Ecocentric

A Warmer World Will Mean More Pests and Pathogens for Crops

Diseases like the potato blight have ruined harvests in the past — and still haunt farmers today. Research suggests climate change will spread those pests and pathogens

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AydAn Mutlu

When we talk about the challenge of ending hunger and feeding a growing global population, most of the focus is put on increasing production. That’s not surprising — “more” is our solution to most social problems. But some of the hunger gap could be closed by making better use of the crops we do produce now. Take plant pests and diseases, which have historically laid waste to whole harvests. The Irish potato famine of the 1840s — caused by the oomycete Phytophthora infestans — led to the deaths of a million people and the emigration of another 2 million Irish. The 1943 Great Bengal Famine in India led to the deaths of some 3 million and was caused by a simple fungus. Even today, when farmers are better equipped to control pests and pathogens, between 10% and 16% of crop production each year is lost to biological threats. That’s enough food to feed hundreds of millions of people.

Pests and pathogens are weather-dependent, and many thrive in hotter, wetter climates — which is exactly the sort of change that global warming is predicted to create over the coming decades. In a new meta-analysis published in the journal Nature Climate Change, researchers from the University of Exeter and the University of Oxford looked at how plant pests and diseases will respond to a warming world, and found that their range has been steadily shifting toward both poles, as climate change warms higher latitudes. They found that crop pests have been spreading north and south a little less than 2 miles (3.2 km) a year since 1960, though there’s a lot of variety within individual species.

(MORE: As Northeast Asia Bakes, Climate Scientists Predict More Extreme Heat Waves on the Horizon)

We can already see the results of some of that pest expansion. Warmer winters have allowed the mountain pine beetle to take hold over a greater swath of the Pacific Northwest, allowing it to spread further and higher, at altitudes that in the past would have been too cold for the insect. As a result, the mountain pine beetle is now at epidemic levels throughout the American West. The rice blast fungus, present in scores of countries, has migrated to wheat, and has become a scourge of farmers in Brazil.

Dan Bebber, an author of the paper at the University of Exeter, said in a statement:

If crop pests continue to march polewards as the earth warms, the combined effects of a growing world population and the increased loss of crops to pests will pose a serious threat to global food security.

The truly scary possibility is that a new or re-emerging plant disease could decimate one of the few crops — rice, wheat, corn — that the global diet is based on. We’ve already had a few close calls. Wheat rust, which is caused by a fungus, devastated wheat crops in Africa, and is poised to spread to other major wheat-producing countries. It doesn’t help that over the years farmers have narrowed the genetic diversity of commodity crops, which limits our ability to respond if a new pest or disease takes hold. That’s why we need to support seed banks, which store a variety of strains within a crop, to ensure that farmers have weapons to respond to a new plant plague. They’ll need those bullets in a warmer world.

MORE: The Trouble With Beekeeping in the Anthropocene

11 comments
AJAIVERMA
AJAIVERMA

what we need is sustainable agriculture practices. our emphasis should be on the use of organic manure and bio pesticides. use of less quantity of synthetic/chemical pesticides. emphasis should be on use of safe technology /practices for increasing the crop yield, agricultural labs should connect to farmers through extension programs more often/frequently. ajai verma , new delhi , India.

DanielWeiss
DanielWeiss

50 years ago my father dug up a sickle in The Bronx (NYC).  I was able to track it to what became True Temper and date it to the 1880-1895 period.  My grandmother looked at it and said "That is why America is great" .  We had just gotten her out from behind the Iron Curtain and she said that in the eastern block they were still using the sickle pictured with this article and still in use.  The American sickle has a bend at the handle base that protects the knuckles from scraping the ground letting the farmer work faster and more efficiently.  I still have it and 120 years later that technology has not spread worldwide.  

How fast do you think the world will adapt to a relatively rapid change in the environment.   See the effect of the little ice age on Europe

DavidNutzuki
DavidNutzuki

Why are you saying a climate crisis WILL happen when science has only agreed it COULD happen and have NEVER said or agreed that any crisis WILL happen?

PrinceROBERT15
PrinceROBERT15

@TIME I WROTE AN AMENDMENT> ABOUT IT. GLOBAL WARMING. & CITIES ARE NOTHING BUT CROP CIRCLES DRYING OUT THE EARTH. LIKE A WET

sggmuw
sggmuw

@TIME aw hell just add more crack to it and keep feeding us your horrible corn syrup death mix

DavidNutzuki
DavidNutzuki

Big Oil doesn’t feed the denier machine; it’s science’s own “could be” consensus that fosters doubt and skepticism as in: 28 years of never saying a crisis WILL happen is as good as saying a crisis NEVER will happen. So how does any climate change believer get away with saying the scientist's crisis WILL happen when science has never agreed on anything past "could be" a crisis and have NEVER agreed or said that their own crisis "WILL BE" a crisis, only might be and could be and maybe and........? Who is committing a hoax here? Who is perceived now as the fear monger when we condemn our own children at the grunt of a “could be” headline of consensus? Science can shut down the denier machine now and end this costly debate to save the planet just by agreeing their own crisis is now inevitable not just "possible" otherwise continued debate will continue stalling CO2 mitigation as we drift to the edge of unstoppable warming. Just what has to happen now for science to switch their consensus of “could be” to a consensus of “inevitable”, like they say comet hits are? Don’t scientists have doomed children as well?

MikeBaillie
MikeBaillie

@GardenDiva3 And the chemical corps will see it as a great opportunity for even more pesticides etc.

MikeBaillie
MikeBaillie

@GardenDiva3 Yeah, that's what it was saying, and pests will have a bigger range of movement. Scary stuff.