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


16/02/2015 5:44:37 AM

This comment stream should be made in a hard copy and made into a book. Model how much food a person needs x 7 years. Store it. Win. I am not religious, but that is actually in the old testament. Climate change is considered in the Bible.
16/02/2015 6:49:20 AM

YES James but old testament style climate change is always going on somewhere or other in the world some good some bad , and is it being directly caused by the atmospheric CO2 rate . Well informed intelligent people know there is little to no connection and that CO2 is good for the environment.
16/02/2015 8:15:02 AM

There you go again Nico, shooting the messenger and avoiding the issue. Not a word about the message, FROM YOUR OWN GODS, just your normal crap. As for Pachauri, one good reason, easy, your own, you discredit anyone who isn't a climate scientist who makes a comment or statement about the AGW crap, so why don't you stick by your own principles. But no in you and the true believers eyes it is a case of whatever it takes. Amazing though when even your own gods come and state the true agenda of AGW, you still claim it is science based and that everyone should just accept it no questions asked.
16/02/2015 10:59:00 AM

Global what? http://www.cato.org/blog/no-globa l-warming-doesnt-lead-more-snow-b oston#ysCWx5:y0o
16/02/2015 11:58:40 AM

And this http://notrickszone.com/2015/02/1 5/joe-bastardi-schools-michael-ma nn-on-how-to-read-a-weather-chart -heavy-snow-is-because-its-cold/# sthash.hFGAjWch.dpbs
16/02/2015 12:05:05 PM

But wait there's more, http://notrickszone.com/2015/02/1 0/the-frigid-winters-of-global-wa rming-uncompromising-cold-conditi ons-that-may-be-recalled-for-gene rations/#sthash.dA6q0M8i.dpbs
16/02/2015 12:11:59 PM

He who controls the past controls the future, he who controls the present controls the past. I do not think George Orwell had climate scientists in mind when he wrote 1984 but he was pretty much spot on with the temperature records.
16/02/2015 12:59:52 PM

Max, you seem quite weirdly obsessed with "gods". I'm not. And I have just one message: we should get our scientific information from a reliable source: from the published science, not from tabloid journalists or denialist blogs. And, Max, try to understand that climate science covers many disciplines: atmospheric science, phenology, geology, biology, oceanography, health, to name a few, and the technologies of energy use, transportation, industrial efficiency, and more. And, Max, nobody accepts science "no questions asked". Science is all about asking questions. You should try it.
16/02/2015 1:15:24 PM

Ah, but Nico, whenever we do ask questions you just call us denialists, avoid the issue in the questions being asked, never answer them and go on your merry way worshiping your new found religion. And, no Nico, that would be you obsessed with gods, your AGW gods who can do or say no wrong no matter how blatantly wrong they may be.
17/02/2015 4:21:30 AM

Why do I get the feeling global warming is not happening. http://www.dailymail.co.uk/news/a rticle-2955250/Biting-cold-air-fo llows-latest-New-England-snowstor m.html
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