Which of the following practices contributes to a larger carbon footprint?

Frequent long-distance air travel contributes significantly to a larger carbon footprint primarily due to the high emissions associated with aviation. Airplanes burn vast amounts of fossil fuel, releasing a substantial quantity of carbon dioxide and other greenhouse gases into the atmosphere. Each flight produces more emissions per passenger compared to many other forms of transportation, especially for trips that could be taken by train or car.

In contrast, using public transportation, consuming locally sourced food, and participating in community gardening all represent practices that can help reduce individual carbon footprints. Public transportation typically emits fewer greenhouse gases per person than cars, and local food systems generally involve shorter transportation distances, thereby reducing emissions. Additionally, community gardening can enhance local biodiversity and carbon sequestration, further diminishing environmental impact. Therefore, frequent long-distance air travel stands out as the practice that contributes most to an increased carbon footprint.