Amazon.com Inc. said its carbon emissions rose in 2020 due to pandemic-fueled business growth, highlighting the challenge of balancing a fast-growing business with pledges to minimize environmental harm.

Amazon’s carbon emissions increased 19 per cent, the company said Wednesday in a 138-page report. While overall emissions increased, the company said its “carbon intensity,” a measure of emissions per dollar of sales, decreased by 16 per cent in 2020, in line with its goals. The e-commerce giant reported a similar shift in 2019.

“This year-over-year carbon intensity comparison reflects our early progress to decarbonize our operations as we also continue to grow as a company,” Amazon said in the report. “Nearly half of our carbon intensity improvement is a result of our investments in renewable energy and operational efficiency enhancements.”

The report attributes other reductions in carbon intensity to behavioral changes of customers and workers tied to the pandemic, such as shoppers making fewer trips to Whole Foods Market locations and employees cutting business travel.

Amazon in 2019 committed to zeroing out its carbon footprint by 2040, or eliminating the greenhouse gas emissions caused by its activities. It has been ordering electric vehicles as part of the push, and expects to have 10,000 of them on the road next year and 100,000 deployed by 2030.

Still, meeting its pledge will be daunting. The company is increasingly transporting goods from warehouses to customer doorsteps, acquiring the planes, long-haul trucks, and delivery vans that make its aggressive delivery promises possible. Amazon’s cloud computing division is building giant, electricity-hungry server farms from Sweden to South Africa. Through contract manufacturers, the Seattle-based company is a major builder of consumer electronics, household essentials and apparel.