According to the Montana Climate Assessment, published last week, the impacts of climate change are already being felt in the state, and will get more significant throughout the rest of the century.
The Assessment is the work of 32 Montana scientists from the public and private sectors doing research with the Montana Institute on Ecosystems, a collaboration of the University of Montana and Montana State University. The publication is the first of a series, and focuses on the impacts of climate trends on three key sectors: water, forests, and agriculture.
Key findings of the study
- Annual average temperatures, including daily minimums, maximums, and averages, have risen across the state between 1950 and 2015. The increases range between 2.0-3.0°F (1.1-1.7°C) during this period. Along the Beartooth Front, in the south central region of the state, the increase has been 0.44°F per decade during the period. [high agreement, robust evidence]
- The Climate Assessment looked at two scenarios for change in the future: a “business as usual” scenario in which there is little action to reduce carbon emissions, and a “stabilization” scenario in which action is taken to substantially reduce emissions. Montana is projected to continue to warm in all geographic locations, seasons, and under all emission scenarios throughout the 21st century. By mid century, Montana temperatures are projected to increase by approximately 4.5-6.0°F (2.5-3.3°C), depending on the stabilization scenario. By the end of the century, Montana temperatures are projected to increase 5.6-9.8°F (3.1-5.4°C) depending
on the emission scenario. These state-level changes are larger than the average changes
projected globally and nationally. See figure below. [high agreement, robust evidence]
Impact on water
- Across the state, precipitation is projected to increase in winter, spring, and fall; but to decrease in summer. The largest increases are expected to occur during spring in the southern part of the state. The largest decreases are expected to occur during summer in the central and southern parts of the state. [moderate agreement, moderate evidence]
- Montana’s snowpack has declined since the 1930s in mountains west and east of the Continental Divide; this decline has been most pronounced since the 1980s. [high agreement, medium evidence]
- Warming temperatures over the next century, especially during spring, are likely to reduce snowpack at mid and low elevations. [high agreement, robust evidence]
- Historical observations show a shift toward earlier snowmelt and an earlier peak in spring runoff in the Mountain West (including Montana). Projections suggest that these patterns are very likely to continue into the future as temperatures increase. [high agreement, robust evidence]
- Earlier onset of snowmelt and spring runoff will reduce late-summer water availability in snowmelt-dominated watersheds. [high agreement, robust evidence]
- Groundwater demand will likely increase as elevated temperatures and changing seasonal availability of traditional surface-water sources (e.g., dry stock water ponds or inability of canal systems to deliver water in a timely manner) force water users to seek alternatives. [high agreement, medium evidence]
- Multi-year and decadal-scale droughts have been, and will continue to be, a natural
feature of Montana’s climate [high agreement, robust evidence]; rising temperatures will likely exacerbate drought when and where it occurs. [high agreement, medium evidence]
- Changes in snowpack and runoff timing will likely increase the frequency and duration of drought during late summer and early fall. [high agreement, medium evidence]
Impact on Forests
- Direct effects of climate change on individual trees will be driven by temperature in energy-limited forests and moisture in water-limited forests. [high agreement, moderate evidence]
- The speed and magnitude of climate change may mean that increased forest mortality and contractions in forest distribution will outpace any gains in forest growth and productivity over the long run, leading to a net loss of forested area in Montana.
- An increase in fire risk — including an increase in size and possible frequency and/or severity — is expected in the coming century as a result of a) prolonged fire seasons due to increased temperatures, and b) increased fuel loads from past fire suppression. [high agreement, robust evidence]
- Rising temperatures are likely to increase bark beetle survival [high agreement, strong
evidence], but climate-induced changes to other insects and forest pathogens are more
varied and less certain
Impacts on agriculture
- Every component of agriculture—from prices to plant pollinators and crop pests—exhibits complex relationships to climate, depending on the location, weather variability, and agricultural and economic practices and policies. Social and economic resilience to withstand and adapt to variable conditions has always been a hallmark of Montana farmers’ and livestock producers’ strategies for coping with climate variability. [high agreement, robust evidence]
- Decreasing mountain snowpack will continue to lead to decreased streamflow and less reliable irrigation capacity during the late growing season. Reduced irrigation capacity will have the greatest impact on hay, sugar beet, malt barley, market garden, and potato production across the state. [high agreement, robust evidence]
- Increases in temperature will allow winter annual weeds, such as cheatgrass, to increase in distribution and frequency in winter wheat cropland and rangeland. Their spread will result in decreased crop yields and forage productivity as well as increased rangeland wildfire frequency. [high agreement, medium evidence]
- Climate change affects global-price-determined commodity agriculture differently than
it affects non-commodity agriculture. Commodity crops, such as small grains, are more
directly driven by global markets and agricultural subsidies, whereas non-commodity crops tend to be more directly tied to local or specialized non-local markets and local microclimates. [high agreement, medium evidence]
- Diversified cropping systems, including rotation with pulse crops and innovations in tillage and cover-cropping, along with other measures to improve soil health, will continue to allow adaptation to climate change.
What it means for the Beartooth Front
Folks, this report is what climate science looks like. These are Montana scientists, employed in state universities and the private sector, taking a transparent look at climate change and the state’s future.
That future is fraught with problems for the state: significantly increasing temperatures, leading to increasng demands on groundwater and more severe droughts, deforestation, more intense fires, and substantial demands for adaptation from the state’s agricultural sector.
And unless we take action, it’s going to be much worse. Look at the temperature maps above — if we do nothing, we’re looking at temperature increases approaching 10°F. That means we’ve got to take dramatic action to reduce carbon emissions: convert the energy sector from fossil fuels to renewables as quickly as possible, shift the transportation sector from internal combustion engines to electric vehicles. It means we’ve got to stop subsidizing the oil industry and put a price on carbon to drive innovation.
And even if we do those things, we’re still looking at significant temperature rise and impacts.
For those of us interested in acting locally, it means we’ve got to put our foot down when the oil man comes knocking, promising to bring the Bakken to the Beartooths. We’ve got to create local regulations to make sure that if they drill they do it responsibly, and we’ve got to push local elected officials who insist on dragging their feet.
Climate change could be devastating to rural Montana. The impacts on water, on forests, and on agriculture demand that we act quickly and with great urgency.
More: Download the complete Montana Climate Assessment