Climate Change Bill [HL]

My noble friend referred to the fact that the Committee on Climate Change would consider all the international evidence on the difference between 60 per cent and 80 per cent. Paragraph 45 of the report of the Joint Committee states: "““Bearing in mind however the weight of scientific evidence before the Committee that a target of more than 60% is likely to be necessary””." To what extent was evidence before the Joint Committee which suggests that the 80 per cent target might be necessary? Has that already been considered in the departments? It would be interesting to know that before the debate on the 60/80 issue.