Here is an example of how he uses "science" to further his cause:
He writes: "Because we eat so much meat, the UK’s diet requires nearly 24 million hectares of land", citing
Henri Ruiter et al (2017) in support of this statement. He seems to have somehow neglected to discuss the results section of this study, which states:
"Our results show that UK ruminant meat (i.e. mutton and beef) supply has decreased over the study period, while the supply of other animal products has increased, particularly for pig meat and poultry meat (see Table 5). On a per-capita basis, supply for all animal products, except pig meat and poultry meat, decreased, with decreases in per-capita ruminant meat consumption of more than 20%. The share of domestic production in the total UK supply has decreased for all animal products, except for mutton where the domestic share increased slightly from 69% in 1987 to 72% in 2010"
and:
"In 1987, an average kilogram of beef supplied to the UK required 64 m2 of grassland. In 2010, this value decreased to about 52 m2."
and:
"the total land footprint of UK food supply has decreased slightly over recent decades, mainly as a result of a lower grassland footprint"
In their discussion, they state:
"many grasslands are not suitable for crop production and livestock production on grassland does not always compete with food for human consumption (Schader et al. 2015), and may be a good option, especially if grasslands are used for milk production (Wilkinson 2011). Moreover, converting grasslands to cropland, if at all possible, may have negative consequences for greenhouse gas emissions in the short term, because grasslands generally store more carbon than croplands (Smith 2014)."
The authors then go on to state:
"Strategies aimed at reducing the consumption of meat should consider social and cultural norms and may be different for different types of consumers (de Boer et al. 2014)."
and:
"Moreover, singling out individual food items, such as animal products, to reduce the environmental impact of food, is an oversimplification. Modelling individual diets to reduce greenhouse gas emissions while optimising nutritional outcomes reveals that there are multiple options to achieve this, and that in some cases, increasing meat intake can actually be the best strategy to ensure an acceptable nutritionally balanced diet (Horgan et al. 2016). Therefore, it is important to consider whole diets and to extend our current analysis using a wider range of nutrients."
This sort of thing seems to be going on all over the place.