Erschienen in:
Biogeosciences, 19 (2022) 12, Seite 3021-3050
Sprache:
Englisch
DOI:
10.5194/bg-19-3021-2022
ISSN:
1726-4189
Entstehung:
Anmerkungen:
Beschreibung:
Abstract. Knowledge of the effects of climate change on agro-ecosystems isfundamental to identifying local actions aimed to maintain productivity andreduce environmental issues. This study investigates the effects of climateperturbation on the European crop and grassland production systems,combining the findings from two specific biogeochemical models. Accurate andhigh-resolution management and pedoclimatic data were employed. Results havebeen verified for the period 1978–2004 (historical period) and projecteduntil 2099 with two divergent intensities: the Intergovernmental Panel on Climate Change (IPCC) climate projections, Representative Concentration Pathway (RCP) 4.5and RCP8.5. We have provided a detailed overview of productivity and the impactson management (sowing dates, water demand, nitrogen use efficiency).Biogenic greenhouse gas balance (N2O, CH4, CO2) wascalculated, including an assessment of the gases' sensitivity to the leadingdrivers, and a net carbon budget on production systems was compiled. Resultsconfirmed a rise in productivity in the first half of the century (+5 %for croplands at +0.2 t DM ha−1 yr−1, +1 % for grasslands at +0.1 t DM ha−1 yr−1; DM denotes dry matter), whereas a significant reduction in productivityis expected during the period 2050–2099, caused by the shortening of thelength of the plant growing cycle associated with rising temperatures.This effect was more pronounced for the more pessimistic climate scenario(−6.1 % for croplands and −7.7 % for grasslands), for theMediterranean regions and in central European latitudes, confirming aregionally distributed impact of climate change. Non-CO2 greenhousegas emissions were triggered by rising air temperatures and increasedexponentially over the century, often exceeding the CO2 accumulation ofthe explored agro-ecosystems, which acted as potential C sinks. The emissionfactor for N2O was 1.82 ± 0.07 % during the historical periodand rose to up to 2.05 ± 0.11 % for both climate projections. Thebiomass removal (crop yield, residues exports, mowing and animal intake)converted croplands and grasslands into net C sources (236 ± 107 Tg CO2 eq. yr−1 in the historical period), increasing from 19 % to 26 %during the climate projections, especially for RCP4.5. Nonetheless, cropresidue restitution might represent a potential management strategy tooverturn the C balance. Although with a marked latitudinal gradient, waterdemand will double over the next few decades in the European croplands,whereas the benefit in terms of yield (+2 % to +10 % over the century)will not contribute substantially to balance the C losses due to climateperturbation.