Twenty-first century hydroclimate: A continually changing baseline, with more frequent extremes

Area of Science:

• Climate Science
• Hydrology
• Environmental Science

Background:

• 21st-century hydroclimate trends are substantial, pushing future averages towards extreme drought or pluvial conditions.
• Understanding the evolving risks of hydroclimate variability is crucial for adaptation strategies.

Purpose of the Study:

• To assess the risk of droughts and pluvials in a changing climate after removing background trends.
• To evaluate the impact of trend removal on the relative risk of extreme hydroclimate events.

Main Methods:

• Utilized large climate model ensembles to simulate future hydroclimate scenarios.
• Employed statistical methods to remove background climate trends and analyze residual risks.

Main Results:

• After trend removal, the relative risk of droughts and pluvials remains similar to 20th-century levels.
• Despite trend mitigation, an increase in the frequency of extremely wet and dry years persists.

Conclusions:

• Adaptation to long-term hydroclimate changes can potentially minimize risks.
• Managing hydroclimate risks in a warmer world will remain challenging due to increased event frequency.