This weekend, Hillary Clinton reportedly will announce her candidacy for president. In doing so, she will be the only legitimate contender for the White House—declared or presumptive—who embraces the scientific reality of climate change.

Clinton could coast through the primary with an environmental platform that rests entirely on this fact and remain vague on her plans for climate action. But she would be blowing a tremendous opportunity.

Environmentalists aren't sure where Clinton stands these days, though she did work to boost her climate credentials in two high-profile speeches months before the official launch of her campaign. At September's National Clean Energy Summit in Las Vegas, Clinton called climate change “the most consequential, urgent, sweeping collection of challenges we face as a nation and a world.” And two months later, in a speech to the League of Conservation Voters, she said, “The science of climate change is unforgiving, no matter what the deniers may say, sea levels are rising, ice caps are melting, storms, droughts and wildfires are wreaking havoc.”

But those speeches only signal that she's not, say, Ted Cruz. Little is known about her specific policies on the environment. She’s never tweeted about climate change, and she’s steered clear of debates over the Keystone XL pipeline. “You won't get me to talk about Keystone because I have steadily made clear that I'm not going to express an opinion,” Clinton said in Canada the same week the Senate debated a Keystone bill. So far, the most promising sign that her campaign will be aggressive on the environment is her hiring former White House senior adviser John Podesta, who led the Obama administration's recent strategy on climate.

Friends of the Earth President Erich Pica hopes Clinton uses her high profile to elevate the climate debate in America, much like President Barack Obama has.

“I think the real difficulty is whether or not it’s a proactive debate where Clinton is proactively pushing her vision and what it means for the United States and globe if she will be responding in a defensive manner to Obama’s climate plan,” Pica said. “She should model what the president is doing right now. He has the bully pulpit of the presidency and he is trying to steer proactively the climate debate.” 

Some environmentalists worry she will dodge difficult policy issues, including methane emissions from fracking, leasing public lands to energy companies, and offshore drilling.

“The question isn’t whether or not Hillary Clinton’s talking points are better than those of Ted Cruz, or if she’ll say nice things about renewable energy,” 350 Action spokesman Karthik Ganapathy said. “Rising above climate denial isn’t the bar here; the real question is how her policies stack up against the science, and whether or not they’ll actually keep fossil fuels in the ground to avert the worst impacts of global warming.” 

Realistically, Clinton will get support from national green groups regardless of what she does. She'll support clean energy and Obama's major climate policies. That's good enough for most supporters.

A few groups, like Friends of the Earth and, have called out the Clinton Foundation's ties to the oil and gas industry and criticized her past comments about Keystone. In 2010, Clinton hinted she was “inclined” to approve the Keystone pipeline when she was secretary of state. She also aggressively promoted natural gas as “the cleanest fossil fuel available” and hired a former oil industry representative to push the fossil fuel abroad. Environmentalists want to see Clinton temper her support for fracking by acknowledging its problems—that it leaks greenhouse gas emissions, causes minor earthquakes, and contaminates groundwater. 

Taking specific stances on environmental issues carries its own risk, but there might be a bigger payoff. After all, Clinton will have to energize the Democratic base in order to win her general-election campaign. “Presidential candidates who propose to aggressively invest in clean energy jobs and reduce climate pollution would enhance their appeal to young and Latino voters, as well as other groups,” LCV Senior Vice President for Campaigns Dan Weiss said. It could even help in swing states. “Iowa farmers, for instance, strongly support investments in wind energy. Small business owners in southern Florida would benefit from such policies that reduce the potential of floods from sea level rise,” he said. 

For too long, Democratic candidates have been content to mock Republican climate-deniers while proudly proclaiming their belief in the science of climate change. In 2016, that will no longer suffice. Obama's recent controversial executive actions ensure that climate change will be an election issue. If an international deal to cut emissions is successful by the end of 2015, then the ensuing debate could dominate the early primaries in 2016. Clinton will have to answer questions about where she stands. She shouldn't wait until then to give us her answer.