A future non pigovian tax: Denmark government wants to tax meat

http://www.independent.co.uk/news/world/europe/denmark-ethics-council-calls-for-tax-on-red-meat-to-fight-ethical-problem-of-climate-change-a7003061.html#gallery

What is the negative externality?
What is the cost of this externality if it exists?
How the government will tax other businesses which are involved in this supposed externality in the same time?

https://mises.org/blog/global-warming-activists-want-make-food-more-expensive

As a meat eater I have to disclose a conflict of interest but as an exclusive grass-fed meat eater (from Cerdagne in Pyrenean mountains) I think that I will receive a check for the positive externality...

http://www.nytimes.com/2013/01/13/magazine/should-we-tax-people-for-being-annoying.html?smid=pl-share