SmogMillions of Americans are breathing easier these days as we announce that the Sierra Club Beyond Coal campaign has crossed the halfway mark toward meeting our goal of securing the retirement of a third of the nations coal-fired power.

It’s only been a year and a half since Bloomberg Philanthropies gave a $50 million grant to the Sierra Club to support the efforts of the Beyond Coal campaign. As part of this partnership, the Sierra Club set the ambitious goal of winning commitments to retire 105,000 megawatts of coal — about one-third of U.S. coal plants — by 2015.

These coal plants are the nation’s number one source of the carbon pollution that is disrupting our climate, the sulfur pollution that causes heart attacks and premature death, and the mercury pollution that harms babies in the womb.

Today, thanks to the hard work of millions of people and dozens of partner organizations, our children, our grandparents, our friends, our neighbors, and so many others are enjoying cleaner air and water, and U.S. carbon emissions are at a two-decade low. Earlier this week, we announced the three coal retirements by American Electric Power that put us across this halfway mark.

I can’t thank our supporters, allies, and volunteers enough for their tireless work in helping us reach this goal. The Sierra Club Beyond Coal campaign is one of the most successful environmental campaigns in U.S. history. The campaign employs more than 175 staff around the country. Our staff and volunteers average more than one local action every day — spanning from huge turnout at public utility commission hearings, to legal actions, to rallies, and more.

We are joined in this work by allied organizations large and small, from coast to coast — I like to think of it as a grassroots, open-source effort that is winning big victories for our health and the planet. Together, our work averaged one coal plant retirement a week in 2012.

Let’s look at this milestone by the numbers:

2,011 -The megawatts of coal retired by AEP that put us at the halfway mark last week.

12 million – The tons of climate-disrupting pollution those three AEP plants will no longer emit.

84,000 – The tons of sulfur-dioxide pollution those three AEP plants will no longer emit.

142 – The number of coal plant retirements the Beyond Coal campaign and its allies have secured.

66,000 – The megawatts of solar and wind power online today, enough to power 13 million homes. That number is increasing every day: In January 2013, every single megawatt of new installed electric capacity was from renewable sources.

According to the Clean Air Task Force, the 54,000 megawatts of coal that the Beyond Coal campaign and its allies have helped retire so far has resulted in these numbers:

3,900 lives saved.

6,000 heart attacks avoided

$1.8 billion in health costs saved.

206 million metric tons of climate-disrupting carbon pollution prevented from being dumped into our air every year — the equivalent of removing 43 million cars from our road.

Our work is not yet done, of course. We must continue working to retire the remaining coal plants, invest in clean energy, and ensure strong transition programs for those workers and communities affected by coal plant retirements.

I write today with a deep commitment to carry that work forward, knowing that city by city and state by state, Americas will continue coming together to move beyond coal, to clean energy. The health, safety, and prosperity of our kids and families depend on it.