Climate change to affect water availability, alter food production: UN report

Water mediated many climate change impacts on agriculture, said the report

By Shagun
Published: Sunday 22 March 2020

Global food production patterns would be fundamentally altered by climate change, causing food insecurity because of small shifts in seasonality and water availability, according to the World Water Development Report released by the United Nations on March 22, 2020.

An increase in food prices would increase rural poverty, the report said.

The impact of regional precipitation patterns on four major crops – wheat, soybean, rice and maize – was already projected to emerge by 2040, according to an article published by journal Proceedings of the National Academy of Sciences of the United States of America in May, 2019.

Portions of land used to cultivate these crops in some countries would witness permanently drier conditions, whereas in others, similar land portions would face permanently wetter conditions from climate change, the report said, quoting the article.

Land currently dedicated for wheat cultivation in India, for example, would get more precipitation between 2020 and 2060, under present trends in greenhouse gas (GHG) emissions.

In land areas of countries like Mexico and South Africa, however, 87 and 99 per cent of the land, respectively, would receive less precipitation.

The tropics and the north would become wetter, while parts of Africa, the Americas, Australia and Europe would become drier, the report’s projections showed.

In India, 100 per cent of the land dedicated to rice cultivation, 91 per cent of land for maize and 80 per cent for soybean would face wetter conditions within the next 40 years, according to the report.

Longer-term shifts in temperature and precipitation and day-to-day weather variations within the next 50 to 100 years would increasingly expose agriculture and impact food security, the report points out.

Major agricultural systems the world-over — including the semi-arid Indian subcontinent and the Mediterranean region in north Africa — were highly vulnerable to climate impacts.

Increased rainfall, drought and flooding coupled with higher temperatures were the climate change drivers that the monsoonal Indian subcontinent would witness.

The climate change drivers include 20 years of increasing flows, followed by substantial reductions in surface water and groundwater recharge, changed seasonality of runoff and peak flows, increased peak flows and flooding, increased salinity and declining productivity.

The Indus and Ganga-Brahmaputra agricultural systems would face limited room to adapt to climate change in the first instance, the report said.

The vulnerability to climate change in these systems is ‘very high’ and ‘high’, respectively.

Non-monsoonal sub-Saharan Africa was also categorised with a ‘very high’ vulnerability, according to the report.

The region would witness declining yields because of increased rainfall variability and more frequent droughts and floods.

Increased volatility of precipitation and rainfall in particular (intensity, duration and frequency), would challenge adaptive responses in some of the most productive agricultural systems, according to the report.

Increased water scarcity also posed a major challenge for climate adaptation in many regions of the world, since water mediated many climate change impacts on agriculture.

The role of agricultural water management was key to adaptive responses in agriculture, allowing flexible crop production cycles in cash crops and staple foods, notably rice.

Challenges for agricultural water management are two-fold under climate change, according to the report:

“First, there is the challenge to adapt existing modes of production to deal with higher incidence of water scarcity (physical and economic) and water excess (flood protection and drainage). Second, the challenge to respond to the policy drives to decarbonise agriculture through climate mitigation measures that reduce GHG emissions and enhance water availability.”

An increase in demand for calories from low and middle-income countries would cause an increase in production, said the report, quoting long-term projections from a 2017 Food and Agriculture Organisation report.

This would in turn risk incremental changes in climatic regimes and extreme events, particularly in west Asia.

The global food system manages to meet growing calorie demands, according to the report

The number of those severely undernourished, however, was rising in absolute terms, from the current 821 million people or 11 per cent of the global population, the report said.

The focus of countries should not just be on the variable of water in agriculture, according to the report.

A broader consideration of water in relation to other inputs, through a package of climate-smart measures, was necessary, it said.

“The adjustments need to match the scale of the hydrological system if they are to produce positive outcomes in agricultural system performance (in relation to climate variability) and lead to net reductions in GHG emissions,” the report added.

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