Climate change not the main driver of Madagascar food crisis, scientists find

§ ‘Highly vulnerable to drought’

Madagascar is a large island nation in the Indian Ocean. It is a country of extreme poverty, where more than 90% of the country’s 26 million inhabitants live on less than $1.90 per day. In 2019, the island ranked as the fourth highest in the world for chronic malnutrition and had among the lowest human capital index in the world.

Agriculture is a mainstay of Madagascar’s economy, providing a livelihood for around 80% of its population. ​​Most farmers rely on rain-fed crops and practice subsistence agriculture, growing rice, cassava, bananas, maize and sweet potatoes. However, yields on the island are generally low and have not been keeping up with population growth (pdf).

Madagascar has a subtropical climate. The country experiences a hot and rainy season between November and March, while May to October are characterised by cooler, drier weather. Southern Madagascar is particularly arid and typically only sees rain for the first few months of the year, while the southwest and extreme south of the island are classified as “semi-desert environments”, typically receiving less than 800mm of rainfall per year.

Denis Bariyanga is an operations coordinator for the Indian Ocean islands cluster at the International Federation of Red Cross. He tells Carbon Brief that communities in southern Madagascar are highly vulnerable to drought:

“Communities in the south of Madagascar have always been vulnerable due to the semi-arid climate, the El Niño phenomenon, the primitive agricultural methods and the difficult access to the different localities in this part of the country. While the drought has been categorised as prolonged and aggravated since 2013, the food-related issues have been emerging even before 2000 due to those recurrent moderate droughts.”

The World Bank says that Madagascar is “one of the African countries most severely affected by climate change impacts”.

§ Drought and food insecurity

Southern Madagascar’s food crisis of 2020-21, which has pushed more than 1.14 million people into food insecurity, was triggered by low rainfall over a 24-month period. The study finds that the rainy seasons of 2019-20 and 2020-21 brought just 60% of “normal” rainfall to the region, driving “significant crop failure” and “famine-like” conditions across much of the region.

The plot below, taken from the study, shows 24-month rainfall totals from the 1980s to the present day. It highlights the droughts of 1990-92 (red) and 2019-21 (purple).

In early June 2021, the World Food Programme (WFP) announced that southern Madagascar was “experiencing its worst drought in four decades”, warning that 14,000 people were already facing “catastrophic conditions”. On 23 June, WFP executive director David Beasley put out an appeal for help for Madagascar:

“There have been back-to-back droughts in Madagascar which have pushed communities right to the very edge of starvation. Families are suffering and people are already dying from severe hunger. This is not because of war or conflict, this is because of climate change. This is an area of the world that has contributed nothing to climate change, but now, they’re the ones paying the highest price.’’

Southern #Madagascar: the frontlines of the climate crisis. These families have done nothing to deserve the worst drought in 40 years. Yet, their lives are devastated and thousands are on the brink of famine.

We must act NOW to save lives. pic.twitter.com/zGVV42rOFf

— David Beasley (@WFPChief) June 21, 2021

The plot below shows food security in southern Madagascar over April-September 2021, based on a five-tier food security scale, where 1 (green) indicates “minimal” food insecurity and 5 (dark red) indicates “famine”.

“This year marks the first time that people have been recorded in IPC5 [the highest tier of the food security scale] since the methodology was introduced in Madagascar in 2016”, Bariyanga tells Carbon Brief. He adds:

“The south of Madagascar depends on rain-fed agriculture. Since the region faced recurrent drought for several years, this had a devastating impact on access to food for communities… In an area where more than 80% of the population are dependent on agriculture, this [rainfall deficit] exerts additional pressure on the very lean resources available and leads to a deterioration in the nutritional situation.”

In mid-November, the WFP appealed again for “solidarity and funding”. The organisation has been supplying some 700,000 people on the island with food and supplemental nutritional products for pregnant and nursing women and children – but still found that that “close to 30,000 people in Madagascar will be one step away from famine by the end of the year, and some 1.1 million already suffer from severe hunger.”

🇲🇬 Madagascar is facing one of the world’s first famines driven by climate change, hunger experts warn.

🔴 Families are now forced to eat insects and cactus leaves as crops fail.

🚨 @WFP says this crisis is a warning to the world. Here’s why you need to pay attention. 🧵 pic.twitter.com/u5vmvcxZ8i

— TRF Climate (@TRF_Climate) November 3, 2021

§ Attributing drought

Attribution is a fast-growing field of climate science that aims to identify the “fingerprint” of climate change on extreme-weather events, such as heatwaves and droughts. In this study, the authors investigate the impact of climate change on rainfall in southern Madagascar over July 2019 to June 2021.

To conduct attribution studies, scientists use models to compare the world as it is to a “counterfactual” world without human-caused climate change. This study aims to distinguish the “signal” of climate change in Madagascar’s rainfall from natural variability. 

The plots below show total (left) and wet-season (right) rainfall in southern Madagascar over 1980-2021. The lines indicate the CHIRPS rainfall dataset (blue), which is based on rain gauges and satellite observations, and the ERA5 reanalysis dataset (orange), which combines observed data and model simulations. 

The study classifies the drought in southern Madagascar is a “1-in-135 year dry event” – meaning that in today’s climate, a drought of this magnitude would be expected less than once per century. Dr Friederieke Otto – a senior lecturer in climate science at the Grantham Institute for Climate Change and the Environment and co-lead of the WWA – tells Carbon Brief that this makes the drought “a rare event”.

However, as rainfall in southern Madagascar varies so much on a year-to-year basis, the study finds that climate change played “no more than a small part” in the drought. It concludes:

“The occurrence of poor rains as observed from July 2019 to June 2021 in southern Madagascar has not significantly increased due to human-caused climate change. While the observations and models combine to indicate a small shift toward more droughts like the 2019-21 event as a consequence of climate change, these trends remain overwhelmed by natural variability.”

Instead, the study highlights the “high pre-existing levels of vulnerability to food insecurity” that have seen the drought turn into a food crisis. The authors say that poverty, poor infrastructure and dependence on rain-fed agriculture are the main drivers, adding that the impacts were “compounded by Covid-19 restrictions and pest infestations”.

This result is consistent with previous research and a conclusion from the most recent Intergovernmental Panel on Climate Change (IPCC) sixth assessment report (AR6) that any perceptible changes in drought would only emerge in this region if global average temperatures exceed 2C above pre-industrial levels, according to the study.

(The findings are yet to be published in a peer-reviewed journal. However, the methods used in the analysis have been published in previous attribution studies.)

§ Complex extremes

The study notes that droughts are “comparably complex extreme events which depend on a number of climate and non-climate factors”, adding that this “poses challenges for their attribution”. 

For example, explains Otto, droughts are more difficult to link to climate change than heatwaves because, while climate change is “really a game changer” for heat, the climate change signal for rainfall tends to be “small” compared to natural variability.

Another complicating factor is “event definition”. There are many ways of defining drought – including agricultural droughts that focus on soil moisture, and pluvial droughts that focus on surface and groundwater flows. This study focuses on hydrological drought – defined only by the amount of rainfall a region receives.

Otto explains that the researchers focused on hydrological drought because “from studies into similar climatic regions, we found that it is really rainfall that determines the drought”. She adds that the meteorological service in Madagascar, who collaborated with the WWA team on the project, also see hydrological drought as “the issue” in the country.

Dr Nikos Christidis – a senior climate scientist from the UK Met Office who was not involved in the study, also highlights the difficulty in defining drought, noting that “this analysis provides useful information about the effect of human influence on rainfall, but not on other variables that also need to be considered so that we understand better the impact of anthropogenic climate change on droughts”.

Dr Peter Stott is a science fellow in climate attribution at the UK Met Office and was also not involved in the study. He tells Carbon Brief that this is “an interesting study by a strong group of researchers”. However, he adds:

“I think a result of this importance – that climate change made a negligible contribution to the devastating drought – would benefit from confirmation from other studies including in the peer-reviewed literature.”

For example, a number of studies of the severe drought in California over 2011-17 came to different conclusions around the influence of climate change.

And Dr Tamara Janes – a Met Office climate scientist focusing primarily on international development in Asia and Africa – tells Carbon Brief that the study “helps to highlight the importance of understanding and building resilience to existing vulnerabilities”. She adds:

“While the results of the study suggest that the current, devastating food security crisis in Madagascar cannot be significantly linked to observed human-induced climate change, it’s important to recognise that events such as these are likely to be exacerbated in a changing climate.”