This story about how an early spring is affecting agriculture, ecosystems and allergies was originally published by the Mississippi River Basin Ag & Water Desk.

COLUMBIA, Mo. — As a row crop farmer in St. Joseph, Mo., Joe Lau said he’s noticing more extreme weather these days. 

Warmer seasons throughout the year. Quarter-inch predictions of rain stamped out by storms that bring three inches. Increased pressure from pests on his corn. He’s also noticed that spring is coming earlier. 

The USA National Phenology Network shows that this year spring arrived three to five weeks earlier than the average between 1991 to 2020 in much of the central U.S. and two to three weeks earlier in southern Midwest states. 

Related: Milder winters, earlier springs and other symptoms of ‘warming winter syndrome’

“I have allergies bad,” said Lau, who also grows soybeans. “And this year in particular, it’s hit me hard. It’s wild that we are talking about allergy issues in winter, but that’s technically the reality of it.”

Last month, Climate Central, a nonprofit specializing in communicating climate science, published an analysis which found that spring is trending to an earlier arrival from 1981 to 2025 in most of the United States.

On average, leaves now emerge six days earlier than they did in 1981 in 88% or 212 out of 242 major U.S. cities. For example, in Lau’s city of St. Joseph, Mo., the spring leaves tend to arrive two days earlier. 

An earlier spring could have consequences for the agriculture industry, ecology and more.

Where are spring leaves arriving earlier?

Climate Central used open-access data that was collected by the USA National Phenology Network, a group of volunteers and researchers who study seasonal events — like when migratory birds arrive, leaves emerge and fruit ripens —  among plants and animals to determine ecosystem health. 

The analysis is based on the NPN’s first leaf index maps, which use models to predict the start of spring. To work, the models are fed data like temperature and the start date of the annual “leaf-out” — when leaves first emerge —  for the early spring plants of lilacs and honeysuckle, which are found throughout the U.S.

“That very leading edge of spring is drifting earlier and has drifted, in some cases, a whole lot earlier in just that last few decades,” said Theresa Crimmins, the NPN’s director, in a briefing last month.

Climate Central’s analysis found that many Mississippi River basin cities are seeing earlier spring, including Hazard, Ky., which is seeing leaves arrive 11 days earlier. Both Memphis, Tenn. and St. Louis, Mo. are leafing out seven days earlier. New Orleans, La. is two days earlier.

While most of the lower 48 states are experiencing an earlier spring, the report did find an exception in the Northern Rockies and Plains region. There, spring temperatures have either cooled or warmed “relatively slowly” since 1970, according to the report.

Kaitlyn Trudeau, a climatologist with Climate Central, said the differences in how much earlier spring is coming from place to place are likely due to what she calls “climate controls” — such as latitude, elevation, wind patterns, proximity to bodies of water, ocean currents and topography.

“All of those different factors really dictate what your local climate is like generally,” Trudeau said.

What does early spring mean for agriculture and more?

The early arrival of spring can have widespread impacts, said Trudeau. People with seasonal allergies, like Lau, will be exposed to more pollen because plants get more time to produce and release it.

Warmer temperatures can also cause birds to migrate too soon. One of the busiest migratory routes or flyways, in North America moves along the Mississippi River. Each year, about half of all migratory bird species on the continent follow it to get from as far north as Canada to Central and South America and then back.

When birds migrate too soon, said Trudeau, they miss out on the peak abundance of food. They can fall out of sync with insects or the flowers they pollinate, which can affect other species, too.

“That can cause this ecological mismatch,” Trudeau said.

Earlier springs can also put the agriculture industry at financial risk, she said. Whether it’s corn, soybeans or specialty fruits, these crops can get hit with a hard freeze following an early leaf out — also known as a false spring. It could lead to major economic damage in the agriculture industry, said Trudeau.

In 2017, a hard freeze in the southeastern U.S. destroyed fruit crops like peaches, pears, blueberries, strawberries and even grass for livestock. It led to more than $1 billion dollars in losses for the agriculture industry, according to a report from NOAA.

“We are so dependent upon what happens in the natural environment,” Trudeau said. “And so when things start to shift and change, it’s also going to cause pretty widespread impacts for our lives.”

Growers of specialty crops — such as apricot trees or iris flowers — will be particularly vulnerable. Row crop farmers, like Lau, have more technology to aid them. He said seed treatments have allowed soybean farmers to plant earlier and grow longer, increasing their production. 

So the effects of an earlier spring have been “minimal” for him.

“From purely a row crop production standpoint, the springs have been very favorable for us,” said Lau.

Related: Three years on, Minnesota’s climate change initiative spurring projects across the state

One thing that does have him worried is the bug activity out in his fields — they’ve been plentiful with the warmer weather. 

“I raise all non-GMO corn and so I don’t have the insect traits bred into the corn genetically modified and so that does concern me that we’re kind of relying on what nature hands us,” Lau said. 

While farmers and communities are doing their part to innovate and adapt to continue producing, Trudeau said addressing the root of climate change is the most urgent need.

“There is no substitute for dramatically reducing our carbon pollution,” she said.

This story is a product of the Mississippi River Basin Ag & Water Desk, an independent reporting network based at the University of Missouri in partnership with Report for America, with major funding from the Walton Family Foundation.

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