US president Barack Obama has a little over a week left in the White House, and he is making use of the time by doing some writing.

The sitting president was published Jan. 9 in the journal Science. In his paper, Obama argues that his national policy toward a clean-energy economy will continue due to “the mounting economic and scientific evidence” of its value and necessity.

First, Obama laid out the economic proof: by encouraging investment into and innovation in the renewable-energy industry, the administration has already helped create around 1.9 million jobs in energy-efficiency products and services, with an additional 257,000 jobs expected in the coming year, according to the 2017 report by US Energy department (pdf, p. 42).

Many of Obama’s efforts will continue after he leaves the White House, too. Last August, his administration released fuel economy standards that are projected to reduce CO2 emissions by 270 million metric tons from 2014 to 2018. Regardless of any policy shifts in the “near-term” under a Donald Trump presidency, Obama writes, ”the trend toward clean energy is irreversible,” and ignoring “carbon pollution will impose tremendous costs to the global economy and will result in fewer jobs and less economic growth over the long term.”

Which is why, Obama writes, the US can’t walk away from the Paris Agreement: the rest of the world is going to keep moving towards a green economy, and the US shouldn’t give up its chance to hold “countries representing two-thirds of global emissions—including China, India, Mexico, European Union members, and others—accountable.”

Trump once claimed that global warming was a lie made up by China, and recently chose Scott Pruitt, a noted climate-change denier with close ties to the fossil-fuel industry, as the new head of the Environmental Protection Agency.

Obama has been busy at the keyboard: On Jan. 5 he published an article on how presidents can influence criminal justice system in Harvard Law Review and on Jan. 6 the New England Journal of Medicine published an Obama-penned piece defending the Affordable Care Act. The outgoing US president has actually been a prolific journal author: between 2006 and 2016, he published 12 articles in peer-reviewed science journals, according to the US National Library of Medicine. But the new green energy article is the first thing that a US president has ever had published in Science, according to Gizmodo science editor Maddie Stone.

While Obama was busy writing, president-elect Trump was busy tweeting: