Yesterday’s State of the Union address could go down as a watershed moment in America’s transition to a clean energy economy. Two years ago, the president wouldn’t mention climate change. Last night, he spoke honestly about the issue to 40 million people and vowed that if “Congress won’t act soon to protect future generations, I will.” The question is: Just what can President Obama do, and what will it mean for our economy and energy system?

Recent experience provides some clues. Even without a Congressional climate bill, the United States has doubled renewable electricity production over the past four years, and reduced carbon emissions to a 20-year low, even as the economy has rebounded from the worst recession since the Great Depression. We’ve also built substantial new energy industries. Solar power alone now accounts for 119,000 American jobs, spread across 5,600 companies in all 50 states. Economy-wide, there are some 2.7 million green jobs, and green job sectors are growing faster than other parts of the economy. 

And so we come back to the present moment. Obama has again called on Congress to pass a big cap-and-trade bill, but also knows that he will be more successful in producing change through a variety of smaller initiatives. 

What would these executive actions look like? Perhaps the administration working through the EPA to tighten regulations on greenhouse gases—a major move that would put a substantial dent in the coal-fired power system. Maybe Obama using his convening powers to bring together a high-level commission on climate change and energy, so that we could shift from a debate about whether climate change is real to a debate about all the ways we can solve the problem. Or the president could slow the pace of fossil fuel development by taking a stand on a big project like the Keystone XL. 

So, let’s take Obama up on his promise of action. Let’s use our money and let’s use our feet. We need to weaken fossil fuel interests through divestment campaigns like that being organized by 350.org and invest in renewable energy through platforms like Mosaic. We also need to turn out. This Sunday, Washington D.C. will host what will likely be the largest climate rally in U.S. history, with a specific goal of stopping the Keystone XL pipeline. It’s a great moment to let Obama know: If he’s ready to take on Congress, or the fossil fuel industry, or both, we’ve got his back.