As Japan swelters, farmers turn to new heat-resistant rice varieties to boost staple crop

Original article by Justin McCurry in Shiroishi

When schoolchildren in Shiroishi were enlisted to plant rice seedlings in June, Shinto priests blessed the land and asked the deities for a bountiful crop. Judging by the fields behind farmer Haruki Kawasaki, their prayers have been answered.

The 63-year-old is preparing to harvest this year’s crop of hinatamaru, a variety of rice whose plump grains have thrived despite exposure to another hot and dry summer, conditions that typically punish rice yields.

Hinatamaru is one of growing number of heat-resistant rice varieties that are giving fresh hope to farmers across Japan that they can overcome a climate emergency that is threatening the country’s staple crop.

Kawasaki and his team once spent the entire day in the fields, but the heat has made that impossible. “Now we start early in the morning and work until around noon,” he says. “It’s way too hot in the afternoon … although the mornings are not what you would call cool.”

Kawasaki and other farmers in Saga are at the centre of the boom as Japan finds ways to cope with a warmer future. The long process of developing heat-tolerant strains involves cross-breeding existing varieties, cultivation in controlled environments and, finally, real-world trials.

Japan’s ageing farmers have toiled through record-breaking heat and below-average rainfall over the last three summers. After heat records were broken again this year, the meteorological agency added a new category – “cruelly hot days” – when the mercury exceeds 40C. El Niño is expected to bring even more extreme weather.

Those conditions create havoc with crops of Japan’s staple cereal, producing chalky, anaemic grains that are susceptible to cracking when polished for commercial sale.

When the temperature stays abnormally high for prolonged periods after rice plants have flowered, what should be translucent, starchy seeds end up as immature grains that can’t be sold as grade 1 polished rice on the open market.

In a report published this month, Greenpeace Japan warned that four of the country’s “iconic” autumn crops, including rice and sweet potatoes, were at risk because of exposure to long periods of high temperatures.

“Over 50 years of accelerating heatwaves have pushed Japan’s most iconic agricultural hubs past their thermal limits, placing both crop viability and supermarket prices on the line,” Ikumi Toyota, from Greenpeace Japan, said in a statement.

“While farmers are showing incredible ingenuity to adapt, single operations cannot outrun systemic climate disruption. When the people who feed us run out of options, national food security becomes everyone’s crisis.”

Embracing heat-loving crops

The climate crisis has made growing traditional rice varieties a calculated risk that fewer farmers are willing to take. In Saga prefecture, located on the coast of the Ariake Sea in Kyushu – a large island in Japan’s south-west – growing numbers are instead taking a chance on something new.

According to the agriculture ministry, Saga now leads the county in the adoption of new strains that can withstand the stifling, bone dry summers that have become the norm.

Heat-tolerant varieties account for almost 67% of Saga’s rice acreage. Neighbouring Nagasaki follows with just under 50% and Shimane, on the Japan Sea coast, with 47%. However, uptake in regions in the north-east, where farmers are traditionally more accustomed to battling cold weather, is still very low.

Heat records have tumbled in Japan in recent years. Record-breaking heat in 2023 was partly to blame for the “Reiwa rice crisis” the following year, when the government was forced to take the unprecedented step of releasing emergency stockpiles to ease severe shortages and price hikes.

Farmers in Saga raised the alarm a decade ago, when low yields of poor quality rice sent prices plummeting. “They were determined to grow delicious rice that could withstand the heat,” says Kazuhiro Matsumoto, a senior official in the crop department of the Saga Prefecture Agricultural Testing and Research Centre.

The solution came in the form of hinatamaru – the product of 12 years of research that is now spreading quickly after successful trials in 2024 – propelling Saga prefecture to the forefront of agriculture’s rearguard action against climate change.

Kawasaki’s crop of hinatamaru is this year is expected to total a modest 600kg but the outlook is promising. And other regions in Japan are following suit.

The use of heat-tolerant rice has expanded to all but three of Japan’s 47 prefectures as agriculture officials rush to combat declines in quality and yield. They covered 248,000 hectares last year – a record 18% of the overall rice crop – according to the agriculture ministry, a dramatic increase from the 42,000 hectares the previous year.

The climate emergency is also changing the way Japan’s farmers work. Fruit and vegetable farmers in some regions have taken to inspecting their crops at night, to avoid higher temperatures, while others are switching to heat-loving crops such as avocado, bitter melon and okra.

Kawasaki, who has been growing rice for more than three decades, says the day could come when farmers across Japan are all growing new heat-resistant varieties. “The priority is that it has to taste good.”

As he prepares to harvest this season’s crop – some of which will be included in an annual ritual at the imperial palace in Tokyo – Kawasaki also notes that the spread of heat-tolerant grains as a race against time. Almost 70% of Japan’s agricultural workers are 65 or older.

“Lots of farmers around here are in their 70s, and I’m in my 60s,” he says. “So as a farmer, I’m just grateful that we have found something that works. And it tastes great.”