Abstract
<p>The 2018 summer was unusually hot in large areas of the Northern Hemisphere and simultaneous heat waves on three continents led to major impacts to agriculture and society. The event was driven by the anomalous atmospheric circulation pattern during that summer and it was only possible in a climate with global warming. There are indications that in a future, warmer climate similar events might occur regularly, affecting major ‘breadbasket’ regions of the Northern Hemisphere.</p><p>This study aims to understand the role of climate change for driving the intensity of the 2018 summer and to explore the sensitivity to changing warming levels. Model simulations are performed using the Community Earth System Model to investigate storylines for the extreme 2018 summer given the observed atmospheric large-scale circulation but different levels of background global warming: no human imprint, the 2018 conditions, and different mean global warming levels (1.5°C, 2°C, 3°C, and 4°C). The storylines explore the consequences of the event in an alternative warmer or colder world and thus help to increase our understanding of the drivers involved. The results reveal a strong contribution by the present-day level of global warming and provide an outlook to similar events in a possible future climate.</p>
Highlights
During the 2018 boreal summer, large parts of the Northern Hemisphere experienced extreme temperatures, leading to major impacts on agriculture and society in the affected countries (Vogel et al, 2019)
We present an analysis of scenario storylines building on the extreme 2018 Northern Hemisphere summer (“NH2018 event”)
The event is alternatively simulated in a natural setting without human imprint on the climate system (“natural”), for the present-day climate conditions and for four scenarios at different levels of global warming (1.5, 2, 3 and 40 ◦C under ◦C (4 ◦C))
Summary
During the 2018 boreal summer, large parts of the Northern Hemisphere experienced extreme temperatures, leading to major impacts on agriculture and society in the affected countries (Vogel et al, 2019). The event (hereafter referred to as “NH2018 event”) was associated with near-simultaneous heatwaves on three continents, including North America, western and northern Europe, as well as Japan and the Korean Peninsula (Kornhuber et al, 2019b; Vogel et al, 2019) Previous studies highlighted both the anomalous atmospheric circulation patterns during the event and the background global warming due to human greenhouse gas emissions as main drivers of the event (Drouard et al, 2019; Kornhuber et al, 2019b; Toreti et al, 2019; Vogel et al, 2019). An analysis of simulations from the fifth phase of the Coupled Model Intercomparison Project (CMIP5; Taylor et al, 2012) showed that the total area affected by hot extremes during the NH2018 event, despite being unprecedented in the historical record, was consistent with the present-day level of global warming (Vogel et al, 2019). These experiments are of particular relevance since events associated with the type of circulation patterns from the NH2018 events could lead to high risks of crop failures across several breadbasket regions of the world (Kornhuber et al, 2019a)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
