How Climate Change Claws at the Four Pillars of Food Security

Note: This is the third and final post reviewing an article in Science magazine’s special section called ‘Natural Systems in Changing Climates’ that covered a range of contemporary research about the impact of recent climate behavior on ecosystems and species stability.  This post will be discussing the article “Climate Change Impacts on Global Food Security found here.

This will be the final review of an article from the ‘Natural Systems in Changing Climates’ special section from the August 2, 2013 issue.  Last but also important, as this article discusses a topic not often discussed in the mainstream media regarding anthropogenic climate change: food security.  Most news coverage discusses sea level rises, threatened species and ecosystems, and predicted extreme weather systems, all of which are  important to understand, but this articles moves away from these topics to discuss how climate change will affect our global fight against hunger and malnutrition, focusing on poorer countries [1].

There’s More To It Than Availability

As discussed in previous posts, the evidence is there: the planet is warming.  Results based on very strong evidence all show a 0.8 C increase in average surface temperature since 1850 and a predicted 1.8 – 4 C increase by the end of this century.  CO2 levels have also risen by 100 ppm in the atmosphere since 1850.  These increases are theoretically linked to global warming due to the increased absorption of infrared light by the atmosphere due to the higher CO2 levels that is then re-emitted back to Earth, leading to the warming trends we’re seeing.

OK, so the Earth is warming – how does this affect food security for humans?  Unfortunately, we know only a small piece of the whole story.  This is due to the fact that previous research has only focused on one aspect of food security: food availability.  According, the UN’s Food and Agricultural Organization (FAO), food security actually encompasses a complex interaction of four different cornerstones (henceforth known as the AAUS of Food Security!):

1) Availability: ability to find necessary QUANTITY of foods above a certain QUALITY threshold (from domestic or imported sources).

2) Access: ability for population to have RESOURCES required to ACQUIRE food of certain nutritional value.

3) Utilization: ability to use food in such a way that maintains nutritious well being – this mainly concerns CLEAN WATER, SANITATION, and HEALTH CARE to maintain a healthy status

4) Stability: ability to fulfill the first three requirements CONSISTENTLY across all times of the year – this is largely affected by local politics and warfare, but I could also see this being one of the major food pillars that climate change threatens due to increased weather severity and variability.

Of these four, only food availability has truly been studied on a global scale in any detail.  For example, the map below colors countries based on their 2012 Global Hunger Index score, which measures percentages of people in each country calorie shortages.  The brighter orange and red colors signify higher scores and hence higher percentages.

Image courtesy of

Image courtesy of

Clearly, sub-Saharan Africa and South Asia face the greatest crises in terms of under-nutrition.  But these statistics are a clear indicator of where our knowledge is lacking as well.  First, this data is averaged across 2010-2012, so we lose all information regarding variability within years that will be largely affected by severe weather or geopolitical strife.  In addition, the data is aggregated and cannot be broken into household or community distributions.   Both these points point to the lack of information about food stability (#4 ab0ve).  Second, these results only measure calorie shortage and contain no information about dietary deficiencies, the level of nutrition in the diet, rates of subsequent health conditions, and access to care for these conditions (#2 and #3 above).   This is not to say this data is not useful; the groups that put this data together – Welthungerhilfe, IFPRI, and Concern Worldwide Hunger – are doing important work, but we must always strife to know more so that we may help more.

So what do we know from research?  Well, continuing with the trend discussed above, research has also focused mainly on food availability.  According to the review done for this Science article, 70% of all publications regarding climate change and food security focused on availability, whereas the other three pillars were discussed in about 10% of the publications.  So, above all, the take-home message should be that our attentions need to be turned to access, utilization, and stability.  Still, we can summarize what’s been found thus far.

Food Availability: A Matter of Latitude

Interestingly, the effect of climate change on food availability, measured in most models by crop productivity, is strongly dependent upon latitude.

Image courtesy of

Image courtesy of

This data is combined across simulations published betwen 1994 and 2010, modeled with increased CO2 concentrations in the atmosphere based on current predictions.  The green and red regions represent positive and negative percentage change in crop yields, respectively.  As you can see, global warming is predicted to actually increase crop yields in the northern latitudes of Canada, Europe, and Asia!  This effect is attributed to an increased rate of photosynthesis due to increased radiation being re-emitted from the atmosphere.  Unfortunately, the same cannot be said of tropical zones, which will see large decreases in crop yields for wheat, maize, sorghum, millet, and maize (rice results are inconclusive).  These decreased yields are purportedly due to the fact that increased temperatures are predicted decrease rainfall in these regions.  It also happens that these regions in sub-Saharan Africa and South Asia that will be affected negatively are also those regions with the greatest prevalence of malnutrition.  This is one clear example of the interaction between climate change and the geographical distribution of hunger that leads to climate change exacerbating major food availability issues.

Access, Utility, and Stability: More Data Needed!

As said before, not much data exists about impacts of climate change on food access.  A main reason for this concerns the complex interrelationships that exist between climate change and adaptability at the household level that is the center of these pillars.  In contrast, food availability can be clearly analyzed looking at single variables such as crop productivity.

Studies at the household level, known as micro-level studies, have become much more prevalent over the past several years, connecting household survey data to climate change data.  A primary example of this is a study done recently by the International Food Policy Research Institute (IFPRI) that associated climate change scenarios with changes in food prices and supply amounts.  The main results from this study are that robust economic growth is associated with resilience to climate change [2].  Quite vague!  Just another example of the reason for more detailed study.

Regarding food utilization, the major effect of climate change is believed to be a shift in the geographic distribution of pests and diseases that will affect water contamination and basic sanitation.  In this regard, technological innovations will likely be mandatory to respond to these new threats to public health care.  This is again a completely new area of research that needs new and bright minds to find solutions!

Finally, stability appears to be the pillar that may be most strongly affected by climate change.  This is largely due to the fact that there is very little flexibility in the ‘world food equation’ – basically the difference between the amount of food grown and the amount required.  Thus, any climate event or shock can lead to great variability in prices.  But once again, there is a paucity of systematic study about these effects!

Where Do We Go From Here?

The article ends with four major priorities for future research based on their review:

1) We need more research on food access, utilization, and stability individually as well as how they interact with one another.

2) Improve modeling that predicts indirect impacts of climate change on food security.

3) Improve projections of effects of climate change on smaller scales within countries and cities/villages.

4) Integrate human dimensions of climate change impacts on food security.

I feel like, after writing this, that everything I’ve included after food availability seems very vague.  But I guess that’s the point!  We don’t really know about much about the pillars of access, utility, or stability.  We have an idea of the type of studies that would help elucidate what the effects will be, but now is the time to enact them!  Beyond that, it appears clear that climate change with exacerbate food insecurity that already exists in some of the tropical regions of the world.

Main Reference

Wheeler T, & von Braun J (2013). Climate change impacts on global food security. Science (New York, N.Y.), 341 (6145), 508-13 PMID: 23908229
Other References

2) Nelson, G.C., et al. “Food Security, Farming, and Climate Change in 2050: Scenarios, Results, Policy Options.” IFPRI, Washington, D.C., 2010.

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