Researchers from the London School of Hygiene and Tropical Medicine have found that the yields of certain fruits, such as soft fruits, grapes, and bananas, are at risk of falling by almost a third due to the threat of climate change. Two of the most important factors are reduced rainfall and increased water salinity which are caused by, for example, the rising sea levels and storm surges. These factors could reduce fruit yields by around 21% and 28%, respectively, unless action is taken.
Grapes, bananas and peanuts would be most affected by drought, while citrus fruits would be most affected by increased water salinity, the study found.
This is the first study, published in the journal Environmental Research Letters, to look at all the available data on how changes in the climate will affect fruit, seeds and nuts.
The study found that increased concentrations of carbon dioxide – which speeds up the rate of photosynthesis in plants – may lead to improved growth of berries and peanuts. However, this positive effect would be offset by the rising temperatures predicted under climate change.
Water stress can affect different crops in different ways, for example the growth phase of hazelnuts and the reproductive phase of peanuts are particularly sensitive to drought, whereas almonds are relatively resistant.
The researchers found that drought and water salinity had a greater effect on yields than higher temperatures – but this might be because there was more research published on drought and its effect on fruit and seeds than on heat.
Pauline Scheelbeelk, assistant professor of nutritional and environmental epidemiology at the LSHTM and one of the authors of the study, said that it was important to look at climate change and its effect on food with a high nutritional value.
Prof Scheelbeelk and her team conducted a similar study on vegetables last year – this also found that climate change could reduce yields by around a third.
“We’re starting to recognise that the fruit and vegetable supply might not be as resilient as we thought. In a world where fruit and vegetable consumption is low – in the UK only 20 per cent of adults adhere to the five-a-day recommendations – any further reduction in consumption could be harmful,” she said.
Parts of the world that were particularly vulnerable included sub Saharan Africa, the Americas and India, the study found.
“Because the world is so connected we will have to rethink how we can have a sustainable and resilient food system.
"Importing large amounts of fruit from countries that are already dealing with water scarcity, such as India, may be something we may not wish to do from an ethical perspective,” added Prof Scheelbeelk.