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Projected climate change impacts on skiing and snowmobiling: A case study of the United States

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We use a physically-based water and energy balance model to simulate natural snow accumulation at 247 winter recreation locations across the continental United States. We combine this model with projections of snowmaking conditions to determine downhill skiing, cross-country skiing, and snowmobiling season lengths under baseline and future climates, using data from five climate models and two emissions scenarios. Projected season lengths are combined with baseline estimates of winter recreation activity, entrance fee information, and potential changes in population to monetize impacts to the selected winter recreation activity categories for the years 2050 and 2090. Our results identify changes in winter recreation season lengths across the United States that vary by location, recreational activity type, and climate scenario. However, virtually all locations are projected to see reductions in winter recreation season lengths, exceeding 50% by 2050 and 80% in 2090 for some downhill skiing locations. We estimate these season length changes could result in millions to tens of millions of foregone recreational visits annually by 2050, with an annual monetized impact of hundreds of millions of dollars. Comparing results from the alternative emissions scenarios shows that limiting global greenhouse gas emissions could both delay and substantially reduce adverse impacts to the winter recreation industry.
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Global Environmental Change
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Projected climate change impacts on skiing and snowmobiling: A case study
of the United States
Cameron Wobus
, Eric E. Small
, Heather Hosterman
, David Mills
, Justin Stein
Matthew Rissing
, Russell Jones
, Michael Duckworth
, Ronald Hall
, Michael Kolian
Jared Creason
, Jeremy Martinich
Abt Associates, 1881 Ninth Street, Suite 201, Boulder, CO, USA
University of Colorado Boulder, Geological Sciences, Boulder, CO, USA
U.S. Environmental Protection Agency, Climate Change Division, Washington, DC, USA
Climate change
We use a physically-based water and energy balance model to simulate natural snow accumulation at 247 winter
recreation locations across the continental United States. We combine this model with projections of
snowmaking conditions to determine downhill skiing, cross-country skiing, and snowmobiling season lengths
under baseline and future climates, using data from ve climate models and two emissions scenarios. Projected
season lengths are combined with baseline estimates of winter recreation activity, entrance fee information, and
potential changes in population to monetize impacts to the selected winter recreation activity categories for the
years 2050 and 2090. Our results identify changes in winter recreation season lengths across the United States
that vary by location, recreational activity type, and climate scenario. However, virtually all locations are
projected to see reductions in winter recreation season lengths, exceeding 50% by 2050 and 80% in 2090 for
some downhill skiing locations. We estimate these season length changes could result in millions to tens of
millions of foregone recreational visits annually by 2050, with an annual monetized impact of hundreds of
millions of dollars. Comparing results from the alternative emissions scenarios shows that limiting global
greenhouse gas emissions could both delay and substantially reduce adverse impacts to the winter recreation
1. Introduction
Projected climate change through the 21st century will generate
warmer temperatures and changes in precipitation that are expected to
decrease the duration and extent of natural snow cover across the
northern hemisphere (e.g., Dyer and Mote, 2006; Brown and Mote,
2009; Dienbaugh et al., 2013). A number of studies have examined
how climate change could inuence seasonal snowpack in the western
United States (e.g., Barnett et al., 2005; Mote et al., 2005; Pierce and
Cayan, 2013), with the aim of understanding impacts on water
resources. However, the geographic extent and economic impacts of a
changing snowpack are likely to extend well beyond the western United
States (e.g., Hayhoe et al., 2007; Campbell et al., 2010). In particular,
large components of the winter recreation industry will face challenges
without reliable access to snow. This could threaten tens of millions of
current annual recreational visits and have important repercussions in
areas where winter recreation is central to economic activity.
This study follows a series of reports that quantify and monetize the
potential for climate change impacts to a number of sectors in the
United States (e.g., Walsh et al., 2014; U.S. EPA, 2015a,b). In particular,
U.S. EPA (2015a) quanties and monetizes impacts from climate
change under a range of scenarios in terms of anticipated impacts to
human health and labor, electricity, forestry and agriculture, water
resources, ecosystems, and the built infrastructure. Here we model
potential changes in snowpack at sites across the United States, and
calculate the eects of changing season lengths on the number of
recreational visits and direct revenue associated with entrance fees. Our
study expands on previous impacts work related to winter recreation by
combining the geographic breadth of previous studies (e.g., Burakowski
and Magnusson, 2012) with the detail that has historically been applied
only to site- or regionally-specic studies (e.g., Burakowski et al., 2008;
Lazar and Williams, 2008, 2010; Scott et al., 2008; Dawson and Scott,
2013). We consider a range of future climate scenarios by examining
outputs from ve global climate models (GCMs), two representative
Received 30 November 2016; Received in revised form 14 April 2017; Accepted 17 April 2017
Corresponding author.
E-mail address: (D. Mills).
Global Environmental Change 45 (2017) 1–14
0959-3780/ © 2017 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (
concentration pathways (RCPs), and both mid- and late 21 st century
time periods. As a result, this study helps expand the type and number
of sectors with national-scale estimates of quantied and monetized
impacts from climate change.
The foundation of our method is a water and energy balance model
that accounts for simplied, but site-specic climatic and topographic
characteristics to project natural snow accumulation at 247 locations in
the continental United States (CONUS). For downhill skiing and
snowboarding, we combine results from this natural snow model with
projections of how resortsabilities to make articial snow will change
in the future. For Nordic (i.e., cross-country) skiing and for snowmobil-
ing, we use the model outputs without consideration for snowmaking,
since these activities are typically more reliant on natural snow. For all
three winter recreation activities, we estimate season length during a
baseline period, and then project the impact of climate change on
season lengths through the 21st century. We summarize these impacts
as anticipated changes in future season lengths, levels of recreational
activity, and entry-based expenditures. Although our results are specic
to the United States, our methods could be easily adapted and extended
to address other international regions (e.g., the Alps, Scandinavia, New
Zealand) where snow-dependent winter recreation is an important
cultural or economic activity.
2. Methods
To produce nationally informative results on climate changes
potential impacts on winter recreation, we considered available sources
of recreational and meteorological data to select representative sites
across the CONUS. We then used a well-vetted snow model to project
natural snow accumulation and melt at each site. We used modeled
future temperatures to project changing snowmaking conditions at each
downhill skiing location. Snow modeling and snowmaking projections
were repeated for baseline and future climate conditions. We then
quantied and monetized the resulting changes in snow conditions by
integrating available baseline recreational and population data with a
series of reasonable, but simplifying, assumptions about future recrea-
tional participation and expenditures.
2.1. Recreational site selection
The rst step in our work was to identify reliable recreational
participation data for multiple locations, ideally with multiple observa-
tions over time, which could be paired with observed and projected
climate data. To link climate projections to specic winter recreation
locations, we downloaded publicly available ski area information (i.e.,
polylines) to create footprints for winter recreation sites in the CONUS
(OpenSnowMap, 2016). We then merged this information with ski area
site names and locations from the National Oceanic and Atmospheric
Administration geospatial data portal (NOAA, 2016). We compared ski
area polygons to aerial photography to verify ski area names, ensure a
match of the area footprints, and record the type of skiing for each area
(i.e., downhill, cross-country, or both) making any edits as necessary
in the review process. Our nal sample included 247 ski locations,
distributed across the 6 National Ski Areas Association (NSAA) regions
and across private and public lands, as shown in Fig. 1.
2.2. Natural snow accumulation and snowmaking model
2.2.1. Utah energy balance model
We chose the Utah Energy Balance (UEB) model (Tarboton and
Luce, 1996), a physically-based model that simulates the water and
energy balance of a seasonal snowpack. We used several criteria in the
model selection process: (1) high computational eciency, as the study
design required over 300,000 years of model simulations; (2) minimal
parameters, given the broad range of site conditions that exist across
the CONUS; and (3) acceptable performance. UEB is a single-layer snow
model, and thus is more ecient and has fewer parameters than more
complex, multi-layer models (e.g., Flerchinger et al., 1996). Even
though the UEB model is relatively simple, its performance is on par
with more complex models, as determined through snow model
intercomparison eorts (e.g., Rutter et al., 2009; Förster et al., 2014).
As discussed below, the selection of a meteorological dataset is even
more important than the model, given that uncertainty from forcing
data often exceeds that from errors due to model physics or parameters
(Raleigh et al., 2015). We used the current version of the model
(UEBveg; Mahat and Tarboton, 2012, 2014) to simulate natural snow
accumulation and snowmelt at two elevations, representing the bottom
and top of a ski area, for our selected locations. The UEB model tracks
three state variables: snow-water-equivalent (SWE), internal energy of
the snowpack, and snow surface age, the latter which aects surface
For implementation, we set the vegetation fractional cover input to
zero to simulate the open areas that predominate on wide ski area
slopes. The shortwave radiation input is calculated based on date/time,
latitude, and slope angle and azimuth. The diurnal cycle of the surface
energy balance, and thus melt, is represented because we used hourly
meteorological forcing. However, we exported only daily SWE from the
UEB model.
2.2.2. Meteorological forcing and topographic adjustments
We used hourly North American Land Data Assimilation System
(NLDAS-2) meteorological forcing data (Xia et al., 2012) to drive the
UEB snow model. NLDAS-2 data were selected because they provide
physically-consistent forcing elds for the entire United States. NLDAS-
2 forcing data are provided on a 1/8th degree (12 km) grid for the
interval from January 1, 1979 through the present. No other multi-
decadal, high-spatial resolution, continental-scale datasets exist, and
thus NLDAS-2 data have been used in hundreds of snow and hydrology
studies (e.g., Sultana et al., 2014; Fu et al., 2015; Raleigh et al., 2015).
We used data for the following NLDAS-2 variables: air temperature,
specic humidity, wind speed, downward shortwave radiation, and
downward longwave radiation. The four non-precipitation variables
were generated on a 32-km grid at 3 hourly intervals as a part of the
National Centers for Environmental Predictions North American Re-
gional Reanalysis, and then interpolated to the NLDAS-2 grid (Cosgrove
et al., 2003). The NLDAS-2 precipitation data are based on daily
weather gauge values gridded to 1/8 °, utilizing information from the
Parameter-Elevation Relationships on Independent Slopes Model
(PRISM; Daly et al., 1994) and disaggregated through time using radar
analyses when available. The UEB snow model has previously been
driven with North American Land Data Assimilation System (NLDAS)-2
meteorological forcing data (as in this study), yielding a reasonable
time series of SWE as observed at individual California Department of
Water Resources Snow Telemetry (SNOTEL) sites (Sultana et al., 2014).
The accuracy of the NLDAS-2 input data aects the SWE simulated
by the UEB model. It is challenging to model SWE in mountain ranges:
precipitation, temperature, and radiation vary dramatically on length
scales from meters to kilometers, resulting in extreme spatial variability
in SWE (e.g., Clark et al., 2011). Even though NLDAS-2 data are
relatively high resolution (1/8th degree), it is impossible for this
dataset to represent the extreme range of conditions that exist within
individual grid cells. In order to represent topographic eects at scales
ner than the NLDAS grid cells, we applied site-specic adjustments in
temperature and precipitation as a function of elevation within each ski
area boundary. To do this, we extracted monthly climate normals for
19812010 from PRISM, and regressed both temperature and precipita-
tion against elevation for each cardinal direction within each ski area
boundary. We used these regression results to calculate an average
temperature and precipitation lapse rate for each ski area. Using these
calculated lapse rates, we adjusted the baseline NLDAS forcing to
estimate precipitation and temperature at the bottom and top of each
ski area.
C. Wobus et al. Global Environmental Change 45 (2017) 1–14
The topographic adjustment accounts for dierences in elevation
between the ski area and the NLDAS model grid cell in which the ski
area exists. However, this adjustment does not account for the low bias
in NLDAS precipitation that exists in mountainous regions (e.g., Pan
et al., 2003; Argus et al., 2014; Fu et al., 2015). In two similar studies
that used NLDAS data as inputs for snow models, a comparison to
SNOTEL data was used to adjust the input precipitation to account for
this bias (Pan et al., 2003; Sultana et al., 2014). We take the same
approach here. We compared both precipitation and temperature from
NLDAS-2 to that measured at individual SNOTEL sites. We identied
SNOTEL sites within NLDAS-2 grid cells containing one of our target
skiing locations and that were within 100 m of the specied NLDAS-2
elevation. Only 27 SNOTEL stations met this criterion. Other SNOTEL
sites were too dierent in elevation, so the comparison would have
been obfuscated by topographic gradients in precipitation and tem-
perature. NLDAS-2 precipitation is 10% lower and temperature is 0.5 °C
warmer than observed at SNOTEL stations, averaged across these 27
sites. We accounted for both this 10% under-prediction relative to
SNOTEL and the documented 20% undercatch of precipitation at
SNOTEL gauges (e.g., Serreze et al., 2001) by multiplying the NLDAS
precipitation by 1.3 prior to use in the UEB model. We also subtracted
0.5 °C from the NLDAS temperature to remove the bias relative to
SNOTEL. The precipitation adjustment factor is smaller than that used
by Pan et al. (2003) and similar to that from Sultana et al. (2014).
The 27 SNOTEL sites used for this meteorological forcing adjust-
ment are all in the western United States. Homogenous monitoring
networks comparable to SNOTEL do not exist in the Midwest or East,
where meteorological observations are not made in environments and
at elevations similar to ski areas. Although SNOTEL stations are in the
western United States, we show below that the UEB model driven by
this bias-corrected NLDAS-2 forcing provides a reasonable ski season
length throughout the United States (see Section 3.1).The slope and
aspect of ski slopes each play an important role in controlling seasonal
snow accumulation and melt, due to the change in net solar radiation
per square meter depending on the incident angle of sunlight relative to
the surface. To account for these topographic inuences, we also
calculated the mean slope and modal aspect of each ski area using a
90 m digital elevation model (USGS, 2008). Our modeling includes
snow accumulation and melt at the average slope and aspect for the top
and bottom of each skiing location.
2.2.3. Modeling hours suitable for snowmaking
Snowmaking is already a critical operational feature for many
downhill skiing locations, and helps to ensure that an area is open for
the Christmas/New Year holidays (e.g., Dawson and Scott, 2013).
Typically, downhill ski areas require between 400 and 500 h of suitable
snowmaking conditions before they can open (Robin Smith, TechnoAl-
pin, personal communication, October 13, 2016), which requires a wet
bulb temperature of 28 °F or less (e.g., Scott et al., 2003; Robin Smith,
TechnoAlpin, personal communication, October 13, 2016). We calcu-
lated cumulative hours of wet bulb temperature below 28 °F beginning
on October 1 of each year as a proxy for snowmaking potential at each
location. We calculated wet bulb temperature from NLDAS-2 humidity
and air temperature (e.g., Stull, 2011) at the lowermost elevation for
each location, under the assumption that most resorts need to cover
their lowest slopes to open. In each simulation year, we recorded the
Fig. 1. Map of skiing locations, by NSAA reporting region, to project climate change impacts on natural snow accumulation and potential snowmaking conditions.
C. Wobus et al. Global Environmental Change 45 (2017) 1–14
date when each location reached 450 h of cumulative snowmaking
conditions. We calculated an average date to reach 450 snowmaking
hours for each location from each of the individual years in the 30-year
climate dataset.
2.3. Climate change scenarios
Computational and resource constraints required that we select a
subset of GCMs from the full suite of the fth Coupled Model
Fig. 2. Comparisons of UEB model SWE estimates with independent measures of season length from SNODAS, averaged over water years 20042010. Small dots represent individual
sites; large dots are regional averages with 1σerror bars.
Fig. 3. Baseline season lengths for cross-country skiing and snowmobiling.
C. Wobus et al. Global Environmental Change 45 (2017) 1–14
Intercomparison Project (CMIP5; Taylor et al., 2012) models. We chose
ve GCMs (CCSM4, GISS-E2-R, CanESM2, HadGEM2-ES, and MIROC5)
with the intent of ensuring that (1) the subset captured a large range of
variability in climate outcomes observed across the entire CMIP5
ensemble, and (2) the models were independent and broadly used by
the scientic community. For each GCM, we chose two RCPs that
captured a range of plausible emissions futures. The RCPs, originally
developed for the Intergovernmental Panel on Climate Changes Fifth
Assessment Report, are identied by their approximate total radiative
forcing in the year 2100, relative to 1750: 8.5 W/m
(RCP8.5) and 4.5
(RCP4.5). RCP8.5 implies a future with continued high emissions
growth with limited eorts to reduce greenhouse gases (GHGs),
whereas RCP4.5 represents a global GHG mitigation scenario.
To provide localized climate projections and to bias correct the
projections to improve consistency with the historical period, we used
the LOCA dataset (Pierce et al., 2014, 2015; USBR et al., 2016). The
LOCA downscaled dataset provides daily minimum and maximum
temperatures (T
and T
), and daily precipitation values at 1/16°
resolution from 2006 to 2100. For each climate scenario, we calculated
an average daily change factor for temperature and precipitation at
each grid cell by comparing 20 years of LOCA projections centered on
2050 and 2090 to a historical 1/16° gridded dataset from the period
19862005 (Livneh et al., 2015). We calculated these daily change
factors as a spatial average of nine 1/16° LOCA grid cells (3 × 3
window) surrounding each location.
We calculated hourly temperature change factors based on model-
projected changes in T
and T
by assuming these temperatures
occur at midnight and noon, respectively, and interpolating between
and T
values over the course of each day. These hourly changes
were then added to the baseline NLDAS-2 temperature time series. For
precipitation, we used the GCM outputs to calculate a multiplier to
apply to the hourly NLDAS-2 precipitation time series. In some cases,
the LOCA-modeled precipitation led to unrealistically high change
factors. To eliminate these outliers, we rst discarded values that
exceeded the 90th percentile of all change factors for each station. We
then calculated daily change factors as a 31-day moving average ratio
of this ltered time series, and applied them to the NLDAS baseline.
Additional details regarding our GCM selection process, an overview of
the selected models, and processes for producing the relevant tempera-
ture and precipitation measures are provided in Supplementary in-
formation le #1.
2.4. Winter recreation activity, season length, and monetization approach
We combined the physical modeling, described above, with avail-
able recreational visit and entrance fee data to advance the under-
standing of how climate change aects winter recreation. First, we
created baseline recreational activity levels for downhill skiing, cross-
country skiing, and snowmobiling using NSAA and National Visitor Use
Monitoring (NVUM) program data (NSAA and RRC, 2016; USFS, 2016).
NSAA provides a comprehensive, annual dataset that uses survey data
from approximately 195 ski resorts to report downhill ski visits by state
(consistent with the NSAA survey, we use the term visitthroughout to
represent one persons activity for a single day of a given type of
recreation). To produce the downhill skiing baseline, we constructed a
decadal average of skier visits by state using visit data from the
20062007 season through the 20152016 season (NSAA and RRC,
2016). The United States Forest Service (USFS) uses onsite surveys to
Fig. 4. Average percent change in annual cross-country skiing and snowmobiling season lengths across GCMs. A) Results for RCP4.5 in 2050. B) Results for RCP4.5 in 2090. C) Results for
RCP8.5 in 2050. D) Results for RCP8.5 in 2090.
C. Wobus et al. Global Environmental Change 45 (2017) 1–14
estimate the level of recreation use on national forests through the
NVUM program. NVUM has a time-series of recreation visits and
expenditure data for cross-country skiing and snowmobiling, as well
as downhill skiing and other recreational activities (USFS, 2016). To
produce the cross-country and snowmobiling baseline, we used the
average of visits from two rounds of survey data (Round 1 from 2005 to
2009 and Round 2 from 2010 to 2014). For national forests that span
multiple states, we allocated baseline visits according to the distribu-
tion of the forest area in the respective states. The NSAA data are
representative of visits in 2011 and the NVUM data are representative
of visits in 2010.
We applied changes in season length, as modeled at each of the 247
locations in the CONUS, to estimate changes in winter recreation visits.
For downhill skiing season lengths, we incorporated snowmaking,
which is consistent with Scott et al. (2003, 2008).Wedened the start
of each season as the earlier of 10cm SWE or 450 h of snowmaking at
the base of each location, and the end of each season as the last date
with 10 cm SWE at the upper elevation of each location. For Nordic
skiing and snowmobiling, the use of snowmaking is relatively uncom-
mon (Reese Brown, Cross Country Ski Areas Association, personal
communication, July 7, 2016) and, therefore, we did not incorporate
snowmaking into our analysis. We used the direct outputs from the UEB
model to simulate snowpack, and determined season length as the
dierence between the rst and last dates with 10 cm SWE at the base
elevation of each location.
Winter recreation use is strongly correlated to season length; this
correlation is particularly strong at the regional level for downhill
skiing (correlation coecients for season length versus total annual
visits range from 0.60 in the Rocky Mountains to 0.99 in the Southeast
NSAA regions). To project potential impacts of climate change on
winter recreation activities, we assumed recreational visits will change
in direct proportion to the length of the associated recreational season.
This assumption is consistent with NSAA data that show the percent
visitation by month is approximately even throughout the ski season,
particularly in the Rocky Mountain region (NSAA and RRC, 2016).
Finally, we monetized the impacts of climate change on winter
recreation using ticket prices for downhill skiing and entry fees at
national forests for cross-country skiing and snowmobiling to reect the
price of access to each recreational opportunity. For downhill skiing, we
used the average of reported adult ticket prices, by region, for the
20142015 through 20152016 seasons (NSAA and RRC, 2016).
Regional ticket prices ranged from approximately $59 in the Midwest
region to $127 in the Rocky Mountain region (NSAA and RRC, 2016; all
prices in year 2015 dollars). For comparability, we used entry fees from
the NVUM data to monetize projected changes in cross-country skiing
and snowmobiling visits in national forests. Entry fees are one
component of USFSs NVUM trip spending proles and include site
admission, parking, and recreation use fees (Stynes and White, 2005;
Dan McCollum, U.S. Forest Service, personal communication, October
12, 2016). The NVUM data ask visitors surveyed about trip-related
spending. We converted trip spending to visitor spending by dividing
the trip entry fees by the average number of people per trip. We use
these entry fee measures to monetize recreational impact given the
scale and goals of the analysis, and to avoid a number of more complex
economic issues discussed in greater detail in the Conclusions section.
For all three winter recreational activities, we rst evaluated
impacts holding population constant over time to isolate the impact
of climate change. A second set of impact estimates were then
calculated to account for projected population growth. We used the
Integrated Climate and Land Use Scenarios (ICLUS) v2.0 (U.S. EPA,
2016) county-level, all-age population projections, to project 2050 and
2090 populations by state. To estimate future visitation, we multiplied
Fig. 5. Baseline and future cross-country skiing and snowmobile season length for Bretton Woods resort in New Hampshire. Boxplots represent the distribution of 30 annual UEB model
simulations for baseline conditions and each of the future scenarios specied. A) Results for RCP4.5 in 2050. B) Results for RCP4.5 in 2090. C) Results for RCP8.5 in 2050. D) Results for
RCP8.5 in 2090.
C. Wobus et al. Global Environmental Change 45 (2017) 1–14
the ICLUS state population projections by the average annual number of
visits in each state per resident calculated for the baseline period, and
then scaled the resulting product by the estimated proportional change
in season length for the activity in that state. The change in season
length used in this calculation represents an average of change for all
sites in each state, by activity type.
3. Results
Below, we summarize results for each NSAA region by RCP and time
period and provide detailed baseline and future snow modeling results
for representative sites across the United States. Detailed annual season
length results for all locations for the 21 simulations (one baseline and
20 future projections) are included in Supplementary information le
#2. We also provide detailed baseline and future winter recreational
activity levels under climate change scenarios. Detailed state-level
changes in winter recreation visits and dollars are included in
Supplementary information le #3.
3.1. UEB model validation
We used season length derived from the Snow Data Assimilation
System (SNODAS; Barrett, 2003) to validate our baseline simulations,
by examining how UEB-simulated season length varies from region to
region across the United States. SNODAS provides daily SWE at 1km
resolution nationwide, based on a multi-layer snow model that is forced
to be consistent with remotely-sensed observations of snow extent.
SNODAS data are available beginning in 2003, so we compared season
length (duration of SWE > 10 cm) at each of the 247 sites averaged
over the 7 overlapping seasons between SNODAS and our baseline
simulations (water years 20042010). The correspondence between
UEB and SNODAS season length estimates at the ski area scale is
reasonable given the coarseness of the NLDAS-2 forcing: including all
outliers, the r
is approximately 0.6 and there is little bias (Fig. 2). The
only clear dierence between UEB and SNODAS is in the Pacic
Southwest, where the UEB season length is longer than SNODAS by
30 days.
We also compared UEB SWE with SNOTEL data at the 27 sites that
are within 1 km of ski areas. Although dierences at individual SNOTEL
sites are in some cases substantial, the average season length from UEB
at these 27 sites is nearly the same as from SNOTEL (UEB season length
for these 27 sites is 112 +/30 days; SNOTEL is 125 +/40 days).
3.2. Baseline and projected season lengths
3.2.1. Cross-country skiing and snowmobiling
For cross-country skiing and snowmobiling, season lengths vary
from less than 1 week for some sites in the Northeast and upper
Midwest to more than 24 weeks for many sites in the western United
States (Fig. 3). These season length projections assume no adaptation
from snowmaking.
Average annual changes in cross-country skiing and snowmobiling
season lengths across the GCMs range from small increases in some
locations, to declines of more than 80% under the RCP4.5 scenarios in
2050 (Fig. 4A). In general, the most signicant reductions in season
length occur in the upper Midwest and the Northeast, and the smallest
Fig. 6. Average date to reach 450 cumulative hours with conditions suitable for snowmaking (Twb < 28 °F), based on 30 years of baseline NLDAS-2 forcing data.
C. Wobus et al. Global Environmental Change 45 (2017) 1–14
reductions occur at locations in the central Rockies and Sierras. The few
locations with increases in season length are generally in arid regions of
the Southwest and parts of the upper Midwest. These increases in
season length are driven by projected increases in precipitation, which
oset projected increases in temperature by mid-century.
The general regional pattern of changes in cross-country skiing and
snowmobiling season length persists across GCMs into the late century
under the higher emissions scenario (i.e., RCP8.5 in 2090; Fig. 4D).
However, under this scenario a much larger fraction of the modeled
locations are projected to see average annual reductions from their
baseline season length of > 80% compared to the RCP4.5 estimates in
2090 (Fig. 4B).
Beneath these regional trends, there is substantial variability across
the GCMs. Fig. 5 illustrates projected changes in cross-country skiing
and snowmobiling season length at the Bretton Woods resort in New
Hampshire for each climate model/RCP combination. For this resort,
the average projected decrease in season length ranges from approxi-
mately 65% by 2050 under RCP4.5, to more than 90% by 2090 under
RCP8.5. While inter-annual variability remains high in 2050 under
some of the models (e.g., CCSM4, GISS), this variability eectively
collapses in the relatively unconstrained RCP 8.5 emissions scenarios,
particularly late in the century.
3.2.2. Downhill skiing and snowboarding
The length of the winter season for downhill skiing reects the
combined inuence of early season temperatures, which modulate
resortsability to make snow; and natural precipitation and tempera-
ture throughout the ski season, which control the water and energy
balance that drive the natural snowpack. Under baseline conditions,
locations with the highest base elevations (e.g., those in the central
Rocky Mountains) typically reach the 450 cumulative hours of snow-
making threshold by late October, whereas this snowmaking threshold
is not reached until late January or later in some locations in the
Southeast (Fig. 6). Including snowmaking, baseline season lengths for
alpine skiing range from just 12 weeks in some resorts in the
Southeast, to more than 28 weeks in the highest elevations of the
Rocky Mountains and Sierras (Fig. 7; Supplementary information File
Under climate change scenarios, the average date to reach the
cumulative 450 h snowmaking threshold increases by approximately
1020 days by mid-century under RCP4.5, and by 3070 days by late
century under RCP8.5 (Fig. 8). Winter recreation impacts are regionally
variable, with the largest delays in reaching this snowmaking threshold
occurring in the Pacic Northwest and smaller delays in the Rocky
Mountain region.
For most downhill skiing locations, opening prior to the Christmas
and New Years holidays is critical to remaining protable and staying
in business (e.g., Dawson and Scott, 2013; Robin Smith, TechnoAlpin,
personal communication, October 13, 2016). While approximately 70%
of modeled downhill skiing sites can reach 450 h of snowmaking by
December 15 under baseline climate conditions, this percentage
declines markedly under each of the future scenarios (Fig. 9). By
2050 this percentage is reduced by nearly half under both RCPs. In
2090 the contrast is sharper, as only 23% of locations would meet the
December 15 date under the RCP4.5 scenarios and only 11% of
locations under the RCP8.5 scenarios.
Nationally, changes in projected downhill skiing season lengths
range from slight increases at a few areas (10 areas and 6 areas,
respectively, for RCP4.5 and RCP8.5 in 2050; and 4 areas for RCP4.5 in
2090) to declines of more than 80% under RCP8.5 in 2050 for some
Fig. 7. Modeled baseline season lengths for downhill skiing, including snowmaking.
C. Wobus et al. Global Environmental Change 45 (2017) 1–14
locations (Fig. 10). As with the cross-country skiing and snowmobiling
season length results, the general spatial patterns of changes in season
length are largely preserved under RCP8.5 in 2090, but are amplied
relative to the 2050 results. Specically, the projected changes in
season length are most dramatic in the Northeast and upper Midwest,
and are less dramatic in the higher elevations in the Rockies and
Sierras. Further, in 2090 under RCP8.5, no areas are projected to have
an increased season and the smallest projected reduction in season
length is 15%.
As with the cross-country skiing and snowmobiling season results,
there is also considerable inter-model variability in climate change
results for downhill skiing season lengths. At Aspen Mountain, for
example, average season lengths decrease by 1020 days under RCP4.5
in 2050 and by 2575 days under RCP8.5 in 2090 (Fig. 11).
While Figs. 8 and 9 highlighted potential delays in opening dates
relative to the critical Christmas and New Years holidays, climate
change generally has a larger impact on closing dates than opening
dates across the combinations of RCPs and future years (Fig. 12). In the
most extreme reductions (RCP8.5 projections for 2090), the median
closing date is more than a month earlier than the baseline, moving
from early April to the end of February. In contrast, the largest shift in
the start date from the baseline involves several weeks from the
beginning to the end of December. Although we did not incorporate
detailed data on user visits by month, we do know that revenue from
spring break is important for some resorts, particularly in the Rockies.
Thus, scaling user visits and entry fee revenue linearly with changes in
season length (see Section 3.3) is likely to be conservative.
3.3. Quantifying and monetizing potential changes in future winter
3.3.1. Baseline winter recreation activity levels
Nationally, we estimated a baseline winter recreational activity
level of approximately 56.0 million downhill skiing visits from the
available NSAA data, with an additional 3.6 million cross-country ski
visits and 2.8 million snowmobile visits from the available NVUM data
(Table 1). Using calculated regional average adult weekend ticket
Fig. 8. Lost season days due to additional time required to reach 450 h of potential snowmaking time, by region. A) Results for RCP4.5 in 2050. B) Results for RCP4.5 in 2090. C) Results
for RCP8.5 in 2050. D) Results for RCP8.5 in 2090. (MW = Midwest, NE = Northeast, PNW = Pacic Northwest, PSW = Pacic Southwest, RM = Rocky Mountain, SE = Southeast; see
Fig. 1 for regions).
Fig. 9. Percentage of modeled areas able to reach 450 h of snowmaking before December
C. Wobus et al. Global Environmental Change 45 (2017) 1–14
prices from the NSAA data, we monetized baseline downhill skiing at
$5.4 billion; using the conceptually-equivalent entry fees results in
$32.4 million for cross-country skiing and $12.6 million for snowmo-
3.3.2. Monetized impact holding populations constant
Holding population constant at baseline levels, we project climate
change would reduce national downhill skiing visits to 35.4 million
visits under RCP4.5 and 19.8 million under RCP8.5 by 2090; this is a
decrease of 20.6 million and 36.3 million visits from the baseline,
respectively (Table 1). Holding population constant, national cross-
country skiing visits would be projected to decrease to 2.7 million
under RCP4.5 and 1.5 million under RCP8.5 by 2090, and national
snowmobiling visits would decrease from approximately 2.8 million in
2010 to 1.9 million under RCP4.5 and 1.0 million under RCP8.5 by
3.3.3. Monetized impact including population growth
In our approach, population growth increases projected winter
recreation visits. As a result, population growth dampens the projected
adverse impacts of climate change on the winter recreation industry.
Nationally, downhill skiing visits decrease slightly after adjusting for
changes in climate and population to 52.8 million under RCP4.5 and
30.6 million under RCP8.5 by 2090; a decrease in 3.2 million and 25.4
million visits from baseline, respectively (Table 1). Under RCP4.5,
cross-country skiing visits increase slightly in 2050 and 2090, and
snowmobiling visits increase slightly in 2090 (Table 1). However, for
RCP8.5, which reects a higher emissions scenario, the shortened
seasons overwhelm the increase in visits driven by population growth,
resulting in an overall decrease in recreational visits in both 2050 and
2090 (Table 1).
To clearly demonstrate the osetting impact of population growth
on these recreational visit results, we aggregated state-level results for
downhill skiing to the NSAA regions and compared projected regional
visits with and without population growth for 2050 and 2090 (Fig. 13).
The eect of population growth on winter recreation visits is most
clearly seen in the results for the Rocky Mountain and Pacic Southwest
regions. Under the RCP4.5 scenarios, downhill skiing visits in these
regions increase in 2050 and 2090 when we account for the combined
impacts of climate change and population growth. However, when we
hold population growth constant and account for only the impacts of
climate change, downhill skiing visits decline in both regions in the
RCP4.5 scenario. In the RCP8.5 scenario, this impact is still observable
in these regions. In all cases, projected visitation at each time period is
larger when population change is included.
As shown in Table 1, holding the population constant at baseline
values, the projected impacts of climate change alone could result in the
loss of tens of millions of winter recreation visits with an undiscounted
annual impact measured in the billions of dollars. Integrating the
impacts of projected climate change and population growth complicates
these results, as seen in Fig. 13. In general, our assumption that winter
recreation visits will increase with population, all else equal, mitigates
but does not fully oset the projected adverse impacts of climate
change at a national level. Regional trends in projected population
growth are also critical. Specically, the combination of relatively large
population increases in the Rocky Mountain and Pacic Southwest
regions, which have the highest average ticket prices, mitigate pro-
jected national-scale losses in visits and ticket revenue, especially under
Fig. 10. Average percent change in downhill skiing season length based on a combination of UEB model and snowmaking results. A) Results for RCP4.5 in 2050. B) Results for RCP4.5 in
2090. C) Results for RCP8.5 in 2050. D) Results for RCP8.5 in 2090.
C. Wobus et al. Global Environmental Change 45 (2017) 1–14
Fig. 11. Example output for Aspen Mountain showing change in season length for downhill skiing across all GCMs under A) RCP4.5 in 2050, B) RCP4.5 in 2090, C) RCP8.5 in 2050, and
D) RCP8.5 in 2090.
Fig. 12. Average baseline and projected season start and end dates for the downhill ski season, across all modeled resorts. Median opening date is represented by the red line at the bottom
of the box and whiskers plot, and median closing date is represented by the red line at the top of the box. Boxes enclose the middle 50% of the season length distribution, and whiskers
extend to the 5th and 95th percentiles. (For interpretation of the references to colour in this gure legend, the reader is referred to the web version of this article.)
C. Wobus et al. Global Environmental Change 45 (2017) 1–14
RCP 4.5 (Table 1).
4. Conclusions
Physical models that account for changes in natural snow and ski
resortsability to make snow demonstrate that season lengths for winter
recreation activities will decline at nearly all sites in the CONUS under
the considered future climate scenarios. In each region of the United
States, these impacts increase in severity over time for a given emissions
scenario, and also increase in severity with GHG emissions for a given
time period: impacts are more severe under RCP8.5 vs RCP4.5 at any
point in time and more severe in 2090 compared to 2050 for a given
Underlying these national results, we found considerable variability
at all levels of the analysis, particularly with respect to the spatial
distribution of impacts. In general, sites at higher elevations (such as
the Rocky Mountains and Sierras) tend to be more resilient to projected
changes in temperature and precipitation, whereas sites at lower
elevations (generally in the upper Midwest and New England) are more
sensitive to climate change. Based on our modeling, the dierence
between RCP4.5 and RCP8.5 could represent the dierence between
preserving skiing and snowmobiling in the eastern half of the country
and losing these activities almost completely by 2090 (Fig. 10). When
these physical modeling results are monetized using current prices for
recreational entry while accounting for population change, we nd that
the changes in winter recreation season lengths under RCP8.5 could
result in a loss of more than $2 billion annually for downhill skiing, and
an additional $5 million and $10 million for snowmobiling and cross-
country skiing, respectively (Table 1).
These results include a number of important caveats. On the
physical modeling side, our snow model was simplied to simulate
average conditions at the top and bottom of 247 areas across the
CONUS, and was driven by a relatively coarse-scale representation of
climate. The UEB model framework is exible enough that it could be
rened on a site by site basis to generate an improved calibration for
each individual site. However, this added level of specicity would
have made both the data requirements and the computational burden
too high for this national study.
Our monetization approach also required a number of simplifying
assumptions. For example, not all downhill ski areas participate in the
NSAA data collection or are located on national forest lands, so our
impacts on estimated visits may be understated. Similarly, considerable
cross-country skiing and snowmobiling activity occurs outside of
national forests, so those impacted visit estimates are likely also
understated. Our entry fee also does not measure the implicit value of
winter recreation or the full monetary impact of these activities in a
specic region or collection of regions. While alternative economic
approaches could be incorporated to try to fully monetize the projected
impacts of climate change on winter recreation, we did not attempt to
do that here.
We also have not attempted to account for the complete loss of
recreational activity with the closure of facilities, as this would require
consideration and development of business models or general operating
rules that are beyond the scope of this study. However, our modeling
does suggest increased pressure on downhill ski facility operators in
general as sequences of what would currently be considered marginal
snow seasons increase over time. This is particularly relevant when
recognizing that revenue and prot for downhill ski operators is often
concentrated into the start and end of the current winter season (e.g.,
Christmas/New Years holiday and spring break). Over time, pressure
on these important revenue periods could result in a facilitys closure.
Since we have not attempted to project potential closures, our projected
estimates of downhill skiing visits could be conservative if visits to a
closed area are not transferred to those that remain open.
Finally, we have not accounted for the dierent types of substitution
that could arise with climate change. The impacts of climate change on
Table 1
National projected impacts in terms of visits by recreational activity averaged across models for dierent time periods and RCPs.
Baseline Impacts in 2050 Impacts in 2090
Visits Dollars Change in visits
Change in visits
Equivalent monetized
impact (RCP4.5)
Equivalent monetized
impact (RCP8.5)
Change in visits
Change in visits
Equivalent monetized
impact (RCP4.5)
Equivalent monetized
impact (RCP8.5)
National impacts of climate change holding population constant
Downhill skiing 56,028,000 $5,400,134,000 (16,131,000) (19,772,000) ($1,367,232,000) ($1,716,806,000) (20,608,000) (36,259,000) ($1,783,996,000) ($3,255,810,000)
3,590,000 $32,368,000 (636,000) (873,000) ($5,949,000) ($8,037,000) (935,000) (2,055,000) ($8,623,000) ($18,711,000)
Snowmobiling 2,821,000 $12,641,000 (681,000) (844,000) ($3,072,000) ($3,798,000) (912,000) (1,802,000) ($4,106,000) ($8,102,000)
Total 62,439,000 $5,445,143,000 (17,448,000) (21,489,000) ($1,376,251,000) ($1,728,641,000) (22,455,000) (40,116,000) ($1,796,725,000) ($3,282,623,000)
National impacts of climate change with anticipated population growth
Downhill skiing 56,028,000 $5,400,134,000 (6,845,000) (11,270,000) ($345,580,000) ($778,142,000) (3,228,000) (25,448,000) $125,888,000 ($2,029,791,000)
3,590,000 $32,368,000 220,000 (87,000) $1,635,000 ($1,060,000) 628,000 (1,106,000) $5,226,000 ($10,299,000)
Snowmobiling 2,821,000 $12,641,000 (113,000) (318,000) ($525,000) ($1,442,000) 83,000 (1,212,000) $352,000 ($5,469,000)
Total 62,439,000 $5,445,143,000 (6,738,000) (11,675,000) ($344,470,000) ($780,644,000) (2,517,000) (27,766,000) $131,466,000 ($2,045,559,000)
C. Wobus et al. Global Environmental Change 45 (2017) 1–14
future winter recreation season lengths and associated conditions raise
the potential for three general types of substitution, including (1)
temporal, where the timing of future recreation will change, generally
shifting to later in the season; (2) spatial, where recreators will change
travel patterns to access dierent areas; and (3) activity, where some
recreators may switch to dierent recreational activities altogether. By
adjusting future recreation for projected season length, we are imposing
a strong assumption that captures some, but not all of these substitution
All of these caveats represent simplications that were required to
complete this national-scale analysis. Despite these simplications,
however, our approach represents an important step forward in that
it combines detailed physical modeling with a nationally consistent
monetization approach to evaluate how climate change might aect
this important industry in the United States. The methodology we have
employed in this study is also easily transferable, and could be rened
and adapted for further insight within the United States or for
applications elsewhere. For example, we could gather more detailed
meteorological, topographic and spending data from a single resort to
develop a site-specic model to dive deeper into the potential impacts
for a specic location. Alternatively, we could synthesize national-scale
meteorological and topographic data from other parts of the world to
develop scoping analyses of climate change impacts on winter recrea-
tion for other countries or regions. In any case, it is clear from this study
that climate change will have profound impacts on usersability to
enjoy skiing and snowmobiling over the 21st century in the United
States. These impacts will ripple through the economies of regions that
depend strongly on these activities, and indicate signicant challenges
for snow-dependent communities under these, and similar, climate
change scenarios.
Funding sources
This work was funded by the U.S. Environmental Protection
AgencysOce of Atmospheric Programs through contract No. EP-
This work greatly beneted from information provided by Robin
Smith of TechnoAlpin and Harry Lynk of the Aspen Skiing Company
with respect to snowmaking and downhill ski area operations. The work
also beneted from discussions with U.S. Forest Service (USFS) sta
including Dan McCollum, Don English, David Chapman, and Eric White
over the use and interpretation of dierent USFS recreational survey
data and reports. The views expressed in this article are solely those of
the authors, and do not necessarily represent the views of their
Appendix A. Supplementary data
Supplementary data associated with this article can be found, in the
online version, at
Fig. 13. Comparison of projected impact of climate change on downhill skiing visits holding population constant and allowing for population changes over time.
C. Wobus et al. Global Environmental Change 45 (2017) 1–14
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... in the pattern of and benefits derived from recreation in the future. Climate change is projected to increase warm-weather based recreation participation at mid-and northern-latitude recreation destinations (Bowker et al. 2013) and to decrease winter recreation where snow-based winter activities are currently prevalent (Loomis and Crespi 2004, Mendelsohn and Markowski 2004, Wobus et al. 2017. ...
... Lower temperatures and the presence of new snow are associated with increased demand for skiing and snowboarding (Englin and Moeltner 2004). and other snow-based recreation activities is negative (Dawson et al. 2009, Scott et al. 2008, Stratus Consulting 2009, Wobus et al. 2017. Low-elevation access areas will probably become less available, and those locations with adequate snow may face more recreation pressure (figs. ...
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The South-Central Oregon Adaptation Partnership (SCOAP) was developed to identify climate change issues relevant for resource management on federal lands in south-central Oregon (Deschutes National Forest, Fremont-Winema National Forest, Ochoco National Forest, Crooked River National Grassland, Crater Lake National Park). This science-management partnership assessed the vulnerability of natural resources to climate change and developed adaptation options that minimize negative impacts of climate change and facilitate transition of diverse ecosystems to a warmer climate. The vulnerability assessment focused on water resources and infrastructure, fisheries and aquatic organisms, vegetation, wildlife, recreation, and ecosystem services. The vulnerability assessment shows that the effects of climate change on hydrology in south-central Oregon will be highly significant. Decreased snowpack and earlier snowmelt will shift the timing and magnitude of streamflow; peak flows will be higher, and summer low flows will be lower. Projected changes in climate and hydrology will have far-reaching effects on aquatic and terrestrial ecosystems, especially as frequency of extreme climate events (drought, low snowpack) and ecological disturbances (flooding, wildfire, insect outbreaks) increase. Distribution and abundance of cold-water fish species are expected to decrease in response to higher water temperature, although effects will vary as a function of local habitat and competition with nonnative fish. Higher air temperature, through its influence on soil moisture, is expected to cause gradual changes in the distribution and abundance of plant species, with drought-tolerant species becoming more dominant. Increased frequency and extent of wildfire and insect outbreaks will be the primary facilitator of vegetation change, in some cases leading to altered structure and function of ecosystems (e.g., more forest area in younger age classes). Vegetation change will alter wildlife habitat, with both positive and negative effects depending on animal species and ecosystem. Animal species with a narrow range of preferred habitats (e.g., sagebrush, riparian, old forest) will be the most vulnerable to large-scale species shifts and more disturbance. The effects of climate change on recreation activities are more difficult to project, although warmer temperatures are expected to create more opportunities for warm-weather activities (e.g., hiking, camping) and fewer opportunities for snow-based activities (e.g., skiing, snowmobiling). Recreationists modify their activities according to current conditions, but recreation management by federal agencies has generally not been so flexible. Of the ecosystem services considered in the assessment, timber supply and carbon sequestration may be affected by increasing frequency and extent of disturbances, and native pollinators may be affected by altered vegetation distribution and phenological mismatches between insects and plants. Resource managers in the SCOAP developed adaptation options in response to the vulnerabilities of each resource, including high-level strategies and on-the-ground tactics. Many adaptation options are intended to increase the resilience of aquatic and terrestrial ecosystems, or to reduce the effects of existing stressors (e.g., removal of nonnative species). In terrestrial systems, a dominant theme of adaptation in south-central Oregon is to accelerate restoration and fuel treatments in dry forests to reduce the undesirable effects of extreme events and high-severity disturbances (wildfire, insects). In aquatic systems, a dominant theme is to restore the structure and function of streams to retain cold water for fish and other aquatic organisms. Many adaptation options can accomplish multiple outcomes; for example, fuel treatments in dry forests reduce fire intensity, which in turn reduces erosion that would degrade water quality and fish habitat. Many existing management practices are already “climate smart” or require minor adjustment to make them so. Long-term monitoring is needed to detect climate change effects on natural resources, and evaluate the effectiveness of adaptation options.
... Seasonal snowmelt-driven streamflow is one of the fastest changing aspects of the global hydrologic cycle in response to climate change (Musselman et al 2017). Warmer winter and spring temperatures are decreasing the fraction of precipitation falling as snow (fs, Knowles et al 2006, Klos et al 2014, delaying the initiation of consistent snow cover, increasing soil frost (Burakowski et al 2008, Wobus et al 2017, increasing water vapor exchanges between snowpack and the atmosphere (Harpold and Brooks 2018, Sexstone et al 2018), advancing the timing and slowing the rate of snowmelt (Musselman et al 2017), and decreasing the persistence of snow cover (Stewart 2009). In contrast to a general consensus on seasonal snow cover decline under a warming climate, predictions about streamflow response are much more diverse. ...
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Climate change is altering the seasonal accumulation and ablation of snow across mid-latitude mountainous regions in the Northern Hemisphere with profound implications for the water resources available to downstream communities and environments. Despite decades of empirical and model-based research on snowmelt-driven streamflow, our ability to predict whether streamflow will increase or decrease in a changing climate remains limited by two factors. First, predictions are fundamentally limited by the high spatial and temporal variability in the processes that control net snow accumulation and ablation across mountainous environments. Second, we lack a consistent and testable framework to coordinate research to determine which dominant mechanisms influencing seasonal snow dynamics are most/least important for streamflow generation in different basins. Our data-driven review marks a step towards the development of such a framework. We first conduct a systematic literature review that synthesizes knowledge about seasonal snowmelt-driven streamflow and how it is altered by climate change, highlighting unsettled questions about how annual streamflow volume is shaped by changing snow dynamics. Drawing from literature, we then propose a framework comprised of three testable, inter-related mechanisms—snow season mass and energy exchanges, the intensity of snow season liquid water inputs, and the synchrony of energy and water availability. Using data for 537 catchments in the United States, we demonstrate the utility of each mechanism and suggest that streamflow prediction will be more challenging in regions with multiple interacting mechanisms. This framework is intended to inform the research community and improve management predictions as it is tested and refined.
... This significant impact on SCA has a direct effect on hydrological droughts, with a general increase in drought magnitude, severity, and duration. Other studies have also demonstrated the significant impact of climate change on SCA in other mountain ranges [97][98][99]; however, there are no studies that have evaluated the impact of climate change on SCA droughts. ...
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Climate change is expected to increase the occurrence of droughts, with the hydrology in alpine systems being largely determined by snow dynamics. In this paper, we propose a methodology to assess the impact of climate change on both meteorological and hydrological droughts, taking into account the dynamics of the snow cover area (SCA). We also analyze the correlation between these types of droughts. We generated ensembles of local climate scenarios based on regional climate models (RCMs) representative of potential future conditions. We considered several sources of uncertainty: different historical climate databases, simulations obtained with several RCMs, and some statistical downscaling techniques. We then used a stochastic weather generator (SWG) to generate multiple climatic series preserving the characteristics of the ensemble scenario. These were simulated within a cellular automata (CA) model to generate multiple SCA future series. They were used to calculate multiple series of meteorological drought indices, the Standardized Precipitation Index (SPI), Standardized Precipitation Evapotranspiration Index (SPEI), and a novel hydrological drought index (Standardized Snow Cover Index (SSCI)). Linear correlation analysis was applied to both types of drought to analyze how they propagate and the time delay between them. We applied the proposed methodology to the Sierra Nevada (southern Spain), where we estimated a general increase in meteorological and hydrological drought magnitude and duration for the horizon 2071–2100 under the RCP 8.5 emission scenario. The SCA droughts also revealed a significant increase in drought intensity. The meteorological drought propagation to SCA droughts was reflected in an immediate or short time (1 month), obtaining significant correlations in lower accumulation periods of drought indices (3 and 6 months). This allowed us to obtain information about meteorological drought from SCA deficits and vice versa.
... This highlights both the importance and limits of snowmaking as an essential adaptation strategy for the ski industry. Mur- The changes in length of the snowmaking season documented here are more optimistic than the 80% to 100% reduction in season length in the northeastern United States reported in Wobus et al. (2017), which used a benchmark of 450 cumulative snowmaking hours with a wet bulb temperature below -2.2 °C to initiate and sustain snowmaking through the snow season. As Scott et al. (2020) note, however, 450 hours is an excessively high benchmark and may not be representative of smaller regional markets, where the number of cumulative snowmaking hours can be as low as 72 hours before terrain is skiable. ...
Winters in northeastern North America have warmed faster than summers, with impacts on ecosystems and society. Global climate models (GCMs) indicate that winters will continue to warm and lose snow in the future, but uncertainty remains regarding the magnitude of warming. Here, we project future trends in winter indicators under lower and higher climate-warming scenarios based on emission levels across northeastern North America at a fine spatial scale (1/16°) relevant to climate-related decision making. Under both climate scenarios, winters continue to warm with coincident increases in days above freezing, decreases in days with snow cover, and fewer nights below freezing. Deep snow-packs become increasingly short-lived, decreasing from a historical baseline of 2 months of subnivium habitat to <1 month under the warmer, higher-emissions climate scenario. Warmer winter temperatures allow invasive pests such as Adelges tsugae (Hemlock Woolly Adelgid) and Dendroctonus frontalis (Southern Pine Beetle) to expand their range northward due to reduced overwinter mortality. The higher elevations remain more resilient to winter warming compared to more southerly and coastal regions. Decreases in natural snowpack and warmer temperatures point toward a need for adaptation and mitigation in the multi-million-dollar winter-recreation and forest-management economies.
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In the context of global warming, relevant studies have shown that China will experience the largest temperature rise in the Qinghai–Tibet Plateau and northwestern regions in the future. Based on MOD10A2 and MYD10A2 snow products and snow depth data, this study analyzes the temporal and spatial evolution characteristics of the snow cover fraction, snow depth, and snow cover days in the three stable snow cover areas in China, and combines 15 modes in CMIP6 snow cover data in four different scenarios with three kinds of variables, predicting the spatiotemporal evolution pattern of snow cover in China’s three stable snow cover areas in the future. The results show that (1) the mean snow cover fraction, snow depth, and snow cover days in the snow cover area of Northern Xinjiang are all the highest. Seasonal changes in the snow cover areas of the Qinghai–Tibet Plateau are the most stable. The snow cover fraction, snow depth, and snow cover days of the three stable snow cover areas are consistent in spatial distribution. The high values are mainly distributed in the southeast and west of the Qinghai–Tibet Plateau, the south and northeast of Northern Xinjiang, and the north of the snow cover area of Northeast China. (2) The future snow changes in the three stable snow cover areas will continue to decline with the increase in development imbalance. Snow cover fraction and snow depth decrease most significantly in the Qinghai–Tibet Plateau and the snow cover days in Northern Xinjiang decrease most significantly under the SSPs585 scenario. In the future, the southeast of the Qinghai–Tibet Plateau, the northwest of Northern Xinjiang, and the north of Northeast China will be the center of snow cover reduction. (3) Under the four different scenarios, the snow cover changes in the Qinghai–Tibet Plateau and Northern Xinjiang are the most significant. Under the SSPs126 and SSPs245 scenarios, the Qinghai–Tibet Plateau snow cover has the most significant change in response. Under the SSPs370 and SSPs585 scenarios, the snow cover in Northern Xinjiang has the most significant change.
As is the case for many semi‐arid regions globally, drought in the Intermountain West of the United States is a recurrent, costly phenomenon that leaves few aspects of human and natural systems untouched. Here, we focus on drought impact data and evaluation challenges across four non‐agricultural sectors: water utilities, forest resources, public health, and recreation and tourism. There are marked commonalities in the way drought indicators—that is, hydrometeorological conditions—are tracked, but considerable differences in how impacts are measured, evaluated, and disseminated. For drought indicator data, researchers and practitioners have a veritable smorgasbord of data at their fingertips. Such data are often spatially and temporally continuous, available at a wide variety of scales, and readily accessible through government‐funded online portals. This is in stark contrast to drought impact data, which are typically collected opportunistically, if at all. These data are thus often limited in spatiotemporal scope and difficult to access relative to drought indicators. Concerningly, even within a given sector, the definition of drought impacts, quantitative or otherwise, can vary considerably, making it difficult to evaluate the true cost of drought. Far from being specific to the Intermountain West, these problems are found in most regions experiencing drought. We suggest such challenges are surmountable through the development of a common drought impact framework based around economic damages and purposeful, continuous, government‐funded drought impact data collection. These tractable changes will allow for a better quantification of drought's true impacts under both present conditions and climate change scenarios in the Intermountain West and beyond. This article is categorized under: Human Water > Value of Water Science of Water > Water Extremes Water and Life > Stresses and Pressures on Ecosystems Drought touches nearly every aspect of life in the semi‐arid Intermountain West, but data availability issues and the lack of a common impact framework obfuscate drought's true costs. We detail these challenges and present potential solutions in the following overview.
Throughout the winter months across the globe, mountain communities and snow-enthusiasts alike anxiously monitor ever-changing snowpack conditions. We model the behavioral response to this climate amenity by pairing a unique panel of 12 million short-term property rental transactions with daily local weather, daily local snowpack, and daily local snowfall in every major ski resort market across the United States. Matching the spatial and temporal variation in the level of the amenity with that of related market transactions, we derive market-specific demand elasticities, explicitly accounting for substitution, to model recreation patterns throughout a typical season. Lastly, we combine downscaled projections of local snowpack under future climate scenarios to estimate within and across season trends in visitation during mid and late-century conditions. Our model predicts reductions in snow-related visitation of -40% to -60%, almost twice as large as previous estimates suggest. This translates to a lower-bound on the annual willingness to pay to avoid reductions in snowpack between $1.23 billion (RCP4.5) and $2.05 billion (RCP8.5) by the end of the century.
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Climate change is affecting natural resources globally, altering ecosystems that support outdoor recreation. In the western United States, effects such as warming temperatures, increased drought, reduced snowpack, and widespread wildfires will change the outdoor recreation landscape. In this article, we synthesize the state of science regarding the effects of climate change on outdoor recreation in the western US and summarize adaptation options that can reduce the consequences of climate change, considering the adaptive capacities of recreationists and managers. We draw from a series of climate change assessments in which researchers and managers collaborated to understand recreation vulnerability to climate change and develop effective adaptations. We conclude that building climate resilience requires a shift in planning and resource allocation decisions, including (1) longer-term planning timeframes, (2) interdisciplinary teams, and (3) collaboration among agencies, recreation providers, and communities. Study Implications: Outdoor recreation in the western US is changing due to the effects of climate change. Organized by five recreational categories, this study describes the vulnerability of outdoor recreation to climate change and synthesizes strategies to adapt recreation management to these vulnerabilities. Multiple direct and indirect factors influence individual recreationists’ and land managers’ capacities to adapt to climate change, as we describe through a diagram. Climate-resilient land management requires long-term planning, integration of multiple resource areas, and collaboration across agencies, recreation providers, and communities.
From hampering the ability of water utilities to fill their reservoirs to leaving forests parched and ready to burn, drought is a unique natural hazard that impacts many human and natural systems. A great deal of research and synthesis to date has been devoted to understanding how drought conditions harm agricultural operations, leaving other drought‐vulnerable sectors relatively under‐served. This review aims to fill in such gaps by synthesizing literature from a diverse array of scientific fields to detail how drought impacts nonagricultural sectors of the economy: public water supply, recreation and tourism, forest resources, and public health. We focus on the Intermountain West region of the United States, where the decadal scale recurrence of severe drought provides a basis for understanding the causal linkages between drought conditions and impacts. This article is categorized under: Human Water > Value of Water Science of Water > Water Extremes Drought in the Intermountain West typically begins during the winter in high elevation mountain basins with reduced snow accumulation and earlier than normal melt. Drought conditions proceed downstream to lower elevations in the form of diminished streamflow, lower reservoir storage, higher plant water demand, increased reliance on groundwater, and desiccated forests. Drought conditions affect the recreation and tourism industry by truncating the winter ski and summer boating seasons. Drought impacts municipal water suppliers by increasing demand amidst lower‐than‐average supply, which in turn stresses utility finances. Drought impacts forest resources by way of tree mortality, wildfire, and diminished ecosystem services. Hot and dry conditions trigger myriad public health impacts, including increased incidences of respiratory disease, mental health issues, and adverse water quality conditions. While the impacts of drought extend to other facets of regional ecosystems and economies, our review focuses on impacts to tourism and recreation, municipal water supply, forest resources, and public health.
Popular snow-based, wintertime activities in Canada and elsewhere such as alpine skiing and snowboarding, cross-country skiing, and snowmobiling require cold, snowy winters to support those practicing these pastimes, but ironically, participation in these activities often accelerates climate change through reliance on fossil fuels. This paper, based on a review of scientific literature, attempts to address this irony by suggesting practices that may contribute to the growth of voluntary carbon offset (VCO) sales in the outdoor recreation industry as currently few outdoor recreation businesses in Canada offer VCO programs. The paper highlights the potential link between outdoor recreation participation and environmental concern, identifies socio-demographic groups of interest for targeted advertising campaigns, and identifies approaches for designing VCO programs and increasing VCO purchases. Management implications A strategy for increasing VCO purchases in the outdoor recreation industry is for outdoor recreation businesses to offer VCO programs themselves rather than outdoor recreationists purchasing VCOs through providers unrelated to the outdoor industry. Through recreation activities important to a person, the outdoor recreation industry can facilitate an outdoor recreationist's environmental concern and behaviour. Furthermore, VCO programs provided by outdoor recreation companies would be more visible and accessible to outdoor recreationists who might then be more likely to purchase VCOs. Outdoor recreation companies can increase their VCO sales by: marketing to people with certain characteristics (younger ages, higher education, low carbon diet, appreciative outdoor activity participation, and existing awareness of VCO programs), addressing barriers that adversely affect current offset schemes, considering both willingness to pay (WTP) when setting offset prices and alternative explanations of individuals' WTP to offset the greatest volume of CO2, and ensuring a positive purchase situation.
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The Earth's climate is changing. Temperatures are rising, snow and rainfall patterns are shifting, and more extreme climate events – like heavy rainstorms and record high temperatures – are already happening. Many of these observed changes are linked to the rising levels of carbon dioxide and other greenhouse gases in our atmosphere, caused by human activities. EPA partners with more than 40 data contributors from various government agencies, academic institutions, and other organizations to compile a key set of indicators related to the causes and effects of climate change. The indicators are published in EPA's report, Climate Change Indicators in the United States. Order print copies or send inquiries by emailing:
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Physically based models provide insights into key hydrologic processes, but are associated with uncertainties due to deficiencies in forcing data, model parameters, and model structure. Forcing uncertainty is enhanced in snow-affected catchments, where weather stations are scarce and prone to measurement errors, and meteorological variables exhibit high variability. Hence, there is limited understanding of how forcing error characteristics affect simulations of cold region hydrology. Here we employ global sensitivity analysis to explore how different error types (i.e., bias, random errors), different error distributions, and different error magnitudes influence physically based simulations of four snow variables (snow water equivalent, ablation rates, snow disappearance, and sublimation). We use Sobol' global sensitivity analysis, which is typically used for model parameters, but adapted here for testing model sensitivity to co-existing errors in all forcings. We quantify the Utah Energy Balance model's sensitivity to forcing errors with 1 520 000 Monte Carlo simulations across four sites and four different scenarios. Model outputs were generally (1) more sensitive to forcing biases than random errors, (2) less sensitive to forcing error distributions, and (3) sensitive to different forcings depending on the relative magnitude of errors. For typical error magnitudes, precipitation bias was the most important factor for snow water equivalent, ablation rates, and snow disappearance timing, but other forcings had a significant impact depending on forcing error magnitudes. Additionally, the relative importance of forcing errors depended on the model output of interest. Sensitivity analysis can reveal which forcing error characteristics matter most for hydrologic modeling.
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Global climate model (GCM) output typically needs to be bias corrected before it can be used for climate change impact studies. Three existing bias correction methods, and a new one developed here, are applied to daily maximum temperature and precipitation from 21 GCMs to investigate how different methods alter the climate change signal of the GCM. The quantile mapping (QM) and cumulative distribution function transform (CDF-t) bias correction methods can significantly alter the GCM's mean climate change signal, with differences of up to 2 degrees C and 30% points for monthly mean temperature and precipitation, respectively. Equidistant quantile matching (EDCDFm) bias correction preserves GCM changes in mean daily maximum temperature but not precipitation. An extension to EDCDFm termed PresRat is introduced, which generally preserves the GCM changes in mean precipitation. Another problem is that GCMs can have difficulty simulating variance as a function of frequency. To address this, a frequency-dependent bias correction method is introduced that is twice as effective as standard bias correction in reducing errors in the models' simulation of variance as a function of frequency, and it does so without making any locations worse, unlike standard bias correction. Last, a preconditioning technique is introduced that improves the simulation of the annual cycle while still allowing the bias correction to take account of an entire season's values at once.