The hot blob in the Tasman Sea and extreme weather in Australasia
Hot Ocean Blob Fuels Record Heat, Extreme Weather, Risk to
21 December, 2017
Australia and New Zealand there’s a kind of climate change fed
thing on the prowl in the off-shore waters. It takes the form of an
angry layer of far warmer than normal surface water. And
it’s been lurking around since late November.
hot, angry blob of
much warmer than normal ocean temperatures has erupted between
Australia and New Zealand.)
can see this disruptive beast pretty clearly in the sea surface
temperature anomaly maps provided by Earth
Today’s readings show temperatures in this new blob hitting between
3.5 and 4.2 degrees Celsius above average across a broad expanse of
much, much warmer than normal for this region of water. A place where
2 degree above average sea surface readings would tend to be unusual.
global temperatures now hitting between 1.1 and 1.2 C above 1880s
we’re starting to see the climate dice more loaded for these kinds
of extreme events. To be clear, this is not the kind of extremity
we’d experience in a world at 2 C warming, or 4 C warming, or 7 C
warming. But we’ve moved up the scale and weather, temperature, and
ocean environmental conditions are being harmfully impacted.
above graph shows how temperatures have shifted outside of 20th
Century ranges. During 2014-2017, the world dramatically warmed —
generating further rightward movement in the bell curve. Temperature
has an impact on everything from drought, to the severity of
thunderstorms, to the length and intensity of fire season, to the
fuel available for the most powerful hurricanes, to algae blooms, to
coral bleaching events. Image source: NASA
ocean blob feeds record breaking heat across Australia on Tuesday.
Image source: WindyTV.)
off shore hot blob is laying its hot, moist tendrils of influence on
these weather extremes in a number of ways. First the blob is
belching an enormous amount of moisture into the atmosphere above the
local ocean. This moisture is being cycled over SE Australia by the
prevailing winds and is adding convective energy to thunderstorms. In
addition, the blob is also contributing to a sprawling ridge of high
pressure that sits squarely over top it. The ridge, in turn, is
baking parts of Australia with record hot temperatures.
ocean blobs like the thing off Australia are a feature of
human-caused climate change in that ocean and atmospheric warming
generates an environment in which these pools of excessive warmth are
more likely to form. These are anomalous events that stretch or break
the boundaries of past weather and climate patterns by adding unusual
amounts of heat and moisture to local and region climate systems in
the environments in which they form. A hot blob forming off the U.S.
West Coast during 2014-2015 contributed to a number of climate change
associated events like the
severe California Drought,
a ridiculously resilient ridge of high pressure, western wildfires,
intense rains into Alaska and Canada and a number of mortality events
among sea life that were triggered by heat, low oxygen content, or
blooms of harmful microbes that thrive in warmer ocean environment.
short-lived in comparison to the Hot Blob that lurked off the U.S.
West Coast for the better part of two years, the Australia-New
Zealand blob is already having a variety of atmospheric and oceanic
impacts. Notably, in addition to the wrenching influences on local
and regional weather described above, the blob is also contributing
to risks to Australia’s corals.
Coral Reef Watch shows strong risk of coral stress continuing through
March of 2018. The hot blob of ocean water off Australia is
contributing to a situation where reefs like the GBR are again at
risk. Image source: NOAA.)
the past two years, the
Great Barrier Reef (GBR) experienced back to back bleaching events.
These were the worst ever seen by the reef. And they were triggered
by human-caused climate change. This year, in part due to the blob,
risks to corals between Australia and New Zealand are again high. If
the blob shifts north and west, then the GBR again falls under the
gun. This time for a third year in a row. Notably coral reef stress
warnings and alerts abound throughout the zone between Australia and
New Zealand in NOAA’s Coral Reef Watch report at present.
to the potential to continue to contribute to various weather and
ocean impacts, the present climate change influenced hot blob between
Australia and New Zealand bears continued monitoring. It has,
however, already generated a number of impacts. And it is likely that
more will follow.