CLIMATE CHANGE AND NUTRITION

 

How "Climate Change" will alter our Food ?

Weather Extremes

RM222,000 worth of crops, 20 paddy farmers affected in Yan floods

 

• When temperatures rise, the warmer air holds more moisture and can make precipitation more intense. Extreme precipitation events, which are becoming more common, can directly damage crops, resulting in decreased yields.
• Flooding resulting from the growing intensity of tropical storms and sea level rise is also likely to increase with climate change, and can drown crops. Because floodwaters can transport sewage, manure or pollutants from roads, farms and lawns, more pathogens and toxins could find their way into our food.
• Hotter weather will lead to faster evaporation, resulting in more droughts and water shortage. As the consequences, there will be less water for irrigation just when it is needed most.

Rising Temperatures

This is photo of a paddy field in Pagoh, Johor taken in 2020 during a dry spell. 9000ha of paddy fields destroyed by drought between 2017 - 2021.

• The ultimate effect of rising heat depends on each crop’s optimal range of temperatures for growth and reproduction. If temperatures exceed this range, yields will drop because heat stress can disrupt a plant’s pollination, flowering, root development and growth stages.

According to a 2011 National Academy of Sciences report, for every degree Celsius that the global thermostat rises, there will be a 5 to 15 percent decrease in overall crop production.

 

• Heat waves, which are expected to become more frequent, make livestock less fertile and more vulnerable to disease. Dairy cows are especially sensitive to heat, so milk production could decline. 
• Parasites and diseases that target livestock thrive in warm, moist conditions. This could result in livestock farmers treating parasites and animal diseases by using more chemicals and veterinary medicines, which might then enter the food chain.
• Climate change will also enable weeds, pests and fungi to expand their range and numbers. In addition, earlier springs and milder winters will allow more of these pests and weeds to survive for a longer time.

Higher levels of Carbon Dioxide

• While higher CO2 levels can stimulate plant growth and increase the amount of carbohydrates the plant produces, this comes at the expense of protein, vitamin and mineral content. Researchers found that plants’ protein content will likely decrease significantly if carbon dioxide levels reach 540 to 960 parts per million, which we are projected to reach by 2100. (We are currently at 409 ppm). Studies show that barley, wheat, potatoes and rice have 6 to 15 percent lower concentrations of protein when grown at those levels of CO2. The protein content of corn and sorghum, however, did not decline significantly.
• When CO2 levels rise, the openings in plant shoots and leaves shrink, so they lose less water. Research suggests that as plants lose water more slowly, their circulation slows down, and they draw in less nitrogen and minerals from the soil. Vitamin B levels in crops may drop as well because nitrogen in plants is critical for producing these vitamins.

 

In one study, rice grown with elevated CO2 concentrations contained 17 percent less vitamin B1 (thiamine), 17 percent less vitamin B2 (riboflavin), 13 percent less vitamin B5 (pantothenic acid), and 30 percent less vitamin B9 (folate) than rice grown under current CO2 levels.

A warmer, more acidic ocean

• Warmer waters can alter the timing of fish migration and reproduction, and could speed up fish metabolism, resulting in their bodies taking up more mercury. (Mercury pollution, from the burning of fossil fuels, ends up in the ocean and builds up in marine creatures.) When humans eat fish, they ingest the mercury, which can have toxic effects on human health.
• Higher water temperatures increase the incidence of pathogens and of marine diseases in species such as oysters, salmon and abalone. Vibrio bacteria, which can contaminate shellfish and, when ingested by humans, cause diarrhea, fever and liver disease, are more prevalent when sea surface temperatures rise too. 
• As ocean acidity increases, there are fewer carbonate ions in the ocean for the marine species that need calcium carbonate to build their shells and skeletons. Some shellfish, such as mussels and pterapods (tiny marine snails at the base of the food chain) are already beginning to create thinner shells, leaving them more vulnerable to predators. 
• Ocean acidification can also interfere with the development of fish larvae and disrupt the sense of smell fish rely on to find food, habitats and avoid predators. In addition, It disturbs the ecosystems that marine life depends upon.

Sea level rises

• Some experts predict that sea levels could rise one meter by 2100 due to melting polar ice caps and glaciers. In Asia, where much of the rice is grown in coastal areas and low-lying deltas, rising seas will likely disrupt rice production, and saltwater that moves further inland could reduce yields.
• Aquaculture of fresh water species is also affected by sea level rise as saltwater can move upstream in rivers. For example, in the Mekong Delta and Irawaddy region of Vietnam and Myanmar, the booming catfish aquaculture could be affected by saltwater intrusion. If this occurs, fish farms would have to be moved further upstream because catfish have little tolerance for saline conditions.