Uncertainties in projected impacts of climate change on European agriculture and terrestrial ecosystems based on scenarios from regional climate models

Abstract

The uncertainties and sources of variation in projected impacts of climate change on agriculture and terrestrial ecosystems depend not only on the emission scenarios and climate models used for projecting future climates, but also on the impact models used, and the local soil and climatic conditions of the managed or unmanaged ecosystems under study. We addressed these uncertainties by applying different impact models at site, regional and continental scales, and by separating the variation in simulated relative changes in ecosystem performance into the different sources of uncertainty and variation using analyses of variance. The crop and ecosystem models used output from a range of global and regional climate models (GCMs and RCMs) projecting climate change over Europe between 1961–1990 and 2071–2100 under the IPCC SRES scenarios. The projected impacts on productivity of crops and ecosystems included the direct effects of increased CO2 concentration on photosynthesis. The variation in simulated results attributed to differences between the climate models were, in all cases, smaller than the variation attributed to either emission scenarios or local conditions. The methods used for applying the climate model outputs played a larger role than the choice of the GCM or RCM. The thermal suitability for grain maize cultivation in Europe was estimated to expand by 30–50% across all SRES emissions scenarios. Strong increases in net primary productivity (NPP) (35–54%) were projected in northern European ecosystems as a result of a longer growing season and higher CO2 concentrations. Changing water balance dominated the projected responses of southern European ecosystems, with NPP declining or increasing only slightly relative to present-day conditions. Both site and continental scale models showed large increases in yield of rain-fed winter wheat for northern Europe, with smaller increases or even decreases in southern Europe. Site-based, regional and continental scale models showed large spatial variations in the response of nitrate leaching from winter wheat cultivation to projected climate change due to strong interactions with soils and climate. The variation in simulated impacts was smaller between scenarios based on RCMs nested within the same GCM than between scenarios based on different GCMs or between emission scenarios

Effect of temperature and precipitation on nitrate leaching from organic cereal cropping systems in Denmark

“…Several studies have addressed the effects of climate change on N leaching of crops like winter wheat and spring barley in Denmark (Olesen et al, 2007a;Patil et al, 2012;Doltra et al, 2014). Conclusions from these studies support the general notion that N leaching from cereal cropping systems may increase substantially in response to projected climate change.…”

“…The observed weather data (temperature and precipitation) were perturbed using the delta change approach (Olesen et al, 2007a) to construct the weather files for the sensitivity analyses to be used with the regression models.…”

“…Most of these studies are model based. For instance, Olesen et al (2007a) modelled the impact of climate change on winter wheat yield and nitrate leaching by applying different impact models at site, regional and continental scales under a range of climate change scenarios. They projected a spatial pattern of changes in nitrate leaching over Europe for the period 2071-2100 showing a patchy variation indicating that local factors could be affecting N leaching under climate change.…”

Resistance and Resilience of A Stream Salamander To Supraseasonal Drought

“…[WGIII Table 8.12] In addition, practices that reduce N 2 O emission often improve the efficiency of nitrogen use from these and other sources (e.g., manures), thereby also reducing GHG emissions from fertiliser manufacture and avoiding deleterious effects on water and air quality from nitrogen pollutants (Dalal et al, 2003;Paustian et al, 2004;Oenema et al, 2005;Olesen et al, 2006). [WGIII 8.8] Agro-forestry systems (plantation of trees in cropland) can provide multiple benefits including energy to rural communities with synergies between sustainable development and GHG mitigation.…”

Coastal Systems and Low-Lying Areas

“…More frequent extreme climate events during specific crop development stages, together with higher rainfall intensity and longer dry spells, may impact negatively on crop yields (Olesen et al, 2006). Cyclone landfalls causing floods and destruction have negative impacts on coastal areas, e.g., on coconuts in India (see Chapter 5, Section 5.4.4), or on sugar cane and bananas in Queensland (Cyclone Larry in March 2006).…”