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


9/02/2015 11:07:26 AM

Get your information from a reputable source, Gummy, and you won't embarrass yourself. The item you cite from around 2007 is by UK Telegraph journalist Christopher Booker, a writer with no scientific expertise, climate or otherwise, a serial denialist (who also defends tobacco and asbestos.) Not a reputable source. Your accusation of lying is indefensible.
Old Crow
9/02/2015 12:24:16 PM

Haha, your so funny Jeffito, that would have to be the world's biggest cop-out. Just another loser with nothing and no one to back you, more like it. I am rolling around on the floor in laughter. What an absolutely ridiculous response from another of the loony global warming cranks and offfffff you go in a huff just like Susan. And you wonder why the world does not take you seriously. Your faith based religion (doomsday cult ) is the laughing stock of the entire world. hahaha LOL. What an idiot.
9/02/2015 12:57:16 PM

I know the truth is big dent in your pride Nico but you have to realise you can't just lie about the temperature data to suit your discredited cause and think you can get away with it. The world is seeing through the global warming hype for what it really is, a totally manufactured (non) problem.
9/02/2015 4:38:05 PM

Jeffito, you just have to realise that the contrarians you refer to here are just yesterday's men - unable to come to grips with things and just go on yapping . The old Arab quotation sums it up " the dogs bark but the caravan moves on".
11/02/2015 3:14:00 PM

Spot on Oliver, you lot are the dogs barking (barking doomsday) while we productive ones (the caravan) just get on with being productive and work with the natural climate variation we get. Unfortunately some of that production goes to feed you undeserving non productive lot of scammers.
Old Crow
12/02/2015 10:29:03 AM

Yep spot on Oliver, yesterday's men (that being yourself) have nothing to offer but old quotations.
13/02/2015 12:16:58 PM

Here's something for Nico and his mates. The real climate change agenda revealed. This headline from the below link, "UN climate official: real plan is “change the economic development model” http://blogs.news.com.au/heraldsu n/andrewbolt/index.php/heraldsun/ comments/un_climate_official_real _plan_is_change_the_economic_deve lopment_model/ So another climate god revealed for what they are and what they are trying to achieve. Again from the linked article,"Note: Figueres is an anthropologist, not a climate scientist."
13/02/2015 1:46:28 PM

So Nico which of your gods that the true believers follow are actually climate scientists. Not your climate commissioner Timmy. Not the IPCC head he's a railway engineer. Not Figueres the UN climate official and spokesperson she's an anthropologist. These are some of the gods the true believers rely on for their information, believable or not. So how is it Nico you repeatedly discredit anyone who refutes any of your climate assertions with "oh but they aren't climate scientists" when in fact neither are many of your gods.
Old Crow
14/02/2015 5:36:49 AM

Well done Max, so much for there being NO conspiracy . The whole AGW climate scam was one BIG conspiracy from day one. Now let them try to deny it. They will be the denialists.
15/02/2015 8:57:30 AM

Max, please calm down. Give me one reason why Professor Pachauri, who has a number of doctorates in different fields of energy science, should not be the chair of an international body set up to collate the work of climate scientists. And please find a better source of information than Andrew Bolt!
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