Tag: Erosion

Rising sea level threatens Southern California beaches

Without expensive measures, some strands will vanish by 2100

Dusk surfing sessions at many Southern California beaches are at risk from sea level rise. @bberwyn photo.
Surfing El Granada in central California. @bberwyn photo.

Staff Report

Scientists are warily watching the impacts of rising sea levels along the world’s coastlines, where a high percentage of the global population lives and works. In some areas — especially narrow strands are pinned between the open ocean and coastal mountains, beaches may vanish by 2100 as higher waves and bigger storm surges wash away the precious sand.

Even with efforts to bolster them, between 31 percent and 67 percent of Southern California beaches may be completely eroded, scientists said this month after using a new climate model to calculate the effects of 3 to 6 feet of sea level rise. Continue reading “Rising sea level threatens Southern California beaches”

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USGS study tracks West Coast El Niño erosion

Some of the biggest waves on record took a toll on beaches

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Santa Monica beach during a break from the El Niño storms of 2015-2016. @bberwyn photo.

The  2015-16 El Niño may have been a bust as far as precipitation in California, but it still ended up as one of the strongest episodes of the last 145 years, according to U.S. Geological Survey scientists who studied erosion along the West Coast.

They found that, on average, erosion was  76 percent above normal, with most beaches in California eroded beyond historical extremes. If, as some research suggests, El Niños become stronger in a warming climate, then the West Coast, with its 25 million inhabitants, will become increasingly vulnerable to coastal hazards.

The study covered seasonal changes at 29 beaches from Washington to Southern California. They used 3-D maps and aerial lidar imaging, GPS topographic surveys, and direct measurements of sand levels, combined with wave and water level data to measure the changes.

Winter beach erosion or the removal and loss of sand from the beach is a normal seasonal process, but the extent of erosion can be more severe during El Niño events than in other years.

Continue reading “USGS study tracks West Coast El Niño erosion”

Climate: Australian study tries to quantify the role of airborne dust in the global carbon cycle

A 2009 NASA satellite image shows dust blowing off the coast of Africa over the Atlantic Ocean.
A 2009 NASA satellite image shows dust blowing off the coast of Africa over the Atlantic Ocean.

FRISCO — airborne dust, blown off dry ground, is a significant source of atmospheric carbon, according to Australian researchers, who recently set out to try and calculate how that source figures into the global carbon cycle.

Subject to intensifying droughts in some parts of the world, top soil is increasingly being blown away as dust in the wind, changing the amount and location of soil carbon. Some carbon falls back to the ground while some leaves Australia or ends up in the ocean.

Dust also plays a more direct role in regional climate. One recent study led by scientists from the University of Wisconsin-Madison and NOAA suggested that a warming in the tropical North Atlantic was largely due to reductions in airborne dust and volcanic emissions during the past 30 years.

“Carbon stored in our soils helps sustain plant growth. Our modelling shows that millions of tonnes of dust and carbon are blowing away, and it is uncertain where all that ends up,” said Dr Adrian Chappell, of CSIRO, Australia’s national science agency. Continue reading “Climate: Australian study tries to quantify the role of airborne dust in the global carbon cycle”