06/26/2013 11:14 am ET Updated Aug 26, 2013

A Pivotal Moment in the Fight Against Global Warming

"These drought conditions have reached historic levels and continue to pose an imminent threat to public health, property and the economy," said Texas Gov. Rick Perry after three years of drought in his state.

And the dire situation in Texas is, unfortunately not an anomaly. Global warming is the biggest environmental threat we've ever faced and it won't be solved with one policy or one speech. But I'd wager that when the world looks back on how the U.S. stepped up to do our part to solve the problem, this week will prove to have been a defining moment. President Obama unveiled his plan to tackle global warming at Georgetown University on Tuesday, and it was one for the history books.

Per capita, the U.S. is the largest producer of global warming pollution in the world. If we can meaningfully address our pollution, the planet will stand a much better chance of averting the worst impacts of climate change. Thankfully, after a grueling year in which record-breaking temperatures, drought, wildfires and severe storms have punished Americans, President Obama showed real leadership by confronting our nation's largest contributor to global warming: dirty power plants.

Of course, we have been building toward this moment for years.

State and regional caps on global warming pollution adopted by California, Hawaii, Maryland, Massachusetts, New Jersey and Connecticut, and the Northeast Regional Greenhouse Gas Initiative have been at work. By 2020, they will have reduced climate-altering pollution by as much as taking 56 million passenger vehicles off the road for a year.

States' policies have also paved the way in producing the clean renewable energy we'll need to replace high carbon and other dangerous energy sources. Twenty nine states have adopted Renewable Electricity Standards, requiring increased production of energy from renewable sources. And the results have been remarkable. Across America, solar energy almost doubled in 2012, with East Coast states like Massachusetts, New Jersey and Maryland joining Arizona and California as national leaders in the industry. Wind power has more than doubled in the last four years and today wind offsets as much carbon pollution as taking 14 million cars of the road.

President Obama's doubling of the nation's fuel-efficiency standards for vehicles last summer was the culmination of more than a decade of work by states to increase their own fuel efficiency standards, setting the stage for federal action. State-level work to improve fuel-efficiency has already yielded carbon reductions that would be the equivalent of simply taking 6.5 million cars off the road.

And many states have put programs in place to reduce carbon pollution through utilities, energy efficiency, building codes and appliance standards. Altogether, by 2020, state-initiated programs will have reduced climate altering pollution by as much as retiring 170 coal-fired power plants every year.

Yet, for all this progress, the International Energy Agency reported recently, that carbon pollution levels continue to head in the wrong direction. Twelve of the last 15 years were the hottest on record, bringing dangerous heat waves, and fueling damaging storms.

To get the full job done, it has always been clear that addressing global warming would require presidential leadership -- the president's announcement this week finally puts America on the path to protecting future generations from a trajectory of more unhealthy air days and worse extreme weather.

In addition to limiting carbon pollution from power plants, the president's plan directs his agencies to advance the production and use of clean, renewable energy like wind and solar and to enforce better standards for buildings and appliance efficiency.

President Obama has charted the right course, but it will take vigilance to ensure that we reach our destination. We can expect that polluters will find ways to attack the president's plan through the courts and likely they will encourage their congressional allies to do all they can to block, delay or weaken progress. Even before details of the plan were available, just the mere announcement that the president was moving forward to tackle global warming prompted Speaker Boehner to say "this is absolutely crazy."

But the vast majority of people across the country know that the very rational thing to do given the scientific evidence of climate change is to control the largest sources of the pollution that is already affecting their families, their communities and the planet. I am confident that over the weeks and months ahead Americans will stand with President Obama -- just as more than 3.2 million Americans did when he proposed standards to limit carbon pollution from new power plants -- because we know the health and well-being of future generations are at stake.

The road ahead will surely have twists and turns. No one speech, no single plan will be enough to get us to the 100 percent clean, renewable energy future we need. But standing together with President Obama's leadership and that of community and state leaders across the nation, we will leave behind a safer, healthier environment for our families and for their families. Doing our part to combat global warming will create a legacy of which we all can be proud.