Energy companies could be on the hook for billions in damages.
Deal, to close in Q2 2015, is valued at $13 billion.
Growing body of research is increasingly able to estimate the costs that rising greenhouse gases impose.
Analysts expect lower earnings from Encana, Talisman as both companies concentrate their operations.
Energy producer has re-focused its portfolio on the Americas and Southeast Asia.
Low natural gas prices force oil and gas producer to cut costs by 20%.
Energy firm could bring in partner to help develop the resource.
Oil and gas producer exits high-risk exploration areas and find ways to cut costs.
May depress the value of some Canadian firms, but only moderately.