Summer Series #1: The year's top science findings
Summer Series #1: The year's top science
findings
A year is a short time in
science but a lot happened in 2016. NIWA highlights its top
scientific endeavours of the past 12 months and reveals we
know a lot more about a whole range of things than we did
this time last year.
MARCH
Scientists pinpointed
agriculture as the most likely reason for rising methane
levels in the atmosphere. Research, led by NIWA atmospheric
scientist Dr Hinrich Schaefer, ruled out fossil fuel
production as the major cause.
The amount of methane in
the earth’s atmosphere is estimated to have increased by
about 150 per cent since 1750. A plateau was observed
between 1999 and 2006 but it then began to rise
again.
Data indicated the source of the increase was
methane produced by bacteria, of which the most likely
sources were rice paddies and livestock. It was already
known that the methane originated from regions in South East
Asia, China and India which are dominated by rice production
and agriculture.
Methane is an important gas to deal with
when it comes to mitigating climate change.
JUNE
Since 1972 NIWA has
operated a Clean Air Monitoring Station at Baring Head, near
Wellington. The data collected there make significant
contribution to the global understanding of greenhouse
gases. In June, Baring Head’s carbon dioxide readings
officially passed 400 parts per million (ppm), a level last
reached more than three million years ago.
Globally, the
400ppm threshold represents an atmospheric landmark as a
focus for the urgency to tackle climate change. The Baring
Head reading was particularly significant because most
emissions occur in the Northern Hemisphere and the air
arriving here originates far to the south, away from human
activities.
Carbon dioxide is the primary greenhouse gas
contributing to warming of the atmosphere and reducing
levels to below 400pm would take many years of emissions
reduction.
AUGUST
The
remarkable long-distance swimming abilities of penguins were
revealed after NIWA scientists tracked 100 birds over winter
in the Southern Ocean. No one had previously known where the
sub-Antarctic rockhopper and Snares penguins went while they
were at sea between April and December each year.
It
turned out that the penguins travelled more than 15,000km in
six months. Campbell Island was once the world’s largest
breeding colony of rockhoppers,but between 1942 and 1984 the
population dropped by about 94 per cent.
Scientists have
speculated the decline may be due to a change in the
penguins’ diet and believe something is going on in the
ocean over winter that is causing it.
OCTOBER
In October, NIWA began a
project to find out what lies beneath the waters of the
Marlborough Sounds using cutting-edge multi-beam technology
which emits a fan of sound beams. In this way NIWA collects
a snapshot of the extent and distribution of different
habitats on the seafloor.
Other technology can also
determine the roughness of the seafloor, the amount and size
of sediment while data recorded in the water column can used
to determine habitats, identify seeps and plumes, detect
fish schools and other features.
It’s been 70 years
since the last survey was done of the Sounds – an area
that makes up about 20 per cent of the New Zealand
coastline. New features are being revealed that may provide
new research ventures for marine science, as well as
providing a base for assessing the effects of economic
activity. The information will also be used to draw new
nautical charts.
NOVEMBER
Several of NIWA’s marine
geologists were aboard research vessel Tangaroa researching
the Hikurangi subduction zone off the North Island’s East
Coast when the mW 7.8 earthquake struck on November 14.
Given the expertise on board, and the need to find out how
the earthquake had changed the seabed offshore, the vessel
was diverted south.
Scientists aboard took coring samples
and mapped the seabed along the Marlborough coast south to
Kaikoura.
They discovered new scarps, or breaks,
confirming the rupture of the Needles Fault, which is the
offshore extension of the Kekrengu Fault. This fault rupture
is now believed to extend for about 70km – 36km on land
and 34km under the sea.
DECEMBER
After months of collecting
and analysing weather data, NIWA climate scientists were
well aware that 2016 was tracking to be the hottest year on
record for New Zealand. Summer 2015/16 was particularly
warm and then autumn set some new temperature records making
it the second warmest autumn on record.
Winter followed
suit, with a balmy June and July with temperatures above
average. It turned out that August ended up being the only
month cooler than average month this year.
The previous
record was set in 1998 but what NIWA scientists say is that
the figures are in line with global average temperatures and
confirm the longer-term trends of climate
change.
Globally, 2016 is also set to be the hottest year
on record by a significant margin. It will also mean a new
high set for the planet for the third year in a row.
ends