Since the Winter 2010 edition of The Climate Report reported the first Petition for Review challenging U.S. EPA's finding that greenhouse gases endanger public health and welfare, 16 additional Petitions were filed on behalf of a wide variety of entities and individuals, including the states of Virginia, Alabama, and Texas; 12 members of the House of Representatives; and businesses involved in the coal, steel, agriculture, mining, manufacturing, and other industries.

In addition, 14 states (Nebraska, Florida, Hawaii, Indiana, Kentucky, Louisiana, Mississippi, North Dakota, Oklahoma, South Carolina, South Dakota, Utah, Michigan, and Alaska) have moved for leave to intervene in support of those challenging EPA's action. These states argue that the greenhouse gas regulations triggered by the endangerment finding will, in turn, trigger millions of new permit applications, resulting in massive administrative burdens on state permitting authorities. The states also argue that limits on greenhouse gas emissions will create complex regulatory requirements that will discourage new business projects, thus hurting the economy.

Conversely, 18 states (Massachusetts, Arizona, California, Connecticut, Delaware, Iowa, Illinois, Maine, Maryland, New Hampshire, New Mexico, New York, Oregon, Rhode Island, Vermont, Washington, Pennsylvania, and Minnesota) have moved to intervene in support of EPA. These states argue they have an interest in the litigation, because impacts from unchecked climate change could cause many adverse effects to their property interests, including sea level rises that would damage coastal properties, damage to hardwood trees, decreased tourism, stress to fisheries, decreased crop yields, and increased respiratory and other health problems from ozone and particulate pollution.

The U.S. Court of Appeals for the D.C. Circuit has consolidated all of the Petitions into a single action, with procedural motions due by April 15, 2010, and dispositive motions due by April 29, 2010. In the meantime, companion resolutions have been introduced in the House of Representatives and the Senate to achieve the same result via the Congressional Review Act.