Amazon.com Inc said on Wednesday that five companies, including Uber Technologies Inc and JetBlue Airways Corp, have joined its fund that invests in companies developing environmentally friendly technologies.

Chief Executive Officer Jeff Bezos last year pledged to make the largest U.S. e-commerce company net carbon neutral by 2040, as employees and consumers around the world protested for broader moves to address climate change. 

Environmental activists welcomed that move but said that cutting all emissions related to Amazon, which delivers 10 billion items a year and has a massive transportation and data center footprint, was a huge challenge.

"The transportation sector plays a critical role in accelerating our carbon reduction goals," Bezos said in a statement on Wednesday.

So far 18 companies, including Best Buy Co Inc and Verizon Communications Inc, have signed up for the Climate Pledge, which was established in 2019.

(Reporting by Chavi Mehta in Bengaluru and Jeffrey Dastin in San Francisco; Editing by Anil D'Silva) ((Chavi.Mehta@thomsonreuters.com;))