2019-06-22_New_Scientist

(singke) #1
22 June 2019 | New Scientist | 5

THIS extraordinary photograph
was taken by climate scientist
Steffen Olsen of the Danish
Meteorological Institute on
13 June. With the help of local
hunters, his team was retrieving
instruments from the sea ice in
Inglefield Fjord in Greenland.
The dogs are running on sea ice
that is still 1.2 metres thick. Sudden
warming caused the surface to
melt and form a shallow layer
of water on top of the ice below.
“The photo documents an
unusual day. I learn now that
it is even more symbolic than
scientific to many. Tend to agree,”

Olsen tweeted after the image
went viral online.
This June has seen temperatures
more than 20°C above normal in
Greenland, leading to extensive
surface melting across large areas
of the ice sheet on the vast island
as well as of the sea ice around it.
According to the National Snow
and Ice Data Center in the US,
more than 40 per cent of the ice
sheet’s surface was melting at one
point, which is the highest level
recorded at this time of year.
The highest level of surface melt
at any time of the year was in July
2012, when 97 per cent of the ice

sheet was melting. Greenland’s
ice sheet, which is more than
3 kilometres thick in places, holds
enough water to raise global sea
level by 7 metres. According to
a 2012 study, all this ice will melt
if the world keeps warming.
The loss of more sea ice each
summer, by contrast, doesn’t
raise sea level. But it gets replaced
with dark water that reflects less
sunlight, which results in yet more
warming – a feedback loop that
adds to the temperature rise
across the Arctic.
There is growing evidence
that Arctic warming is leading to
more extreme weather across the
northern hemisphere, by altering
the behaviour of high level winds
known as the jet stream. ❚

This month has seen temperatures tens of degrees higher
than normal in Greenland, reports Michael Le Page

Health

Microbe mix may
prevent asthma
CHILDREN who grow up on
farms have a lower risk of
developing asthma and now
it seems that may be due to
microbes that can also be
found in non-farm homes.
Pirkka Kirjavainen at the
National Institute for Health
and Welfare in Finland and
his colleagues studied about
400 children who lived on
farms or in rural, urban or
suburban homes.
They found that those
who grew up on farms had
the lowest risk of developing
asthma, but children raised
in non-farm homes with a
similar mix of microbes to
a farm also had a lower risk
(Nature Medicine, doi.org/
c7df). ❚ Chelsea Whyte

Animals

The evolution of
puppy dog eyes
HUMAN selection has seen
dogs evolve a muscle that
allows for expressive faces.
It means they can lift their
inner “eyebrow”, making
their eyes seem larger and
their faces sad – the familiar
“puppy eyes” look of dogs.
Juliane Kaminski at the
University of Portsmouth,
UK, and her team dissected
six dogs and four wolves,
none of which died for the
study. All but one dog had a
muscle on the inner side of
the eye near the nose, but
none of the wolves had it.
Kaminski thinks this
muscle evolved because
people favoured dogs that
could make this expression
(PNAS, doi.org/c7dd). ❚ MLP

Melting ice in Greenland


News


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