Sample Writing Task 2 on Agriculture and Greenhouse Gas Emissions

Agriculture nourishes the world but also contributes significantly to greenhouse‑gas emissions. Livestock, especially cattle and sheep, are major sources of methane. Cattle are the top agricultural source of greenhouse gases worldwide. Each cow belches about 220 pounds (100 kilograms) of methane per year. Methane has a much shorter atmospheric lifetime than carbon dioxide, but it is 28 times more potent over a century. Globally, livestock are responsible for about 14.5 % of greenhouse‑gas emissions. Because beef consumption is low in some countries—such as India—cattle live longer and emit more methane over their lifetimes. Improving feed efficiency, breeding and management has allowed the United States to produce more meat with fewer cattle than in the 1970s, but worldwide demand is rising. Scientists at UC Davis have experimented with adding a small amount of red seaweed to cattle feed; initial trials show it can cut methane emissions by up to 60 %.

Agricultural emissions are not limited to methane. Synthetic fertilizers used to boost crop yields emit nitrous oxide, a greenhouse gas with about 300 times the warming potential of carbon dioxide. Over‑application of nitrogen fertilizers also causes pollution of waterways and soil degradation. Better farming practices—such as precision fertilization, crop rotation and the use of legumes—can reduce nitrous oxide emissions while maintaining productivity. Climate‑smart agriculture, which combines sustainable land management with resilient crop varieties and efficient irrigation, is gaining traction. Consumer behavior also plays a role; shifting diets toward plant‑based foods can reduce demand for methane‑emitting livestock. Policies that support farmers in adopting low‑emission practices and provide incentives for innovation are vital.

The role of agriculture in climate change illustrates the trade‑offs between food security and environmental sustainability. While reducing livestock numbers could cut methane, it must be balanced with nutritional needs and livelihoods. Investments in research—such as feed supplements, vaccines to reduce enteric fermentation and improved manure management—offer promising pathways. Ultimately, transforming agriculture will require collaboration among scientists, farmers, consumers and governments to lower emissions while feeding a growing global population.