Extreme Heat, Drought Could Occur Earlier And Repeatedly In Europe, Experts Say

Studies showed that extreme heat and drought can occur earlier and repeatedly in Europe.

According to experts, the extreme heat and drought typical of an end-of-century climate could soon occur over Europe, and repeatedly.

European Climate

Meteorologists said that despite the European climate being potentially prone to multi-year successive extremes due to the influence of the North Atlantic variability, it remains unclear how the likelihood of successive extremes changes under warming, how early they could reach end-of-century levels, and how this is affected by internal climate variability.

Through the use of Max Planck Institute Grand Ensemble, researchers found that even under moderate warming, end-of-century heat and drought levels virtually impossible 20 years ago reach 1-in-10 likelihoods as early as the 2030s.

They noted that by 2050 to 2074, two successive years of single or compound end-of-century extremes, unprecedented to date, exceed 1-in-10 likelihoods; while Europe-wide 5-year megadroughts is plausible.

Moreover, whole decades of end-of-century heat stress could start by 2040, by 2020 for drought, and with a warm North Atlantic, end-of-century decades starting as early as 2030 become twice as likely.

They said that under further global warming, extreme heat will become more frequent, and more extreme.

On the other hand, currently extremely rare end-of-century events - those that would be average in a much warmer world at the end of the century - can happen earlier than expected due to internal variability.

In Europe, this occurred during the 2010 summer, which reached heat levels expected every other year by the end of the century; but at the time it happened was deemed extremely rare, remaining the warmest summer observed over most of Europe.

Experts predicted that record-shattering extreme heat events that exceed previous records by large amounts will become up to seven times more likely in the next three decades than they were in the recent past.

However, they noted that they still lack a systematic understanding of how soon typical end-of-century levels of extreme heat and drought stress become a possibility over Europe.

When these extreme conditions occur repeatedly year after year, they become even more threatening to the already vulnerable socioeconomic and ecological resilience of the region.

Prone to Heat and Drought

Europe could be especially prone to such year-after-year successive heat and drought extremes, due to the influence of the multi-year variability in the North Atlantic over the European climate acting as a long-term preconditioner.

Despite the relevance of their potential cascading impacts and preconditioning in the European climate, it remains unclear how the likelihood of such multi-year successions of extreme heat and drought changes under warming, and moreover, how this likelihood is affected by the internal variability of the climate system.

The study said that the intensification of heat and drought, either independently or together, is attributed to be largely anthropogenic and is expected to be accentuated over Europe under further warming.

However, changes in the frequency and intensity of heat and drought stress depend not only on the level of global warming; they can also be dampened or amplified by internal variability on interannual to multi-decadal scales.

Furthermore, the oceanic origins of concurrent atmospheric drivers of heat and drought imply a long-term preconditioning on decadal timescales that may make the European climate system particularly prone to such year-after-year successive high-impact heat and drought stress extremes.