Increasing risks of apple tree frost damage under climate change

Peter Pfleiderer,Inga Menke,Carl-Friedrich Schleussner

doi:10.1007/s10584-019-02570-y

Peter Pfleiderer, Inga Menke + Show 1 more

Open Access

https://doi.org/10.1007/s10584-019-02570-y

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Abstract

Anthropogenic climate change is affecting agriculture and crop production. The responses of horticultural and agricultural systems to changing climatic conditions can be non-linear and at times counter-intuitive. Depending on the characteristics of the system, the actual impact can arise as a result of a combination of climate hazards or compound events. Here, we show that compound events can lead to increased risk of frost damage for apple fruit trees in Germany in a 2 °C warmer world of up to 10% relative to present day. Although the absolute number of frost days is declining, warmer winters also lead to earlier blossom of fruit trees, which in turn can lead to regionally dependent increased risks of the occurrence of frost days after apple blossom. In southern Germany, warmer winters may also lead to an increase in years in which apple yield is negatively affected by a lack of sufficient amount of cold days to trigger the seasonal response of the trees. Our results show how cropping system responses to seasonal climate can lead to unexpected effects of increased risk of frost damage as a result of warmer winters. An improved understanding of ecosystem responses to changes in climate signals is important to fully assess the impacts of climate change.

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)
Simulations are run under the HAPPI (“Half a degree Additional warming, Prognosis and Projected Impacts”) protocol (Mitchell et al 2017) with three climate scenarios: a current climate forced by observed ocean and sea ice coverage conditions of 2006–2015 and two 10-year future scenarios representing a 1.5 °C and a 2 °C world above pre-industrial levels
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

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