Climate change is a big problem for farmers in Hawaii

September 26, 2021

Michelle Galimba has always been aware of the danger of forest fires to her cattle.

Galimba is a second generation rancher in Hawaii who learned long ago that a cigarette, lightning strike, or spontaneous campfire can cause disaster if the grass that feeds her family’s herd turns brown and brittle.

For the Kuahiwi Ranch, fire hazard was usually a seasonal issue. Something to look out for in the hot and dry summer time. That has changed in the last 10 years, she said.

“We’ve lost a lot of seasonal patterns, so drought can happen anytime,” said Galimba, who watched a fire scorch 800 acres of land her family leased in 2017. “It used to be a little more predictable. You knew when to be on your guard. ”

When people in Hawaii talk about climate change, it is often through the lens of what could happen if global temperatures continue to rise. But climate change is already here, and the effects of a warming planet are being felt by the state’s farmers and ranchers.

On the north coast of Oahu, corn farmers have a harder time pollinating crops. In Kauai, farmers are struggling with topsoil loss from intense flooding. On the island of Hawaii, warmer nights make it difficult for the macadamia nut trees to bloom.

“Agriculture is probably more affected by climate change than any other industry I can think of,” said Jerry Ornellas, a farmer in Kauai. “We really are the canary in the coal mine.”

Ornellas grows fruit orchards such as lychee and rice crops such as rice on a 15-acre farm in Kauai. An intense flood in 2018 washed away nearly an inch of topsoil – something that takes at least 100 years to naturally form – on his farm. It has also diverted a stream that runs through its land.

Intense weather events are just one of the challenges facing the state. Farmers are grappling with persistent drought, more unpredictable weather patterns and a general loss of rain on the leeks of the islands.

The weather has always been a popular topic for farmers. But now those conversations are shifting to something more sinister than the rains this year.

“We’re talking about whether climate change will threaten the existence of macadamia nuts in Hawaii? From certain food crops? ”Said Nathan Trump, president of the Hawaii Macadamia Nut Association. “Are the weather events just getting too severe to make it so that we can no longer farm?”

To ensure that agriculture in Hawaii has a future, researchers at the University of Hawaii are looking for crops that can withstand the increased heat, soil salinity, and droughts expected in the future. Farmers, meanwhile, say more research is needed, along with investments in infrastructure that will help agriculture thrive in more unpredictable climates.

The time to invest in this type of research – and support the types of sustainable agriculture that extract more carbon from the atmosphere than it produces – is now, they say.

“The time to fix the roof is obvious when it’s not raining,” Ornellas said.

A warming, unpredictable climate

Hawaii is blessed with a year-round growing season and a range of microclimates that allow farmers to grow a dizzying variety of crops. But the state has seen a long-term decline in rainfall, said Chip Fletcher, a climate scientist with the University of Hawaii.

Perennial flowing creeks are no longer running on Oahu’s Leeward Coast, and the state has observed similar drying of watersheds in rain-shadow areas on the islands – a major concern given that agriculture is so water dependent.

At the same time that the state is seeing an overall decline in rainfall, the rains are getting more intense, Fletcher said.

Essentially, we are experiencing prolonged periods of drought combined with more intense storms – like the one that caused catastrophic flooding on Kauai in 2018. This is a global phenomenon, said Fletcher. A fundamental characteristic of a warmer atmosphere.

It’s getting warmer in the state too. According to the National Oceanic and Atmospheric Administration, the average temperature in Hawaii rose about 2 degrees between 1950 and 2010. On Oahu, 2019 was the hottest year ever recorded. Nationwide, temperature records were broken 300 times this year, Fletcher said.

Changes in temperature, wind, rain patterns, and extreme weather events can all have devastating effects on crops.

Hotter summers on Oahu have seen a decrease in sweetcorn pollination, says Amjad Ahmad, an assistant extension agent at UH Manoa’s College of Tropical Agriculture and Human Resources who is helping bridge the gap between college researchers and farmers who do Need help. Part of this could be because corn silk needs to stay moist so that pollen can adhere to it and form seeds, and heat can dry out the corn silk, among other things.

Not only pollination is at risk.

With additional heat, plants have difficulty absorbing moisture from the soil, Ahmad said. If plants cannot absorb enough water to make up for the loss of moisture from their stomata – essentially the plant-based version of the pores – then plants will not be able to produce food and will not grow.

Ahmad personally grows around 10 types of okra. A recent harvest is half the size of the plants a few summers ago, he said – something he attributes to the heat. Too much heat can cause other plants, such as lettuce, to bloom or bloom, essentially ending the plant’s life prematurely and rendering it unusable for harvest and sale.

Ahmad, who is testing different varieties of plants to see which are best for the islands, said he left several types of beets and daikons prematurely this summer.

A bigger concern for Hawaii than the corn or lettuce challenges is that too much heat can increase the salt content in the state’s popular taro fields, which over time can create major crop problems.

Heat can also be a challenge for growing macadamia nuts – one of the most successful crops in the state.

In order for macadamia nut trees to bloom well, winter nighttime temperatures need to reach 63 to 64 degrees for a certain number of days. In years when temperatures were higher than normal, larger farms in the Hilo and Ka’u area had lower yields because flowering wasn’t as good, said Trump of the Hawaii Macadamia Nut Association.

A surge in pests and root-borne pathogens – made worse by heavy rains that create soil conditions for microorganisms to thrive – has compounded the decline in macadamia nut trees on the Hilo side of the island of Hawaii, Trump said. Several hundred hectares of trees have been abandoned by farmers in recent years, he said.

Many factors affect the harvest and the challenges for Hawaiian farmers go beyond climate change. For example, the abandoned macadamia nut trees in the Hilo area of ​​Island of Hawaii are old – which could make them more susceptible to disease and pests.

However, farmers and scientists say the link with climate change is significant. And climate change doesn’t just affect things like pollination and plant growth.

“What about our human resources? Will we be able to find people to work in really scorching heat?” said Ornellas.

The production processes have to adapt to climate change. Transport is impaired. Marketing. Even things like capital are a problem for farmers, he said. Will farmers have the money to make the necessary changes?

Look to the future

Farmers are naturally optimistic, Ornellas said.

“We will always make money next year. We will always be fine next year,” he said.

But Ornellas doesn’t sound too optimistic when he talks about the future of agriculture in Hawaii.

“Realistically, it doesn’t look good. Unfortunately, agriculture in Hawaii is not doing well and climate change is not going to help improve the situation.”

In order for farmers to thrive in the decades to come, more needs to be done now, according to Ornellas.

Hawaii’s agriculture has long been in flux, moving away from the plantation era towards a system of more diversified agriculture. But the larger plantations used to have a lot of infrastructure for agriculture, Ornellas said. Channels. Drainage ditch. Gauging stations to monitor water and river volumes – something the east side of Kauai no longer has, he said.

Addressing the state’s water supply is a major challenge. Aquifers are recharged with long, gentle rainfall that lasts for several days, Fletcher said.

When it rains heavily, most of the water flows into the sea. If the state sees a decrease in the type of rain that maintains the state’s water supply and an increase in intense rainfall, how can Hawaii’s water engineering system adapt?

Another approach to adaptation is to change the types of plants grown in Hawaii. Ahmad and other advisors at the university looked for different types of sweet corn and other crops that would better adapt to the changing temperatures in Hawaii.

This is a successful tactic for farmers in the Philippines, Ahmad said. At some point, salty water began to affect rice production and so the farmers found rice varieties with a higher salt tolerance.

More research is needed on all fronts. Researching the state’s climate change, how to make agriculture more adaptable – and how best to use agriculture in the fight against climate change.

Tree crops can be more resilient than other plants. They also remove carbon from the atmosphere and release it into the soil. A macadamia nut orchard – if well managed – can sequester 5.8 tons of carbon per acre per year, Trump said.

“We see the challenges of climate change,” said Trump. “But we also see the opportunity to expand our industry in order to curb climate change.”

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