When we talk about why the planet is warming, we talk about fossil fuels — oil, gas, coal and their many variants. What we rarely say or think to say, though, is that’s not the whole story.

The fact is that plants take in carbon dioxide in the process of photosynthesis, and release it again when they die. So if you clear large swaths of land, so that it does not contain as many trees, crops, or grasses as before, then you are also contributing to global warming. The same goes for other agriculture related emissions, ranging from nitrous oxide emissions from the use of fertilizers to methane emissions from “enteric fermentation” in cattle (those infamous  “cow farts” — although really, it’s mainly cow burps).

No wonder there have been complaints over the years about U.S. agriculture “getting a pass,” or land-use changes being “largely ignored,” when it comes to greenhouse gas emissions and climate policy. It’s in this context that a new move by the Department of Agriculture to slash the sector’s emissions markedly by the year 2025 — and to do so simply through voluntary measures  — is so significant.

“It’s roughly the amount of emissions that would be generated from the energy use of 11 million homes on an annual basis,” said Agriculture Secretary Tom Vilsack, who is slated to unveil the plans at Michigan State University on Thursday.

The expected reductions would come from curtailing agricultural emissions, increasing the ability of lands to store or sequester carbon, and also increasing renewable energy use in rural areas and energy efficiency in farming. If achieved, the net effect would help the United States reach its intended goal of slashing total emissions by 26 to 28 percent below 2005 levels by the year 2025, a target announced in the fall in a historic agreement with China.

The new policy will include 10 “building blocks” which the Agriculture Department says will cut more than 120 million metric tons of carbon dioxide equivalent annually by 2025. The broad suite of policies includes targeting livestock related emissions — by increasing anaerobic digestion, making sure there are roofs to contain some methane emissions, and also changing grazing habits so as to preserve more carbon in soils — the reforestation of fire or pest-damaged areas, and much more.

Most intriguing, perhaps, is a program to use damaged trees from those same kinds of disasters to construct buildings, thereby storing the wood’s carbon (which would otherwise be released back into the atmosphere when the tree decomposes).

“We’re basically treating them, putting them into a building,” said Vilsack. “That will restore and retain that carbon storage, but also, as a building material, has less emissions than cement or steel.”

The Agriculture Department also said it is using the federal crop insurance program to bring about emissions reductions, since farmers have to fill out several forms about conservation practices to be able to receive such insurance, and that it will work to increase renewable energy and energy efficiency on farms and in rural areas.