I'd ask you to cite something that demonstrates evidence for that claim but you'll just post a link to a website funded by the plastics industry.

For example - "Paper bags have a much higher global warming potential (GWP)." (http://www.allaboutbags.ca/papervplastic.html) but when you scroll to the bottom of the page you see "Content compiled by the Canadian Plastics Industry Association.".

Paper bags are not 250 times worse.