Agence France-Presse: Three major US companies said Tuesday they were leaving a coalition pushing for action on climate change, dealing a potential fresh blow to landmark legislation to cut carbon emissions. The companies — oil groups ConocoPhillips and BP America and equipment maker Caterpillar Inc. — said they backed efforts for a green economy but felt that proposed laws were unfair to them. The firms said they would not renew membership in the US Climate Action Partnership (USCAP), a coalition …