Coastal hurricanes are intensifying faster due to climate change

Anyone living along a coastline knows the threat of a hurricane. These swirling storms of destruction pack incredible wind, torrential rain, and perilous storm surges. People constantly worry about the damage coastal hurricanes can do.

Unfortunately, a new study led by the Department of Energy‘s Pacific Northwest National Laboratory (PNNL) reveals that hurricanes are changing – and not in a good way. Since 1979, coastal hurricanes around the world have been intensifying faster and they’re only going to get worse thanks to climate change.

Factors causing hurricanes

A hurricane is a massive, rotating storm system characterized by intense low pressure, powerful winds, and heavy rainfall. Hurricanes form over warm ocean waters near the equator in several stages.

Warm ocean water evaporates, creating hotter, moist air that rises rapidly into the atmosphere. As this air rises, it cools and condenses, forming massive storm clouds and releasing huge amounts of energy. This energy powers the hurricane’s destructive winds.

Due to the Earth’s rotation (called the Coriolis effect), this rising air begins to swirl in a giant, rotating pattern. At the center of this swirling storm system is the “eye” of the hurricane – a deceptively calm area of low pressure. The strongest winds and heaviest rain occur in the “eyewall” surrounding the eye.

Several key factors play a role in how strong a hurricane becomes:

• Ocean temperatures: The warmer the ocean water, the more evaporation occurs, providing more fuel and energy to the storm.
• Atmospheric moisture: Hurricanes thrive in areas of high humidity. The more moisture in the air, the more potential for heavy rainfall and storm intensification.
• Wind shear: Wind shear refers to changes in wind speed and direction at different altitudes of Earth’s atmosphere. Low wind shear allows a hurricane to maintain its organized structure, promoting strengthening.

What’s changing with hurricanes?

The PNNL study has revealed several worrying facts:

Alarming pace of coastal hurricanes

Hurricanes, particularly those close to coastlines, are now intensifying at an alarmingly fast rate. In the past, a hurricane might have increased its wind strength gradually. Today, a hurricane can become significantly more powerful within a very short period.

A global threat

This rapid intensification isn’t just happening in one part of the world. Coastal areas across the globe are facing the escalating risk of rapidly intensifying hurricanes.

The role of climate change

Scientists have determined that the primary driver of this dangerous trend is climate change. As the planet continues to warm due to human activities, the conditions that favor rapid hurricane intensification become more prevalent and severe.

Rapid intensification of coastal hurricane

Let’s make this clearer with an example. Before the year 2000, a typical hurricane might begin with a certain wind speed and then intensify by around 1.5 knots (nautical miles per hour) over a 24-hour period. After 2000, that same hurricane could increase its wind speed by a worrying 4.5 knots during the same time frame.

“We’re not talking about intensification out in the middle of the ocean,” said study lead author and climate scientist Karthik Balaguru. “We’re talking about it happening right at the coastline, where it matters most.”

This rapid intensification near the coast is terrible news because it gives people less time to prepare and evacuate. The potential for devastating damage from high winds, flooding, and brutal storm surges increases dramatically.

Why are coastal hurricanes getting worse?

The scientists behind this study point to two critical factors behind the increase in hurricane intensification:

Increased humidity

As the atmosphere warms due to climate change, the air’s capacity to hold water vapor increases. This leads to higher levels of humidity in hurricane-prone regions.

Hurricanes essentially use moisture as fuel. This excess moisture in the air gets absorbed by the storm system, and when it condenses, it releases massive amounts of energy. The released energy intensifies the hurricane’s destructive winds and increases its rainfall potential.

Weakened wind shear

Wind shear describes the difference in wind speeds and directions at varying altitudes in the atmosphere. Think of it as layers of air moving at different speeds or in different directions.

Strong wind shear can disrupt the organized structure of a hurricane, essentially tearing it apart and limiting its intensification. However, climate change is causing wind shear to weaken across the globe, particularly near coastlines.

This diminishing wind shear allows hurricanes to maintain their structure and intensify more easily. It’s essentially removing a natural barrier that would have otherwise helped limit the hurricane’s strength.

A worrying forecast

“This work holds profound implications for people living on the coast, as well as operational forecasters and decision-makers,” said study co-author and Earth scientist Ruby Leung. “The rising intensification rates we observed could mean that landfalling hurricanes are on track to grow stronger and thus more destructive. It’s important that we understand how the risks posed by these storms could change as our climate changes.”

There’s positive news on the scientific front. Researchers are diligently working to improve our understanding of these changes in hurricane behavior. This includes refining climate models to predict future hurricane activity and developing more sophisticated forecasting techniques to provide earlier and more accurate warnings.

However, the reality remains concerning. The data suggests a clear trend – coastal areas are becoming increasingly vulnerable to more powerful hurricanes. While advancements in forecasting are crucial, we must acknowledge this heightened risk.

Unfortunately, for those living in hurricane-prone areas, the potential consequences of these stronger storms are significant. It’s vital for individuals and communities to take proactive steps to prepare for these potential threats. This includes creating comprehensive emergency plans, assembling disaster kits, and staying informed about local weather advisories.

It’s not just coastal hurricanes

Another recent study led by PNNL’s Karthik Balaguru investigated surprising links between hurricanes and wildfires.

While it might seem strange that these two disasters could be connected, the research showed that hurricanes originating in the Eastern Pacific Ocean could sometimes dampen wildfire risk in the Southwestern United States by bringing much-needed rain and moisture.

Unfortunately, climate change might reduce the frequency of these storms, increasing the risk of wildfires in the region.

What can we do?

Facing the growing threat of more intense hurricanes, it’s easy to feel overwhelmed. However, the most important thing is awareness and preparedness. This means:

• Know Your Risk: Find out if you live in a hurricane-prone area. Local authorities will usually have excellent information available.
• Have a Plan: Prepare an emergency plan for your family, including how you’ll communicate and where you might evacuate.
• Prepare an Emergency Kit: Stock up on supplies for if you must stay home during or after a storm.
• Stay Informed: Pay attention to weather forecasts and warnings issued by the authorities.

Studies like the one conducted by PNNL scientists can improve our ability to model and predict increasingly powerful hurricanes and help save lives with more accurate forecasts.

The study is published in the journal Earth’s Future.

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