Short-lived climate pollutants and food security

Climate change and air pollution increasingly threaten food production and supply, making the challenge of ending hunger and malnutrition more difficult than ever.

As the climate warms, changing weather patterns, natural disasters and heat events are becoming more frequent and severe, resulting in reduced crop yields. On top of this, air pollution stunts the growth of major staple crops like rice, corn, soya and wheat and even reducing the nutritional value of certain foods.

With food demand projected to sharply increase by 2050, urgent action is needed to prevent the worst impacts of climate change and air pollution on food security and allow time for agricultural production systems to adapt and become more resilient.

Short-lived climate pollutants (SLCPs) – methane, hydrofluorocarbons (HFCs), black carbon and tropospheric ozone – are powerful climate forcers and responsible for nearly half of warming today.

Because of their multiple impacts, there are many reasons to reduce short-lived climate pollutants. Here is why reducing them can protect food security:

Reducing SLCPs can prevent up to 0.6°C of warming by 2050, providing the best chance of limiting near-term temperature increase and reducing the risks to food security.

A warmer climate adds many challenges to food production such as increased pests and diseases, and more frequent and extreme droughts and floods. Heat-stress causes poor yields, or worse, crop failures. Together these impacts put pressure on domestic and global food systems, and increase the likelihood of supply chain disruptions and competition for increasingly limited resources.

In addition to being powerful climate forcers, SLCPs have direct impacts on local climates, shifting rainfall and weather patterns, with diverse implications for agriculture. The SLCP black carbon also has an outsized effect on the Earth’s cryosphere (regions of ice and snow) which are a sources of fresh water that billions of people depend on.

As short-lived climate pollutants are only in the atmosphere for a relatively short time - a few days to a few decades - reducing them can prevent quickly slow the rate of warming and prevent irreversible damage in these highly sensitive regions.

Air pollution stunts crop growth by weakening photosynthesis. Tropospheric ozone alone causes annual losses of approximately 110 million tonnes of major staple crops: wheat, rice, maize and soybean. This represents around 4% of the total annual global crop production, and up to 15% in some regions.

Black carbon (a component of fine particulate matter or PM_2.5) also harms crops when it covers their leaves, where it absorbs more sunlight and increases the plant’s temperature. While in the atmosphere, black carbon affects plants by reducing the amount of sunlight that reaches the earth and disrupting rainfall patterns.

We can halve global crop losses from these pollutants by 2050 by reducing methane emissions, an ingredient in the formation of tropospheric ozone. This would save between US$4 to US$33 billion.

Currently, 1 in 9 people go hungry every day. Worldwide 2.5 billion people depend on agriculture for their livelihoods. Many are smallholder farmers surviving on the margins of productivity from their agricultural products. For them, small changes in the climate and crop growth can have immediate and devastating consequences.

Air pollution and climate change affect the global food system in such a way that those who suffer from hunger and malnutrition are also the most vulnerable to these added threats. In order to end hunger — one of the Sustainable Development Goals for 2030 — we must tackle these linked crises, and the inequities they cause.

Countries with high levels of hunger are also highly vulnerable to air pollution and climate change and have low capacity to adapt. Acting on climate change, especially in the near-term, is critical to ensuring food security and preserving the livelihoods of millions.

At the same time, the agriculture sector is a contributor to climate change. Agriculture is responsible for 11% of total anthropogenic greenhouse gas emissions. This rises to around 25% when land-use change is included.

Governments and farmers around the world now recognize the need to adapt and reduce emissions. Actions in the agriculture sector have been prioritized in the Nationally Determined contributions (NDCs) of at least 119 countries.

Solutions to cut short-lived climate pollutants not only go a long way to protect near term food security, they also benefit the people who rely on agriculture for their livelihoods.

Solutions to cut short-lived climate pollutants can be implemented today. All are based on existing technology and can be carried out at no or low cost.

Concerted global efforts to implement these solutions can provide climate and health benefits in a short amount of time. They can cut methane emissions by at least 40% and black carbon by up to 70% by 2030, and virtually eliminate (99.5%) high-global warming potential hydrofluorocarbons by 2050 (all compared to 2010 levels).

Solutions include actions like replacing and properly disposing HFCs in refrigeration and air conditioning; reducing methane from waste (including food waste) and agriculture; reducing black carbon emissions from household cooking, lighting and heating, heavy-duty engines in trucks, buses and ships; and reducing methane leaks from oil and gas production.