Climate Change in our Backyard

Climate change can be hard to grasp, because climate involves understanding larger patterns over long periods of time. While from year to year there are natural variations in weather - temperature, precipitation – such as those caused by climate cycles like El Niño, this “short-term variability” is different from the long-term trends we see when we compare historical conditions with current data.  

Analyzing long-term trends and comparing historical conditions to current data tells us how our climate is changing. These long-term trends also influence the short-term variability of our weather from day to day and year to year. In Western Montana, we’ve already seen changes in our temperature and precipitation patterns. Click the links below to learn more about some of the local impacts of climate change. ​

In September 2017, a statewide team of scientists released the first Montana Climate Assessment report - an excellent, detailed look at the ways our climate has changed and projections for the future, with a particular focus on impacts to agriculture, forestry, and water. Future reports will focus on other industries, including recreation and tourism. 
Temperature
Water
Wildfires

Rising Temperatures

Rising temperatures correspond with the growing amount of CO2 in our atmosphere. The greenhouse effect allows CO2 to build up and trap heat around the earth, causing global temperature increases and other climate effects. Across Montana, we've experienced this firsthand. In Missoula, the average annual temperature during the 20th century was 44.3 degrees Fahrenheit. But every year since 2000 has been above that average – by as much as 2.5 degrees in 2015.  Average annual temperatures have risen between 2 and 3 degrees Fahrenheit since 1950, with the greatest warming occurring during winter and spring. Higher winter and spring temperatures mean less snowpack and earlier snowmelt, often causing dry late summer conditions.
                 Source: 2017 Montana Climate Assessment
Source: NOAA Climate At a Glance      
Average temperatures have increased in all regions of Montana. The trend lines in the graph to the left show average temperature change per decade. Each region has seen increases.
Graph from the 2017 Montana Climate Assessment.

Warmer springs mean early snowmelt. With winter snowpack melting early, forests and streams have less water during late summer. Various ecosystems, wildlife, and agricultural practices are all impacted by reduced streamflow and less soil moisture.
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Summer temperatures are hotter, too. Average June through August temperatures in Montana over the period 2000 – 2018 were 1.5 degrees hotter than the 20th century average. One and a half degrees may not seem like much, but even a small temperature increase can have significant effects.​ Heat waves can be more intense.
Nighttime temperatures are warmer, too. It's not your imagination - we're not getting as much of a break from the heat overnight. 
The upward sloping line on the graph to the left shows the trend of warmer average minimum temperatures during the summer. Public health officials warn that hotter nights can make heat waves even more dangerous.
To look at more temperature data and graphs, visit the NOAA Climate At A Glance webpage.
Increasing temperatures have vast effects on people, animals, and ecosystems. For humans, hotter temperatures pose more obvious threats to our health and happiness when there are intense heat waves, crop deaths, and drought or limited water supply. There are also many impacts to wildlife and ecosystems, that, not only are bad for those species, but also can more indirectly effect us. Learn more about the climate impacts to wildlife and ecosystems on our Wildlife and Climate Impacts page.

Snowpack and Precipitation

Changing rain and snowfall patterns across the entire Pacific Northwest impact our watersheds here in Western Montana. Here in Missoula, we haven't seen a statistically significant change in our total amount of precipitation. But as temperatures have increased, across our region more of our precipitation is arriving as rain instead of snow, which has a significant impact on our valley. Mountain snowpack is an important part of the water cycle, helping to store water needed for irrigation, drinking water, hydro-power, and more. 
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Reduced snowpack is a trend affecting the entire west, and especially the Pacific Northwest. At both lower elevations (2,000 to 5,000 feet), and higher elevations (above 5,000 feet), about two thirds of weather stations across Washington, Oregon, Idaho and Montana are seeing a lower percentage of winter precipitation falling as snow. Overall, 66 percent of Montana weather stations have seen an increase in rainfall as a percentage of winter precipitation. Roll over the map below (left) to see how we stack up to other states. All the red dots on the map below (right) indicate places where there's less snow - click through to see recent research on snowpack trends in the West.
​​Warmer winters come with their own challenges – like icier ski slopes! But warmer and rainier winters also have a major impact on our summer conditions. It's challenging to predict precipitation patterns, but whether climate change brings wetter or drier conditions to our region in the future, warmer winters mean reduced snowpack and earlier spring runoff, which in turn means less water is available in the summer when demand is highest. Reduced snowpack also affects stream flows and water for irrigation, and contributes to more intense droughts and wildfires. ​Wondering what these dry conditions mean? We've got you covered - learn more about drought and wildfires.
Picture
Source: US EPA


Wildfire Smoke and Air Quality

Hotter temperatures and earlier snow melt contribute to dry conditions that fuel wildfires. Here in the West, alongside increasing temperatures, the average annual number of large wildfires (fires over 1000 acres) has more than doubled since 1970, and wildfire season is now an average of 105 days longer. This trend is particularly extreme in the Northern Rockies, where large wildfires are 10 times more common and the area burned is up to 45 times greater.
The graph above shows the annual number of fires (vertical bars) alongside the annual average temperature (purple line). In Missoula, our bowl-shaped valley traps wildfire smoke from as far away as California, contributing to poor summer air quality. Wood smoke contains high levels of fine particulate matter (PM 2.5), which can cause many adverse health impacts. (Learn more about smoke-related health issues here.) The American Lung Association ranked Missoula 10th worst out of 186 US cities in terms of number of days with high PM 2.5 concentrations, earning us a grade of “F”. Many of the days with the worst air quality have occurred during summer wildfire season. With more fires burning in the region, we can expect more smoky days in the future, as seen in the map below. (Check out the complete map of wildfire smoke risk by county and click on Missoula to see a comparison of current and projected future smoke intensity.) 
​Even when wildfires aren’t burning, hotter temperatures carry the possibility of increased amounts of ground-level ozone, making our air less healthy to breathe.

​What Will the Future Bring?

No one can predict future climate impacts with complete certainty, but climate projections for our region give us an idea of what to expect.
  • Over the next century, fire season is expected to get longer, and fire danger and drought are also expected to increase. "Smoke waves", defined as two or more days of unhealthy air, are likely to be longer, more intense, and more frequent.
  • We are likely to see an increase in mean air temperature of between 2 and 5 degrees F over the next 20 to 30 years. 
  • In addition to hotter temperatures, we may see increases in winter precipitation, decreases in summer precipitation, and earlier and greater spring snowmelt, widening the gap between peak runoff and peak water demand and fueling more intense wildfires.
The 21st century continues to smash records left and right: not only was 2016 the hottest year on record globally, followed closely by 2015 and 2017 (and probably 2018), but 16 of the 17 hottest years have occurred since year 2000.  ​

Read the Climate Central article where this graphic (right) came from, published January, 2018.
Researchers at the Montana Climate Office have just released the first Montana Climate Assessment, focused on climate impacts to agriculture, forests, and water resources. Check it out!



​Climate Change: a Global Phenomenon

​http://climate.nasa.gov/     
These local impacts are just part of the bigger picture of global climate change. Heat trapped in Earth’s atmosphere by greenhouse gases impacts global climate patterns – so it makes sense to talk about global climate change and global warming. On a global scale, warming trends are clear as day. The average surface temperature across the planet increased by 1.6 degrees F from the 1880s to 2014. Check out this time-lapse from NASA (left) to see how temperatures have increased across the globe since the 1880s. 
Wondering what summer climate impacts across the globe look like? Check out this recent photo essay that pulls it all together. 

Dig Deeper into Local and Global Climate Conditions

Bummed about hotter and smokier summers? We've got lots of tips and ideas about how to "weather the weather": learn how to be summer smart when it comes to heat, smoke, shade, and more.  

Interested in learning more about how our climate is changing? There are many excellent resources on local, national, and global climate change indicators and projections for the future. Here are a few we recommend checking out.

Local and Regional Climate Data
National and Global Climate Data