(Reuters) - Delta Air Lines said on Thursday it would spend more than $30 million to offset 13 million metric tons of carbon emissions over 10 months last year as part of its pledge to help combat climate change. The Atlanta-based company said its medium-term goal is to replace 10% of its jet fuel, which is currently refined from fossil fuel, with sustainable aviation fuel by the end of 2030. Delta also said it cut emissions by retiring more than 200 older aircraft early in 2020 as it dealt with a plunge in demand from the coronavirus pandemic. Replacement planes will be 25% more fuel-efficient, the U.S. airline said. In February 2020, Delta announced plans to invest $1 billion over the next decade in initiatives like offsets, sustainable aviation fuel and carbon sequestration that would limit the impact of global air travel on the environment, the first airline to make a commitment of that scale. That followed moves in Europe by easyJet to offset emissions on all its flights and by British Airways and Air France to do the same on their domestic flights. Delta has agreed to purchase a future supply of 70 million gallons of sustainable aviation fuel per year. The amount the U.S. carrier plans to pay for offsets from March 1 to Dec. 31 would equate to less than 0.35% of its revenue during the period, based on Reuters calculations using Delta’s financial results from April 1 to Dec. 31. Delta said the carbon tonnage offset was equal to the carbon sequestered by 17 million acres of U.S. forests in one year, enough to cover the state of West Virginia. The Biden administration is pressuring U.S. airlines to do more to reduce emissions. The chief executives of major U.S. carriers met with White House officials last week to discuss tackling aviation pollution and urge U.S. support for greener aviation fuel. United Airlines has committed to a multimillion-dollar investment in carbon capture, a technology designed to suck carbon dioxide from the atmosphere, as part of a plan to be 100% green by 2050. Delta said it also believed carbon capture had significant potential. Delta owns its own oil refinery, making it unique among its peers. The company posted a $102 million refining segment loss in the fourth quarter and a $441 million loss on third party fuel sales. The refinery, located in Trainer, Pennsylvania, emitted about 1.45 million metric tons of carbon dioxide or equivalent gas in 2019, according to the latest data available from the U.S. Environmental Protection Agency. That year, the net quantity of greenhouse gasses of the petroleum products the refinery produced totaled roughly 26 million metric tons, according to the EPA.