Heat shock ahead for global croppers

02 Feb, 2015 01:00 AM
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.

Gregor Heard

Gregor Heard

is the national grains writer for Fairfax Agricultural Media
Date: Newest first | Oldest first


5/02/2015 12:18:13 PM

Another 'international' report? move along folks, nothing to see here. It's never going to happen.
Bill Pounder
5/02/2015 1:07:27 PM

The biggest problem for AGWers is that they can't keep track of their lies. Example, Antarctic Ice Cores, repeated ad nauseum, why even by he of "An Inconvenient Truth", that CO2 precedes warming. See questions 73-76 Pg 31, http://www.climatechange.gov.au/s ites/climatechange/files/document s/03_2013/prof-plimer-answers.pdf - Whereby the graphs are kept deceptively separated. Overlayed, we see CO2 follows warming, not the other way round. http://wattsupwiththat.com/2009/0 1/30/co2-temperatures-and-ice-age s/ Myth busted, AGW feary damned, by its own data.
5/02/2015 1:13:36 PM

What heat shock? Man made global warming is a total con and a scam to lighten your wallet through carbon taxes. Wake up people.
5/02/2015 1:24:11 PM

And clearly your probably a bit of a dill, Brence.
5/02/2015 6:04:12 PM

Qlander, your piled-up assertions are interesting, for what they reveal about your thinking. "That's not science, that's politics" you repeat. Why? By all means, query the accuracy of the science, but how do you get politics out of it? What is political about measuring temperatures? And then to persist with the notion that the published scientific research from around the world is "belief" - well, that suggests a very odd view of the world. Are you scared of a great big global conspiracy, Qlander?
Black Stump
5/02/2015 7:22:48 PM

The heading should be " Cold shock ahead because of dormant sun " Our Govt is preparing for the wrong thing. http://quadrant.org.au/opinion/qe d/2015/02/inherit-wind-much-else/
6/02/2015 6:00:32 AM

True believers, Nico and co, why haven't you reported this, another dodgy headline shattered. 2014 hottest year ever, now the reality quietly revealed. The link http://blogs.news.com.au/heraldsu n/andrewbolt/index.php/heraldsun/ comments/warmists_are_a_bigger_da nger_than_warming/ From the link, "The so-called record is well within the margin of error and it cannot be concluded it was the warmest year of the decade, let alone in recorded history. The more reliable satellite data put 2014 as likely the third or sixth warmest…". Nico, I await your usual.
John Wayne
6/02/2015 6:31:14 AM

Black Stump that is one of the best articles I have read for quite awhile and I highly recommend it. People can find it at quadrant.org.au its called Inherit the Wind ( and not much else). A must read.
6/02/2015 8:39:18 AM

Max, how often do we have to tell you? Belief plays no part in science. As for my "usual", it is to say (how often do we have to tell you?) don't get your information from tabloid journalists or denialist blogs. Go to the published science, and if it is wrong, refute it with evidence. What you are quoting is no more than a journalistic beat-up from start to finish. It is however a fact that the graph of global temperature is, allowing for natural variation, going up. See eg: https://scripps.ucsd.edu/news/dis tinct-rise-global-ocean-temperatu res-detected
6/02/2015 9:11:18 AM

nico. Never assign a conspiracy to incompetents. The main thing that this article highlights is the no problem, no funding situation, that research scientist find themselves in. The only thing that a research scientist without funding researches is the job ads, and if you want funding. First you must find a problem. There are $billions available to research potential problems caused AWG. Nothing at all to find it's a non issue and just a part of the normal climate cycle.
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