Abstract:

Based on meteorological data from 11 stations in Shanghai and food crop carbon absorption data from 2000 to 2020, this study integrated the accumulated hot damage temperature index (AHDT), precipitation intensity index (SDII), continuous rain comprehensive index (Z) and cumulative sunshine to investigate the relationship between agricultural extreme disasters and food crop carbon absorption. Utilizing composite analysis, this study analyzed and quantified the intensity differences of extreme disasters between years with high and low food crops carbon absorption and projected the future impact of agrometeorological disasters on food crops carbon absorption in Shanghai. The results showed that the regional average carbon absorption of food crops in Shanghai was 80.82gC·m⁻² during the 2000−2020 period. Food crops carbon absorption decreased by 10.20gC·m⁻² for every 10.7℃·d increase in AHDT, 2.7mm·d⁻¹ increase in SDII, 0.09 increase in Z index, or 27.1h decrease in cumulative sunshine. Compared to the 2000−2020 baseline, projections under the SSP5−8.5 scenario using the HadGEM3− GC31−LL model for 2031−2050 suggested that fluctuations in AHDT could lead to a reduction in food crops carbon absorption ranging from −5.36 to 139.30gC·m⁻². Fluctuations in SDII were projected to increase food crops carbon absorption by 28.03 to 41.16gC·m⁻², while Z fluctuations might cause food crops carbon absorption to vary between a maximum decrease of 38.97gC·m⁻² and a maximum increase of 66.91gC·m⁻². Furthermore, the impact of future solar radiation changes on food crops carbon absorption exhibited a trend of initial decline followed by an increase. These findings provide a scientific foundation for optimizing disaster management and formulating adaptive policies in Shanghai, offering significant insights for ensuring food security and supporting the realization of "Dual Carbon" goals.

Key words: Food crops carbon absorption, Agricultural extreme events, Future projection, Shanghai agriculture