1. California's Gavin Newsom (D)

Few states embody the climate challenge quite like California.

The Golden State is America's second-largest carbon emitter. It was ravaged by wildfires in 2018, and it's home to one of the country's leading climate hawks, outgoing Gov. Jerry Brown (D).

That means there will be considerable focus on Newsom when he takes office Monday. Newsom, the lieutenant governor and former San Francisco mayor, inherits the country's most ambitious carbon-cutting policies. California has committed to slashing greenhouse gas levels 40 percent of 1990 levels by 2030 and is striving to make its grid carbon free by 2045.

Emissions are trending downward. The latest state data show emissions fell below 1990 levels in 2016. State law requires emissions to meet the 1990 threshold by 2020.

But serious questions abound for Newsom.

Transportation emissions, which account for 40 percent of California's greenhouse gases, have steadily edged upward in recent years. They climbed 2 percent in 2016. That complicates California's path to a 40 percent reduction by 2030.

The governor-elect has said he wants to eliminate pollution from diesel engines by replacing trucks and port equipment with electric or hydrogen fuel alternatives by 2030 (Climatewire, Sept. 26, 2018).

He also expressed some support for the $77 billion high-speed rail project championed by Brown. Newsom told the Los Angeles Times he supports a northern leg of the rail line connecting the Central Valley to the Bay Area, but he raised questions about the southern section of the project.

Another item to watch is whether Newsom will have a heavier hand when it comes to the state's oil and gas industry. Some greens were miffed by Brown's decision to permit new wells in the state, but Newsom has signaled he may be willing to take a stricter approach (Climatewire, Oct. 9, 2018).

Florida's Ron DeSantis (R)

State officials weren't allowed to mutter the phrase "climate change" under outgoing Gov. Rick Scott (R). Whether that changes under DeSantis remains to be seen.

Florida's governor-elect has sought to walk a fine line on climate. He has committed to addressing sea-level rise and cleaning up the state's waterways. But when asked whether he accepts mainstream climate science during one of last fall's debates, he famously quipped: "I don't want to be an alarmist. I want to look at this and do what makes sense for Florida" (Greenwire, Oct. 22, 2018).

The stakes in Florida are considerable.

Sea-level rise is already affecting parts of the coastline, and the state is the country's fourth-largest carbon emitter. Several large coal units retired in 2018, but there are major questions about what replaces them. Solar installations, which languished for years in the Sunshine State, have just started to increase thanks in part to a ballot measure in 2016.

DeSantis said little about renewables on the campaign trail, but he was a vocal opponent of the production tax credit for wind during his time in Congress. The League of Conservation Voters gave him a 2 percent lifetime score.

Illinois' J.B. Pritzker (D)

Pritzker's victory over Gov. Bruce Rauner (R) means Illinois could be in for a sharp turn from its current course.

Rauner isn't from the climate-denying wing of the Republican Party, but he also rarely mentioned the issue during his four years in Springfield. And he did try to relax air quality standards on the state's large coal fleet.

That's not happening now. State regulators recently rejected the idea, and Pritzker is likely to cement the shift away from the black mineral.

An heir to the Hyatt Hotels fortune, Pritzker has said he wants to put the state on track to generate all its power from renewables. He has also cast wind and solar as an economic development solution for southern Illinois, which is home to several large coal mines.

Implementing a 2016 law that provided subsidies to two nuclear power plants and called for a big increase in renewable generation figures to be one of Pritzker's most important tasks.

Why does it matter?

Illinois is America's second-largest coal-consuming state (Climatewire, Oct. 29, 2018). There has long been speculation that Vistra Energy Corp. may move to shutter some of its downstate coal plants, but mining interests are pushing a plan that could help those facilities swap Wyoming-mined coal for Illinois coal (Climatewire, Dec. 21, 2018). The plants burn Wyoming coal to comply with the Clean Air Act.

How Pritzker approaches the situation will help determine the trajectory of Illinois' emissions and its coal sector.

Wyoming's Mark Gordon (R)

Speaking of coal, no state mines more of the stuff than Wyoming.

And the decline of the industry means Gordon will have a lot on his hands when he assumes the governor's office Monday.

Gordon, the state treasurer, hails from his party's moderate wing. He even did a stint as chairman of the Sierra Club's state chapter. But he campaigned as an ardent supporter of the coal industry. Which Gordon shows up in the governor's office is a matter of considerable speculation in Cheyenne.

Several big questions confront Wyoming right away. Chief among them: Will Gordon continue his predecessor's policy of pushing coal exports and carbon capture and sequestration? Both figure to be central to the industry's long-term future. The question is whether they arrive soon enough.

The rapid pace of coal plant retirements has ravaged two large coal mining firms in the state. Westmoreland Coal Co. filed for bankruptcy in October, and Cloud Peak Energy Inc. could soon follow. The company's stock traded for less than a dollar in December.

At the same time, PacifiCorp, Wyoming's largest utility, recently released a report suggesting that many of its coal plants are gasping financially. It suggested moving up the retirement dates of several units in the state (Climatewire, Dec. 5, 2018).

With all the talk of coal, it's easy to forget Wyoming has also played host to a minor oil boom in the Powder River Basin. The state recently tightened its rules governing methane emissions from new wells, but some greens worry it doesn't go far enough (Climatewire, Nov. 30, 2018).

Gordon, in other words, will have plenty to do.

New Mexico's Michelle Lujan Grisham (D)

The sharpest turn on climate this year may be in the Land of Enchantment, where a renewable booster takes over from a fossil fuel ally.

Susana Martinez, the outgoing Republican governor, frustrated greens throughout her tenure in Santa Fe by supporting the oil and gas industry.

Now she's being replaced by Lujan Grisham, a congresswoman who campaigned on a pledge to generate half the state's power from renewables by 2030 (Climatewire, Nov. 7, 2018).

The climate impacts could be considerable. Half of the state's energy-related carbon emissions came from its coal-heavy power sector in 2015, according to the U.S. Energy Information Administration.

But a major shift is underway. State regulators recently approved a plan by the Public Service Company of New Mexico to eliminate coal by 2031. And Lujan Grisham will have solid majorities in the state House and Senate to help her pursue her renewable goals.

Still, that might not be the biggest climate issue in New Mexico, which has witnessed an oil boom in the Permian Basin. The surge in oil production has led to an increase in methane emissions.

Lujan Grisham has committed to curbing emissions from new and old wells, saying methane leaks are not only bad for the atmosphere but are a hit to the state's coffers (Climatewire, Nov. 26, 2018).

Reprinted from Climatewire with permission from E&E News. E&E provides daily coverage of essential energy and environmental news at www.eenews.net.