Months of hard work paid off for climate justice activists on Monday when hundreds of Massachusetts millennials rallied at the Statehouse and earned an upcoming meeting with Gov. Deval Patrick. Braving freezing rain and hail, they converged on Boston from throughout the commonwealth — walking out of their classes and taking time away from their professions — to implore the governor to “be our climate champion” and “stop building new fossil fuel infrastructure.”

At their forthcoming meeting with Patrick, representatives intend to stress the urgency of placing a moratorium on all new construction of fossil fuel power plants, pipelines, extraction sites, and import and export terminals before the governor leaves office next year. As one walkout coordinator explained in a Harvard Crimson op-ed, “Essay due dates are not the most important deadlines we face.”

Activists contend that the state could compensate for lost energy output through a combination of energy efficiency measures, conservation and new renewable energy projects. The policy details of this proposition are articulated in a recent white paper that — according to a source within the Statehouse — Patrick considered “thoughtful.”

While ostensibly a radical request, these young activists noted their demand is commensurate with the conclusions of the world’s most respected energy authority, the International Energy Agency. In its 2011 World Energy Outlook report, the IEA — known for its conservative findings — warned that nations must reject new carbon-fueled electricity plants by 2017 or risk “locking in” catastrophic levels of warming. Since fossil-fueled infrastructure requires decades to repay its large capital costs, power stations built in 2016 will continue to emit unsustainable levels of carbon until at least 2046. The IEA contends that the accumulated effects of these infrastructure projects amount to the most significant driver of climate change.

In an open letter to the governor, youth climate organizers made their position on this matter clear, stating, “Your legacy is our future because the energy choices that you make determine the future that our generation will inherit. You should not make these decisions without us.”

Coordinating their efforts through the growing climate justice network, Students for a Just and Stable Future, or SJSF, have been organizing since last November to garner Patrick’s attention. Many of the young activists believe he is in an unparalleled position to take decisive action on mitigating climate change. With the authority vested in him by the state’s Global Warming Solutions Act — considered by many to be the nation’s most comprehensive climate legislation — activists assert that the governor can become a global climate champion.

Signed into law by Patrick in 2008, the Global Warming Solutions Act mandates a 20 percent reduction (compared to 1990 levels) in carbon emissions by 2020 and a full 80 percent reduction by 2050. The law gives the governor the authority to enact regulatory emissions standards for power plants and supercharge renewable energy and efficiency investments — effectively banning future fossil fuel infrastructure. Unlike easily overturned executive orders, these new regulations would endure beyond Patrick’s tenure.

The commonwealth’s own Clean Energy and Climate panel found that in order to meet mid-century reduction goals, the electricity grid must be powered by 100 percent renewable energy sources. If new natural gas plants are approved in the next few years, they risk violating this law, or stranding millions in capital investments to shutter the plants before their natural demise.

For many, like SJSF organizer and Harvard history major Alli Welton, Patrick represents the last best hope for timely climate action.

“Where else in the world are we going to find a state willing to support this step, with a governor guided by foresight and a strong moral compass?” she said. “The time has to be now, the place is Massachusetts, and the man — I hope — is Deval Patrick.”

Drawing a firm line against new fossil fuel infrastructure not only aligns with the IEA’s conclusions and Massachusetts law, it also — according to Welton — represents a “viral” idea that has the power to shift mainstream thinking. Since the narratives surrounding carbon taxes and cap-and-trade policies have been compromised by the fossil fuel industry, a new solution is required.

“Not only is the ban a step commensurate with the climate crisis, it’s also common sense,” she said. “That idea has the ability to completely change the discourse and to refocus the conversation on the future and what we build instead of fossil fuels.”

Similar to the logic of the divestment movement, which is the mainstay of SJSF’s campus activism, banning new carbon-based infrastructure would deal a blow to the political capital and social license of the fossil fuel industry. Since solar and wind power are on the cusp of undercutting the price of fossil fuel, a ban enacted by the governor could help turn the tide against fossil fuels once and for all.

Yet, while Patrick may seem like a clear ally to young climate justice activists like Welton, it’s possible the governor is already content with his favorable record on renewable energy and may refuse to take bolder action. David Cash, a key energy advisor to Patrick and the architect of the commonwealth’s renewable energy transformation, has touted the administration’s efforts to make Massachusetts “number one in the country in energy efficiency while saving customers billions of dollars.”

On Monday, renowned climate activist and Harvard Divinity student Tim DeChristopher climbed the Statehouse steps and rebuffed any notion that Massachusetts’ advances were sufficient. Rather than compare their efforts to other failing states and politicians, DeChristopher said leaders like Patrick should look instead to a far more important benchmark: “the severity of the climate crisis.”

Over the past few years climate justice activists across New England have been doing just that, promising to “rise faster than the seas.” Last summer, massive protests and civil disobedience actions worked in combination with rising coal prices to ensure the closure of the state’s largest coal plant by 2017. Then, last month, over 400 rallied for Gov. Patrick to block a proposed natural gas plant in Salem that will almost certainly process fracked gas.

As the largest generation in American history and those most affected by an unstable climate, millennials constitute a growing force in these demonstrations. And perhaps that shouldn’t be surprising, since those born after April 1985 have never lived through a month when the global average surface temperature was colder than average.

Despite the sense that they have an ally in the Statehouse, these young climate activists are not planning to sacrifice their agency to the blind hope that the governor will make the right choice — let alone follow through on it. Many believe they made this very mistake with President Obama after his first election. With a network of thousands of millennials growing every day, organizers are in the midst of developing escalation strategies in case Patrick fails to take the necessary action.

Ultimately, though, millennials like Welton fiercely want a climate visionary to rally behind.

“I genuinely believe in him,” she said following Monday’s action. “He has the power to steer an entire nation, and this is an opportunity that we can seize together.”