TOEFL統合ライティング

📖 読解文章

The use of biofuels, such as ethanol derived from corn, has been proposed as a key solution to reduce greenhouse gas emissions from transportation. Proponents argue that biofuels offer a renewable alternative to fossil fuels, with three main advantages. First, biofuels are considered carbon-neutral because the carbon dioxide released during combustion is roughly equivalent to the carbon dioxide absorbed by the plants during their growth. This cycle theoretically does not add new carbon to the atmosphere, unlike burning fossil fuels which releases ancient carbon. Second, biofuel production can stimulate rural economies by creating new markets for agricultural crops. Farmers can diversify their income, and the construction of biofuel processing plants generates jobs in rural areas. Third, biofuels can enhance national energy security by reducing dependence on imported oil. Countries with ample agricultural land can produce their own fuel, insulating them from global oil price volatility and geopolitical tensions. For these reasons, many policymakers advocate for increased biofuel mandates and subsidies.

🎧 リスニング講義

However, the arguments presented in the reading are misleading. While it is true that biofuels absorb CO2 during growth, the full lifecycle analysis shows that they are not carbon-neutral. The cultivation of corn requires significant fossil fuel inputs for fertilizers, pesticides, and farm machinery. Additionally, processing and transporting biofuels involve energy-intensive steps. When these factors are accounted for, the net reduction in greenhouse gas emissions compared to gasoline is minimal, sometimes as low as 10-20%. Second, the economic benefits to rural areas are often overstated. The push for corn-based ethanol has led to a dramatic increase in corn prices, which hurts livestock farmers who rely on corn as feed. Moreover, large-scale biofuel operations tend to favor industrial agribusinesses, not small family farms, and the promised job creation is often temporary. Third, energy security is not significantly improved because many biofuel programs still rely on imported inputs, such as fertilizers and even the fuel used in production. In countries like the United States, the majority of biofuel plants are located in specific regions, and the distribution infrastructure is limited. Furthermore, diverting agricultural land from food production to fuel can increase food prices globally, creating food insecurity in developing nations. Thus, the purported benefits of biofuels are largely illusory.