• Energy Research

This study focuses on the northward shift of homogeneous agro‐climate zones in Europe analyzed for the observed past and projected climate conditions for the next decades. Statistical cluster analysis is used to derive eight main agro‐climatic zones driven by two agro‐meteorological indicators, namely, active temperature sum and thermal growing season length. The northward shift of homogeneous agro‐climate zones and the corresponding change of crop growth suitability are analyzed together with the change of exposure of crops to temperature‐related climate extremes during the growing season. Gradual warming over Europe has contributed to a lengthening of the growing season and an increased active temperature accumulation, accompanied by more frequent occurrence of warm extreme climate events. Using a set of five high‐resolution regional climate scenarios, we calculate that a major part of Europe will be affected by further northward climate zone migration. In the next decades, the migration of agro‐climatic zones in Eastern Europe may reach twice the velocity observed during the period 1975–2016. Several regions of the Mediterranean may lose suitability to grow specific crops in favor of northern European regions. This indicator‐based assessment suggests that the potential advantages of the lengthening of the thermal growing season in northern and eastern Europe are often outbalanced by the risk of late frost and increased risk of early spring and summer heat waves.

Existing descriptions of bi-directional ammonia (NH 3 ) land–atmosphere exchange incorporate temperature and moisture controls, and are beginning to be used in regional chemical transport models. However, such models have typically applied simpler emission factors to upscale the main NH 3 emission terms. While this approach has successfully simulated the main spatial patterns on local to global scales, it fails to address the environment- and climate-dependence of emissions. To handle these issues, we outline the basis for a new modelling paradigm where both NH 3 emissions and deposition are calculated online according to diurnal, seasonal and spatial differences in meteorology. We show how measurements reveal a strong, but complex pattern of climatic dependence, which is increasingly being characterized using ground-based NH 3 monitoring and satellite observations, while advances in process-based modelling are illustrated for agricultural and natural sources, including a global application for seabird colonies. A future architecture for NH 3 emission–deposition modelling is proposed that integrates the spatio-temporal interactions, and provides the necessary foundation to assess the consequences of climate change. Based on available measurements, a first empirical estimate suggests that 5°C warming would increase emissions by 42 per cent (28–67%). Together with increased anthropogenic activity, global NH 3 emissions may increase from 65 (45–85) Tg N in 2008 to reach 132 (89–179) Tg by 2100.

AbstractWe estimate the effects of climate anomalies (heat stress and drought) on annual maize production, variability, and trend from the country level to the global scale using a statistical model. Moderate climate anomalies and extremes are diagnosed with two indicators of heat stress and drought computed over maize growing regions during the most relevant period of maize growth. The calibrated model linearly combines these two indicators into a single Combined Stress Index. The Combined Stress Index explains 50% of the observed global production variability in the period 1980–2010. We apply the model on an ensemble of high‐resolution global climate model simulations. Global maize losses, due to extreme climate events with 10‐year return times during the period 1980–2010, will become the new normal already at 1.5 °C global warming levels (approximately 2020s). At 2 °C warming (late 2030s), maize areas will be affected by heat stress and drought never experienced before, affecting many major and minor production regions.