This generalization is a problem. Assessing the whole life cycle, the carbon footprint of glass bottles is problematic and plastics is a viable alternative.
You have to consider the significantly higher weight of glass increasing carbon emissions from transportation.
While plastics bottles can only be reused about half as often as glass bottles, their production is far more energy-efficient (glass production is done at temps of 1400-1600 °C or 2500-3000 °F while plastics use temperatures from 160-300 °C or 320-600 °F) which also reduces carbon footprint in basically every country.
Of course recycling has to be taken seriously and properly organized to prevent plastics just ending up in nature. But we have to balance the micro-plastics problem against climate change. We need to solve both.