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Climate Toolbox Activities

FUTURE CROP SUITABILITY

EXPLORE FUTURE CROP SUITABILITY

NEAR PORTLAND, OREGON

In this activity, we will explore future grape suitability under climatic conditions near Portland, Oregon, using the Future Crop Suitability Tool in the Climate Toolbox.

A crop can be damaged by periods of extreme cold temperatures for even a few hours. In a warming climate, we expect fewer frost days annually. But with warmer winters and earlier springs, a late frost could cause crop losses.

Climate Effects

Crop Suitability due to Temperature Effects

The crop suitability of a geographical region for growing a certain crop is the ability of a crop to grow to maturation with a good harvest year after year. Farmers accept that crops may fail occasionally. But when crops fail more than 1-2 years every 10 years, a farmer starts to question continually growing a crop. In a warming planet, the ranges of suitable regions for different crops are likely to shift. Temperature effects are a dominant cause of crop failures.

A crop can generally survive in a region when the average minimum temperatures exceed a threshold value determining the cold hardiness zones used by gardeners. In a warming climate, we expect more crops to survive in what are today colder regions.

A crop advances through stages of development after accumulating enough heat or growing degree days (GDD), calculated as the sum of average daily temperatures above a set threshold. In a warming climate, we expect crops to achieve maturation and harvest sooner than today.

Some crops require exposure to cooler temperatures, i.e. hours between 32 - 45 F, in order to break winter dormancy with adequate growth in the growing season. In a warming climate, we expect some tree crop harvests to fail in warmer regions due to not accumulating enough chill hours in the winter months. To try to accumulate more chill hours, budbreak may occur later in cooler regions thus delaying the reproductive growth phase.

ClimateToolbox.org

Frost Damage

Cold Hardiness

Heat Accumulation

Chill Accumulation

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ClimateToolbox.org

Data

FUTURE CROP SUITABILITY

A year is considered not suitable if:

  • frost damage can occur in spring
  • the crop cannot reach maturation
  • chill accumulation is insufficient
  • cold hardiness has changed

Future crop suitability data used in this activity were produced using daily minimum and maximum temperature data from 20 global climate models and 2 future emission scenarios (RCP4.5, 8.5) from CMIP5. Hourly temperature data are estimated using minimum and maximum daily temperatures and latitude.

Activity

  • Go to the Future Crop Suitability Tool (ClimateToolbox.org)
  • Select Cabernet Sauvignon grapes.
  • Assume farmer needs 8/10 successful years
  • Check box for 1971-2000. Select Portland. Is Portland currently suitable for these grapes? Take screenshot of map and legend. Uncheck box for 1971-2000.
  • Check box for 2040-2069. Select Portland. Is Portland suitable in future? Take screenshot of map and legend for RCP 4.5 and for RCP 8.5.
  • Search the internet for a picture of these grapes (or the wine) to add to your slide.

In the crop model, growth stages of different crops are simulated using growing degree days. If the crop achieves maturation, i.e. ready for harvest, before the first Fall freeze triggers crop dormancy, the year is considered suitable for that crop.

Crop Simulations

Overall Thermal Suitability

Create a climate data story on future crop suitability near Portland.

Prepare a 3-5 min presentation (2 slides) on your story.

The Facts (Slide 1)

The Meaning (Slide 2)

To Do

To Do

Prepare Slide

  • 3 maps- today, low & high emissions
  • Add title, text to highlight Portland values
  • Picture of grapes and/or wine

Prepare Slide

Prepare Talking Points

  • Does it look like Portland farmers will be able to grow grapes in future?
  • What is the thermal reason for your conclusion?
  • The future is not set in stone. If we reduce emissions (esp. coal), our future could be the RCP 4.5 scenario not the RCP 8.5.
  • Graph of climatic limitations
  • Table of GDD50 data for Portland
  • Check box for 1971-2000, 2010-2039 and 2040-2069. Take a screenshot of the bar chart and the legend.
  • Analyze the bar chart to conclude why Portland becomes more suitable for growing grapes.
  • Cabernet growth phases use GDD with 50F. Look up how this is calculated. The minimum GDD50 for Cabernet needed for maturity is 3000 F.
  • Go to the Future Climate Dashboard Tool.
  • Choose Portland. Select GDD 50F
  • Add table to slide with GDD50 values.