Reduced Food & Water Availability

The crops that modern society cultivates, harvests, and transports globally in the worldwide food supply chain have adapted to very specific temperatures, growing seasons, and climates for proper growth cycles.  Climate change is starting to change those long-held environmental patterns, which is starting to impact crop yield1.  Similarly, fresh drinking water is starting to decrease in availability as well, as snowpack on mountains decreases each year with rising temperatures.  This decreased snowpack means less freshwater to feed the myriad rivers of the world where most human population centers have settled (the Sierra Nevada mountains that help supply Los Angeles with fresh water, the mountains of eastern Turkey that feed the Tigris and Euphrates rivers in the Middle East, etc.)2.  According to the World Health Organization and the Intergovernmental Panel on Climate Change (IPCC), the impact of climate change on temperature and rainfall on agricultural production will be the single largest negative effect of the crisis because of the sheer amount of people it will harm3.

Figure 1

Figure 2


Researchers at the International Food Policy Research institute developed an aggressive climate model to demonstrate the severity of the crisis on the top four crops globally - corn, potatoes, rice, and what. The model, known as HadGEM2, showed that farmers in regions such as South America and West Africa will suffer great losses, while Canada and Northern Europe will see longer and more productive growing seasons. India and China will also see major losses in arable land by 20504

Figure 3

Source: International Food Policy Research Institute


Figure 4

Source: International Food Policy Research Institute


This decrease in crop yield will have direct negative health effects on the world’s poorest populations.  Maternal and child undernutrition can lead to stunting, development disabilities, and metabolic and cardiovascular diseases.  A study done by Tirado et al. for the  Food and Nutrition Bulletin described the process flow of this nutritional health impact shown in the chart below.


Figure 5


To combat this nutritional crisis, the Climate Change, Agriculture and Food Security research program under the Food & Agriculture Organization and the World Bank promotes agro ecological food production systems, low external input agricultural systems, and integrated agroforestry and silvo-pastoral systems.  In essence, they encourage climate mitigation measures that also have co-benefits in sustainable food production, enhanced food production per unit of energy, land, and water resources consumed, as well as enhanced access to nutritional food in low- and middle-income countries5.

Perhaps even more dire than the availability of food is the availability of fresh, drinkable water.  Humans can only go about three days without water, and climate change is threatening the Earth’s finite supply of fresh water.  UNICEF published a list of facts on World Water Day 2021 that is important for every public health professional:


  1. Extreme weather events and changes in water cycle patterns are making it more difficult to access safe drinking water, especially for the most vulnerable children.
  2. Around 74 per cent of natural disasters between 2001 and 2018 were water-related, including droughts and floods.  The frequency and intensity of such events are only expected to increase with climate change.
  3. Around 450 million children live in areas of high or extremely high water vulnerability. This means they do not have enough water to meet their everyday needs.  
  4. When disasters hit, they can destroy or contaminate entire water supplies, increasing the risk of diseases like cholera and typhoid to which children are particularly vulnerable.
  5. Rising temperatures can lead to deadly pathogens in freshwater sources, making the water dangerous for people to drink.
  6. Contaminated water poses a huge threat to children’s lives. Water and sanitation related diseases are one of the leading causes of death in children under 5 years old.
  7. Every day, over 700 children under 5 die from diarrhoea linked to inadequate water, sanitation and hygiene.   
  8. Climate change exacerbates water stress – areas of extremely limited water resources – leading to increased competition for water, even conflict.
  9. By 2040, almost 1 in 4 children will live in areas of extremely high water stress. 
  10. Rising sea levels are causing fresh water to become salty, compromising the water resources millions of people rely on6.


Water has been treated as an infinite resource for far too long, with the majority of fresh water being used for wasteful agricultural practices like plain-flooding for irrigation.  A couple cities around the world have experimented with taxing water based on consumption and on income.  Additionally, green infrastructure like rain catchment systems have helped Mexico City’s outlying areas with access to fresh drinking water.  


1. Black, R. (2006). New crops needed to avoid famines. BBC News. 
2. Conservation in a Changing Climate. (2021). Changes in Mountain Snowpack. 
3. Tirado, M. C., Crahay, P., Mahy, L., Zanev, C., Neira, M., Msangi, S., Brown, R., Scaramella, C., Coitinho, D. C., & Müller, A. (2013). Climate Change and Nutrition: Creating a Climate for Nutrition Security. Food and Nutrition Bulletin, 34(4), 533–547. 
4. How To Live With It: Crop Changes. (2021.) National Geographic. 
5. Tirado, M. C., Crahay, P., Mahy, L., Zanev, C., Neira, M., Msangi, S., Brown, R., Scaramella, C., Coitinho, D. C., & Müller, A. (2013). Climate Change and Nutrition: Creating a Climate for Nutrition Security. Food and Nutrition Bulletin, 34(4), 533–547.
6. UNICEF. (2021). Water and the global climate crisis: 10 things you should know.