Increasing risks of apple tree frost damage under climate change

Inga Menke,Carl-Friedrich Schleussner,Peter Pfleiderer

doi:10.5194/egusphere-egu2020-11527

Inga Menke, Carl-Friedrich Schleussner + Show 1 more

Open Access

https://doi.org/10.5194/egusphere-egu2020-11527

Copy DOI

Abstract

&lt;p&gt;The impacts of global warming on agriculture and crop production are already visible today and are projected to intensify in the future. As horticultural and agricultural systems are complex organisms, their responses to changing climate can be non-linear and at times counter-intuitive. These systems undergo yearly cycles of growth with different plant characteristics in each of their phenological phases. They are thus especially sensitive to changes in seasonality besides changes in the annual mean and single extreme events.&lt;/p&gt;&lt;p&gt;Here we show that as a result of warmer winters, the risk of frost damages on apple trees in Germany is projected to be about 10% higher in a 2&amp;#176;C world compared to today. Warmer winters lead to less frost days but also to earlier apple blossom. This can result in overall increase in years where frost days occur after blossom.&lt;/p&gt;&lt;p&gt;Using large ensemble climate simulations, we analyze this compound event of frost days after blossom &amp;#8211; frost days after warm winters. Although the projected shift in blossom day and the decrease in frost days is relatively homogeneous over Germany, the change in frost risk varies considerably between regions. Our results highlight the importance of treating frost risk as a compound event of frost days after warm winters instead of comparing the average shift in blossom days with the decrease in frost days.&lt;/p&gt;&lt;p&gt;Reference: Pfleiderer, P., Menke, I. &amp; Schleussner, C.-F. Increasing risks of apple tree frost damage under climate change. Clim. Change (2019). doi:10.1007/s10584-019-02570-y&lt;/p&gt;

Highlights

The relatively linear response of global mean temperatures to anthropogenic greenhouse gas emissions leads to a complex pattern of changes in local and seasonalElectronic supplementary material The online version of this article contains supplementary material, which is available to authorized users.Climatic Change (2019) 157:515–525 climatic conditions (IPCC 2013; Saeed et al 2018)
To assess the risks arising from changing climate conditions on a system or sector, the characteristic responses of that system need to be incorporated (Sillmann et al 2018), as impacts may be highly sensitive to even minor changes in the climate hazard
Frost days after blossom are rarer in northern Germany than in southern Germany where 20% of all years’ frost days happen after blossom

Summary

Introduction

The relatively linear response of global mean temperatures to anthropogenic greenhouse gas emissions leads to a complex pattern of changes in local and seasonal. To assess the risks arising from changing climate conditions on a system or sector, the characteristic responses of that system need to be incorporated (Sillmann et al 2018), as impacts may be highly sensitive to even minor changes in the climate hazard. Horticultural crops, e.g., apple trees, are sensitive organisms, and their yield strongly depends on each year’s climatic conditions. Apple trees are especially vulnerable during their blossom period when a few frost days can lead to vast yield reductions (von Storch and Claussen 2012). The internal clock of apple trees that triggers blossom depends on various factors as the temperature history during winter and spring and the change in day length

Methods

Results

Conclusion