Clean Air Act

The Clean Air Act is arguably the most successful and cost-effective environmental law in history. It is already a mature and flexible instrument designed to integrate the work of all economic sectors and all levels of government. Honed in three stages of effort – the original lawmaking, and two rounds of amendments – it is a functioning national regulatory structure that spans decades of deliberation, compromise and practice.

The law's applicability to greenhouse gases was confirmed in April 2007 by the Supreme Court’s groundbreaking decision in a landmark case known as Massachusetts v Environmental Protection Agency. The high court essentially said the United States currently has a law for regulating carbon dioxide called the Clean Air Act, and unless the EPA can overturn established climate science, it must apply the law. The Bush administration ignored the ruling.

Under new EPA Administrator Lisa Jackson's leadership, with the support of White House climate policymaker Carol Browner – herself a former EPA chief – we're already seeing action.

Less than three weeks into the Obama administration, Jackson's office dropped a Bush-era appeal of a ruling on the exempting of coal-fired power plants from mercury emissions limits, and it vowed to act quickly on Massachusetts v. EPA.

Jackson also started the 60-day process toward granting of a long-contested waiver to California to allow the standard-setting state to set more stringent auto emissions rules. Seventeen states have said they would follow California's lead, effectively ratcheting up the pace at which automakers will have to deliver vehicles with greater fuel economy.