ETC HE Report 2024/9: Wheat and potato yield loss in 2022 in Europe due to ozone exposure.

Tropospheric ozone impacts agricultural crop and timber production entailing significant economic effects for the sector. In the early 2000’s an indicator for calculating this impact was proposed by the expert group in the IPC-Vegetation working in support of the Air Convention. That indicator is based on the phytotoxic ozone dose above a threshold y (PODy). Within the ETC HE and its predecessor ETC/ATNI, annual production of PODy maps started in 2020. To make it more relevant for air quality assessment the ozone flux calculations are not only translated into yield losses in %, but also into yield losses expressed in terms of quantity and economic value. In this present report an impact modelling chain to quantify and monetize the loss in wheat and potato production due to tropospheric ozone exposure for 2022 has been implemented. The sensitivity of the results to the degree of spatialization of the input data was also investigated.

29 Nov 2024

Simone Schucht (Ineris), Frédéric Tognet (Ineris), Laurent Létinois (Ineris)

This study quantifies and monetizes losses of bread (soft) wheat and potato production due to tropospheric ozone pollution in 2022 in Europe. It uses the POD6spec methodology and the flux-effect function recommended by the Mapping Manual of the Air Convention. Wheat and potato production data from Eurostat are used together with international wheat and potato prices calculated by dividing the Gross production value of wheat and potatoes in 2022 by the production quantities, both from FAOSTAT.

Although an approximation, monetary valuation of crop losses by sales prices is the approach followed in many European and non-European studies, and it needs to be seen in the context of further uncertainties, which accumulate at each step of the calculation chain of ozone impacts on crops.

The study quantified losses in wheat and potato production due to ozone for a reference case that started from wheat production data at regional level (NUTS 2, the highest spatial resolution available in European statistics), geolocated the production at grid level using Corine Landcover, and then calculated impacts at a grid level, before aggregating them at country level. Two sensitivity cases were also studied with degraded geolocation, the second of which calculated impacts directly at country level.

The results for the reference case show losses of wheat production in 2022 that exceed 6 % in 4 countries (for a mean of approximately 3 %), and 4 % in 17 countries (mean of 4 %) for potatoes. In terms of quantities and monetary equivalent, losses for wheat were highest in France (2.5 million tonnes or 490 million €). For potatoes they were highest in Germany (933 kt or 197 million €). Economic losses exceeded 10 million € in 16 countries for wheat and in 12 countries for potatoes.

When comparing these results to the two sensitivity cases, on a country level, losses differed up to 1.7 percentage points for wheat and 5.5 percentage points for potatoes. Aggregated at a European level, the differences were limited. This may be due to error compensation.