is that more of the transportation will be by boat instead of planes.

Apple aims to be carbon neutral by 2030, including its supply chain. One of the biggest challenges to achieving that is cutting emissions from Apple's speedy transportation network, which relies heavily on planes.

Apple was a pioneer in using planes to haul consumer electronics from factories in China to destinations around the world, helping reduce the inventory it needs to hold and boosting its profits.

For the three new watches, half of shipments by weight, from factory to destinations such as regional distribution hubs, will happen over boats, trains or other non-air methods that burn less fuel and create fewer carbon emissions that warm the planet, Apple executives said in an interview at Apple's Cupertino, California, headquarters.

The three green-tagged versions of the Apple Watch Series 9, Apple Watch SE and Apple Watch Ultra 2 will have lower emissions than Apple's baseline estimations based on previous products, and Apple will buy carbon offsets for remaining emissions, said Lisa Jackson, the head of the company's environmental and governance efforts.

"We could in theory do that (buy offsets) tomorrow, and everything would be carbon neutral, but we wanted to be really clear that we're taking action on everything we know how to do to reduce (emissions) with existing technology," Jackson said.

The company has said previously that a Series 8 watch created 33 kg (73 lb) of carbon emissions, from raw materials to delivery to end customers.

The new climate-friendlier aluminum Series 9 with a sport loop band will have 8.1 kg (18 lb) of emissions remaining after Apple's changes, and the company will cover that remainder by buying carbon credits. That compares with 29 kg (64 lb) of emissions for the standard stainless steel version of the Series 9 with the same band.

Apple has been focused on cutting carbon emissions for some time. All new watches, including standard editions, also use custom alloys of aluminum and titanium that are made from recycled materials and batteries that contain only recycled cobalt, a mineral whose mining poses both climate and human rights concerns.

"We're absolutely planning to roll that out across" more of Apple's products in the future, John Ternus, the firm's hardware engineering chief, told Reuters. "As we push forward and we engage with suppliers on these recycled material supply chains, we find that we're usually the first ones talking to them about it."

The green-tagged watches will cost the same as the standard versions. Executives did not comment directly on whether they would be less profitable than the standard ones, but Jackson said Apple is focused making changes that it and other businesses can carry into the future.

"In order to make this replicable, it couldn't be a premium, because most businesses are willing to make the change, but they need to still be able to be in business, make money and pay their workers and buy materials," Jackson said.

(Reporting by Stephen Nellis in Cupertino, California; Editing by Peter Henderson and Lisa Shumaker)