MINNEAPOLIS (AP) _ A Minnesota judge has taken the unusual step of allowing
four protesters to use a ``necessity defense,'' enabling them to present evidence that the threat of climate change from Canadian tar sands crude justified their attempt to shut down two Enbridge Energy pipelines last year.

Emily Johnston and Annette Klapstein acknowledge they turned the shut-off valves on two pipelines in Minnesota as part of a coordinated action against five pipelines in northern states. A total of 11 activists were charged.

Johnston and Klapstein, of the Seattle area, say that as far as their team knows, this is the first time a judge has allowed a full necessity defense on a climate change issue. They're due to go on trial Dec. 11. Two co-defendants who filmed them will stand trial later.