Evaluating Environmental Claims on Biodegradables

In a recent study published in a leading environmental journal, researchers concluded that the use of biodegradable plastics significantly reduces plastic pollution in oceans compared to traditional plastics. They cited various instances where biodegradable alternatives have effectively broken down over time, leading to lower levels of microplastics in marine environments. However, critics argue that the production of biodegradable plastics still contributes to greenhouse gas emissions, which may counteract their environmental benefits.

Based on the argument presented, which of the following pieces of information would be most necessary to evaluate the researchers' conclusion?