Climate
events put NZ coast at risk
An
international study suggests New Zealand's coastlines could be harder
hit by climate patterns than scientists previously thought
22
September, 2015
Coastal
impacts from La Niña could be worsened by rising ocean levels. Photo: RNZ
/ Robin Martin
Researchers
analysed data from 48 beaches bordering the Pacific Ocean from 1979
to 2012 to see whether patterns in coastal change were related to
major climate cycles such as El Niño and its counterpart, La Niña.
La
Niña is related to the cooling of surface ocean waters along the
tropical west coast of South America. The El Niño weather
pattern, expected
to hit New Zealand this summer,
is characterised by unusually warm ocean temperatures in the
equatorial region of the Pacific Ocean.
The
researchers from 13 institutions, including the University of
Waikato, discovered that during periods of La Niña many stretches of
New Zealand's coast had to cope with powerful waves and erosion.
Lead
author Patrick Barnard from the US
Geological Survey said
New Zealand could have more coastal damage than in earlier years.
"More
extreme La Niñas in the 21st century, as projected by recent global
climate models, suggest New Zealand could experience more extreme
coastal impacts during La Niña events than recently experienced,
which would be even more amplified by global sea level rise."
He
said this research would be helpful in future weather events.
"Understanding
the effects of severe storms fueled by El Niño or La Niña helps
coastal managers prepare communities for the expected erosion and
flooding associated with this climate cycle."
The
research group found that all the regions in the study were affected
during either weather pattern.
When
the west coast of the US mainland and Canada, Hawaii, and northern
Japan felt the coastal impacts of El Niño, including bigger waves,
higher water levels and erosion, the opposite region in the Southern
Hemisphere of New Zealand and Australia experienced 'suppression,'
such as smaller waves and less erosion, the study said.
The
pattern then generally flipped; during La Niña, the Southern
Hemisphere experienced more severe conditions.
Sea
damage to a cliff in the South Island (file photo)
Photo: RNZ
Cold
spring ahead as El Niño tightens grip
New
Zealand is facing a cold spring and dry summer as strong El Niño
weather patterns persist, according to the National Institute of
Water and Atmospheric Research (NIWA).
3
September, 2015
Photo: 123RF
The
institute's latest climate outlook said there were signs this year's
event could be one
of the four strongest ever recorded.
The
report said the phenomenon, which increases the chance of drought in
the east, heavy rainfall in the west and cooler weather, was
extremely likely to continue into early 2016.
It
said there was an increased risk of drought this summer in the north
and east of the North Island, and the east of the South Island.
Cold
weather and low rainfall are also expected for parts of the country
during spring.
What's expected for spring:
- The west and east of the South Island are most likely to experience colder-than-average temperatures. Cold snaps and frosts are expected in some parts of the country from time to time.
- In the North Island and in the north of the South Island, average or below average temperatures across the season are about equally likely.
- The north and east of the North Island - Northland, Auckland, Waikato, Bay of Plenty, Gisborne, Hawke's Bay and Wairarapa - are most likely to experience below normal rainfall.
- River flows in the east of the South Island are most likely to remain low - but there are about equal chances of normal or below normal levels of rain.
Photo
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