More than one-third of Earth’s animals, ranging from insects to large mammals, depend on plants as their primary food source. However, plants, particularly those that herbivores consume, are often low in calories, making it difficult for these animals to obtain enough energy for survival. This challenge is being further exacerbated by climate change, which is reducing the nutritional quality of plant-based foods.
Human activities, such as burning fossil fuels, have led to higher levels of carbon dioxide (CO₂) and rising global temperatures, accelerating plant growth. While this "greening of the Earth" can absorb more carbon and offset some greenhouse gas emissions, it has unintended consequences. Faster-growing plants tend to have fewer nutrients, a phenomenon known as nutrient dilution.
This decline in plant nutrition poses significant risks for herbivores, from small insects to large mammals like giant pandas. With plants offering less nutrition, herbivores must spend more time foraging to meet their energy needs, which increases their exposure to predators and environmental stressors. The reduced nutritional value can also hinder their growth, reproduction, and overall survival.
Research has shown that climate change is already diminishing the nutritional value of human food crops, particularly in vital micronutrients like iron, zinc, and magnesium. Livestock also face challenges, as lower protein levels in grasses negatively affect weight gain and profitability. Wild species, such as giant pandas, are similarly impacted, with rising temperatures diminishing the nutritional content of bamboo, their primary food source.
Insects, which play a crucial role in pollination and food webs, are also suffering. Herbivorous insects like caterpillars and grasshoppers are seeing reduced reproduction rates and smaller body sizes due to nutrient-poor plants. However, some insects, like locusts, may thrive on the increased carbon in vegetation.
Nutrient dilution is particularly pronounced in regions like the Amazon and Congo basins and affects smaller animals with higher metabolic demands. More research is essential to fully understand the broader impacts of these changes on ecosystems and global food webs.
