Variability of growing degree days in Poland in response to ongoing climate changes in Europe

Abstract

An observed increase in air temperature can lead to significant changes in the phenology of plants and, consequently, changes in agricultural production. The aim of the study was to evaluate the spatial differentiation of thermal resources in Poland and their variability during a period of changing thermal conditions in Europe. Since the variability of thermal conditions is of paramount importance for perennial crops, the study focused on apple, plum, and cherry orchard regions in Poland. The analysis was conducted for the period of 1951–2010 using air temperature daily data. Thermal resources have been defined using the growing degree days (GDD) index calculated independently for the whole year and during in frost-free season for three air temperature thresholds: 0, 5, and 10 °C, which determine the non-winter period, growing season, and the period of full plant growth, respectively. In addition, due to the high significance for perennials in particular, the incidence and intensity of frost during flowering were calculated. In this study, a detailed analysis of the spatial differentiation of thermal resources was first performed, followed by an evaluation of long-term variability and associated change patterns. The obtained results confirmed an increase in thermal resources in Poland as a consequence of the lengthening of the growing season. However, the frequency and intensity of spring frost, especially during flowering or even during ripening of plants, remain a threat to harvests in both the eastern and western parts of the country.

Increasing Synchrony of Annual River‐Flood Peaks and Growing Season in Europe

“…Depending on the region, annual flood peaks can occur predominantly within or outside of the growing season during the study period (Figure a). There is a general divide between river gauges North and East of the Alps where flood peaks occur predominantly outside of the ≥5°C thermal growing season (with <200–250 days durations in agreement with estimates by Wypych et al, for Poland) and South and West of the Alps where annual flood peaking occurs predominantly (>50%) within the ≥5°C thermal growing season (with >200 days duration; Figures a and S1 in the supporting information). Not surprisingly, longer growing seasons generally increase the percentage of flood peaks occurring within the growing season (Figure b), and consequently, river gauges with high flood‐peak occurrence outside the ≥5°C thermal growing season do not exist for stations with long annual growing seasons in our dataset.…”

Temporal Variability of Summer Temperature Extremes in Poland

“…Except for mountain regions, the largest changes in the 95th percentiles exceeding 0.4 • C per 10 years are generally observed in southern Poland compared to northern part of the country (Figure 7). The thermal burden of southern Poland has already been described by Wypych et al [32] in the context of an increase in growing degree days.…”

“…Thermal conditions in Poland and their variability have become correspondingly a subject of local studies, raising a point of temperature extreme occurrence and principles [25,28], their long-term variability, e.g., [29][30][31][32] or extreme events, i.e., heat waves, e.g., [29,33]. As Poland, due to its location ( Figure 1A), is particularly exposed to weather extremes occurrence, many papers have also been …”

Assessment of Air Thermal Conditions in the Lowland Part of South-Western Poland for Agriculture Development Purposes

“…Similarly, recommendations for agricultural adaptation to climate change usually cover the entire area of the country, as they are needed at local and even individual farm level [16][17][18][19][20]. The impact of climate change on the phenology of crops is still of interest to many researchers [6,[21][22][23]. The recognition of changes in the dates of plant growth and development, as well as the duration of development periods, is essential with regard to the activities of adapting agriculture to climate change, among others.…”

“…However, there is an increasingly notable need to take into account regional climate changes in economic forecasts for many sectors, including agriculture, and in preparation of recommendations for adapting farms to climate change [12,[32][33][34]. The research conducted so far in Poland concerned various aspects of climate change [35][36][37][38][39] and its impact, among others, on the shaping of agro-climatic conditions on a national scale [21,23,40], on the development of pests [25], as well as on a regional scale, which includes works describing crop-weather relationship studies [41]. A separate group is the research that is related to the development and use of climate change scenarios [33].…”