The “M” trail above Bozeman. Photo courtesy of Scott Bischke.


Cathy Whitlock and Alexandra Adams


The purpose of this assessment is to a) present understandable, science-based, Montana-specific information about the impacts of climate change on the health of Montanans; and b) describe how our healthcare providers, state leaders, communities, and individuals can best prepare for and reduce those impacts in the coming decades. This assessment draws from, and is an extension to, the 2017 Montana Climate Assessment (MCA[1]) (Whitlock et al. 2017), which provides the first detailed analysis of expected impacts to Montana’s water, forests, and agriculture from climate change. MCA explains historical, current, and prospective climate trends for the state based on the best-available science.

The 2017 Montana Climate Assessment did not address the impact of climate change on the health of Montanans. This special report of the MCA fills that important knowledge gap; it represents a collaboration between climate scientists and Montana’s healthcare community and is intended to help Montanans minimize the impacts of climate on their health. The report is broken into five additional sections:

  • Section 2 summarizes key findings about climate change in Montana, drawing on information from the 2017 Montana Climate Assessment.
  • Section 3 details the consequences of climate change on human health, globally and in Montana.
  • Section 4 explains the health effects of climate change on our state’s most vulnerable populations, such as the very young and very old, people with chronic disease, pregnant individuals, and those living remotely and in poverty.
  • Section 5 provides recommendations and resources for planning, policy changes, adaptations, and actions to ensure positive health outcomes for Montanans in the face of climate change.
  • Section 6 provides important concluding remarks.

Both Sections 4 and 5, which are less technical than previous sections, may be read as stand-alone resources. Throughout the report, we provide sidebars with stories specific to Montana.


The purpose of this assessment is to a) present understandable, science-based, Montana-specific information about the impacts of climate change on the health of Montanans; and b) describe how our state can best prepare


Concerns for the Vulnerable

Climate change is a global phenomenon, and the anticipated impacts to health and well-being affect all humankind to some degree. Given its northern and interior location in the US, Montana will avoid some of the health impacts of climate change facing other parts of the country and the world. Nonetheless, some of the health consequences experienced here will likely be more serious than elsewhere. Projected temperature increases in Montana, as described in the MCA (Whitlock et al. 2017), are of foremost concern to climate scientists and health practitioners alike. For example:

  • Average temperatures in Montana have increased across the state by 0.42°F (0.23oC) per decade since 1950, which is faster than the US average (0.26°F [0.14oC]).
  • Climate projections indicate continued warming in the coming decades with temperature increases of 4.5-6.0°F (2.5-3.3oC) by mid century.[2]
  • Days above 90°F (32oC) are anticipated to increase by 5-35 days by mid century, with greatest increases occurring in the southeastern part of the state.

Along with increased temperature, four other climate change projections in the 2017 Montana Climate Assessment are issues that threaten the health of Montanans. Those issues are increased occurrence of wildfire and its impact on smoke and air quality; early snowmelt and intense precipitation events; projected changes in water availability and quality; and extreme and unexpected climate-related weather events. MCA finds that although there has been no significant change in statewide average annual precipitation since 1950, summer precipitation has decreased, while spring and fall precipitation have increased slightly. Projections indicate more year-to-year and season-to-season variability in precipitation, earlier loss of snow, and more summer drought (Whitlock et al. 2017).

Montana is a rural state with widely spaced urban centers. Its population of 1,062,305 in 2018 included 5.9% under five years old, 17.6% over 65 years old, and 2% over 80 years old. Older age groups—that is, people over 65—are increasing in number across the state. The state’s economy has become more diversified in recent decades, with one-third of the workforce now in the service sector (e.g., healthcare, trade, leisure activities), while goods-based industries (e.g., manufacturing, construction, mining, agriculture) collectively account for about 24% of the economy (Montana Department of Labor and Industry undated). Montana ranked 39th in median household income in 2018, but poverty is a problem in several parts of the state, especially on Indian reservations (US Census Bureau 2019). About 14% of Montanans live in poverty; of those 6% live in deep poverty, earning <50% of the federal poverty level.

Montanans will experience both benefits and harm to human health from climate change, depending on location and individual. While warmer winters may help some Montanans, for example, a number of negative consequences are foreseeable for others. Added heat stress and other climate changes may cause or exacerbate cardiovascular and respiratory infirmities, gastrointestinal ailments, infectious diseases, premature births, and morbidity. Vulnerability to such impacts will vary depending on where individuals live, as well as on their age, gender, occupation, residence, socioeconomic status, and underlying medical conditions (see sidebar).




Populations Most Vulnerable to Climate Change in Montana

Multiple sectors of Montana’s population are at special risk of having their health impacted by our warming climate, including people…

  • …threatened by increased heat
  • …living in proximity to wildfire and smoke
  • …facing food and water insecurity
  • …who are very young, very old, or pregnant
  • …having limited access to healthcare services
  • …living in poverty
  • …lacking adequate health insurance
  • …with existing chronic conditions
  • …with mental health issues
  • …whose livelihoods or traditional ways are closely tied to the land or environment, including those working outdoors in construction, agriculture, recreation, and resource-extraction industries



Report Purpose and Genesis

To date there has been no single  source of information about how climate change will affect the health of Montanans. Climate Change and Human Health in Montana seeks to fill this gap in our knowledge, drawing on the best available, current information. Scientific assessments are essential tools for linking knowledge to decision-making, by surveying and synthesizing peer-reviewed scientific information across disciplines, sectors, and regions. Assessments highlight key information that can improve understanding of complex issues and identify topics where study is needed. The work presented here on climate change and human health should be a sustained effort, updated and expanded on a regular basis as part of the overall MCA program.

Climate Change and Human Health in Montana is intended to help communities, healthcare professionals, and other decision makers understand the climate-health connection and evaluate different strategies for response. The flow of information should also go in the opposite direction, with this report helping decision makers identify critical information gaps that require new scientific investigation, tool development, and future assessment. Along with its statewide focus, Climate Change and Human Health in Montana contributes to the larger flow of information on this topic that occurs between national, regional, state, and local levels.

Climate Change and Human Health in Montana is the product of a diverse partnership of over 40 scientists and healthcare professionals who first met in August 2018 to discuss the issue and plan the assessment. Before its release, the report received public comment and rigorous scientific review by health and climate experts at state and national levels (see Acknowledgments section).

This report makes it clear that Montana’s changing climate will have measurable impacts on our state’s human health and well-being in the future. We hope that this information motivates much-needed discussion on this topic, one that leads to greater awareness, considers multiple sources of knowledge, and helps planning efforts and action in this important area. During the 2020 COVID-19 pandemic, we have had to acknowledge how much we are all connected, and now more than ever realize how clearly our health and economic well-being are tied to the health of the planet. It is our hope that this report will motivate our collective action towards innovative mitigation and adaptation strategies for improving health in the face of climate change.



The Montana Climate Solutions Plan

In 2019, Governor Bullock issued an executive order creating the Montana Climate Solutions Council, tasked with developing a plan of recommendations and strategies to prepare Montanans for climate impacts, reduce greenhouse gas (GHG) emissions to achieve net GHG neutrality by mid century, and advance new technologies and other innovations to meet these goals. The Council was composed of members from state agencies, the universities, businesses, tribal communities, and non-governmental organizations; and during its deliberations received input from experts and the public. The Montana Climate Solutions Plana was released in September 2020 with a broad list of recommendations, many of which are relevant and align with this report on climate change and human health:

  • Develop a Montana Climate Solutions Network to share climate information and resources and build capacity in communities so that climate solutions connect at state, local, regional, and tribal nation levels
  • Build community resilience to climate change through better coordination with existing planning efforts
  • Adapt buildings, homes, and other infrastructure to better withstand climate change
  • Maintain a diverse and healthy economy, positive mental and physical health outcomes, and a resilient high quality of life for Montanans and visitors
  • Safeguard Montana’s water quality and quantity from climate change
  • Enhance local air quality monitoring and support indoor air quality needs for vulnerable communities during intense periods of wildfire smoke


a State of Montana. 2020. Montana Climate Solutions Plan: a report by the Montana Climate Solutions Council. Helena MT. 73 p. Available online http://deq.mt.gov/Portals/112/DEQAdmin/Climate/2020-09-09_MontanaClimateSolutions_Final.pdf. Accessed 4 Nov 2020.




[1] This report uses “MCA” in discussing the Montana Climate Assessment program. We provide the reference (Whitlock et al. 2017) only when speaking of specific results published in the 2017 Montana Climate Assessment, not the overall program.

[2] The increase depends on the scenario of global greenhouse gas emissions, as described in Section 2.



Literature Cited

Montana Department of Labor and Industry. Undated. Montana labor market information: industry employment by sector June 2020 [website]. Available online http://lmi.mt.gov/Industry/cesSector. Accessed 7 Aug 2020.

US Department of Commerce. 2019. Washington DC: Census Bureau, American Community Survey Office. Analysis derived via Headwaters Economics’ Populations at Risk: Montana [web tool]. Available online headwaterseconomics.org/par. Accessed 7 Aug 2020.

Whitlock C, Cross W, Maxwell B, Silverman N, Wade AA. 2017. 2017 Montana Climate Assessment. Bozeman and Missoula MT: Montana State University and University of Montana, Montana Institute on Ecosystems. 318 p. Available online http://montanaclimate.org. Accessed 9 May 2020. doi:10.15788/m2ww82.