Climate is hotter, longer and wetter? North Dakota sees steep change in trends
FARGO — Warmer winters, longer growing seasons and wetter wet cycles: This is what climate change looks like in the Red River Valley.
Over the past 124 years, North Dakota has warmed at a steeper rate than all other states except Alaska, according to the North Dakota state climatologist.
Northwestern Minnesota has followed suit. Data going back 120 years show that in recent decades it has experienced eight of its top 10 warmest winters, a state climatologist said.
This follows the trend of global warming, an increase in the Earth’s temperature that can be partly blamed on human consumption of fossil fuels, said Adnan Akyuz, the North Dakota State climatologist.
The third National Climate Assessment was released last month and concluded that extreme weather events influenced by climate change — including heat waves, droughts and heavy precipitation — have grown more frequent and intense across the country.
For North Dakota and other Great Plains states, according to the report, climate change means rising temperatures and increased demand for water and energy.
The report states it also means an increase in winter and spring precipitation, and more very heavy precipitation events leading to increased runoff and flooding.
For Minnesota and other Midwestern states, the report states climate change will bring similar events: extreme precipitation and large-scale flooding, a longer growing season, and the loss of habitat for iconic tree species.
Local weather and climate experts, Akyuz among them, are quick to say that not everything happening in the Red River Valley can be attributed solely to climate change.
Akyuz has also argued that climate change is good for the state. For one, it has led to a longer growing season — brought on by later fall frosts and earlier spring thaws — which is good for North Dakota’s agricultural industry.
“Today it is beneficial. I think we should take advantage,” said Akyuz, adding that there are possible negative effects.
For one, more invasive pests and plants could come to the region if winters continue to be warmer than normal.
“We rely upon the winter weather to help keep our pests in check,” said Tom Kalb, a North Dakota State University Extension horticulturist.
Since 1890, the average annual temperature in North Dakota has increased about 0.27 degree Fahrenheit every decade or 2.7 degrees every century, Akyuz said.
“Except for Alaska, this is the largest or the steepest trend in the U.S.,” he said.
Winters in North Dakota, on average, have warmed by 0.44 degree Fahrenheit each decade since 1890, Akyuz said, far greater than the 0.19 degree-per-decade warming in spring, 0.14 degree-per-decade warming in fall and 0.2 degree per-decade warming in summer.
The trends have been similar in northwestern Minnesota, said Pete Boulay, a climatologist for the Minnesota Department of National Resources.
While winter 2013-14 was the coldest winter since 1978 in northwestern Minnesota, the rest of them have been unusually warm. Eight of the top 10 warmest winters in northwestern Minnesota have occurred since 1982, based on data from the past 120 years, Boulay said.
Akyuz said it’s tough to say if the warming of the valley will continue.
Climate change forecasting is based on historical trends, he said. While using those trend lines might be fine to forecast in the near term, extrapolating them out to predict the climate 50 to 100 years from now is “dangerous forecasting,” Akyuz said.
“Some people go crazy asking about 100 years later, what the precipitation and temperature will be in a given region,” he said. “It’s just almost impossible.”
But if winters keep warming, it could increase the likelihood that pests or invasive weeds normally killed off by frost might survive the milder temps, according to the National Climate Assessment.
North Dakota could then become a breeding ground for Japanese beetles or emerald ash borers, which have so far been unable to stake a claim in the state because of bitterly cold winters, Kalb said.
“The Japanese beetle is very active in surrounding states, but it has struggled to overcome winter in North Dakota,” he said. The bug attacks up to 300 different types of plants.
Studies from northern Minnesota have also shown that 90 percent of emerald ash borers die off in wintertime, Kalb said. While the borer has made a home in Minnesota, it’s failed to survive in North Dakota. About a third of the trees in North Dakota are ash, he said.
“So, yeah, if we have gradual warming, we’ll have all kinds of new pests coming,” he said. “That’s why we should appreciate the bitter cold winters of North Dakota. Maybe not six months of it, but a little bit would be helpful.”
Longer growing season
With warmer winters comes a longer growing season. In Fargo, the first frost of fall is coming later — a full 9.5 days later, on average, than it was a century ago, Akyuz said.
The final frost of spring is also happening earlier — about eight days earlier, on average, in Fargo. That makes the growing season 17.5 days longer today than it was 100 years ago.
A longer and warmer growing season means a larger variety of profitable crops can planted. For instance, more varieties of corn can now be planted in areas where it wasn’t profitable or possible before.
“Prior to 1970, corn didn’t exist to the north of Interstate 94,” Akyuz said.
The warmer, wetter weather has prompted farmers throughout the southern Red River Valley to shift away from small grains such as wheat and barley to corn and soybeans, said John Kringler, an NDSU Extension agent for Cass County.
The shift to planting more corn varieties happened in the past few years, while the soybean shift started about 15 years ago, Kringler said.
Much of the lower two-thirds of North Dakota was also changed in the past two years to a new USDA hardiness zone, a standard by which gardeners and growers can determine which plants are most likely to thrive in certain regions. The lower part of North Dakota warmed from a Zone 3b to a Zone 4a when the U.S. Department of Agriculture updated its map in 2012.
That change reflects a subtle warming of the state. The average annual extreme minimum temperature in a Zone 3b is minus 35 to minus 30 degrees Fahrenheit, while in a Zone 4a it is minus 30 to minus 25 degrees Fahrenheit.
Kalb said the zone change, which reflects temperatures recorded from 1976 to 2005, could have occurred because there are better tools available to get a more accurate map, not necessarily because of global warming.
“I don’t think we can say for certain that’s because of warmer winters,” he said.
Wetter wet cycles
Global warming can also exacerbate the naturally occurring wet cycles in the Red River Valley because increasing air temperatures can hold more water vapor, Akyuz said.
The National Climate Assessment claims climate change will lead to more winter and spring precipitation, and more volatile precipitation events.
This could make agriculture in the Northern Plains more productive by increasing available water in the soil during the early growing season, the report states.
The report also warns it could mean fields become too soggy to plant, which is happening this year in the Upper Midwest because of heavy rain events.
Local weather and climate experts are quick to say that wet and dry cycles in the Red River Valley are not happening because of climate change.
The valley’s current wet period, which has been going on since 1991, is the wettest on record, and since 1993 there’s been an increase in average annual precipitation up and down the valley, said WDAY Chief Meteorologist John Wheeler
But that doesn’t mean climate change is causing it, he said.
“There’s really no good evidence yet to equate that with the global climate change that is ongoing,” he said. “Now, that doesn’t mean there isn’t something that’s related that we haven’t discovered yet. It’s just there’s no evidence for it now.”
Akyuz said there has been an increase in average spring precipitation across North Dakota, but that’s also not necessarily because of climate change.
“It would be so much easier to blame on something that most people do blame so you don’t have to explain,” he said, referring to global warming. “That’s why most people do attribute everything on increasing temperatures, and it goes unquestioned because it sounds like it is very obvious. Increasing spring precipitation, it could be as simple as the local impacts.”
The Red River Valley will still go through periods of drought as part of its natural wet and dry cycling, Akyuz said. Wheeler said the valley could also see a drought in the next few years.