New climate data show Spokane summers are hotter and drier, but what does that really mean for the area?

On any given July afternoon, a difference in one degree Fahrenheit barely registers.

But an increase of one degree in the average temperature over the span of 30 years is worth pausing to consider.

It doesn’t take a climate science degree to sense that Spokane summers are getting hotter and drier, but science has indeed confirmed that intuition. A new report released last week documents that, over the last three decades, average temperatures in Spokane have increased by 1.2 degrees in July compared to the previous report released a decade ago.

And while the trend is hardly a surprise to climate observers, the data serves as another reminder we live on a warming planet.

“If you’re starting to find that much warming in a decade, that’s a pretty significant number. Is that catastrophic for us in this area? No, no, it’s not,” said Brian Henning, director of Gonzaga University’s Center for Climate, Society and the Environment.

While the data is not apocalyptic for Spokane, it portends serious consequences, even if the domino effect is tricky to predict with precision.

Spokane might not suffer from a one-degree increase in summer temperatures as severely as Southern California, for example. But local experts described a future in which crops in Eastern Washington struggle to grow, wildfires are more likely and the Spokane River’s ecosystem is upset by low flows and high temperatures.

“This is simply putting a fine point on what we’ve actually understood for a while, which is that the climate is changing,” said Jerry White Jr., executive director of Spokane Riverkeeper. “This report plainly and clearly establishes that we’ve been feeling these impacts for some time.”

The data

The National Oceanic and Atmospheric Administration released its new U.S. climate normals report last week. The report catalogs climate data over the past 30 years and is updated every decade.

The new 30-year normal drops the 1980s and incorporates the 2010s.

The new normals can reframe how we talk about the weather and climate. To simplify the concept, when a meteorologist tells television viewers it’s five degrees hotter than normal, this is the “normal” to which they are referring.

For example, the “normal” precipitation amount is one factor considered in gauging whether a region is experiencing a drought. A drier normal means it will take an even drier period to enter drought status.

Spokane’s new normal

In Spokane, the average annual temperature increased 0.4 degrees Fahrenheit compared to the report issued a decade ago.

In the summer months, the warming effect was even more pronounced.

Compared to the last report, the average temperature is 1.2 degrees warmer in July, 1 degree warmer in August, and 0.9 degrees warmer in September.

Just as importantly, the summers have gotten drier.

“That’s especially been the case of late; we’ve had some really dry summers in the last three or four years,” said Jeremy Wolf, a meteorologist with the National Weather Service in Spokane.

Despite a near-record dry March and April this year, Spokane’s spring season has actually trended wetter, while the average temperatures in those months have barely moved.

From the national perspective, the new normals show the eastern half of the continental United States receiving more precipitation, while the west – particularly the southwest – is drying out.

To track long-term climate change, NOAA leans on the last century of data.

“If we compare the 1991-2020 annual temperature normals to the 20th-century average, we see warming everywhere across the map,” a NOAA explainer states. “No region in the U.S. is cooler than it was during the 20th century, and much of the West and Northeast are one to two degrees warmer.”

A person born after 1976 has never lived through a year in which the global average temperature was below the 1951-80 average.

Still, it’s difficult to convey the importance of a few degrees in the global temperature.

Henning often points to the difference between a person’s surface temperature and their internal temperature.

In the cold weather, the skin of a person’s hands can easily drop several degrees. But if their internal body temperature were to drop by the same amount, they’d be in serious peril.

The difference of a few degrees in the temperature is negligible from day to day. But over time, across the globe – the internal body temperature in Henning’s analogy – a few degrees can make all the difference.

What it means for Spokane

There are limitations to what the new report can tell us about climate change, the impacts of which are too varied to encapsulate in a single article.

A reduction in precipitation, for example, can leave less moisture in the ground and increase the risk of wildfires. But other factors play into fires, such as lightning strikes and wind patterns, that are more difficult to attribute directly to climate change, Wolf said.

“Ultimately, what the fire seasons are going to do is dependent more on just the weather – there’s other factors that go into fires,” Wolf said.

Still, the drier the climate, the more easily wildfire fuel will burn.

The Climate Toolbox, a system developed by scientists at the University of California Merced’s Applied Climate Science Lab and the University of Washington’s UW Hydro group, offers insight into projected climate risks.

Assuming greenhouse gas emissions continue at their current rate, the toolbox predicts an average of a 340% increase in the risk of a very large fire in Spokane from between 2040 and 2069 compared to 1971-2000.

A group of local stakeholders collaborated with the Pacific Northwest Climate Impacts Research Consortium (CIRC) and used the climate toolbox to make a Spokane-specific report, viewable at spokaneclimateproject.org.

Rebecca MacMullan was a volunteer contributor to the Spokane Climate Project and co-authored a report that put temperature increases into Spokane-centric context. As the warming trend continues, chances increase of having a particularly hot Bloomsday or Hoopfest – like the scorcher of 2015 when temperatures rose above 100 degrees.

“Climate just gives us this general trend, but all of the climate changes together put us at higher risk for more dangerous risks and dangerous weather patterns,” MacMullan said.

Nighttime temperatures have also increased. Many of Spokane’s older homes don’t have central air conditioning because cool overnight temperatures used to suffice, but that could be changing.

According to the National Weather Service, heat was the leading cause of weather-related death in the United States from 1988 to 2018. Spokane will have to prepare for more hot weather, which particularly impacts people who work outdoors, the elderly, young children and even pets.

Meanwhile, the Spokane River relies on a trickle of snowmelt that, even though precipitation levels haven’t dropped in the winter months, is getting harder to come by.

“We get this moisture in the mountains, but it’s not being stored as snow, or if it is stored as snow it doesn’t stay very long. That does not bode well for our river in July, August or September,” White explained.

Lower water levels, combined with hotter temperatures, can warm the river and make it more hospitable to invasive species, too.

“We do worry deeply about the future of fish recovery,” White said, noting that “aquatic ecosystems are already stressed.”

The changing climate can even impact the spread of disease.

Hugh Lefcort is a colleague of Henning’s at Gonzaga who studies the effects of carbon emissions on disease spread, particularly in ticks.

It’s clear that Spokane is getting hotter, but Lefcort stressed the unpredictability of whether it will dry out or get wetter. The new NOAA report shows late winter and early spring precipitation increasing, while it decreases in the summer.

The difference is of major significance to insects like ticks.

There are two species of ticks common in the area that spread disease at different rates, Lefcort said, one that prefers a dry climate and the other a humid one.

Depending which way the precipitation trends, Lefcort said there could be an increase in the species that carries Rocky Mountain spotted fever, which is much rarer in the Inland Northwest than, say, Lyme disease on the East Coast.

“The key thing about climate change is change. That’s the word. Things are going to happen – which way it’s going to happen, that’s hard to say,” Lefcort said.