Climate Change in Montana
Author: Mariah Cannon, Department of Earth Sciences, Montana State University
Rolling fields of amber wheat, vast green forests, and rushing rivers are just a few images that come to mind when thinking about Montana. Not only is there beautiful scenery, but also some of the extremes of weather and climate can be seen here. From scorching hot temperatures and thunderstorms in the summer shifting into crisp cool autumns, to extreme amounts of snow and below freezing temperatures in the winter giving way to wet, green spring seasons. In this page, you'll learn about the topics of Montana, and how the climate has changed over time, and what the potential future could look like.
Montana's Climate Divisions
Montana, being the 4th largest state of the United States, has a lot of ground to cover. To make this easier, it has been divided into seven different climate divisions. They have split up according to location and the environment that thrives there. The following are the seven divisions: northwestern and southwestern, central, north central, south central, northeastern, and southeastern.
Our particular area of interest, around the Augusta/Choteau area, would fall into the north central climate division. This would make sense when looking at the type of agriculture found here, along with the amount of water to irrigate the dryland with.
- Northwestern and southwestern.—The mountain valleys of the northwestern and southwestern regions are dominated by hay and livestock production with a few isolated areas of small grains, seed potatoes, malt barley, and other rotational crops. In addition, this region has irrigated, small-scale market garden and orchard crops surrounding urban centers and Flathead Lake.
- Central.—The southern portions of the central region are dominated by livestock and hay production. A large part of the area is irrigated, with some isolated small-grain production.
- North central.—The Golden Triangle, known primarily for its wheat production, represents a large part of the north central region. The region is dominated by dryland, small-grain production (with alternate fallow years to store soil moisture), with some legume and oil seed rotational crops. Livestock agriculture is less important than in other regions of the state.
- South central.—The west half of the south central region is dominated by livestock and associated irrigated hay production. The east half (Yellowstone, Big Horn, and Treasure counties) is characterized by river valleys with irrigated crops and by dryland winter wheat production.
- Northeastern.—The northeastern region is dominated by dryland small-grain production, including spring wheat with more continuous cropping by rotation with legume and oil seed crops. Livestock agriculture is less important than in other regions of the state.
- Southeastern.—The southeastern region includes extensive rangeland with cattle production, dryland winter wheat, and some rotation with oil seed crops. Row crops, including sugar beets, dominate the river valleys, with corn and soybean production increasing.
This image shows how each climate division's temperature has increased over time. Not only does it show total temperature increase from 1950, but the increase within each decade. You can see in the diagram that the north central area shows the highest increase per decade of all the divisions.
Continue below to read more about how these rises in temperature effect Montana. This page will go into three topics that could potentially feel major changes in the future if the climate continues to change as it has so far. For even more in depth information on the subject, check out the website for the 2017 Montana Climate Assessment.
Information from the 2017 Montana Climate Assessment
What's at Stake in Montana?
When it comes to Montana, two things can usually come to mind: agriculture and forests. These two types of landcover are what make Montana, well Montana. Without water, the other two would not be able to grow and thrive. So find out what could change regarding them down below. Each topic has a link leading you to the respective page on the 2017 Montana Climate Assessment website, highly recommend reading there for more in depth information.
- Agriculture plays a huge roll in the Big Sky Country. Between crops and livestock, agriculture is a multi-billion dollar industry. The type of agriculture that prospers in an area depends on many different things: the soil type, whether or not that land can be irrigated, the annual precipitation, temperature and general climate of the area. As the climate shifts, so does the timing of the seasons. This can play a role in the crops being planted and whether or not it is the right time for them to grow. Many don't know that there are different variations of wheat, all that prosper in different weather and at varying times in the year.
- The "issue" that arises is that as temperatures rise, a shift in what type of wheat that dominates more takes place. With warmer summers, Spring wheat will have a shorter growing season and won't have as much time to prosper. On the other hand, with warmer winters, Winter wheat's season becomes more profitable.
- Augusta/Choteau agriculture
- Being in the 'Golden Triangle' of Montana, the main source of agriculture found here is wheat production. Because the majority of the land here is dryland, livestock agriculture isn't as prominent here as it is in other divisions. When it comes to making decisions regarding agriculture, there are so many factors that contribute. In the figure below, some of the contributing factors that impact these decisions are shown, and climate can indirectly affect the decisions through these factors.
- Most of western Montana is primarily forested areas. In fact, approximately 23 million acres of Montana's land is some type of forest. This means that much of this land could potentially be affected by climate change, negatively or positively, depending on the species. One example is how some trees, like the Douglas fir, are drought resistant and capable of living in a variety of weather, others are not as ready to acclimate. The table below list some of the potential effects that a change in climate could have on forests.
Some other dangers to forests include:
- Bark beetles and other diseases among trees cause even more concerns. Beetles are capable of killing entire forests, and with warming temperatures, this could become an increasing threat. As temperatures rise, beetle populations tend to increase as well.
- Fire severity is always a concern, but increases along with the temperatures. The summer of 2017 proved how dangerous fires can be. Over a million acres of Montana land was burned throughout the season, even after a wet spring with decent snow packs.
In Montana, "Whiskey's for drinking and water's for fighting over!" (attributed to Mark Twain).
- When it comes to Montana and the way it thrives, water holds one of the highest spots on the list of important factors. Not only for agriculture, but for plenty of other ways as well. Montana boasts great fishing opportunities, and they are some of the first things that come to mind when thinking about the outdoor activities in Montana's waters. When it comes to climate change, the effect it can have on the water system is important.
- When you think of water, you shouldn't just think of standing bodies of water (such as lakes or ponds) or even running water (streams and rivers). Think of snow. Montana is notorious for white winters and can accumulate large snow packs in higher elevations. While it might not seem like it would contribute very much, spring runoff from melting snow provides much of the water needed for the approaching warmer months. Over time, snow packs have been generally decreasing in size.
- With snow packs at mid to low elevations decreasing in size, a number of potential effects could arise.
- More frequent and longer drought seasons due to earlier snow melt that leaves later summer months with decreasing amounts of water
- Earlier peak in spring runoff adds to the above effect
- Effects on Montana's water supply will take place due to these contributing factors
Glacier(less) National Park?
Since the park was founded in 1910, a lot of things have changed. Glaciers are disappearing before our eyes and before you know it, the name Glacier National Park will just be a sad irony. Back in 1997, a project was started to document the change in glacier sizes. The Repeat Photography Project compares historic photos of these glaciers to photos taken recently, in the exact same location (or as close as accessibility allows).
Comparing Past and Present: Climate in Montana
To accompany the above information, these maps were created as a visual aid. This way, you can read the implications and potential effects of climate change and then relate that information to the data below.
To compare past and present data is relatively easy. The average person has access to download data sets, and there are free options for software to use the data, such as ArcGIS Online. For this project, ArcMap 10.5.1 was used. All of the data used was sourced from Montana State Library Clearinghouse.
Check out the online story map here!
Yearly Mean Temperature 1950-2012
These three images show the differences in yearly mean temperature over a period of time. I wanted to do a sort of "30-year average", so I started at 1950, which is almost the oldest data available. When comparing these images, be sure to make note of the values in the legend. You can see that over time, the temperature ranges increase. So, even though 1980 and 2012 don't look that much different, the highest values differ by just over a full degree.
Yearly Totals of Precipitation 1990 vs 2012
Comparing 1990 and 2012 yearly total precipitation, it is easy to make out some of the differences. For example, the southeast corner of the map shows a good amount of change, showing less precipitation.
When looking at our focus area, however, an increase in precipitation can be seen. This is a clue to warming temperatures, so now we'll take a look into that.
It is also worth noting that the ranges for each image do not match up perfectly. In fact, in 1990, the lowest value is 92.6 mm compared to in 2012 the lowest value dropped to 58.6 mm. This could be misleading if someone were to not read the legend and see the differences.
*NOTE*These maps were created by Mariah Cannon as a student in the GPHY484 class. These are not official maps and should not be reused without knowing the uncertainties and errors of the data. These are simply made to used data that is available to the average person and compare past and present data.