On Monday, President Obama’s inauguration will officially mark the beginning of his second term, and with it his second chance at finally taking strong action on one of the most important issues of our time, climate change.

Two months ago, on the night of his re-election and in front of an audience hopeful to move forward on so many issues, the president brought climate change back to the forefront of the nation’s mind by listing it as a top priority for his second term. Now, President Obama must go beyond the mere mention of the issue and use his bully pulpit to make the connection between carbon pollution and extreme weather. Just as Franklin Delano Roosevelt used his first inaugural address to declare war on the Great Depression, Obama must use his own confirmation to declare war on another societal ill that threatens to destroy life as we know it.

Of course, the president’s rhetoric will mean nothing if it is not backed by concrete actions in the next four years. And the time for action couldn’t be more urgent.

Scientists have officially deemed 2012 the hottest year on record in the U.S. And a newly released report known as the National Climate Assessment says that the climate is only going to get worse, with increasing risks of asthma, widespread power blackouts, pest outbreaks, record high temperatures and possibly even food shortages.

Meanwhile, the dirty energy industry continues to lead Congress by the nose.

As a result, President Obama has no choice but to step ahead of the fray and march past special interests and their friends in Congress. He must lead a path to a clean energy future by building upon his previous accomplishments such as historic vehicle standards that will cut carbon emissions and double the fuel efficiency of today’s vehicles by 2025.

To start, Obama should use his executive authority and the power of the Clean Air Act to set standards that will cut carbon pollution from America’s aging power plant fleet by at least 25 percent by 2020. These new standards will finally address our nation’s largest source of carbon pollution while creating tens of thousands of clean energy jobs. In addition, the president should also reject dirty fuels like tar sands oil, which leading scientists agree must be kept in the ground if we want to avoid the most catastrophic aspects of a warmer world.

Though he must lead the charge, President Obama need not walk alone in tackling this issue. The resignation of EPA Administrator Lisa Jackson will leave a void that can be filled by another leader who’s eager to continue using our nation’s environmental laws to slash carbon emissions. Vacancies in the Interior Department and elsewhere may also present opportunities for appointing strong leaders on climate change. In addition to his inner circle, President Obama is backed by a majority of the public who believe climate change is real, humans are the cause and cleaner energy is needed.

Earthjustice, together with more than 70 environmental, civic, health and labor groups, recently pledged to work with Obama every step of the way in tackling the climate crisis and securing a healthy future, so long as he does lead. Leading the charge will not only save the world from catastrophic climate change; it will also reestablish America’s credibility among world leaders who still look to the United States for guidance and direction on this issue.

On the night he was re-elected, President Obama told supporters that “we want our children to live in an America…that isn’t threatened by the destructive power of a warming planet.” At the time, the nod to climate change was a hopeful indicator that this issue would finally be taken seriously.

But merely acknowledging the issue is no longer enough. Leaders don’t talk. They do. And if Obama leads the nation on climate change, he will need the support and involvement of everyone who cares about the fate of humanity to stop climate change before it’s too late. It is by those actions that future generations will use to judge the President’s leadership in a time of climate crisis.