About the Seasonal Produce Savings
This calculator estimates the transportation-related CO2 emissions avoided by buying in-season, locally grown produce instead of out-of-season produce shipped or flown in from distant growing regions. It's built for shoppers who want to see whether the common claim about seasonal eating and emissions actually adds up to a meaningful number for their own habits.
How It Works
You enter how many pounds of out-of-season produce you currently buy per week and the typical distance that produce travels to reach you. The calculator scales your weekly amount to an annual weight, then compares the transport emissions of shipping that weight the entered import distance against a flat 100-mile baseline distance meant to represent locally grown, in-season produce, using a fixed freight emissions factor per pound per mile.
Examples
8 lb weekly at 3,000 miles
With the default inputs, 8 lb per week scales to 416 lb per year; at 3,000 import miles that's 416 x 3,000 x 0.00012 = 149.8 kg of transport CO2, versus 416 x 100 x 0.00012 = 5.0 kg for the local baseline, an avoided total of about 144.8 kg CO2 per year.
5 lb weekly from 6,000 miles away
A lighter but more distant habit, such as 5 lb per week of Southern Hemisphere fruit shipped 6,000 miles, scales to 260 lb annually; the import transport footprint comes to 260 x 6,000 x 0.00012 = 187.2 kg CO2 against a 3.1 kg local baseline, avoiding about 184.1 kg of CO2 a year.
Advantages
- Puts a specific number behind the frequently repeated but rarely quantified claim that eating seasonally cuts transport emissions
- Lets shoppers test different import distances to see how much the source region of their produce matters
- Uses the same freight emissions methodology as the site's farmers market calculator, so results from both tools can be compared directly
Common Mistakes
- Assuming all out-of-season produce is air-freighted and mentally applying a worst-case footprint, when much of it actually travels by ship or truck at a fraction of the emissions per mile
- Treating the 100-mile local baseline as an exact figure for their own region rather than a standardized simplification used for comparison purposes
- Comparing this transport-only estimate to a food item's total footprint, which would also include growing, refrigeration, and packaging emissions not captured here
Edge Cases to Watch For
- The 0.00012 kg CO2 per pound-mile factor is a single blended freight rate; it doesn't distinguish between truck, sea, or air freight, even though air-freighted produce carries a per-mile footprint many times higher than the others, as noted for perishables like out-of-season berries.
- The 100-mile 'seasonal' baseline is a fixed simplification, not a measurement of the actual distance to your nearest farm, which could be shorter or considerably longer.
- Only transport emissions are captured here; growing-method differences such as heated greenhouse production are not part of this calculation, so a locally grown but greenhouse-heated item could still carry a larger total footprint than this transport-only figure suggests.
Common Use Cases
- Home cooks planning menus around what's actually in season locally
- Sustainability-conscious grocery shoppers deciding between local and imported produce options
- Food writers or bloggers illustrating the emissions tradeoff of eating out-of-season produce with concrete figures