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

Chick Olsson
7/02/2015 12:22:56 PM

It is all such a load of crap. Apelike creatures affecting the planets temperature ? Babel like Hubris.
Jeffito
9/02/2015 6:07:05 AM

Science is NOT based on faith in contrast to you contrarians who have adopted BLIND faith. The other difference between you lot and climate scientists is that they look at and consider ALL data whereas you lot are world leading cherry pickers, taking and often distorting the facts that support your FAITH and sweeping all else under your carpets.
Old Crow
9/02/2015 6:45:28 AM

Pure hypocrisy and crap if I ever heard it, Jeffito.
Rose
9/02/2015 6:59:51 AM

Jeffito , stop claiming you have science and climate scientists on your side, you don't. You cranks are the ones cherry picking and distorting facts to support your dangerous man-made global warming faith. Your nothing but a doomsday cult.
nico
9/02/2015 7:20:48 AM

Qlander, your argument is fairly silly. You predict the destruction of intelligent life by an alien invasion in 90 years. Of course, I can't refute this idea. But neither do you offer any evidence. Whereas the science of climate change has been accruing evidence for the past century, and by using scientific publication, has subjected this evidence to intense and well-informed critique. And another reminder to one-eyed Max: belief has nothing to do with it. If you refuse to look at the science it's easy to claim, wrongly, there's not much science involved.
Max
9/02/2015 7:21:27 AM

Yep that would be right jeffito, cherry picking all right, like the widespread freezing conditions in the northern hemisphere, like discrediting the 'record heat' announcement which are hastily made with big fanfare only to be later quietly renounced by the announcers, like showing up the many and varied dud predictions by your gods which have come nowhere near the mark, like showing up your gods as being nothing but snouts in the trough gravy train bludgers doing nothing productive but continually developing ways to suck off the productive sector. So yep blind faith indeed.
Brence
9/02/2015 7:40:16 AM

Obviously Qlander, you just don't get it! Scientists develop a theory based on all of the information available. They continue to do research in that particular area to test the theory. They will modify or discard the theory if their new data are not consistent with it. What you call a theory ( the in 90yr time) is just not a theory in their terms because you don't have any data on which to base that theory. You need to get yourself better informed on science matters so that you present comments here that have some measure of credibility.
jeffito
9/02/2015 8:24:27 AM

I'm signing of from this discussion. I have been part of it because of an interest in education. I note that the majority of correspondents are in the contrarian camp. Do you wonder why professional climate scientists, the majority of whom consider that evidence supports a human induced effect in climate change, don't get involved here more? Because they realise that the contrarians are a minority of society and they just don't have time or interest to converse with you.
Rose
9/02/2015 8:37:35 AM

Its you that needs to get better informed Brence. Your CAGW belief system is discredited and bankrupt and has zero credibility but the only one that does not seem to realise it is you.
Gumtree
9/02/2015 8:50:02 AM

So much for your credibility Brence, its not looking very good is it? Why is it you have to lie about the temperature data Brence/Nico/Jeffito ? Is this how your science works ? Just make it up as you go along. http://www.telegraph.co.uk/news/e arth/environment/globalwarming/11 395516/The-fiddling-with-temperat ure-data-is-the-biggest-science-s candal-ever.html
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