Navigation Links
Toll of climate change on world food supply could be worse than thought
Date:12/3/2007

Global agriculture, already predicted to be stressed by climate change in coming decades, could go into steep, unanticipated declines in some regions due to complications that scientists have so far inadequately considered, say three new scientific reports. The authors say that progressive changes predicted to stem from 1- to 5-degree C temperature rises in coming decades fail to account for seasonal extremes of heat, drought or rain, multiplier effects of spreading diseases or weeds, and other ecological upsets. All are believed more likely in the future. Coauthored by leading researchers from Europe, North America and Australia, they appear in this weeks issue of the Proceedings of the National Academy of Sciences (PNAS).

Many people assume that we will never have a problem with food production on a global scale. But there is a strong potential for negative surprises, said Francesco Tubiello, a physicist and agricultural expert at the NASA/Goddard Institute of Space Studies who coauthored all three papers. Goddard is a member of Columbia Universitys Earth Institute.

In order to keep pace with population growth, current production of grainfrom which humans derive two-thirds of their proteinwill probably have to double, to 4 billion tons a years before 2100. Studies in the past 10 years suggest that mounting levels of carbon dioxide in the airbelieved to be the basis of human-caused climate changemay initially bolster the photosynthetic rate of many plants, and, along with new farming techniques, possibly add to some crop yields. Between now and mid-century, higher temperatures in northerly latitudes will probably also expand lands available for farming, and bring longer growing seasons. However, these gains likely will be canceled by agricultural declines in the tropics, where even modest 1- to 2-degree rises are expected to evaporate rainfall and push staple crops over their survival thresholds. Existing research estimates that developing countries may lose 135 million hectares (334 million acres) of prime farm land in the next 50 years. After mid-century, continuing temperature rises5 degrees C or more by then--are expected to start adversely affecting northern crops as well, tipping the whole world into a danger zone.

The authors of the PNAS studies say that much of the previous work is oversimplified, and as a consequence, the potential for bigger, more rapid problems remains largely unexplored. The projections show a smooth curve, but a smooth curve has never happened in human history, said Tubiello. Things happen suddenly, and then you cant respond to them. For instance, extreme-weather events of all kinds, including heat waves or sudden big storms, could easily wipe out crops on vast scales if they occur for even a few days during critical germination or flowering times. Tubiello says this is already happening on smaller scales. During a heat wave in the summer of 2003, temperatures in Italy soared 6 degrees C over their long-term mean, and the corn yield in the rich Po valley dropped a record 36%. Nearly all the worlds pastures are rain-fed; in Africa, droughts in the 1980s and 1990s wiped out 20% to 60% of some nations herds. Such events on larger scales could arise with little or no warning in the near future, the authors suggest.

Higher temperatures may also prompt outbreaks of weeds and pests, and affect plant or animal physiologyfactors also left out of most projections. One of the new PNAS studies, Crop and Pasture Response to Climate Change, says that more recent modeling suggests cattle ticks and bluetongue (a viral disease of sheep and cattle) will move outward from the tropics to areas such as southern Australia. Other new models suggest that higher temperatures will limit the ability of modern dairy-cow breeds to convert feed into milk, and lead to declines in livestock fertility and longevity. As temperatures rise in northerly latitudes, the ability of crop pests to survive winters is expected to improve, enabling them to attack spring crops in regions where they were previously kept at bay during this vulnerable time.

The authors say that farmers may temporarily mitigate some effects of changing climate by moving toward adaptations now. Adaptations already being considered or set up include regional climate-forecasting systems that enable farmers to switch to different crops or change the timing of plantings; introduction of new varieties or species that can withstand anticipated conditions; and improved flood-mitigation and water-storage facilities. One of the PNAS studies, Adapting Agriculture to Climate Change, says that such adaptations might help tropical farmers cut damages wrought by rises of 1.5 to 3 degrees, and temperate-region farmers, damages from 1- to 2-degree rises. This would buy a few decades of time for nations to agree on ways to slow or reverse the warming itself. After that, all the bets are off, said Tubiello.


'/>"/>

Contact: Kevin Krajick
kkrajick@ei.columbia.edu
212-854-9729
The Earth Institute at Columbia University
Source:Eurekalert

Related biology news :

1. Climate change goes underground
2. Opportunity for students displaced by Katrina to assess climate vulnerability of Southeast US
3. Climate -- no smoking gun for Neanderthals
4. NASA celebrates a decade observing climate impacts on health of worlds oceans
5. NASA celebrates a decade observing climate impacts on health of worlds oceans
6. University and state agencies to forecast local health effects of climate change
7. A greenhouse in order to study the impact of climate change on plants
8. European lead in reading past climates from ice cores
9. International team of scientists warns of climate changes impact on global river flow
10. Heaps of climate gas
11. Nobel Peace Prize 2007 to intergovernmental panel on climate change
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:6/22/2016)... WASHINGTON , June 22, 2016 On ... highly-anticipated call to industry to share solutions for the ... by U.S. Customs and Border Protection (CBP), explains that ... nationals are departing the United States ... criminals, and to defeat imposters. Logo - ...
(Date:6/9/2016)... control systems is proud to announce the introduction of fingerprint attendance control software, allowing ... are actually signing in, and to even control the opening of doors. ... ... ... Photo - http://photos.prnewswire.com/prnh/20160609/377487 ...
(Date:6/2/2016)... , June 2, 2016   The Weather Company , ... Watson Ads, an industry-first capability in which consumers will be ... able to ask questions via voice or text and receive ... Marketers have long sought an advertising ... that can be personal, relevant and valuable; and can scale ...
Breaking Biology News(10 mins):
(Date:6/23/2016)... June, 23, 2016  The Biodesign Challenge (BDC), a ... ways to harness living systems and biotechnology, announced its ... in New York City . ... students, showcased projects at MoMA,s Celeste Bartos Theater during ... , MoMA,s senior curator of architecture and design, and ...
(Date:6/23/2016)... , June 23, 2016 Apellis Pharmaceuticals, ... 1 clinical trials of its complement C3 inhibitor, ... and multiple ascending dose studies designed to assess ... of subcutaneous injection in healthy adult volunteers. ... either as a single dose (ranging from 45 ...
(Date:6/23/2016)... , ... June 23, 2016 , ... ... quality, regulatory and technical consulting, provides a free webinar on Performing ... July 13, 2016 at 12pm CT at no charge. , Incomplete investigations are ...
(Date:6/22/2016)... June 22, 2016 Research and Markets has ... report to their offering. ... 2014 from $29.3 billion in 2013. The market is expected to ... from 2015 to 2020, increasing from $50.6 billion in 2015 to ... forecasts during the forecast period (2015 to 2020) are discussed. As ...
Breaking Biology Technology: