Apples estimates new iPhones lower carbon emissions by 14 to 16 percent from last year

Apple has given its latest iPhones an environmental upgrade to go along with a better camera and a few new features.

The world's biggest technology company says the iPhone 6s and 6s Plus have reduced their carbon emissions by 14 to 16 percent from last year's models. The estimates are based on measurements that quantify how much pollution is caused during the production, distribution, consumer usage and recycling of the devices.

Most of the improvements reflect changes made in the purchasing and manufacturing of the aluminum used in the iPhone enclosures. Lisa Jackson, Apple's top environmental executive, says carbon emissions tied to the production of those iPhone enclosures have been cut in half from last year.

The new phones are scheduled to be in stores on Sept. 25.