Bean crop will be under ‘severe climate stress’ by 2050 - scientists

Climate change will reduce growth and nutritional value of key staple crop

Harvested common beans at Field Day in Bugesera District, Rwanda in June 2018. Photograph: T Muchaba, CGIAR Research Programme on Climate Change, Agriculture and Food Security.

Harvested common beans at Field Day in Bugesera District, Rwanda in June 2018. Photograph: T Muchaba, CGIAR Research Programme on Climate Change, Agriculture and Food Security.

 

By 2050 one of the world’s key staple crops – the common bean – will be under “severe climate stress” and will have less nutritional value where it’s still possible to grow it, scientists at NUI Galway have predicted.

As it takes decades to develop and establish new crop varieties, major investment is needed now to climate-proof many of the world’s crops and cropping systems, they warn.

The common bean is critical to the diet of hundreds of millions of people, especially in Africa.

The development of new crops and new varieties of existing crops is to ensure “both their yields and nutritional quality can be resilient to future climate change stresses”, the scientists conclude.

Their research, published on Thursday in the journal Nature Scientific Reports, indicates both the nutritional quality and yields of the common bean will be reduced “under drought stresses” arising in south eastern Africa by 2050 as a result of climate change.

Cultivation

The scientists conducted crop simulation modelling, combined with field trials and molecular laboratory experiments to analyse yields and nutritional quality of the crop through a collaboration between Ireland and Malawi.

Their analysis reveals the majority of current common bean varieties growing in areas in south eastern Africa will become unsuitable for cultivation by the year 2050.

They demonstrated reductions in yields of common bean varieties in field trial experiments at a research site that was representative of future predicted drought conditions.

Nutritional analysis of the different varieties revealed important micronutrients for human health, such as iron, were reduced in all bean varieties, while “anti-nutritional compounds” such as phytic acid and lead were increased.

Lead scientist on the study, Prof Charles Spillane, cited an emerging body of evidence that climate change will reduce the quality of many of the world’s staple crops due to the effects of rising temperatures, reduced rainfall and rising CO2 levels on the nutritional composition of the crop-derived foods that underpin global food security and human health.

“Our results highlight the need for accelerated development and seed-system distribution of heat-tolerant and drought-tolerant common bean varieties that can maintain yields while also improving nutritional quality, for example, through genetic ‘biofortification’ breeding under future climate change scenarios,” he added.

Food security

The NUIG research, funded by Irish Aid, Science Foundation Ireland and the CGIAR Research Programme on Climate Change, Agriculture and Food Security, outlines “challenges for ongoing climate-proofing of bean production for yields, nutritional quality, human health, and food security”.

“Given that diets in Africa rely significantly on plants, there is major cause for concern if climate change leads to lower levels of essential nutrients such as protein, iron and zinc in our diets by 2050,” according to Dr Andy Jarvis of the CGIAR Research Programme on Climate Change, Agriculture and Food Security.

“Such loss of dietary nutrients in foods will further aggravate the nutritional deficiency experienced by hundreds of millions of people, particularly the poorest in developing countries in Asia and Africa,” he added.

Dietary deficiencies of micronutrients such as iron constitute major public health problems globally, particularly among women and children in sub-Saharan Africa, according to NUIG PhD students Marijke Hummel and Brendan Hallahan who worked on the study.

They noted that for the third year in a row there has been a rise in world hunger, where climate variability and extremes are “now a key force behind the recent rise in global hunger”. Their research showed crop outcomes by 2050 “would most heavily impact on the poorest and most nutritionally insecure in our societies”.