Climate explained: how climate change will affect food production and security
Many temperate crops require winter chilling to initiate flowering or fruit ripening, and orchards may need to shift to
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According to the United Nations, food shortages are a threat due to climate change. Are food shortages a major threat to
New Zealand due to climate change?
Climate change is altering conditions that sustain food production, with cascading consequences for food security and
global economies. Recent research
evaluated the simultaneous impacts of climate change on agriculture and marine fisheries globally.
Modelling of those impacts under a business-as-usual carbon emission scenario suggested about 90% of the world’s
population – most of whom live in the least developed countries – will experience reductions in food production this
New Zealanders are fortunate to live in a part of the world blessed with relatively fertile soils, adequate water
supplies and mild temperatures. This gives us a comparative advantage for agriculture and horticulture over many other
countries, including our main trading partner, Australia.
New Zealand produces more than enough food for its population. Exports exceed local consumption, and climate-change
induced food shortages should not be an imminent risk for New Zealand. But behind every general statement like this lies
some rather more troubling detail.
Overcoming domestic challenges
As residents of a developed country, we are accustomed to accessing the world’s resources through supermarkets. New
Zealanders take for granted that most foods (even those we do not produce, like rice or bananas) will be available all
Asparagus, new potatoes and strawberries are examples of foods New Zealanders may expect to see only at particular times
of the year, but if apples or kiwifruit are out of stock, people usually complain. Our expectations are based on imports
of products when they are out of season in New Zealand. The availability of those imports may be seriously compromised
by climate change.
A recent Ministry for the Environment report
describes climate impacts, including detailed projections of the average temperature increase and changes in rainfall
patterns across New Zealand. The consistent trends are towards wetter conditions in the west, drier in the east and the
largest average temperature rises in the north.
Implications for agriculture
are manifold. For example, many temperate crops require cool autumn or winter temperatures to initiate flowering or
fruit ripening. Orchards may need to be relocated further south, or novel low-chill varieties
may need to be bred, as is already happening around the world.
Insect pests and diseases are normally controlled by our low winter temperatures, but they may become more of a problem
in the future. Introduced pests and diseases
include fruit flies that have a major impact in Australia and other more tropical countries, but struggle to establish
breeding colonies in New Zealand. Strong biosecurity controls are our best bet for reducing this risk.
What matters more than the gradual increase in temperature predicted by climate change models, is the greater frequency
of extreme weather events. These include droughts, floods and hail, which can lead to total crop losses in particular
regions. One obvious mitigation strategy is to expand the provision of irrigation in our drier eastern regions, but
concerns over water quality in our rivers mean this is not a popular option with the public – for example on the Heretaunga Plains
or in Canterbury
Risks to imported products
New Zealand is a net exporter of dairy, beef, lamb and many fruit and vegetables, but for some products, we depend
heavily on imports. Figures from the US Department of Agriculture
are not perfect, but they highlight trade imbalances for major commodities.
New Zealand imports all rice and most of its wheat. It is a net importer of pork products. Horticultural data released
annually in Fresh Facts
show New Zealand’s major horticultural imports are (in order of value) wine, nuts, processed vegetables, coffee,
bananas and table grapes. These imported products come primarily from Australia, China, the US and Ecuador – all
countries that may be less resilient to climate change
than New Zealand.
As a recent report
by the UN Food and Agriculture Organisation (FAO
) explains, rising temperatures, rising seas and the increasing frequency of adverse weather events will interact to
reduce agricultural and horticultural productivity in many regions around the world. While New Zealand is unlikely to
experience food shortages in the near future as a direct result of climate change, the price and availability of
imported products may increase significantly.
Unfortunately, there is another important consideration. Some New Zealanders already experience food insecurity. The
2008/9 Adult Nutrition Survey
found 14% of New Zealand households reported running out of food often or sometimes due to lack of money.
Perhaps rather than worrying about the future impact of climate change on the price or availability of imported rice or
bananas, we should be paying more attention to this social inequity.
As a wealthy agricultural nation and a net exporter of food, it does not seem right that one sector of our society is
already regularly experiencing food shortages.
, Head of School of Food and Advanced Technology@ISHS_CMFV, Massey University
This article is republished from The Conversation
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