Heat shock ahead for global croppers

02 Feb, 2015 01:00 AM
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103
 
Temperatures could rise a whopping 4.2 degrees on average by 2090

AN international report has made a sobering finding, with computer models showing global wheat production could fall six per cent for every one degree of temperature rise.

The study, published online in Nature Climate Change, found that not only would production fall, but volatility would increase.

The rate of decreases in productivity is a massive concern for Australian producers, given a joint release from the Commonwealth Scientific and Industrial Research Organisation (CSIRO) and the Bureau of Meteorology (BoM) last week showed temperatures could rise up to 1.2 degrees on average in southern Australia from the average from 1986-2005.

The BoM/CSIRO study showed temperatures could rise a whopping 4.2 degrees on average by 2090 under a high emissions scenario and also forecast lower rainfall in key cropping zones in southern and eastern Australia, especially in winter and spring, the critical seasons for winter crop production.

However, contributor to the Nature Climate Change study on wheat production, Garry O’Leary of the Victorian Department of Economic Development, Jobs, Transport and Resources (DEDJTR) said the study was based on no adaptation to a changing climate.

"This study is concerned solely with rising temperatures, we have just used standard varieties and have not factored in the impact of rising carbon dioxide levels," Dr O’Leary said.

The work involved comparing 30 simulation crop models against field experiments where crops were grown at mean temperatures ranging from 15 to 32 degrees.

CSIRO and BoM researchers say their study, which makes use of 40 different global models, shows warming patterns will continue after an increase in average temperatures of 0.9 degrees since 1910.

"There is very high confidence that hot days will become more frequent and hotter", CSIRO principal research scientist, Kevin Hennessy said.

Rainfall declines will be first felt in southern mainland Australia before the area with lower rainfall increase across subtropical regions after 2030.

Mr Hennessy said the agriculture sector would need to prepare for the changes predicted in the report.

"This research has been strongly aligned with the needs of Australia's natural resources sector", Mr Hennessy said.

"Other researchers are using this information to assess potential impacts and management options."

And in worrying news for growers, Dr O’Leary said many crop production modelling products had not adequately factored in the damage done by high temperatures.

"The wheat yield declines due to temperature increases were likely to be larger than previously thought and are likely to begin taking effect earlier than expected with only small temperature increases having an impact," he said.

Tim McClelland, the co-ordinator for forecasting tool Yield Prophet with Birchip Cropping Group (BCG) said there were a number of ongoing challenges with forecasting tools.

"We’ve factored in increased temperatures and the impact it has on the crop in terms of earlier flowering, but modelling systems inherently overestimate the yield slightly."

Mr McClelland said the tool could also make allowances for different cultivars and maturity dates.

"We have eight different categories in terms of variety choice and that is factored into our modelling."

He said with Yield Prophet, challenges now included creating a system for new crops and better accounting for mineralised fertiliser.

Dr O’Leary said Australia, with large tracts of near-arid cropland, could be especially hard hit by rising temperatures.

However, he said adaptation of new practices could help.

"Drought and heat tolerant varieties will be the holy grail for breeders, and there is also a lot of work to be done to extreme events at sensitive stages of a crop’s development, such as heat or frost at flowering."

In terms of in-crop yield monitoring, Dr O’Leary said that the Australian models performed well but not in all tests and no single model of all the 30 was shown to be superior.

Australian models used included the Agricultural Production Systems Simulator (APSIM) and other experimental forms of that system.

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FarmOnline
Gregor Heard

Gregor Heard

is the national grains writer for Fairfax Agricultural Media
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READER COMMENTS

Max
6/02/2015 10:23:08 AM

Hey Nico I predicted you would do your usual and as usual you obliged. You didn't even read the link because if you had you would have seen it was one of your gods making the statement, just being reported by an evil denialist blogger. Led you right into your usual as the following is the previous bit from the link. The headline of “2014 was the warmest year on record” and then stating who made the statement, "Taken from a press statement issued by NASA/Goddard Institute for Space Studies, it was later acknowledged by director Gavin Schmidt that the release was only 38 per cent certain."
jeffito
6/02/2015 10:30:10 AM

Qlander, you have a lot of nerve claiming that scientists are unscrupulous and inventing problems then manipulating data to draw out the funding! Yes, like any field of endeavour, there are a vast majority of honest workers and a minority of unscrupulous frauds, the Lance Armstrongs if you like. Those rare frauds eventually get caught out. To claim that the vast majority of scientists working in the climate area and who find the data support the hypothesis of human induced climate change indicates clearly which group you sit in.
Qlander
6/02/2015 11:31:23 AM

Touched a nerve did I, jeffito. There's a reason all articles about AGW are full of 'could', 'may', 'might', 'perhaps', 'potential'. This article is an excellent example. The trick is to imply a problem while still being vague enough to avoid outright fraud. The science in this article sound .... IF the temperature rises. However you will never see an article detailing the upside to a rise in temperature.
jeffito
6/02/2015 12:35:01 PM

Qlander, the articles you and team constantly refer to are always and only popular press or low brow deniers' blog sites, not the original scientific literature. The money spinners are the guys who write to contrary opinion books (not scientists) and you and your foolish mates are the ones who buy them and put money in these guys pockets.
nico
6/02/2015 12:47:53 PM

Qlander, you believe (the correct word, this time) that climate science is the domain of incompetents or conspirators. You assert this unpleasant and unlikely theory. But you never offer evidence. (Incidentally, for the "upside" of global warming, do you own research into the various research programs examining enhanced CO2 and warming. Some up, some down, but, as is the nature of science, reported objectively.
nico
6/02/2015 12:51:00 PM

Incidentally, Qlander, if you knew as much about science as you claim, you would recognise that, because science is based on theory and prediction, the normal convention is to use words implying probability. Only in Q'land is this seen as evidence of conspiracy.
Max
6/02/2015 1:02:13 PM

Not only in Q'land Nico in the case of the AGW scam. And its belief when it suits you to describe it that way Nico.
Qlander
6/02/2015 2:20:34 PM

Nico Science is based on theory, and prediction backed up by evidence. When the evidence shows the prediction is wrong - so is the theory. Unless of cause you push your prediction out past the normal span of your life/career. Then your safe, and so is your theory. My theory is that in 90 years, all intelligent life on earth will be destroyed by an alien invasion - prove me wrong.
Max
6/02/2015 5:30:48 PM

For the AGW faithful, a couple of gospel quotes from your gods. “This planet is on course for a catastrophe. The existence of Life itself is at stake.” – Dr Tim Flannery, Climate Council “We’ve got to ride this global warming issue. Even if the theory of global warming is wrong, we will be doing the right thing in terms of economic and environmental policy.“ – Timothy Wirth, President of the UN Foundation So Nico you claim it's not based on belief. I can't see much other way to describe it because it's obvious that there's not much science involved.
Bluey
7/02/2015 9:08:22 AM

Around 2007 during the millennium drought our area of Western NSW was deemed "the world's litmus test" by global warmists. A documentary of our area was made called "Waiting For Rain", and the consensus was that the drought would be permanent. Funny then, how the drought broke after a decade, as had all the previous big droughts and was followed by flooding across Eastern Australia which seemed to surprise many. Even funnier that last winter our region dipped to near record lows of -5.2C and this January was certainly the coolest any local can remember. We don't seem to be the litmus test now!
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