Congestion last year at the ports of Los Angeles and Long Beach contributed to a rise in greenhouse gas emissions, port officials have reported.

The Port of Long Beach on Tuesday released its annual emissions inventory report, which showed greenhouse gases were up more than 9 percent in 2015 compared with 2014, though still well below the 2005 baseline for its ongoing efforts to reduce air pollution.

The Port of Los Angeles, which released its emission report last week, also saw greenhouse gases rise more than 9 percent.

“The latest emissions inventory shows the effects of last year’s congestion and increased ships at anchor. Thanks to labor and shipping partners, we cleared the backlog quickly,” said Long Beach Harbor Commission President Lori Ann Guzmán.

That congestion at the beginning of 2015, which Port of Los Angeles officials also blamed for the lackluster emission results, was largely caused by a labor dispute that led to a West Coast dockworkers slowdown.

Still, overall both ports have made huge strides in reducing overall air pollution after investing in “green” efforts such as requiring cleaner-running trucks and installing hookups so cargo ships can run off electricity and shut off their engines while docked. Diesel particulate matter was down last year by 84 percent compared with 2005 at the Port of Long Beach, slightly below the 85 percent mark reached in 2014. The Port of Los Angeles saw diesel particulates drop 85 percent last year since 2005, the same level as in 2014.

Officials said air quality at the ports, which together make up the largest shipping complex in the country, should improve this year as they continue toward a goal of zero emissions.

“With this temporary situation behind us, we expect to see clean air progress when the numbers come in for 2016,” said Port of Los Angeles Executive Director Gene Seroka.

Trade, transportation, and manufacturing reporter Paul Eakins can be reached at [email protected]. Follow him on Twitter @Pauleakins.