Compound weather extremes are now more frequent and severe

As our climate warms, global nations are witnessing an alarming increase in extreme weather events, characterized by severe wind and heavy rainfall occurring simultaneously. Recent research reveals that these compound extremes are set to become more frequent and severe, posing new challenges to both infrastructure and emergency responses.

Emerging threats from a warmer climate

Researchers from Newcastle University have documented significant changes through climate simulations spanning historical periods (1981-2000) to projected future scenarios (2060-2081).

The findings highlight a stark increase in the severity of extreme weather events as global temperatures continue to rise. This intensification is primarily due to increased rainfall, a direct thermodynamic response to the warming climate.

Additionally, alterations in the jet stream – with its southward movement – are anticipated to steer storms through warmer regions, which will further amplify rainfall.

Escalation in compound weather extremes

The UK and Ireland are expected to face more frequent and severe windstorms paired with extreme rainfall, increasing the risk of catastrophic flooding.

This escalation in compound weather extremes presents a significant threat to coastal areas prone to flooding and could severely impact emergency services and infrastructure, including power and transportation networks.

Dr. Colin Manning, who led the study, noted the dire implications if current trends persist. “Our work shows that such compound extremes will occur more frequently as our climate warms and likely bring more severe impacts.”

The aggregation of damage from both wind and flooding is expected to significantly strain emergency response capabilities.

In response, Dr. Manning recommends a dual strategy to lessen these impacts: reducing greenhouse gas emissions and bolstering the resilience of essential infrastructure.

Decoding the dynamics of compound weather extremes

To better understand and predict these compound weather extremes, the researchers implemented a comprehensive analytical approach. They linked severe wind and rainfall events to the occurrence of extra-tropical cyclones (ETCs) in the region.

Using indices like the Wind Severity Index (WSI) and Rainfall Severity Index (RSI), the researchers measured the intensity of extreme weather events.

They also calculated the return periods for both individual and combined extremes to determine their likelihood and characterized the events by their specific wind and rainfall traits. This approach was key in identifying changes in the intensities of wind and rainfall.

Professor Lizzie Kendon, a key contributor to the research, emphasizes the significance of the advanced climate projections that were utilized. These projections, based on high-resolution models, provide an in-depth view of how local weather extremes are expected to develop over the next decades.

“This is highlighting the importance of considering compounding effects, including co-occurrences of different hazards, as well as the clustering of extreme events, in fully capturing the potential impacts of climate change,” noted Kendon.

Research to enhance climate resilience

The insights garnered from this study set a crucial groundwork for further investigation into the mechanisms driving these compound weather extremes. Future research will expand to include a broader array of climate models to confirm the robustness of the results.

Understanding the direct link between these compound events and their resultant impacts is vital. As the evidence mounts, it becomes increasingly clear that a proactive and informed approach is essential for managing and mitigating the effects of climate change on weather patterns.

More about compound weather extremes

Compound weather extremes refer to scenarios where multiple adverse weather events occur simultaneously or sequentially, often exacerbating the impacts compared to what would be expected from any single event.

These combinations can include heatwaves coinciding with droughts, heavy rainfall alongside storm surges, or simultaneous occurrences of extreme winds and precipitation. Such compound events often result in more severe consequences for ecosystems, infrastructure, and human health than the sum of their individual parts.

For example, when a heatwave and drought occur together, the strain on water resources intensifies, stressing agricultural systems and increasing the risk of wildfires.

Another example is when heavy rainfall happens in conjunction with a storm surge; the resulting floods can be far more destructive than either event would be alone.

The study is published in the journal Weather and Climate Extremes.

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