Global
warming reduces wheat production markedly if no adaptation takes place
Natural Resources Institute Finland, Science Daily
Future global wheat harvest is likely to be reduced by six per
cent per each degree Celsius of local temperature increase if no adaptation
takes place. Worldwide this would correspond to 42 million tons of yield
reduction, which equals a quarter of current global wheat trade.
Wheat plays an important role in feeding the world, but climate
change threatens its future harvest. Without adaptation, global aggregate wheat
production is projected to decline on average by six per cent for each
additional degree Celsius temperature increase. Worldwide this would correspond
to 42 million tons yield reduction for one 1°C global warming.
This result has been generated by an international research
consortium to which Natural Resources Institute Finland (previously known as
MTT Agrifood Research Finland) substantially contributed. The results were
published online in the high impact journalNature Climate Change.
Losses
expected throughout the world
The researchers found out that in response to global temperature
increases, grain yield declines are predicted for most regions in the world.
Considering present global production of 701 million tons of wheat in 2012,
this means a possible reduction of 42 million tons per one degree Celsius of
temperature increase.
"Therefore it is essential to understand how different
climate factors interact and impact food production when reaching decisions on
how to adapt to the effects of climate change."
Increased
variability weakens stability in grain supply
In the study, the researchers systematically tested 30 different
wheat crop models against field experiments in which growing season mean
temperatures ranged from 15 °C to 26 °C. The temperature impact on yield
decline varied widely across field test conditions. In addition, year-to-year
variability increased at some locations because of greater yield reductions in
warmer years and lesser reductions in cooler years.
"Increased yield variability is critical economically as it
could weaken regional and global stability in wheat grain supply and food
security, amplifying market and price fluctuations, as experienced during
recent years," says Professor Rötter.
In its recent Assessement Report (AR5), the Intergovernmental
Panel on Climate Change (IPCC) projects that global mean temperature may rise
up to 5 °Celsius by the end of this century.
"Timely and adequate adaptation, such as cultivating more
heat-tolerant wheat cultivars could substantially reduce climate change induced
risks," Rötter continues.
Unique
and multi-locational study
Agrosystems modellers, Dr. Fulu Tao, Dr. Taru Palosuo and Prof.
Dr. Reimund Rötter from Natural Resources Institute Finland participated to
this collaborative research under the umbrella of AgMIP, The Agricultural Model
Intercomparison and Improvement Project coordinated by Columbia University,
NASA and University of Florida, USA. Apart from Finland, scientists from
Germany, France, Denmark, Netherlands, Spain, UK, Columbia, Mexico, India,
China, Australia, Canada and USA participated in this global study.
In a unique study set-up, the scientists first compared
simulation results from a large ensemble of wheat crop growth models with
experimental data, including artificial heating experiments and
multi-locational field trials. They found that discrepancies between
observation and simulation varied among individual models, whereby deviations
increased with increasing growing season temperature.
Most reliable estimates of observed yields over the range of
temperature regimes were achieved by using the multi-model ensemble median
estimate. Based on these test results, scientists subsequently applied the
multi-model ensemble to estimate wheat yields under increasing temperature in
the main cultivation areas of the world.
Story
Source:
The above story is based on materials provided by Natural Resources Institute Finland. Note: Materials may be edited for
content and length.
Journal
Reference:
S. Asseng, F. Ewert, P. Martre, R. P. Rötter, D. B. Lobell, D.
Cammarano, B. A. Kimball, M. J. Ottman, G. W. Wall, J. W. White, M. P.
Reynolds, P. D. Alderman, P. V. V. Prasad, P. K. Aggarwal, J. Anothai, B.
Basso, C. Biernath, A. J. Challinor, G. De Sanctis, J. Doltra, E. Fereres, M.
Garcia-Vila, S. Gayler, G. Hoogenboom, L. A. Hunt, R. C. Izaurralde, M.
Jabloun, C. D. Jones, K. C. Kersebaum, A-K. Koehler, C. Müller, S. Naresh
Kumar, C. Nendel, G. O’Leary, J. E. Olesen, T. Palosuo, E. Priesack, E. Eyshi Rezaei,
A. C. Ruane, M. A. Semenov, I. Shcherbak, C. Stöckle, P. Stratonovitch, T.
Streck, I. Supit, F. Tao, P. J. Thorburn, K. Waha, E. Wang, D. Wallach, J.
Wolf, Z. Zhao, Y. Zhu. Rising
temperatures reduce global wheat production. Nature Climate Change, 2014;
DOI: 10.1038/NCLIMATE2470
Cite
This Page:
Natural Resources Institute Finland. "Global warming
reduces wheat production markedly if no adaptation takes place." Science Daily,
12 January 2015.
<www.sciencedaily.com/releases/2015/01/150112082944.htm>.