A slew of states and electricity companies are committing to aggressive targets to reduce greenhouse gas emissions in a trend underway since President Trump took office.

Expand chart Data: Clean Air Task Force; Chart: Chris Canipe/Axios

Why it matters: These actions show that substantive efforts — not just rhetoric — are underway across America in the face of Trump's rollback of climate policy at the federal level.

Between the lines: The actions over the past year signal a subtle, but significant shift away from policies promoting just renewable energy — like wind and solar — toward those that target emissions reductions no matter the technology. This brings into consideration other non-renewable but still clean-burning technologies like nuclear power.

“We’re now focusing on what actually matters, which is the atmosphere, and not the technology pathway, which people have been focused on.”

— Armond Cohen, executive director, Clean Air Task Force

By the numbers:

Since last fall, 5 states have enacted standards mandating 100% carbon-free electricity within the coming decades, according to new data compiled by Clean Air Task Force, an environmental group.

4 additional states are actively debating similar measures.

More than 20 utilities have committed to carbon reductions of at least 80%, most of which have come since Trump was elected.

Added up, these moves represent nearly 40% of U.S. electricity sales and almost a third of national utility carbon dioxide emissions.

But, but, but: These policies only target the electricity sector, which emits the second-most greenhouse gas emissions in the U.S., after transportation. Carbon emissions in the electricity sector also went back up in 2018, after a few years of declining.

What to watch: Sen. Tina Smith (D-Minn.) is poised to introduce a clean electricity standard as soon as Wednesday, according to multiple sources tracking the policy. A spokesperson for her office says the senator is "still hoping to introduce [the bill] soon."

Under the bill, America's electricity could reach around 90% carbon-free by 2050, according to multiple sources familiar with the proposal. Right now, the breakdown is more than 60% coal and natural gas.

No Republicans are expected to sign on, at least initially.

Go deeper: Renewable energy mandates have not sparked that much new renewable energy