Rising Global Temperatures Alter Drought Conditions in Eurasia

Research indicates that rising global temperatures are key drivers of modern drought conditions in Eurasia, challenging the notion that they result solely from natural variability. A study using tree ring data across Europe and Asia suggests that many regions are experiencing changes in moisture levels, underscoring the impact of climate change on regional drought patterns.

Determining the causes of global drought conditions, whether due to natural variability or climate change, is a complex task. Scientists use sophisticated computer models to simulate historical climate conditions and identify unusual drought patterns, although these models may have biases that affect their accuracy. Additionally, factors such as land use, temperature, and precipitation influence drought conditions and complicate the assessment further.

Tree ring analysis provides a complementary method to model-based assessments, serving as an indicator of natural climate variability. Researchers led by Marvel et al. utilized the Great Eurasian Drought Atlas (GEDA), which comprises tree ring measurements from thousands of trees spanning from 1000 to 2020 CE, to investigate drought in Europe and Asia. They categorized the data according to regions specified in the Intergovernmental Panel on Climate Change’s Sixth Assessment Report.

Using tree ring data from 1000 to 1849, the team estimated the preindustrial Palmer drought severity index (PDSI) for each region. They analyzed whether these historical values could account for modern PDSI readings from 1850 to 2020. The results indicated that rising global temperatures play a crucial role in current drought conditions, rather than solely natural variability.

The findings revealed that regions such as eastern Europe, the Mediterranean, and Arctic Russia are experiencing increasing dryness due to climate change, while northern Europe, east-central Asia, and Tibet are becoming wetter. Although tree ring growth can be influenced by non-climatic factors, the researchers believe these influences did not significantly affect their conclusions, as GEDA primarily focuses on sites where climate is the predominant growth factor.

The study by Marvel et al. suggests that modern drought conditions in Eurasia are predominantly driven by rising global temperatures rather than natural climate variability. The significant changes observed across various regions underscore the impact of anthropogenic climate change. This research highlights the utility of tree ring data in understanding historical and current climate patterns while emphasizing the need to account for various contributing factors in climate assessments.

Original Source: www.preventionweb.net