Climate change may affect the production of maize (corn) and wheat
as early as 2030, according to a new NASA study.
Climate change may affect the production of maize (corn)
and wheat as early as 2030 under a high greenhouse gas
emissions scenario, according to a new NASA study published
in the journal, Nature Food. Maize crop yields are projected
to decline 24%, while wheat could potentially see growth of
Using advanced climate and agricultural models, scientists
found that the change in yields is due to projected increases
in temperature, shifts in rainfall patterns, and elevated
surface carbon dioxide concentrations from human-caused
greenhouse gas emissions. These changes would make it more
difficult to grow maize in the tropics, but could expand
wheat’s growing range.
“We did not expect to see such a fundamental shift, as
compared to crop yield projections from the previous generation
of climate and crop models conducted in 2014,” said lead author
Jonas Jägermeyr, a crop modeler and climate scientist at NASA’s
Goddard Institute for Space Studies (GISS) and The Earth
Institute at Columbia University in New York City. The projected
maize response was surprisingly large and negative, he said.
“A 20% decrease from current production levels could have
severe implications worldwide.”
To arrive at their projections, the research team used two sets
of models. First, they used climate model simulations from the
international Climate Model Intercomparison Project-Phase 6 (CMIP6).
Each of the five CMIP6 climate models used for this study runs its
own unique response of Earth’s atmosphere to greenhouse gas
emission scenarios through 2100. These responses differ somewhat
due to variations in their representations of the Earth's climate
Maize, or corn, is grown all over the world, and large quantities
are produced in countries nearer the equator. North and Central
America, West Africa, Central Asia, Brazil, and China will potentially
see their maize yields decline in the coming years and beyond as
average temperatures rise across these breadbasket regions,
putting more stress on the plants.
Wheat, which grows best in temperate climates, may see a broader
area where it can be grown as temperatures rise, including the
Northern United States and Canada, North China Plains, Central
Asia, Southern Australia, and East Africa, but these gains may
level off mid-century.
Temperature is not the only factor the models consider when
simulating future crop yields. Higher levels of carbon dioxide
in the atmosphere have a positive effect on photosynthesis and
water retention, increasing crop yields, though often at a cost
to nutrition. This effect happens more so for wheat than maize,
which is more accurately captured in the current generation of
models. Rising global temperatures also are linked with changes
in rainfall patterns, and the frequency and duration of heat
waves and droughts, which can affect crop health and productivity.
Higher temperatures also affect the length of growing seasons
and accelerate crop maturity.
“You can think of plants as collecting sunlight over the course
of the growing season,” said Ruane. “They're collecting that
energy and then putting it into the plant and the grain. So, if
you rush through your growth stages, by the end of the season,
you just haven't collected as much energy.” As a result, the
plant produces less total grain than it would with a longer
development period. “By growing faster, your yield actually
“Even under optimistic climate change scenarios, where societies
enact ambitious efforts to limit global temperature rise, global
agriculture is facing a new climate reality,” Jägermeyr said.
“And with the interconnectedness of the global food system,
impacts in even one region’s breadbasket will be felt worldwide.”
Provided by the IKCEST Disaster Risk Reduction Knowledge Service System