Climate Change

In 2009 budgies in their thousand’s fell from the sky – dead – totally covering the brown earth with bright green. Another heat wave in Western Australia.

In 2010 at a golf course in southern Western Australia an entire flock of endangered Carnaby’s Cockatoo’s literally cooked where they were roosting when the temperature reached 48 degrees.

These are only 2 examples of what is happening to our wildlife and its environment as our weather patterns change. The Bureau of Meteorology formed 100 years ago has recorded all weather patterns since then. The following is a 100 year weather check from the bureau records.

There are almost 800 weather stations across Australia with more than 500 fully automated. Twelve sites have data going back far enough and accurate enough to use as part of the 100 year record. Data from all stations is automatically fed back to the National Weather Bureau in Melbourne. There are 22 IT ‘slaves’ [people] working 24hrs a day in this very special area of the computerised record room.

Snow depth measures have been taken every week since 1954 at Spencer’s Creek at the Snowy Hydro scheme. In 60 years there has been a total loss of one third of snow cover. The snow season begins as normal about July but drops off by September and by October is noticeably less, ie spring is coming earlier. Thaw is now 2 weeks earlier than in the 1960’s. The snow line has also moved from 1500mt from sea level to 1600mts.

Graphs show extreme heat days have doubled the extreme cold days. There are more and more of the weather stations breaking extreme heat days over the last 100 years and in the last 10 years the extreme heat records have doubled those breaking extreme cold days, extreme heat days are much more common. There are fewer records breaking the extreme cold days and there are fewer frosty nights.

Records from grape growers in Australia’s south show grapes are ripening on average 20 days earlier than in 1985. Companies are having to move further south, into Tasmania.

Now the chance of one month having above average temperatures is one in two. This means the chance of the next months average temp being above average becomes one in four. The following month it becomes one in eight. Since February 1984 we have had 330 months in a row of above average temperatures.

In Tasmania fishermen are seeing and catching fish never seen so far south before. About 2010 a fisherman saw and caught Yellow-tailed Kingfish, a species found further north in warmer waters. New fish and sea creatures are being seen regularly including Green Sea-turtles. A total [in 2010] of 45 new species have been found around Tasmania that are normally found further north around NSW.

WHY : The sea is warmer. Since 1900 around Australia the sea temperature has risen about 1 degree. The sea around our east coast is warmer than along the west coast. There are hot spots between Victoria and Tasmania with a sea temperature rise of 2.28 degrees. This is about 4 times the global average.

At Cottesloe [Rottnest WA] on February 28, 2011 the water temperature hit 26.4, it killed the coral. It was the biggest heat wave to hit Australian waters ever [CSIRO report]. Heated water arrived first just north of Ningaloo reef, the effect was described as being like a pot of boiling oil. Up to 80% of what was there is now gone – dead, covered in algae. The heated water travelled 1200km south reaching the southernmost tip of WA [Albany]. Whale sharks were seen off Albany. They are moving south to find cooler water and food. This warm water phenomena lasted 5 months and is the most extreme hot water event on record. Changes in ocean temperatures impact on the type of weather we see – warmer water = expect more rainfall.

SEA LEVEL : At Fremantle, WA, records show there has been a 1.5mm rise in tide levels per year since 1900, over 100 years that equals 17cm.

In 1841 at Port Arthur, Tasmania, a storekeeper put a tidemark in the water, it is the oldest scientific tide marker in the country. The original records were rediscovered a decade ago. The sea level here has risen 17cm since 1897, the same as for Fremantle.

A rise in sea level of 10cm triples flood events. Double that rise to 20cm and increase in flood events becomes 9 times.

SEA LEVEL READINGS SINCE 1993 [satellite readings] : Sea level has risen right around Australia but more around the north of Australia and less around the South.

RAINFALL : From September 2010 – March 2012 : more rainfall in this period of 24 months than ever been recorded in our historical records.

CAUSE : Record sea surface temperature rises around Australia.

An exception to flooding was south west WA, the Karri tree forests. Underground at the Jewel Caves the water line in the caves from the late 1960’s where the underground lakes were showed water was almost 3 feet deep. Gradually all the water drained away. It had disappeared altogether by 2000. It was the same story around the entire region. All the Margaret river caves no longer have their underground lakes and streams.

Land use changes have compounded the problem but it is a symptom of chronic lack of water.

April – November rainfall in the last 15 years, particularly in the SE of the Continent has shown a 10-20% reduction. In the west it shows the same but has been occurring since 1970 – much less rainfall.

SUMMARY : In the last 100 years:

  •  wetter in the tropics
  • drier in the south, particularly SW of WA
  • sea levels are increasing right around Australia
  • temperature has risen by approximately 1 degree
  • we have less cold weather and more heat
  • some areas are heating more than others – the Centre and WA

Overall Australia’s core minimum and maximum temperature has risen point 9 of a degree. Melbourne’s record temperature has risen 4.6 degrees over the last 50 years. The recorded temperature for Melbourne on Black Saturday was 46.5. On that day Hopetoun recorded 48 degrees.

Every parcel of air, ocean current and weather system is approximately 1 degree warmer.

One degree warmer across our planet means much more energy added to the climate system. What happens with each extra degree?

On the same subject, did anyone notice the abundance of Common Brown butterflies this season, clearly the wetter weather of the last couple of years coupled with the heat provided an abundance of food plants for this [and other species]. It has been noted that the Common Brown butterfly now emerges from the chrysalis stage 2 weeks earlier than it did in 1940 – the temperature is point 7 of a degree hotter, our seasons are starting earlier.

Ed. note – see Issue 48 for a piece on climate change affecting many bird sp. Issue 41 for threats to penguin sp. Issue 40, amphibians and Issue 37, Mountain Pygmy Possum.

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