We have been growing rice for 9,000 years under the same thermal rule. We’re about to break it forever

The rice It is not just another cerealbut it is the fundamental pillar that supports the diet of more than half of the world’s population. For millennia, humanity has relied on its ability to thrive in different latitudes and feed entire civilizations, but now we are about to bring this ancient crop to to unknown territory due to the increase in temperatures we are experiencing.

They are documenting it. Rice has a limit to the conditions it can withstand in order to thrive, and science has sounded the alarm by pointing out that the thermal tolerance of rice has remained practically constant for the last 9,000 years, but now, in a matter of decades, we are about to break this barrier.

A thermal limit. The research work has focused mainly on cross-referencing archaeological data from millennia ago with contemporary records of cultivation and future climate projections. In this way, after tracing the evolution of rice cultivation over the millennia, researchers discovered that its historical limits have barely changed.

This means that ancient civilizations planted rice under temperature conditions surprisingly similar to the maximum temperatures supported by the current varieties we use. This is why the bug, evolutionarily speaking, has not adapted to extreme heat that it had never experienced before.

The increase in temperature. The study estimates that, towards the end of the century, the geographical area that will exceed thermal thresholds could multiply between 10 and 30 times in the main rice-growing countries of Asia. This means that the regions that are now the world’s rice granaries could become biologically hostile to the plant, not allowing it to grow.

The first cracks. It is not necessary to go to the year 2100 to see the effects of this crisis, but thermal stress is already affecting rice fields. This is evidenced by a recent study that analyzed the practical cultivation of rice in China and showed that global warming is already altering the rules of the game.

According to this workthe increase in temperatures is causing alterations in the life cycles and flowering of the plant, in addition to a worse use of the thermal resource in several of the most important rice-growing areas of the Asian giant. In other words: extreme heat is desynchronizing the rice’s biological clock, making the plant less efficient at growing and producing grain.

Its consequences They do not focus only on withered plants, but also translate into a drastic drop in production globally. Already in 2017, published research warned of plausible rice yield losses under future climate warming, and now we are seeing that the hotter the heat, the less grain per ear.

The social problem. Something to keep in mind is that, although the increase in atmospheric carbon dioxide can increase plant growth, the reality is that its effects are distributed tremendously unevenly. Here science warns that these climate alterations are increasing the achievement gap between low-income and middle- and high-income countries.

This also means that, while the richest nations will be able to invest in new infrastructure, cooling systems for crops or genetically modified varieties to be more resistant, the nations most dependent on rice will suffer the onslaught of production losses without being able to do almost anything.

Race against the clock. A priori, we cannot trust that the natural evolution of rice will save us, because if we look back, we will see that if the thermal limit of the crop has not changed in 9,000 years, it will not do so magically in the next five decades. This means that alternatives must now be considered to save the most basic food or even prepare for a restructuring of agricultural areas in Asia.

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