Ozone Layer Protection and Food Security: How UV Radiation Affects Phytoplankton, Agriculture, and Biodiversity

Every year on September 16, the global community observes World Ozone Day to commemorate the signing of the Montreal Protocol (1987), a landmark environmental agreement that has been hailed as the most successful international treaty to date. The Protocol, backed by strong scientific evidence, led to the phaseout of ozone-depleting substances (ODS) such as chlorofluorocarbons (CFCs), saving Earth’s protective shield from further destruction.

The 2025 theme, “From Science to Global Action,” reflects how discoveries in atmospheric chemistry have not only protected the ozone layer but also inspired coordinated international action for planetary well-being. Today, ozone protection is not just about skin cancer prevention; it is deeply intertwined with ecosystem health, agriculture, biodiversity, and food security.

This article explores the critical connections between the ozone layer and food security, with a special focus on how UV radiation affects phytoplankton, agriculture, and biodiversity, the cornerstones of human survival.

The Ozone Layer: Earth’s Protective Shield

The ozone layer, located in the stratosphere (10–50 km above Earth’s surface), absorbs 97–99% of harmful ultraviolet-B (UV-B) radiation from the sun. Without it, Earth would be bombarded with intense UV radiation, causing widespread ecological damage.

When CFCs and other ODS were released in large quantities during the 20th century (in refrigeration, aerosols, and industrial solvents), they rose into the stratosphere. There, UV radiation broke them down, releasing chlorine and bromine atoms that destroyed ozone molecules. This process led to the discovery of the ozone hole over Antarctica in the mid-1980s.

Thanks to the Montreal Protocol and its amendments, ODS emissions have been drastically reduced. In 2024, the Antarctic ozone hole was the 7th-smallest on record, and scientists project full recovery by:

• 2040: Most parts of the globe

• 2045: The Arctic

• 2066: Antarctica

This is a remarkable global achievement. But new challenges are emerging, including the re-entry of decommissioned satellites, which release aluminum oxides into the upper atmosphere. Recent research suggests this may delay ozone recovery and alter climate patterns. Thus, the journey is not complete.

Phytoplankton: Microscopic Life with a Massive Role

Phytoplankton are tiny photosynthetic organisms in oceans and freshwater systems. Despite their microscopic size, they play an outsized role in planetary life:

• They generate 50% of Earth’s oxygen, every second breath we take comes from the ocean.

• They form the base of marine food webs, sustaining zooplankton, fish, whales, and ultimately humans.

• They act as carbon sinks, absorbing CO₂ and helping regulate Earth’s climate.

Impact of UV Radiation on Phytoplankton

Phytoplankton are extremely sensitive to UV-B radiation. Increased exposure leads to:

• DNA damage and cell mutations

• Reduced photosynthetic efficiency, lowering productivity

• Altered species composition, favoring UV-resistant but less productive species

Consequences for Food Security

If phytoplankton populations decline:

• Fish stocks shrink, affecting global fisheries and the diets of billions (especially in coastal and island nations).

• Nutrient cycling is disrupted, weakening marine ecosystems.

• Global carbon balance is disturbed, worsening climate impacts.

Thus, the ozone layer’s health is directly linked to the oceans’ productivity and the food security of millions.

Agriculture: Feeding Billions Under UV Stress

Agriculture is perhaps the most visible link between ozone protection and human food security. Crops require sunlight for photosynthesis, but excess UV-B radiation harms plants in multiple ways.

How UV-B Affects Crops

• DNA damage: Mutations reduce plant vigor.

• Photosynthesis inhibition: UV-B disrupts chlorophyll and reduces efficiency.

• Altered leaf morphology: Smaller, thicker leaves with reduced surface area.

• Flowering and reproduction changes: Altered pollination timing and seed set.

• Weakened defenses: UV-stressed plants are more vulnerable to pests, diseases, and droughts.

Case Studies and Data

• Experimental studies have shown yield declines of 20–25% in crops like soybeans, wheat, rice, and maize under elevated UV-B exposure.

• UV stress reduces not only quantity but also nutritional quality, lowering protein and vitamin content in grains and vegetables.

• Regions already facing climate change stress, such as South Asia and Sub-Saharan Africa, are most vulnerable, as even small declines in yields affect millions.

Broader Economic Impacts

• Farmers face lower productivity and income.

• Countries dependent on agriculture face rising food imports, increasing vulnerability to global price fluctuations.

• Food insecurity and malnutrition risks increase, particularly among the poor.

Biodiversity: The Hidden Foundation of Food Security

Biodiversity underpins agriculture and ecosystems. Yet, excess UV radiation disrupts this foundation in subtle but powerful ways.

Amphibians

Amphibian eggs and larvae, especially in shallow waters, are highly sensitive to UV radiation. Increased mortality threatens species survival. Since amphibians are both predators and prey, their decline destabilizes food webs.

Pollinators

Plants under UV stress emit altered scents and display modified flower patterns, confusing bees, butterflies, and other pollinators. Given that 75% of crops rely on pollinators, this is a direct food security threat.

Soil Microorganisms

Soil microbes recycle nutrients, maintain soil fertility, and support plant growth. Excess UV weakens microbial activity, reducing soil health and long-term agricultural productivity.

Aquatic Biodiversity

Increased UV penetrates shallow waters, harming larvae and eggs of fish, crustaceans, and amphibians, disrupting food chains and fisheries.

Ozone Layer and Food Security: The Bigger Picture

When we connect the dots, the story is clear:

• Oceans → Phytoplankton sustain fisheries.

• Agriculture → Crops provide global nutrition.

• Biodiversity → Pollinators and soil microbes sustain productivity.

All three are vulnerable to UV radiation. Without the ozone layer, food security would be drastically undermined.

The Montreal Protocol not only saved the ozone but also indirectly benefited climate action, as many phased-out ODS were also powerful greenhouse gases. Its Kigali Amendment (2016), targeting hydrofluorocarbons (HFCs), continues this dual benefit by reducing climate forcing and protecting the ozone.

From Science to Global Action: Lessons and Responsibilities

World Ozone Day 2025’s theme reminds us of an important lesson: science alone cannot save the planet, science must lead to action.

• Science identified the threat (ozone depletion).

• Policy acted globally (Montreal Protocol).

• The ozone layer is healing, proving cooperation works.

But to secure food systems for the future, we must:

• Invest in UV-resistant crop varieties through biotechnology.

• Strengthen fisheries management to adapt to changing marine productivity.

• Support biodiversity conservation, ensuring pollination, soil fertility, and ecosystem resilience.

• Regulate satellite disposal and other emerging risks to atmospheric chemistry.

The ozone layer is far more than a shield against skin cancer, it is a life-support system for ecosystems and food security. By filtering harmful UV radiation, it protects the phytoplankton that sustain marine life, the crops that feed billions, and the biodiversity that underpins agriculture.

World Ozone Day 2025 reminds us of a profound truth: Protecting the ozone layer means protecting food, life, and the future. Science showed us the way; now global action must continue, because the health of our food systems, ecosystems, and humanity itself depends on it.