Abstract. Knowledge of the effects of climate change on agro-ecosystems is
fundamental to identifying local actions aimed to maintain productivity and
reduce environmental issues. This study investigates the effects of climate
perturbation on the European crop and grassland production systems,
combining the findings from two specific biogeochemical models. Accurate and
high-resolution management and pedoclimatic data were employed. Results have
been verified for the period 1978–2004 (historical period) and projected
until 2099 with two divergent intensities: the Intergovernmental Panel on Climate Change (IPCC) climate projections, Representative Concentration Pathway (RCP) 4.5
and RCP8.5. We have provided a detailed overview of productivity and the impacts
on management (sowing dates, water demand, nitrogen use efficiency).
Biogenic greenhouse gas balance (N2O, CH4, CO2) was
calculated, including an assessment of the gases' sensitivity to the leading
drivers, and a net carbon budget on production systems was compiled. Results
confirmed 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 productivity
is expected during the period 2050–2099, caused by the shortening of the
length 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 the
Mediterranean regions and in central European latitudes, confirming a
regionally distributed impact of climate change. Non-CO2 greenhouse
gas emissions were triggered by rising air temperatures and increased
exponentially over the century, often exceeding the CO2 accumulation of
the explored agro-ecosystems, which acted as potential C sinks. The emission
factor for N2O was 1.82 ± 0.07 % during the historical period
and rose to up to 2.05 ± 0.11 % for both climate projections. The
biomass 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, crop
residue restitution might represent a potential management strategy to
overturn the C balance. Although with a marked latitudinal gradient, water
demand 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 climate
perturbation.