Overcoming climate-threat to rice production: Bangladesh and beyond

Rice is a primary food source of the world along with wheat and maize and is the major source of food in Asia, including Bangladesh.  Bangladesh has 10 million hectares of rice land with an average of a bit more than 4 tonne per hectare.  Rice is a major pillar of our economic development and food security.  As climate changes ravage the world rice production faces unknown threats in coming years.  The rise in earth's temperature has set in motion storms, droughts and heat waves.  Rice production in coming years will not be immune from these changes sweeping the world.  

A major worry is that rice is being grown in some of the most climate-vulnerable parts of the world, including the deltas of our nation.   Any disturbance in the weather pattern such as storms, heat-waves or rise of sea levels will impact on rice production.  In spite of many proclamations we do not have the necessary resilient processes in place to protect undisturbed production of rice. 

In fairly recent memory in 2008, we witnessed a food crisis that sent rice prices soaring. That was 13 years ago, when we had one billion fewer people amongst us in the world.  If we project to the next 15 years to 2035 the world’s climate is expected to warm in an uncertain way and the population is expected to boom by another one billion, 8.8 billion people. Are we ready for that change?

The latest report from the Intergovernmental Panel on Climate Change—(IPCC) brought together 234 scientists to analyse the  recent climate studies—opined that  global warming is happening at an unprecedented pace.  Such changes are causing the deadly floods, heat and droughts we’re already witnessing.  Our farming system world-wide and the rice farming system in particular are vulnerable to such changes.  

The report says pointedly “higher temperatures lead to increased evaporation, resulting in soil drying, increased plant stress and impacts on agriculture, even in regions where large changes in precipitation are not expected.”

Rice is particularly vulnerable to these expected changes. Rice grows in riverine ecosystems with low elevation and vulnerable to rising seas; such as the southern deltaic regions of Bangladesh.   Rice is also being grown in areas that are already experiencing high heat. Any climate-mediated additional temperature increase could push it beyond the threshold and into chronic crop failure.

A 2018 study in the Archives of Agronomy and Soil Science found severity of hot weather could reduce rice yields by up to 40% by the end of this century.

 “……….. any further rise in mean temperature or short episode of high temperature during sensitive growth stages, will be catastrophic.”

Rice can grow in temperatures of 40 degrees Celsius (104 degrees Fahrenheit), but heat stress can impair the ability of its flowers to pollinate, Temperatures above 35 C can significantly decrease yields.  The weather data suggests that such temperature is routinely encountered in Bangladesh during rice growing season strongly indicating a need for heat resistant rice varieties. One recent study found that each 1 C increase in night temperatures above 35 C leads to around a 10% decline in rice yields.

In addition to heat the increased potential for flooding, drought and the rising seas that can inundate low-lying farmland with salt water threaten future rice production.

 In Bangladesh population booms and urbanization is putting continuous pressure on rice land.  Rice growing areas are incessantly being converted into homesteads, shops, industries as shown in vast areas gobbled up by non-rice activities in Madhabpur area of Sylhet division over resistance of local farmers.  Such short-sighted industrialization and removal of rice growing areas to other uses threatens our food security.  

Rice production increased during the Green Revolution of the 1960s but it also led to a loss of rice biodiversity.  Most of the heritage rice varieties of Bangladesh, poetic names such as Dumai, Kasalath, Chengri , Baurosh are either extinct or are being maintains in the freezer of BRRI and IRRI.  The alteration of soil and ecosystem due to rice mono-culture is also a part of this modernity-mediated destruction of soil and eco-system.

While global rice production is forecast to hit a record 506 million tonnes for 2021-2022, global consumption is expected also to be a record 514 million tonnes.  Without a major change in policy and major new discoveries increasing production this level of production is not sustainable in the face of climatic changes of the coming years. 

The transformation of the landscape in rice growing countries including Bangladesh is occurring right in front of our eyes.  Ideas coming from economic rationalism in which agriculture must pave the way to industrial development is destroying agricultural land in an unprecedented scale.   There is nobody around who can stand up on behalf of the farmers and the farming system to draw a line on the sand.  The long term future of the whole rice farming system is now under threat.   

A lot is being asked from the researchers.  Faced with the prospect of depleting land and adversity of climate science is being asked to deliver the magic solution of increasing production from a smaller land area under high environmental stress.  That demand is occurring in a situation in which less than 1% of the GDP is delineated for research and development and young scientists, devoid of a good career prospect leaving science altogether in increasing numbers.  

We in the historic village of Kanihati in greater Sylhet have stepped forward in a spirit of patriotism to develop rice varieties with higher climate resilience and greater production.  Over the last 20 years we have developed multiple varieties that grow for the whole year and can be harvested five times after one planting.  In addition we have developed high yielding Aman and Boro varieties that can be harvested one month earlier than the existing varieties.  These multiple-harvest varieties combined with earliness of life cycle will lead to a quadrupling of rice production.  When deployed into 87,000 villages of Bangladesh, these varieties will provide a powerful example of climate-responsive rice production for increased food security in Bangladesh and beyond.

Writer: Scientist