Present day global relative yield losses are estimated to range between 7 % and 12 % for wheat, between 6 % and 16 % for soybean, between 3 % and 4 % for rice, and between 3 % and 5 % for maize (range resulting from different metrics used). Taking into account possible biases in our assessment, introduced through the global application of “western” crop exposure–response functions, and through model performance in reproducing ozone-exposure metrics, our estimates may be considered as being conservative.
Under the 2030 CLE scenario, the global situation is expected to deteriorate mainly for wheat (additional 2–6 % loss globally) and rice (additional 1–2 % loss globally). India, for which no mitigation measures have been assumed by 2030, accounts for 50 % of these global increase in crop yield loss. On a regional-scale, significant reductions in crop losses by CLE-2030 are only predicted in Europe (soybean) and China (wheat).
Translating these assumed yield losses into total global economic damage for the four crops considered, using world market prices for the year 2000, we estimate an economic loss in the range $14–$26 billion. About 40 % of this damage is occurring in China and India. Considering the recent upward trends in food prices, the ozone-induced damage to crops is expected to offset a significant portion of the GDP growth rate, especially in countries with an economy based on agricultural production.