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The Australian Heat Wave [Greg Laden's Blog]
Australia is experiencing a heat spell. The Climate Information Services of the Australian Bureau of Meteorology has issued a special statement (I’ll provide some details below). This is not unexpected, since over the last few years global warming due to the human release of large amounts of fossil Carbon into the atmosphere has been heating everything up. In fact, a paper that came out mid (southern) winter 2008 predicted that by the end of the century, extreme high temperatures in Australia would reach 50 degrees or more. I’ll provide some data for that too. But first, since most of the readers of this blog live in the US I’ll provide a table showing the relationship between degrees F an degrees C.
| C | F |
|---|---|
| 20 | 68 |
| 30 | 86 |
| 40 | 104 |
| 50 | 122 |
So, when you reach 50C … well, there are recipes that are called “cooking” that use temperatures in that range.
The 2008 paper found the that we can expect extreme high temperature “values in excess of 50°C in Australia, India, the Middle East, North Africa, the Sahel and equatorial and subtropical South America at the end of the century.” The paper simulates future climate by looking at past and present conditions and factoring in the expected temperature changes from the ECHAM5/MPI-OM climate model which is a combination of the IPCC atmospheric general circulation model (ECHAM5) and MPI-OM ocean-sea ice component developed at the Max Planck Institute for Meteorology. You can read the gory details here (PDF).
That work was done a few years ago, and one of the things I’ve noticed about predictions of future climate change done over the last five or six years is that they are under-estiamtes. If a 2008 paper says Australia will be hitting highs of 50 degrees C by 2095, then based on this heuristic (and it is merely a heuristic but so far one that is working pretty well) you might expect regular extremes higher than 50 degrees C in Oz by 2030 or so. (That uses the Thumsuck Climate Model technique in which we divide all the conservative estimates by three.)
We’ll see. I’m sure that work will be revised and updated soon enough and we’ll have a better model to work with. Meanwhile, climate science denialists are already cooking up a conspiracy theory in which evidence of an extremely warm period in the 19th century was erased by the Australian Scientists and NASA so we would think things are warmer now than today when in fact the warmest period was prior to WW I. Look for that, and laugh, because it is funny. (Not “funny ha ha,” so much. More like “funny, why are they still doing this?”)
So, what has been going on in Australia over the last few months and what is going to happen over the next several days? It’s been hot and it is going to be hot. From the BoM:
Large parts of central and southern Australia are currently under the influence of a persistent and widespread heatwave event. This event is ongoing with further significant records likely to be set. …
The last four months of 2012 were abnormally hot across Australia, and particularly so for maximum (day-time) temperatures. For September to December … the average Australian maximum temperature was the highest on record with a national anomaly of +1.61 °C, slightly ahead of the previous record of 1.60 °C set in 2002 (national records go back to 1910). In this context the current heatwave event extends a four month spell of record hot conditions affecting Australia. These hot conditions have been exacerbated by very dry conditions affecting much of Australia since mid 2012 and a delayed start to a weak Australian monsoon. … The current heatwave event commenced with a build up of extreme heat in the southwest of Western Australia from 25-30 December 2012 … Particularly hot conditions were observed on the 30th, with Cape Naturaliste observing 37.7 °C, its hottest December day in 56 years of record. From 31 December the high pressure system began to shift eastward … Temperatures reached 47.7 °C at Eyre on the 2nd its hottest day in 24 years of record, while Eucla recorded 48.2 °C on the 3rd, its hottest day since records began in 1957. … Hobart experienced a minimum temperature of 23.4 °C on the 4th (its hottest January night on record), followed by a maximum of 41.8 °C (its hottest maximum temperature on record for any month in 130 years of records) and the highest temperature observed anywhere in southern Tasmania.
The report includes the following two figures:
The maximum temperature anomaly from the 1961-1990 average for the last week of December (the start of the heatwave event in Western Australia). Units are °C.
The maximum temperature anomaly from the1961-1990 average for January 1 to 6. Units are °C.
According to the most recent news reports, things are pretty hard for people in Australia but there have been few deaths, possibly only one so far, due to heat as yet recorded. This is probably because Australia is in fact a fairly hot and dry country. This is not the same as a heatwave in the Upper Midwest in the US where conditions are different, the population may be more vulnerable, and there are a lot more people per unit area and heat waves often result in dozens, sometimes hundreds, of deaths.
As mentioned in an earlier post, fires have also been an issue in Australia. For example:
Fires are already burning in five states as a search continued for people missing after devastating wildfires in the island state of Tasmania.
Prime Minister Julia Gillard toured Tasmanian townships and promised emergency aid for survivors.
Residents told of a “fireball” that engulfed communities across the thinly-populated state at the weekend.
“The trees just exploded,” local man Ashley Zanol told Australian radio, recounting a wall of flames that surrounded his truck as he carted water to assist fire crews in Murdunna.The township was largely levelled in the inferno.
Global warming. Not just a theory any more.
——————————————————–
More discussion of climate change here.
Sources:
SPECIAL CLIMATE STATEMENT 43: Extreme January heat. Last update 7 January, 2013. Climate Information Services. Bureau of Meteorology
Sterl, A., Severijns, C., Dijkstra, H., Hazeleger, W., Jan van Oldenborgh, G., van den Broeke, M., Burgers, G., van den Hurk, B., Jan van Leeuwen, P., & van Velthoven, P. (2008). When can we expect extremely high surface temperatures? Geophysical Research Letters, 35 (14) DOI: 10.1029/2008GL034071
2013-01-07 19:15:22
Source: http://scienceblogs.com/gregladen/2013/01/07/the-australian-heat-wave/
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