Super Tuesday means it's the first primaries in the oil patch, so it's a good time to compare Joe Biden and Bernie Sanders, who are battling for frontrunner status in the Democratic primary.

Why it matters: They have important differences on energy and climate policy, although both would restrict development and take a more adversarial posture toward fossil fuel industries than President Trump.

Driving the news: A rapid-fire burst of developments shows why it's increasingly a two-person race, even though Elizabeth Warren and Michael Bloomberg are still competing.

Amy Klobuchar dropped out yesterday and endorsed Biden, while Pete Buttigieg, who quit Sunday, also endorsed the former VP.

More broadly, the party establishment is coalescing around Biden, making him Sanders' main rival heading into today's 14-state showdown.

Where it stands: While their policy similarities and differences are vast, here are some top-line points...

Zoom out and they both have very ambitious (and very hard to reach) goals. Biden calls for achieving net-zero U.S. emissions by 2050 and Sanders wants "complete decarbonization of the economy" by that date.

Both want to impose new restrictions on oil-and-gas development and regulate the industry more, vastly speed up transition to electric cars and renewables, and expand R&D.

Neither emphasize carbon pricing, with Biden backing an as-yet-undefined program and Sanders largely avoiding it too, though his campaign just told Emily Atkin's Heated newsletter that taxing carbon "could be a valuable tool in specific circumstances."

But, but, but: While both would go further than former President Obama (to say nothing of Trump), Sanders goes further left in his proposals, posture and emphasis. He wants...

A complete nationwide ban on fracking, which isn't in Biden's plan.

To end "all new and existing fossil fuel extraction" on federal lands, while Biden wants to end "new oil and gas permitting" on those lands.

To reimpose the ban on crude oil exports and block other fossil fuel exports too. Biden has nodded in the direction of thwarting exports but hasn't included it in his detailed written plan and his campaign declined to answer questions yesterday.

To bring federal lawsuits against fossil fuel producers over climate change (though Biden hasn't ruled it out).

Plus, Sanders' wider Green New Deal plan has a $16 trillion price tag, which is vastly more than Biden wants to spend.

It also has more aggressive targets, including the moon-shot ambition to reach 100% renewables for power and transportation by 2030.

The intrigue: One caveat — and it's a big one! — is that differences between the plans shrink a lot if you consider what has any chance of getting through Congress and the courts.

But it's also true that Sanders has signaled his intent to use executive powers and discretion more aggressively than Biden, so the stakes are high today.

Go deeper: Inside the Bernie economy