Menu ENN Search

The Effects of Global Warming on Food Security

By Kate Godden

Kate is a Senior Lecturer in the Centre for Public Health Nutrition at the University of Westminster where she teaches food security, programme planning and emergency nutrition. She has over 10 years experience within the emergencies sector.

With so many reports on climate change coming out from different quarters, it can be hard to know which are based on reliable information. Those of us who work in the food and nutrition sector do have real cause for concern, as it is highly probable that there will be a general increase in food insecurity in many of our most vulnerable populations over the coming years. Additionally, it is very likely that there will be an increased frequency of natural disasters caused by extreme weather, including flooding, heat waves and drought.

Sourcing objective information

The Intergovernmental Panel on Climate Change (IPCC) was set up in 1988 to review objectively and consolidate the latest scientific literature on the subject. In 2007, they released their Fourth Assessment Report (AR4)1 based on 29,000 observational data series from 75 studies around the world (though data from developing countries are seriously lacking). The AR4 reflects that global warming is a reality, the average air temperature has warmed by 0.74o C (0.56-0.9 o C) over the past 100 years. This is an average global figure and doesn't truly reflect localised temperature variations. It is also feared that the rate of global warming is increasing - eleven of the twelve years to 2006 rank among the twelve warmest years on record since 1850. Land regions are warming faster than the oceans and the northern latitudes are warming faster than southern ones with the average arctic temperature increasing at twice the global rate. There are also increased sea levels (global average 1.8, 1.3-2.3 mm per year 1961-2003). The rate of increase of the sea level accelerated in the last decade of the century but it is not yet clear if this was due to decadal variation or not. The world's third largest natural disaster of recent years, (after the tsunami of 2004, Pakistan earthquake of 2005) was, in fact, a heatwave that killed over 64,000 people2 in southern Europe in July/Aug of 2003.

Observed changes in the climate

'Warming of the climate is unequivocal as is now evidenced from observations of increases in global average air and ocean temperatures, widespread melting of the snow and ice caps, and rising global average sea level ' (IPCC, 2007).

Warm air is able to hold more water vapour than cooler air and this means that warm air is less likely to provide rainfall until it cools. Cooling, however, results in very heavy, localised rainfall coming from the water laden skies. Simplistically, this means hot regions become hotter and drier whilst cooler ones become warmer, wetter and with a higher potential for flooding. The rate of global warming is thought to be increasing at a rate of 0.2 degrees centigrade/ decade.

The AR4 observes that trends in precipitation have changed, with eastern parts of North and South America, northern Europe and northern and central Asia having significantly higher rainfall in contrast to lower rainfall in the Sahel, Mediterranean, southern Africa and parts of southern Asia. Globally, the area affected by drought has almost certainly increased since the 1970s.
There has also been an increase in the frequency and/or intensity of extreme weather events over the past 50 years. Hot days and nights have become more frequent and cold days and nights less common. It is likely that heat waves are more frequent over most land areas, that the frequency of heavy precipitation has increased over most areas, and that the incidence of extremely high sea level has increased at a wide range of sites worldwide.

What does this mean for food security?

Naturally, these climate changes have direct effects on agricultural production. It is anticipated that for moderate global average temperature increases (estimated between 1-3oC), there will be an overall increase in global food production. Additional temperature increases, however, would cause an o v erall fall in food production.

So who are likely to be the winners as the climate changes and who are likely to lose out? In very general terms, some regions at lower latitudes will become hotter and drier with a shortened growing season. Small scale and subsistence farmers will be at particular risk. The AR4 has also confidently predicted that by 2020, rain fed agricultural production will fall by 50% in many African countries. A number of arid and semi-arid areas may simply fall out of agricultural production. In contrast, other regions, in higher latitudes and including parts of Europe and the western USA, will become warmer and wetter with an extended growing season. This provides the potential of an increased level of production, though producers may need to adapt and change their agricultural techniques and the types of crops grown. The ability of a country to respond to this may well depend on its preparedness and wealth.

Future changes in the climate

If predictions based on the current levels of global warming are realised, between 75 and 250 million people will be exposed to increased water stress due to climate change. By 2030, production from agriculture and forestry is projected to decline over much of southern and eastern Australia due to increased drought and fire. By 2050, freshwater availability will be decreased in Central, South, East and S E Asia. Coastal areas will be at increased risk of flooding from the sea or the river megadeltas.

Overall, this means that we can expect malnutrition levels to increase in some of the worlds most vulnerable populations. Additionally, we need to anticipate more droughts, heat-waves and floods. This article has focused on the impact of climate change upon food security through agricultural production effects alone. However, the impact of climate change on other sectors like human health through changes in infectious disease vectors will also impact food security but are difficult to quantify.

To contact the author, email:

Additional information, including the entire IPCC report series, can be found at

Show footnotes

1IPCC 2007. Climate Change 2007. Synthesis Report. A Report of the Intergovernmental Panel on Climate Change. World Meteorological Organisation (WMO) and the United Nations Environment Programme (UNEP). Available at

2Centre for Research on the Epidemiology of Disasters. (CRED),

More like this

FEX: Climate Changeas a driver of humanitarian crisis and response

Summary of published research1 Thousands of Somalis have been displaced by what is described as the worst floods in the country in 10 years. Tufts University has recently...

FEX: Climate change causing deaths worldwide

Families wade waist high in flood water in the Philippines, to receive family pack distributions A report from the Global Humanitarian Forum1 asserts that more than 300,000...

FEX: Climate change and food security: The view from sub-Saharan Africa

View this article as a pdf This is a summary of the following paper: Adesete A, Olanubi O & Dauda R (2022) Climate change and food security in selected sub-Saharan African...

FEX: Bioenergy and nutrition: Reflections from a week of learning in Bangkok

View this article as a pdf Patrizia Fracassi Senior Nutrition and Food System Officer at the Food and Agriculture Organization (FAO) Maria Michela Morese Senior Natural...

en-net: What are specific nutrition interventions linked to climate change.

In our department we want to mainstream nutrition in global framework of climate-change strategy Thank you very much Veronika for such useful information. Climate change...

FEX: Adapting to climate change

Summary of published paper1 A house destroyed by flooding in Bangladesh A special issue of the IDS bulletin contains a series of case studies from different countries showing...

FEX: Barriers to resilience: chronic poverty, climate change and disasters in the southwest of Bangladesh

By Caitlin Macdonald, Peggy Pascal and Dany Egreteau Caitlin Macdonald has been working for Solidarités International as a DRR & Climate Change Officer in the...

NEX: Global Panel statement on climate change, food systems and nutrition

“The Global Panel on Agriculture, Food Systems and Nutrition1 strongly believes that urgent policy action is needed to tackle the challenges that climate change poses to...

FEX: Rapid response and long-term solutions: Christian Aid and food security in Ethiopia

By Antoinette Powell Antoinette Powell is the Communications and Information Officer, Africa with Christian Aid since 2007. Previously she worked as Advocacy Officer, The...

FEX: The Lancet Countdown on health and climate change: The 2023 report

This is a summary of the following report: Romanello M, di Napoli C, Green C et al (2023)The 2023 report of the Lancet Countdown on health and climate change: The imperative...

FEX: Research snapshots

Factors influencing pastoral and agropastoral household vulnerability to food insecurity in Kenya Kenya has a population of more than 38 million, 10% of whom are classified as...

FEX: False banana: the potential of Ethiopia's enset to address food insecurity in the face of climate change?

View this article as a pdf This is a summary of the following paper: O Koch et al (2022) Modelling potential range expansion of an underutilised food security crop in...

FEX: Impact of restocking on animal genetic resources after disaster

Summary of published research1 Herding cattle into water, in Bangladesh Restocking is a favoured option in supporting livelihoods after a disaster. With the depletion of local...

FEX: 2011 famine in South Somalia: the role of the early warning information System

By Abukar Yusuf Nur - Nutrition Analyst, Ahono Busili - Nutrition Team Manager, Elijah Odundo - Nutrition Data Analyst, Joseph Waweru - Nutrition Analyst, Louise Masese -...

FEX: Bioenergy and Nutrition nexus: An exploration of the links for win-win opportunities

View this article as a pdf This is a summary of the following paper: Global Bioenergy Partnership (2022) Literature review of the linkages between bioenergy and nutrition....

FEX: Increasing Access to Ready-to-use Therapeutic Foods (RUTF)

By Jan Komrska Jan Komrska is a pharmacist working at UNICEF Supply Division leading Nutrition unit and responsible for procurement of products related to nutrition...

Resource: Nutrition and Climate Change - Current State of Play: Scoping Review

Climate change is one of the biggest challenges facing both our, and future, generations. In a world where undernutrition is declining very slowly and overnutrition is...

FEX: Resilient farming in Satkhira, Bangladesh

By Emmanuelle Maisonnave and Julie Mayans View this article as a pdf Lisez cet article en français ici Emmanuelle Maisonnave is the Institutional Knowledge Building...

FEX: Issue 27 Editorial

Every emergency has a habit of throwing up fresh challenges which force us to re-examine our understanding of vulnerability and how best to respond. However, as shown in this...

FEX: Aquaponics in Gaza

By Christopher Somerville and Cyril Ferrand Christopher Somerville holds an MA in Development Studies and has lead on a number of UNFAO urban agriculture projects in Gaza...


Reference this page

Kate Godden (). The Effects of Global Warming on Food Security. Field Exchange 33, June 2008. p20.



Download to a citation manager

The below files can be imported into your preferred reference management tool, most tools will allow you to manually import the RIS file. Endnote may required a specific filter file to be used.