Although plants produce 54 billion metric tons of carbohydrates per year, when the population is expected to grow to 9 billion by 2050, the plants may not be able to keep up (Biello).
虽然植物每年生产540亿吨碳水化合物，但若人口增至2050年的90亿，这些植物就供不上了（Biello）。