2. Select a feature or set of features in the map
3. Explore results generated for the selected area.
(Results will appear here)
Projected Change (Model Averages, Annual) | |
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The average max temperature in the selected area is projected to exceed the historical average by
1.8 °C over the next 30 years2.9°C over the 30 years after that |
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The average min temperature in the selected area is projected to exceed the historical average by
1.8 °C over the next 30 years2.9°C over the 30 years after that |
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The average precipitation in the selected area is projected to the historical average by
1.8 % over the next 30 years2.9% over the 30 years after that (Note that precipitation projections vary widely among models) |
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The average aridity in the selected area is projected to the historical average by
% over the next 30 years % over the 30 years after that
|
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The average potential evapotranspiration in the selected area is projected to the historical average by
% over the next 30 years % over the 30 years after that
|
A climate trend is a progressive change in the state of the climate based on weather statistics evaluated over long periods, typically of at least 30 years (definition borrowed from Pacific Institute for Climate Solutions).
To learn more about the differences between climate and weather, click on the play button below.
Climate data used for the historical period (1971- 2000) correspond to the LT71m PRISM (Parameter-elevation Relationships on Independent Slopes Model) 30 arc-second spatial climate dataset for the Conterminous United States (Daly et al. 2008). For future climate projections, we selected four climate models, either General Circulation Models (GCMs) or Earth System Models (ESMs), (Table 1) from the 5th Coupled Model Intercomparison Project (CMIP5; Taylor et al. 2012). These models were chosen based on evaluations of their ability to simulate historical climate conditions globally and over the western United States (Rupp et al. 2013).
Model | Model Name | Model Institution |
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1 | CanESM2 | Second Generation Canadian Earth System Model |
2 | CCSM4 | Community Climate System Model version 4 |
3 | CNRM.CM5 | Centre National de Recherches Météorologiques Coupled Global Climate Model, version 5.1 |
4 | HadGEM2-ES | Hadley Centre Global Environmental Model, version 2-Earth System |
The four GCM/ESMs capture a wide range of projected change for both annual average temperature and annual precipitation under the representative concentration pathway 8.5 (RCP8.5; Meinshausen et al. 2011; van Vuuren et al. 2011). RCP8.5 is a highly energy-intensive scenario that results from high population growth and a moderate rate of technology development without establishment of climate change policies.
We used the downscaled climate projections from the NASA Earth Exchange (NEX) U.S. Downscaled Climate Projections (NEX US-DCP30) dataset (Thrasher et al. 2013) for the western United States. We chose two thirty-year periods, 2016-2045 and 2046-2075, to represent the projected futures. Each climate model projections were averaged over those periods and a multi-model ensemble mean of the ten model projections shown in the chart above was also calculated for each time period.
Calculation of Climate Variables
Climate variable values (tmax, tmin, and prec) were calculated as means of annual average temperatures and of annual total precipitation for each time period (1971-2000, 2016-2045, and 2046-2075) .
Two derived climate variables, potential evapotranspiration (PET) and aridity(the ratio of annual precipitation over PET), were also calculated for historical and future periods. PET was calculated using the 1985 version of the Hargreaves potential evaporation equation (Hargreaves and Allen 2003):
PET = 0.0023 x 0.408RA x (Tavg + 17.8) x TD 0.5        (1)
where RA is the extraterrestrial radiation expressed in (MJ m-2 d-1), Tavg (oC) is the average daily temperature, and TD (oC) is the temperature range. The constant 0.408 is the inverse of latent heat flux of vaporization at 20 oC. It is used to convert extraterrestrial radiation units from MJ m-2 d-1 to mm d-1. RA was calculated using the r.sun (Šúri & Hofierka 2004) routine in the GRASS geographic information system (GRASS 2015).
Aridity was defined as P/PET where P is annual precipitation. The percentage change in aridity was calculated by following Feng and Fu's method (2013):
Δ(P/PET)/(P/PET)≈ΔP/P−ΔPET/PET        (2)
All climate variables for historic and future projections (from four climate models and one ensemble mean) were calculated from the NetCDF files in the NCAR Command Language (NCL) software program (NCL 2014) and are listed in Table 2.
1971-2000 | 2016-2045 | 2046-2075 | |||||||||
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Average for the Period | Seas- onal | Average for the Period | Seas- onal | Delta for Period | Delta for Seas- sons | Average for the Period | Seas- onal | Delta for Period | Delta for Seas- sons | ||
Tmax | X | X | X | X | X | X | X | X | X | X | |
Tmin | X | X | X | X | X | X | X | X | X | X | |
Prec | X | X | X | X | X | X | X | X | X | X | |
PET | X | X | X | X | X | X | |||||
Aridity | X | X | X | X |
The delta or change values between historic and future for minimum and maximum temperature were calculated by subtracting historical values from future values. However, for precipitation and aridity change was calculated as a percent change from the historical (((future-historical) / historical) * 100).
Representative Concentration Pathways (RCPs) describe future concentrations and emissions of greenhouse gases, air pollutants and land-use change, created by four different international teams using different sets of assumptions. The word ‘representative’ means that each RCP is only one of many possible scenarios found in the literature. The term ‘concentration’ is used because atmospheric concentrations of greenhouse gases are the primary simulation product rather than emissions. RCPs are tagged for their radiative forcing target level for year 2100. RCP2.6 is a stringent mitigation scenario that aims to keep global warming below 2°C above pre-industrial temperatures, with radiative forcing peaks near 3 W/m2 before 2100 and then declines. RCP4.5 and RCP6.0 are two intermediate stabilization scenarios in which radiative forcing is stabilized at approximately 4.5 W/m2 and 6.0 W/m2 after 2100. RCP8.5 (used here) is a scenario with high greenhouse gas emissions where radiative forcing reaches >8.5 W/m2 by 2100 and continues to rise for some time. (Van Vuuren et al. 2011; Stocker et al. 2013)
The LT71m PRISM dataset is a gridded time series of monthly-modeled values for precipitation (rain + melted snow), maximum, minimum, and mean temperatures. It uses data from station networks that have at least some stations with ≥ 20 years of observed data. To create a grid with PRISM, Daly et al. (2008) use the climatologically-aided interpolation (CAI) method with 1971-2000 monthly climatologies.
The NEX US-DCP30 future climate dataset includes climate projections from 34 GCMs that have been statistically downscaled to 30 arc-second spatial resolution using the Bias-Correction Spatial Disaggregation (BCSD) method (Maurer and Hidalgo 2008). First the bias in temperature and precipitation projections is corrected by comparing GCM results with “observations” from the PRISM dataset. The projections are then downscaled to the finer 30 arc-second grid using the complex spatial interpolation method during the “spatial-disaggregation” step (Thrasher et al. 2013).
Climate Data Extraction
All PRISM data used for the historical period were converted from the ESRI ASCII raster format (ESRI 2014) to the Network Common Data Form (NetCDF; Rew et al. 1997, UNIDATA 2015). We discovered that when the NEX data were processed by Thrasher et al. (2013) the left lower corners of the PRISM data were erroneously used as the center coordinates for processing the NEX NetCDF files. Therefore, the origin of the NEX US-DCP30 data had to be altered to conform to the PRISM data. The NEX grids were adjusted by one-half grid cell (0.004166666667 decimal degrees) so that the two datasets would be spatially aligned and consistent.
Once all of the data were in the NetCDF format and spatially aligned, climate variables [maximum average monthly temperature (tmax), minimum average monthly temperature (tmin), and average monthly precipitation (prec)] were extracted just for the western United States. The multi-model ensemble was then created for each variable by taking the un-weighted mean of the projections from the ten climate models of interest.
Post Processing
Each climate dataset was projected to USA Contiguous Albers Equal Area Conic (USGS version) using a cubic convolution resampling method in ArcGIS 10.3. The zonal mean for both climate and impact projection datasets was calculated for each of the reporting units and stored in a spatial database which can then be queried against using the tools provided on the left hand side of the map or by simply clicking on a feature of interest. This allows the user to examine future climate projections and climate change impacts within one or more administrative units or ecological boundaries of interest.
To learn about the differences between climate and weather, click on the play button below.
The data in these files represent probability of exceedance values. The field headers (98, 95, 90 ,80, 70, 60, 50, 40, 30, 20, 10, 5, 2) indicate the probability that the actual temperature or precipitation level during the three month period expressed by the LEAD time will be greater than the stated value within the specified climate division (CD). Click here for complete field descriptions and additional information on the forecast distribution files above.
The historical means and forecast means displayed in the climate console come directly from the values in the climatological mean field (C MEAN) and the forecast mean field (F MEAN), respectively. The forecast mean corresponds to the 50% probability of exceedance value. These data are automatically updated on the third Thursday of each month (Barnston et al. 2000).
Overview of the EEMS Modeling Process
EEMS derives from the Ecosystem Management Decision Support System (EMDS; Reynolds, 2006). With fuzzy logic modeling (a quick introduction to fuzzy logic modeling can be found at: http://tinyurl.com/ox76lhb), input variables are normalized by converting them to a common numeric domain or range (also referred to as fuzzy space) varying between, in this case, -1.0 (representing a "fully" false statement) and +1.0 (representing a "fully" true statement). Fuzzy values are assigned based on the relationship to a proposition. For instance, projected change in minimum temperature can be tested against the proposition, “will experience substantial departures from historical temperature” using fuzzy values varying between +1.0 (true statement) and -1.0 (false statement).
Normalized inputs are combined using logic operators to create a hierarchical, logic tree that produces an answer to a particular question (for instance “will this area experience considerable climate change?”). Each grid cell in the study area is evaluated independently, producing a map of fuzzy values answering the question for all the grid cells across the landscape.
We implemented the models using data in NetCDF format for the study area matching the domain of the input files.
To learn more about logic models, click on the play button below.
The Condition & Impacts tab shows results for several EEMS models averaged over the area selected by the user. The bar colors correspond to colors of the model inputs on the map. Clicking on the bar causes the entire dataset to display in the map.
In addition, when you click on a column, you’ll see the model diagram appear below the chart. The model diagram is an interactive graphical representation of the model used to create each of the EEMS results shown in the chart. The model flows from the bottom up — meaning that input nodes appear below the output nodes they create. The text in the gray boxes indicate the operation used to combine the input data (e.g., Fuzzy Union).
Clicking on any box makes the corresponding spatial dataset show up on the map on the left. By clicking on the color ramps on the right hand side of each box in the logic tree, the user can choose to display either of the two color scale (classified or stretched). When the user clicks on a box, the model diagram expands to show the underlying inputs used to create the box that was selected. Box colors indicate the number of inputs (see color scale below logic tree). The active box representing the map on display will be highlighted in green.
Soil Data for Soil Sensitivity Calculation
Soil data for this analysis were obtained from the conterminous United States Multi-Layer Soil Characteristics data (Miller & White 1998) and the STATSGO soil database (Soil Survey Staff 2015). All variables used are listed in Table 3.
Variable | Acronym | Database | URL |
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Available Water Capacity | AWC | CONUS-SOIL | http://www.soilinfo.psu.edu/index.cgi?soil_data&conus&data_cov |
K-Factor | Kffact | CONUS-SOIL | http://www.soilinfo.psu.edu/index.cgi?soil_data&conus&data_cov |
pH | pH | CONUS-SOIL | http://www.soilinfo.psu.edu/index.cgi?soil_data&conus&data_cov |
Depth to Bedrock | RD | CONUS-SOIL | http://www.soilinfo.psu.edu/index.cgi?soil_data&conus&data_cov |
Salinity | SAL | STATSGO | https://gdg.sc.egov.usda.gov/ |
Wind Erodibility Index | WEG | STATSGO | https://gdg.sc.egov.usda.gov/ |
Processing of Soil Data
All soil variables were downloaded for the conterminous United States and processed in ESRI ArcInfo workstation (ESRI 2014). Polygon data were converted to a raster dataset with a cell size of 0.0083333333 decimal degrees. The data were then clipped to the western United States and exported in NetCDF format.
Calculation of Water Erodibility Index
The index of susceptibility to water erosion (LSKf) was calculated from the Universal Soil Loss Equation (Wischmeier & Smith 1978) which is given as:
A = R * K * L * S * C * P          (3)
where A is predicted average annual soil loss, R is measured rainfall erosivity, K is soil erodibility, L is slope length factor, S is steepness of the slope, and C and P represent the respective erosion reduction effects of management (C) and erosion control practices (P).
Combining L and S represents the impact of topography on erosion and is calculated as (Hickey 2000):
LS= (As/22.13)^0.4∙ (sinθ/0.09)^1.4∙1.4
where As is the unit of contributing area (m), θ is the slope in radians. We then combined the K factor with LS to estimate the potential susceptibility of a soil to water erosion.
The original values in the human modification dataset ranged from 0 to +1.0. A linear transformation (y=2x-1) was applied in order to scale the data to the range of fuzzy values allowed in the EEMS modeling framework (-1 to +1). Larger values indicate a higher degree of human disturbance on the landscape, whereas lower values indicate lower levels of human disturbance.
Because the model runs used historical (PRISM) climate through 2014, the value for the first decade (2011-2020) is a combination of the final 4 years of the run using PRISM data, and the first 6 years of the run using MACA-downscaled data. Since the future runs end in 2099, the final decade is a mean (mode) of 9 years (2091-2099) rather than 10 as for the other decades. Time values for each step in the charts represent the beginning of each decade.
The fine-grained vegetation classes from MC2 were simplified before the 10-year modes were calculated. The vegetation classes are:
1: Tundra
2: Taiga tundra
3: Conifer forest
4: Cool mixed forest
5: Deciduous forest
6: Warm mixed forest
7: Tropical broadleaf forest
8: Woodland/Savanna
9: Shrubland/Woodland
10: Grassland
11: Arid land
The Nature's Stage Climate Mapper is a web-based mapping application developed by the Conservation Biology Institute (CBI) in collaboration with the Nature Conservancy for the purpose of allowing users to explore the Climate Resilience data generated from the CNS project together with Climate Departure data produced by CBI.
From these two variables (climate resilience & climate departure), the tool was programmed to calculate a new variable termed Geoclimatic Stability, which is defined as a measure of a natural system's capacity to remain stable as the climate changes over time. The information provided by the tool is intended to help land managers prioritize conservation efforts and help guide future conservation investments.