According to a study from the University of California, San Diego, the sporadic atmospheric river storms that hit the western US could result in flood damage of more than $3 billion annually by the end of the century, a figure that is three times higher than the university's estimate from 2019.

GHG + Flood Damages

Researchers also claim that if nations significantly cut the emissions of greenhouse gases they release into the atmosphere, the figure could be reduced to about $2 billion annually.

The study was based on an updated analysis of various climate models, one of which estimated annual flood damage at $2.3 billion in the 2090s and $3.2 billion by 2100.

Tom Corringham, a climate economist from UCSD's Scripps Institution of Oceanography, said that Flood damages are projected to triple by the end of this century as atmospheric rivers intensify, but there is still time to reduce the risk.

Atmospheric rivers (ARs) are airborne plumes of moisture that travel from the tropics to the mid-latitudes. They can significantly strengthen storms that travel to the western US, particularly to California, Oregon, and Washington.

Sometimes the ARs will strike the mountainsides in areas like San Diego County, unleashing heavy rains that occasionally cause floods and mudslides. Because Scripps began to classify ARs like hurricanes, rating the ARs on a scale of 1 to 5, with 1 being the least powerful, the phenomenon has recently gained more public awareness.

Read also: Climate Change Cause Devastating Australian Flood, National Emergency Declared As Damages Increase 

Megaflood

The new UCSD study follows a report from UCLA that claims climate change has roughly doubled the likelihood that California would then experience a "megaflood" bigger than the 30-day flood that devastated the Sacramento region in 1862. According to the report, some areas may experience the equivalent of 100 inches of rainfall in a single month.

The term "100-year storms" has been used for systems of this size for a long time, but many scientists think that climate change will increase the frequency of mega storms, Phys Org reports.

There are distinct differences between the causes of regular floods and megafloods. Megafloods differ from regular floods in that they are brought on by large amounts of water being released from behind a building or by changes in sea level, whereas regular floods are caused by rainfall.

Both man-made and natural dams are examples of stores.

  • Recent history has seen two extreme events that were both brought on by the failure of man-made dams.
  • On the other hand, the malfunction of natural dams can also result in megafloods. These are created when a river is blocked by a landslide or glacier. These can store a lot of water if they are particularly large. In Attabad, Pakistan, a landslide recently blocked a river, for instance. A sizable landslide that blocked the Hunza river in 2010 caused the creation of Attabad Lake.
  • Changes in sea level are another reason for megafloods. Around 450,000 years ago, a megaflood of this kind occurred in the Dover Straits, which separate modern-day England and France.

Related article: Climate Change to Ramp up Flood Damage Cost in US by More Than 25% in 2050