Agriculture is the world’s largest industry, and employs more than one billion people annually, generating approximately $1.3 trillion worth of food. Agricultural practices like pastures and crops occupy 50% of the Earth’s habitable surface. It is therefore important that farming practices are sustainable, to ensure the continued provision of food and employment, but also to prevent harm to the surrounding natural areas, including the ocean. Demand for agricultural commodities is increasing due to the increasing global population, which is placing strain on our natural resources. Sustainable farming operations can preserve and restore habitats, protect watersheds, and improve soil health and water quality.

Whereas agriculture occupies 50% of the surface of the planet, coral reefs only cover 1%. Despite this, coral reefs are some of the most diverse and important habitats on Earth. They form part of a complex marine ecosystem and are made up of many millions of tiny organisms known as coral polyps. It is estimated that 10% of the world’s coral reefs have been destroyed, with a further 60% currently dying. At this rate, it is estimated that our coral reefs may be completely gone by 2050.

Why Are Coral Reefs Important?

Coral reefs house the highest biodiversity of any ecosystem, and host more than one quarter of all marine fish species, as well as many other marine animals. Coral reefs also provide ecosystem services, such as subsistence food, protection from flooding, sustaining the fishing industry, and providing tourism opportunities. The disappearance of corals therefore has economic, social and environmental consequences (IUCN).

Threats To Coral Reefs

Several factors can result in the deterioration and degradation of coral reefs, including:

• Coastal development,
• Mining of the seabed,
• Natural stressors like El Nino,
• Dredging of the seabed,
• Overfishing and destructive fishing practices,
• Introduction of alien species, and
• Global climate change

Effects of Agricultural Land Uses on Coral Reefs

It is estimated that 25% of coral reefs are threatened by pollutants from agriculture. Unsustainable and intensive agriculture transmits sediment, inorganic and organic nutrients and chemical contaminants to waterways, aquifers and the ocean. The release of chemicals into the water results in algal blooms, which causes anoxic conditions, starving the symbiotic plants within the corals of sunlight and oxygen (BBC). These harmful algal blooms also have the ability to clog fish gills, reduce water quality and starve other species of oxygen.

Climate Change and Coral Reefs

Unsustainable farming practices can also result in climate change due to greenhouse gas emissions, and climate change leads to the deterioration and bleaching of coral reefs.

Climate change is defined as “any long-term alteration in average weather patterns, either globally or regionally” (LiveScience). Although climate change is a natural phenomenon and has occurred many times in Earth’s history, the changes in weather patterns that are being seen today are caused by human activities, e.g. burning fossil fuels like oil, gas and coal (National Geographic) and are occurring much faster than the natural climate variations.

A shift in the climate of a region profoundly affects temperature and rainfall patterns. These shifts cause corals to expel the symbiotic algae living within their tissues. The algae are responsible for the vibrant colors of corals, and therefore a sustained increase in ocean temperatures results in what is known as “coral bleaching” – when corals turn white. If corals are bleached for long periods, the corals eventually die. A 2015 study done by WWF projected that the climate-related loss of ecosystem services provided by reefs will cost $500 billion per year or more by 2100 (WWF).

Sustainable Agriculture

The agriculture industry is uniquely placed as an industry both suffering from, and contributing to, climate change. It is estimated that farming accounts for 32% of greenhouse gas emissions (Action Aid), however the droughts and water scarcity resulting from climate change, as well as floods and unpredictable rainfall patterns, are negatively affecting food production.

Effective adaptation to sustainable farming practices has the potential to mitigate the impacts of climate change. The challenge is to find a way to develop sustainable agriculture practices which can increase production to meet the demands of and ensure food security and equitable distribution of resources for the growing global population.

The following technologies and practices are available to reduce the impact of agriculture on the environment, including a reduction in greenhouse gas emissions (ISSD):

• Use agricultural inputs (i.e. energy, chemicals and water) considerately.
• Conserve and use ecosystem services for increasing production, e.g. nutrient cycling in soil to improve fertility and biological control of insects and diseases to reduce dependence on pesticides.
• Manage soil health to enhance crop nutrition through use of green manure, low or no-tillage agriculture, and reducing dependence on chemical fertilizers.
• Use irrigation water efficiently to save water. Conserve the quality of water by maintaining natural vegetation.
• Select crops that are adapted to the region and resilient to adverse climatic conditions. Use a wide range of crop species in rotation.
• Using soil as a carbon sink and switching to carbon-smart farming.

How Sustainable Farming Helps Conserve Coral Reefs

Land-based sources of pollution are a critical threat to coral reefs as all pollutants that enter catchment areas end up in the ocean, and understanding of ridge-to-reef changes is needed to ensure the conservation and survival of coral reefs.

The sustainable farming practices highlighted above will result in a reduction in runoff of sediment and harmful chemicals due to efficient use of irrigation systems and reduced dependence on chemical pesticides and fertilizers, thus resulting in fewer and less intense algal blooms in the ocean, allowing the coral reefs to survive.

Sustainable agriculture and the use of new technologies that assist in reduction of greenhouse gas emissions will also slow down the current rate of climate change. Reducing tillage, planting cover crops and using organic matter for fertilizer can increase the amount of carbon stored in soil, which will reduce the negative impacts of climate change across a region.

Although agricultural areas and coral reefs are often miles apart, it is important to acknowledge the interconnectedness of agricultural practices and coral reef survival. Sustainable and environmentally aware farming operations can directly contribute to the survival of Earth’s coral reefs, while continuing to provide food security to the 7.9 billion people on Earth.