Take a look at the Paris Climate Accord, like the UN it's a toothless tiger and a joke. Having the CPC agree to sit at the table accomplishes 2 things 1) takes away an arrow in the lieberals 2) always good to have someone in the enemy's camp.
Canada has failed to meet all it's promises and deadlines under the lieberals, so by going after the CPC( if government) for failure to meet objective will open them up to criticism.
Greenies have shown they are more interested in perception( being on committees etc) rather than results otherwise were is the outcry on our failure to meet the numbers?