It hard to see this as anything other than a bad faith comparison.

1. It compares trans-oceanic LNG vs. US domestic coal
2. It makes a lot of assumptions about inefficient and leaky extraction, processing, and transport approaches
3. It only considers CO2 and methane ignoring other ways that LNG is far cleaner than coal

It is important to consider the entire life cycle of LNG, but a more even-handed author would conclude we should address these inefficiencies (e.g. via regulation), rather than fixating on promoting coal.

Direct link to paper: https://scijournals.onlinelibrary.wiley.com/doi/10.1002/ese3.1934