Tag Archives: floods

California will see both more flooding and more drought by the end of the century

The entire state of California could see a 54% increase in rainfall variability by the end of the century, according to a new study, which predicts fluctuations in extremely dry and wet weather in the entire West Coast of the United States.

Floods in California in 2017. Credit Flickr

Wenyu Zhou, a postdoctoral researcher at the Lawrence Berkeley National Laboratory, and his team focused their research on the Madden-Julian oscillation (MJO) — an atmospheric phenomenon that influences rainfall in the tropics and can trigger everything from cyclones over the Indian Ocean to heatwaves, droughts, and flooding in the United States.

Researchers were surprised by the magnitude of the effect: 54% more rainfall variability by the end of the century

Although recent studies have investigated the response of the MJO to anthropogenic climate change, not much is known yet about its potential impact on teleconnections. As the Earth’s climate warms, the dynamics controlling MJO are set to expand eastward, causing a huge uptick in extreme weather in California, the study showed.

“I was surprised by the magnitude of the effect,” said Da Yang, an assistant professor with the UC Davis Department of Land, Air and Water Resources, in a press release. “A 54% increase in rainfall variability will have very significant impacts on agriculture, flood control and water management.”

The study showed that the MJO teleconnection pattern during the boreal winter will likely extend further eastward over the North Pacific. This is mainly due to an eastward shift in the exit region of the subtropical jet, to which the teleconnection pattern is anchored, and assisted by an eastward extension of the MJO itself.

The eastward-extended teleconnection enables the MJO to have a greater impact downstream on the Northeast Pacific and North American west coast, the researchers argued. Over California specifically, the study projects a 54% increase in MJO-induced precipitation variability by 2100 under a high-emissions scenario.

Yang and his team used satellite observations and computer models to study the physics of rainstorms and atmospheric circulation in a changing climate. They are now working to understand what environmental factors control the size and duration of rainstorms and how the collective effects of rainstorms, in turn, shape Earth’s climate.

About 85% of California’s population live and work in coastal counties. The sea level along California’s coasts has risen nearly 8 inches (20cm) in the past century and is projected to rise by as much as 20 to 55 inches (50 to 139cm) by the end of the century, according to government estimations.

This could put nearly half a million people at risk of flooding by 2100, and threaten $100 billion in property and infrastructure, including roadways, buildings, hazardous waste sites, power plants, and parks and tourist destinations. Coastal erosion could have a significant impact on California’s ocean-dependent economy, which is estimated to be $46 billion per year.

The study was published in the journal Nature.

Italian council in Venice rejects climate measures — immediately gets flooded

In an ironic twist of events, a council palace was flooded right after failing to take measures in the climate crisis.

It was a fairly normal Tuesday night at Ferro Fini Palace in Venice, Italy, when Italy’s right-wing party rejected action on the climate crisis. The council voted against all proposed measured: funding renewable energy, replacing diesel buses with less polluting ones, and scrapping pollution stoves. There was no room in the regional budget for any of these things, the council decided, and then adjourned.

But around 10 PM, the floods that would bring Venice to its knees also invaded the Ferro Fini Palace. Democratic Party councilor Andrea Zanoni detailed the events in a Facebook post, also publishing photos of the flooded rooms.

“Ironically, the chamber was flooded two minutes after the majority League, Brothers of Italy, and Forza Italia parties rejected our amendments to tackle climate change,” Zanoni, who is deputy chairman of the environment committee, said in the post, which also has photographs of the room under water.

“There is no more meaningful image than a chamber being flooded, causing the representatives of the Venetian people to flee, to illustrate all the inconsistency and political nullity of a current miserable administrative led by the League, Brothers of Italy and Forza Italia,” he added.

https://www.facebook.com/andreazanonix/posts/10159116946155299

The blamed council members rejected Zanoni’s accusations, saying that they are doing a lot of work to limit flooding.

After a couple of devastating days which killed two people and flooded numerous historical landmarks, Venice has been hit by a new high tide of 154cm (5ft) — putting about 70% of the city underwater.

‘This is result of climate change,’ the Venice mayor Luigi Brugnaro said in a statement. “Now the government must listen,” he added. “These are the effects of climate change… the costs will be high.”

Brugnaro may very well be right. While linking climate to individual events is rarely possible, rising temperatures are causing sea level rise, and they are shifting flooding patterns.

More than 13 million Americans could be at risk from sea level rise by 2100

A new study analyzing sea level rise forecasts as well as population growth projections found that we’ve underestimated just how many people would be impacted by rising waters. Anywhere from 4.3 to 13.1 million people from the US alone will face the risk of inundation by 2100, according to their estimate.

Brackish sea water washes over the center line of a street in Charleston Oct. 1, 2015.
Image credits Stephen B. Morton/AP.

The team, with members from the University of Georgia and Stetson University in Florida used population trends and sea level rise estimates to establish a county-by-county risk assessment across the US. Their results suggest that previous research, based on current population numbers, underestimates the risk coastal states face.

An important implication of this is the estimated cost of adapting to sea level rise might be too low, since it doesn’t take population growth and the associated installation of more long-lasting, vulnerable infrastructure into account.

“There are 31 counties where more than 100,000 residents could be affected by 6 feet of sea level rise,” said study co-author Mathew E. Hauer, of the University of Georgia in a press release.

The southeastern U.S. coast is a hotspot for inundation risk related to sea level rise, the authors say. This is partly due to the high population growth that the area is experiencing. Over 10 percent of coastal populations in states such as Georgia and South Carolina will be affected by a global sea level increase of 1.8 meters (5.9 feet) by 2100. A similar rise would affect an estimated one million people in California and Louisiana each. Florida faces the most risk, with up to 6 million residents affected under the same scenario.

Densely populated counties in coastal areas, such as Broward or Miami-Dade Counties in Florida, San Mateo in California or Jefferson in Louisiana are expected to see more than 100,000 residents “potentially impacted” by a 0.9 meters (around 3 feet) rise in sea levels.

The study also identified three counties as having an “extreme exposure” to inundation: North Carolina’s Tyrrell and Hyde Counties, and Monroe County in Florida. Tyrell and Hyde Counties are home to abundant nature preserves on North Carolina’s Outer Banks, while Monroe County is located at the southwestern tip of Florida, encompassing a swath of Everglades National Park as well as the Florida Keys. People living in these areas will suffer “catastrophic impacts” by 2100 if steps aren’t taken to address the issue.

Image credits misterfarmer/pixabay

The authors also warn that the lack of protection for coastal residents could lead to a population migration on par with the “Great Migration” of southern African Americans after the first World War. They estimate that the cost of relocating all the people affected by sea rise by 2100 would exceed $14 trillion dollars.

“The impact projections are up to three times larger than current estimates, which significantly underestimate the effect of sea level rise in the United States,” Hauer added.

Compared to previous estimates, these are worrying numbers. The team’s estimates revolve around those 1.8 meters of sea rise used in their calculations. The study also doesn’t take factor in regional variations in the rate of sea level rise. But, while the consensus seems to be set around a 1 meter (3.6 feet) rise by 2100, there is growing concern around the stability of the Greenland and West Antarctic ice sheets in today’s warmer oceans. Faster melting of these ice sheets would rise the waterline significantly, possibly way above the 1.8 meter level the team set.

Ben Strauss told Mashable that the lack of regional variations in sea level rise would affect the results out to the year 2100, and the study also “assumes that people will be moving to the shore essentially just as briskly” in the latter half of the century as in 2020, despite the evident effects of sea level rise expected by 2070.

The full paper, titled “Millions projected to be at risk from sea-level rise in the continental United States” has been published online in the journal Nature Climate Change and can be read here.

Fire ants building life-saving rafts against floods [amazing photos]

In what can only be described as an incredible natural engineering feat, fire ants in times of floods have the remarkable ability link up with one another to form a life-saving, floating and impenetrable raft. While this is an attested ability for a long time now, scientists have only recently managed to understand how the fire ants can assemble a raft made out of millions of insects in under 100 seconds and which can stand afloat for days, even weeks.

Photo by JungleCat.

This ability developed by the fire ants is an evolutionary developed byproduct so they can survive the intense downpour and floods in their native South America, but exactly how the process goes through is what interested scientists lead by Nathan Mlot, a doctoral student studying bio-inspired engineering at the Georgia Institute of Technology and lead author of the ant-raft report published in Monday’s Proceedings of the National Academies.

The uneven, hairy surface of the ant’s skin explains this phenomenon, which works under the Cassie-Baxter law of wetting which states that as a surface gets rougher, water has a directly proportional rougher time in touching it. Another fine example is Duck feathers which also repel water because of their tiny bumps.

Photo by Maggie, via Flickr.

Photo by Maggie, via Flickr.

Researchers collected fire ants by roadsides in Atlanta and then filmed and froze the ants when they formed these floating clusters – once deposited into water in the lab, a spherical cluster of ants spread outward, like a drop of molasses.

“They’ll gather up all the eggs in the colony and will make their way up through the underground network of tunnels, and when the flood waters rise above the ground, they’ll link up together in these massive rafts,” Mlot said.

In less than two minutes the ants had linked “hands” to form a floating structure that kept all the insects safe. Even the ants down below can survive this way, thanks to tiny hairs on the ants’ bodies that trap a thin layer of air.

“Even when they’re on the bottom of the raft, they never technically become submerged,” Mlot said.

The resulting floating structure has a tremendous resistance and a very good water resistant property, since the Cassie-Baxter law which applies to a single individual is amplified when a massive group of ants  all get linked together.

Why can’t swarms of ducks combine and form similar rafts you may ask? Researchers say that the life saving ant rafts are made possibly primarily because of the millimetric constitution of the ants.

“At the scale of millimeters, ants have great strength, high speed and the ability to trap air pockets when submerged, which in turn makes their rafts water repellent,” they write in the most recent issue of the journal Proceedings of the National Academy of Sciences. “These abilities will likely vanish at large sizes.”

And as is the case in the nature, every maker has its breaker, and for the floating fire ants this is soap.

It and other surfactants — substances that break up surface tension of the water — wreak havoc with the rafts.

“If you introduce just a small amount of soap to the surface of the water to lower surface tension then the raft will begin to immediately sink,” he said. The individual ants lose their plastron layer and can drown within seconds, he said.

Engineers, Mlot went on to explain, think the rafting behavior might aid the quest for new waterproof materials and offer lessons for robotics research.