Heather Zichal, the top White House adviser on energy and climate, has resigned her post, the White House announced on Friday. Zichal "crafted my energy and climate change agenda in the 2008 campaign, then again on my presidential transition and as my top energy and climate adviser at the White House," President Barack Obama said in a statement. Zichal "has been a strong and steady voice for policies that reduce America's dependence on foreign oil, protect public health and our environment, and combat the threat of global climate change," Obama said. She oversaw "some of our biggest achievements in energy and climate change, including establishing historic new fuel-economy standards that save consumers money, reducing mercury pollution from power plants to keep our kids safe, supporting the growth of homegrown clean energy that creates good new jobs, and enacting my Climate Action Plan that will help us leave a safer planet for our children," the President said. "Above all, Heather's efforts have proven that strengthening America's energy security does not have to be a choice between economic growth or good environmental stewardship; it can mean both," he said.