In News: Hurricane Ian is expected to make landfall in Cuba and then lash Florida with storm surges and downpours.
- Ian follows Hurricane Fiona, a powerful Category 4 storm that carved a path of destruction last week through Puerto Rico, leaving most of the U.S. territory without power and potable water. Fiona then barrelled through the Turks and Caicos Islands, skirted Bermuda and slammed into Canada’s Atlantic coast, where critical infrastructure might take months to repair.
Impact of climate change on Hurricanes:
- Climate change is making hurricanes wetter, windier and more intense.
- It is causing storms to travel more slowly, meaning they can dump more water in one place.
- In the last 40 years, the ocean has absorbed about 90% of global warming (caused by heat-trapping greenhouse gas emissions). Much of this ocean heat is contained near the water’s surface. The additional heat from ocean warming can fuel a storm’s intensity and power stronger winds.
- Climate change can also boost the amount of rainfall delivered by a storm. Because a warmer atmosphere can also hold more moisture, water vapor builds up until clouds break, sending down heavy rain e.g., 2020 Atlantic hurricane boosted rainfall rates by 8%-11%.
- The world has already warmed 1.1 degrees Celsius above the preindustrial average. At 2 degrees Celsius of warming, hurricane wind speeds could increase by up to 10%.
- The proportion of most-intense levels hurricanes – Category 4 or 5 – could rise by about 10% this century.
- The “season” for hurricanes is shifting, as climate warming creates conditions conducive to storms in more months of the year e.g., in Bay of Bengal, where cyclones since 2013 have been forming earlier than usual – in April and May – ahead of the summer monsoon.
- Hurricanes are also making landfall in regions far outside the historic norm
- Hurricane Sandy was the fourth costliest U.S. hurricane on record, causing $81 billion in losses.
- Formation: Hurricanes need two main ingredients – warm ocean water and moist, humid air.
- When warm seawater evaporates, its heat energy is transferred to the atmosphere. This fuels the storm’s winds to strengthen. Without it, hurricanes can’t intensify and will fizzle out.
- Difference in names:
- Storms that form over the Atlantic Ocean or central and eastern North Pacific are called “hurricanes” when their wind speeds reach at least 74 miles per hour (119 kilometres per hour). Up to that point, they’re known as “tropical storms.”
- In East Asia, over the Northwest Pacific are called “typhoons”
- Indian Ocean and South Pacific, are called “cyclones”
Source: Economic Times