Research involving tree ring data from the Great Eurasian Drought Atlas indicates that rising global temperatures are significantly influencing drought conditions across Europe and Asia. The analysis contrasts historical drought measurements with modern data, revealing notable climatic shifts. Key findings highlight drier regions in eastern Europe and wetter conditions in northern areas, underscoring the role of climate change in these changes.
Determining the causes of changing drought conditions globally is a complex process involving both natural variability and climate change. Researchers employ advanced computer models that simulate historical climate patterns to help distinguish between these factors and identify key drivers such as temperature and precipitation. However, these models can exhibit biases that may compromise the accuracy of drought assessments in certain regions.
Tree ring analysis serves as an alternative method to assess natural climate variability, complementing the modeling approaches used in hydroclimate research. Scientists, including Marvel et al., utilized the Great Eurasian Drought Atlas (GEDA), which compiles tree ring data from thousands of trees that grew between the years 1000 and 2020 CE. This extensive dataset aids in understanding drought conditions across Europe and Asia.
The researchers categorized GEDA tree ring data into regions as defined by the Intergovernmental Panel on Climate Change’s Sixth Assessment Report. They specifically analyzed tree rings from the years 1000 to 1849 to estimate preindustrial drought severity using the Palmer Drought Severity Index (PDSI), which measures drought risk. Subsequently, they analyzed whether these historical variations could account for contemporary PDSI values recorded between 1850 and 2020.
Findings indicated that modern changes in PDSI are more closely linked to increasing global temperatures rather than solely attributable to natural variability. Regions such as eastern Europe, the Mediterranean, and Arctic Russia are experiencing drier conditions as temperatures ascend, while areas like northern Europe, east central Asia, and Tibet are becoming wetter. This suggests a significant disconnection from historical drought patterns.
Though tree ring growth can be influenced by various factors beyond climate, the researchers believe these factors minimally impacted their outcomes. Data from GEDA is selectively compiled, ensuring that the sampled locations and tree species primarily reflect climate-induced variations in growth. This careful selection strengthens the reliability of their results.
The study reveals that the modern drought conditions across Eurasia cannot be explained solely by natural variability, indicating a strong link to climate change. Areas like eastern Europe and the Mediterranean are getting drier, while parts of northern Europe and Tibet are experiencing increased moisture. The findings emphasize the need for continued monitoring and understanding of climate impacts on regional hydrology.
Original Source: eos.org
