January 19, 2020 at 4:12 pm #108088Chief Editor TTKeymaster
How are Tasmanian land and sea climates changing?January 23, 2020 at 10:55 am #108447Phill ParsonsParticipant
Observed effects: longer autumn, warmer winter and earlier spring. Changed flowering periods, increased plant growth rates, changing rainfall pattern and declining annual rainfall total, and a wider range of species from warmer climates growing where they struggled or failed.
For the deniers who can be bothered reading this, low temperatures still occur, but fewer, and not as low as often.January 23, 2020 at 11:54 am #108448Mark SmithParticipant
As a writer and commentator on the Tasmanian wine industry for more than 25 years, I contributed an article to the January 2019 edition of Australian & New Zealand Grapegrower & Winemaker magazine, profiling the career of Bream Creek Vineyard owner/operator Fred Peacock, who was named 2018 Australian Viticulturist of the Year by national publication Gourmet Wine Traveller. Peacock purchased his vineyard on Tasmania’s East Coast in 1990, some 26 years after the site was first planted by the vineyard’s founders. Today, Bream Creek Vineyard produces award-winning wines that are acknowledged nationally and internationally as among Australia’s best. An extract from the article follows, and includes references to data obtained from BOM:
“When we first took over Bream Creek Vineyard, this part of Tasmania’s southeast coast was especially challenging viticulturally because growing conditions were so cool and so marginal,” Peacock says.
“Rainfall was a lot higher then than it is today and we had real problems keeping disease at bay. We now know that average annual rainfall at Bream Creek has fallen by 10% since 1990. In fact, reliable data indicates October rainfall during the same period has fallen by 20%. December rainfall has declined by 25%.”
“Average monthly temperature maxima, however, don’t appear to have moved much over the century. It’s the levels of solar radiation that have changed. In spring, levels of solar radiation since 1990 have increased between 2.3% and 4.3% when compared with long-term averages dating back to 1900. In summer, increases in solar radiation since 1990 have been far less impressive, with increases somewhere between 0.4% and 3.2% – not statistically significant, but perhaps the start of a trend that will increase over time.
“It’s a bit ironic, but climate change to date has been beneficial to parts of the Tasmanian industry. Scientists recently discovered that the East Australian Current that runs down Tasmanian’s east coast is the fastest warming ocean current in the world. That current used to peter out around Maria Island, just north of Bream Creek. Nowadays, it extends further south and runs closer inshore.
“Its effects have been something of a boon for Bream Creek. While there don’t appear to have been any changes in mean monthly temperature maxima, my gut feeling is that the monthly minima may have lifted. Sea breezes are now lighter and warmer than during the vineyard’s earliest years. This observation is supported by evidence of the rising temperature of the offshore East Australian Current.”
Climate sceptics may challenge some of the causal factors at work in southeast Tasmania over the past 30 years, but one conclusion appears irrefutable. Consistently more favourable growing conditions have made this part of the island far more reliable as a wine-producing area.
“They have also enabled us to fully ripen a wider range of varieties despite all that the seasons can throw at us,” Peacock concludes.
“In fact, I’m confident well managed vineyards have a great future here, and with the Tasman Sea affording us protection from many of the predicted extremes of global warming, Tasmanian wine producers will have a lot to offer over the next 30 years or so.”January 23, 2020 at 5:01 pm #108472Keith RobertsParticipant
As an amateur weather recorder in South Hobart for 60 years, observation over the years shows a shift over that time.
One of my main interests is snowfall on Mt Wellington and Tasmanian peaks. The decline is marked. I have researched records and articles from old sources in the 1800s. Snowfalls from those times would bring our city to a grinding halt. Snow drifts on higher peaks have declined markedly in recent decades. Mt Wellington pre WW2 was a ski location which moved to Mt Field, which in turn is decreasing in depth and cover.
I used to walk to work in the late 1960s to 1990s, and I’ve noticed that fog and frost have just disappeared in that time.
The number of hot days is increasing. None of these as a single item would be noteworthy, but observed over the years they add up to a changing climate.
Tasmania is not immune, but for a while we will be removed from the new extremes on the mainland.
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