The graph uses data that has been made publicly available by the Carbon Dioxide Information Analysis Center - the Center's policy on data usage can be found here: https://cdiac.ess-dive.lbl.gov/permission.html
Original data citation: Boden, T., Marland, G. and Andres, B. (September 4, 2011). "CO2 Emissions from North Korea (Democratic People's Republic of Korea)". Carbon Dioxide Information Analysis Center. doi:10.3334/CDIAC/00001_V2011