Local authorities will have to consider international climate change when granting resource consents if an environment group gets its way.
The West Coast Environment Network's lawyer Davey Salmon said the consequences of burning West Coast coal was relevant to whether to grant resource consents to mine coal.
West Coast Regional Council and Buller District Council appointed independent commissioners who granted consents for Buller Coal to open cast mine at the Escarpment Mine on the Denniston Plateau.
Environment groups West Coast ENT and Royal Forest and Bird Protection Society appealed against the decision on the grounds that the commissioners were wrong to not consider the effects the Escarpment mine would have on climate change.
It is intended the coal will be sold to steel manufacturers in India and China.
Then Solid Energy applied for consents for mining in the Mt William North area intending the coal to be exported to steel manufacturers in India, China, Japan, Brazil and South Africa.
Salmon said the select committee that considered 2004 changes to the Resource Management Act chose not to limit climate change considerations to effects in New Zealand.
It would be striking if major climate change effects were not taken into account, he said.
"One would expect clear language to take away the biggest environment hit of our time," Salmon said.
Councils have to grapple with the effects on and of climate change, not just emissions but also to plan for the effects of climate change on conditions such as rising water levels.
The Supreme Court hearing in Wellington is expected to end tomorrow.