SAN FRANCISCO, April 10 (Xinhua) -- More than 4,000 Amazon employees on Wednesday urged their CEO Jeff Bezos to adopt an extensive plan to combat climate change crisis.

In an open letter to the Amazon leadership, which was signed by 4,074 Amazon workers, they said Amazon has the resources and scale to fight climate change, which they called "an existential threat."

"We believe this is a historic opportunity for Amazon to stand with employees and signal to the world that we're ready to be a climate leader," they said in the letter.

Although Amazon has taken some measures to reduce emissions, including an introduction of the Shipment Zero program that was intended to make 50 percent of all shipments net zero by 2030, the U.S. e-commerce giant's growth rate could still miss the target and see an increase in emissions compared to today, said the Amazon employees.

They criticized Amazon's sustainability goals for "lacking context" as the company's target of installing at least 50 solar installations in warehouse facilities by 2020 represents only 6 percent of buildings in Amazon's global fulfillment network.

An Amazon spokesperson reaffirmed in a media statement the company's "unwavering" commitment to environmental issues.

"We have launched several major and impactful programs and are working hard to integrate this approach fully across Amazon," said the spokesperson.

The open letter came after hundreds of Amazon workers called last year on the company to stop selling its facial-recognition software to the U.S. government for fears of the tools being used to violate people's rights.