Monday, July 22, was the hottest day on record according to a European Union climate change monitoring organization. It’s a record that will be beaten again, though no one wants that.

According to multiple media reports, the Copernicus Climate Change Service said the world averaged a daily high temperature of 17.16 degrees Celsius, or about 63 degrees Fahrenheit. That’s for the world as a whole, including the Southern Hemisphere where it’s now winter.

This unfortunate milestone was achieved due to a brutal heatwave in the Northern Hemisphere. Most of the news on the global heatwave focused on record temperatures hitting cities in North America and Europe like Philadelphia, London, and Moscow. However, the Global South felt the same punishing heat, only people there can’t always take cover with air conditioning.

The heat hits smallholder farmers in the Global South, as well. Much has been written about how smallholder farmers face climate change risks mainly in the form of droughts and flooding. Global warming is delivering longer, harsher droughts, dooming unirrigated farms. Torrential rains and violent storms can wipe out fields of crops in minutes. But rising average global temperatures smallholder farmers in other ways.

Grow Further is keeping an eye on other climate change-related challenges. There are potential solutions to these problems, and new innovations will find others. But we first must understand the threats smallholder farmers face before we can consider how people-driven research and innovation can help them achieve a food-secure future.

Carbon dioxide and nutrition

One of the less obvious linkages between climate and farming is the effect of carbon dioxide, which serves as a fertilizer to plants, on nutrition. In many crops, including wheat, maize, rice, and soybeans, higher levels of carbon dioxide mean more carbohydrates but lower levels of protein, iron, zinc, and vitamins in food. According to a groundbreaking 2014 study published in Nature, “Increasing CO2 threatens human nutrition”, higher levels of carbon dioxide in the atmosphere lead to a reduction in zinc and iron content in food. A Harvard study the following year estimated that increases in carbon dioxide concentrations by 2050 could place 132-160 million people at risk of zinc deficiency, and other studies have forecast large increases in protein deficiency as well.

Grow Further is currently funding a project to improve the cultivation of Bambara groundnut, which is particularly high in iron, and is considering several other projects that would help improve nutrition through agriculture.

Saltwater intrusion

Farms located in coastal regions are threatened by climate change on two fronts.

First, they are in the direct line of fire from major typhoons and cyclones. Many climate models are predicting major typhoons forming in the ocean earlier and becoming stronger, fueled by warm ocean waters. These storms can become supercharged by the time they make landfall, and anyone farming along the coasts will bear the brunt of these furious storms first.

Second, climate change also threatens to literally salt the earth and groundwater. This can happen from storm surge and coastal flooding caused by typhoons. A slower but longer-term risk stems from sea level rise and saltwater intrusion.

“An estimated 1.06 million hectares of arable land in Bangladesh and 6.7 million hectares in India are affected by salinity,” according to a brief on saltwater intrusion and smallholder agriculture.

This brief was produced by International Food Policy Research Institute and CGIAR’s Research Program on Climate Change, Agriculture, and Food Security (CCAFS). The scientists who wrote it warn that the area of arable land in Bangladesh’s coastal areas has been steadily decreasing due to rising seas. Farm yields are also declining, “and many studies have identified salinity as the chief cause for yield reduction in coastal agriculture,” they said.

Freshwater flows from the surface and underground aquifers into the oceans. The process works in reverse at the coast, as well, with seawater seeping into groundwater reservoirs or spoiling coastal freshwater resources at high tide. Saltwater intrusion both underground and on the surface is getting worse, scientists warn, because the sea level is rising, as multiple readings across the world have confirmed. The seas are rising because land-based glaciers and ice caps on Greenland and Antarctica are steadily melting away.

Just as humans cannot survive on salt water, neither can crops. “The extent and intensity of salinity in the coming years are likely to increase due to climate change-induced saltwater intrusion,” the CCAFS researchers warned.

Low-lying coastal farming regions in Bangladesh and India aren’t the only regions seeing damage from saltwater intrusion. It’s a particularly challenging issue for farming in small island developing states. Scientists also see signs that saltwater intrusion is damaging rice farming in coastal parts of Southeast Asia.

Heat stress

People who don’t deny the reality of climate change understand that daytime temperatures have been steadily rising for decades, as the EU’s climate monitor has confirmed (among thousands of other sources). Less well-known is the fact that average temperatures at nighttime have been rising even faster. Since the sun doesn’t shine at night, it’s obvious what’s causing nighttime temperatures to increase: the atmosphere is becoming thicker and more capable of retaining heat throughout the evening hours.

This is bad news for smallholder farmers growing crops that need cooler evenings to thrive. The impact of heat stress is felt far inland and may be worse the farther a farm is located away from the coast.

A study in the journal Environment International worries that wheat production will decline as temperatures increase and heat stress worsens. Wheat crops will feel heat stress the most when these plants are in their reproductive cycle, these scientists warn. “The area suffering from high-intensity heat stress during the wheat reproductive phase is predicted to increase by 37.3% with 2.0 degrees C warming,” they wrote. The study, led by scholars at Beijing Normal University, found that farms in Central Asia are especially vulnerable.

Temperature is critical to agriculture everywhere. Too cold, and crops cannot grow. Too hot, and crops cannot thrive or even reproduce. As the Center for Climate and Energy Solutions explains “plant growth is negatively impacted by high daytime temperatures and some crops require cool night temperatures.” Rice is one. Maize is another. The threat can be countered somewhat by daytime and nighttime watering, but that’s not an option for the millions of smallholder farms that depend on rainfall alone.

However, it’s not only the crops that we must be worried about.

CGIAR-funded research published in The Lancet uncovered evidence that rising temperatures are stressing livestock, as well. The consequences include less milk and less meat. The world’s pastoralists are predicted to lose billions of dollars from heat-induced production losses, and “losses in most tropical regions were projected to be far greater than they were in temperate regions.”

Pests and Disease

In the United States, an outbreak of the mountain pine beetle is attributed to climate change. Milder winters are killing off fewer of the beetle’s larvae. That means more beetles survive to attack and kill millions of trees in US forests. Changing weather patterns are also making life more difficult for smallholder farmers struggling to beat back infestations of pests and crop diseases.

Tropical agriculture has always been challenged by pests and diseases. Now, the International Maize and Wheat Improvement Center (CIMMYT) is warning that rising temperatures are seeing pests and diseases migrating further north and south to more temperate farming environments.

The Center says pests and diseases that attack crops have been steadily migrating closer to the poles by around 3 kilometers per year since the 1960s. Pests and diseases are also migrating to higher elevations, meaning highland farming areas in Mexico, India, and elsewhere now must deal with threats that their ancestors never had to worry about.

Global warming threatens smallholder farming in multiple ways. Grow Further and its partners are undeterred.

Research and development will unveil solutions that will help farms adapt to all the threats that climate change poses. Delivering these innovations to smallholders’ fields is another challenge, but not an insurmountable one. The situation is not hopeless. 

— Grow Further

Photo credit: Rice fields in Bangladesh. Mariusz Kluzniak, Flickr and Creative Commons (CC BY-NC-ND 2.0).