* Rising yields, slowing population means farmland peaks
* Food crop area could shrink by 10 pct in half a century
* Cropland 2.5 times France can return to nature by 2060
By Alister Doyle, Environment Correspondent
OSLO, Dec 17 The amount of land needed to grow
crops worldwide is at a peak and an area more than twice the
size of France can return to nature by 2060 due to rising yields
and slower population growth, a group of experts said on Monday.
The report, conflicting with U.N. studies that say more
cropland will be needed in coming decades to avert hunger and
price spikes as the world population rises beyond 7 billion,
said humanity had reached what it called "Peak Farmland".
More crops for use as biofuels and a shift towards more meat
consumption in emerging economies such as China or India -
demanding more cropland to feed livestock - would not offset a
fall from the peak driven by improved yields, it calculated.
If correct, the land freed up from crop farming would be
some 10 percent of what is currently in use - equivalent to 2.5
times the total area of France, Europe's biggest country bar
Russia, or more than all the arable land now farmed in China.
"We believe that humanity has reached Peak Farmland, and
that a large net global restoration of land to nature is ready
to begin," said Jesse Ausubel, director of the Program for the
Human Environment at the Rockefeller University in New York.
"Happily, the cause is not exhaustion of arable land, as
many had feared, but rather moderation of population and tastes
and ingenuity of farmers," he wrote in a speech about the study
he led in the journal Population and Development Review.
The report, supplied to Reuters by Ausubel, projected that
almost 150 million hectares (370 million acres) could be
restored to natural conditions such as forest by 2060. That is
also equivalent to 1.5 times the area of Egypt or 10 times Iowa.
It said the global arable land and permanent crop areas rose
from 1.37 billion hectares (3.38 billion acres) in 1961 to 1.53
billion (3.78 billion acres) in 2009. It projected a fall to
1.38 billion hectares (3.41 billion acres) in 2060.
A June 2012 report by the U.N.'s Food and Agricultural
Organization (FAO), however, said that a extra net 70 million
hectares of land worldwide would have to be cultivated in 2050
compared to now: "Land and water resources are now much more
stressed than in the past and are becoming scarcer," it said,
referring to factors such as soil degradation and salinisation.
Ausubel's study admits to making many assumptions - rising
crop yields, slowing population growth, a relatively slow rise
in the use of crops to produce biofuels, moderate rises in meat
consumption - that could all skew the outcome if wrong.
It also does not factor in major disruptions from climate
change that U.N. studies say could disrupt farm output with
rising temperatures, less predictable rains, more floods,
droughts, desertification and heatwaves.
Still, it points out that both China and India have already
spared vast tracts of land in recent decades.
In India, for instance, wheat farmers would now be using an
extra 65 million hectares - an area the size of France - if
yields had stagnated at 1961 levels. China had similarly spared
120 million hectares by the same benchmark.
The authors said that the idea of "Peak Farmland" was
borrowed from the phrase "Peak Oil", the possibility that world
use of petroleum is at its maximum.
The study also projected that world corn yields would rise
at a rate of 1.7 percent a year until 2060, against a 1.8
percent annual gain from 1983-2011. That would raise world corn
yields by 2060 to roughly the current U.S. average, it said.
It said that biofuels were a wild card in calculations. The
study concluded that non-food crop production - for instance not
just sugar or corn used as fuel but also the likes of cotton and
tobacco - was likely to exceed growth in food supply until 2060.
Growth of all crops would outstrip food supply by 0.4
percent a year until 2060, up from 0.24 percent a year from
1961-2010, it projected. That indicated a continued, but not
spectacular, rise for biofuels.
Changing diets were also a big uncertainty as the world
population headed towards about 10 billion and grappled with
simultaneous problems of obesity and malnourishment. But there
were some encouraging signs, the report found.
Meat consumption in China was only rising moderately, far
below rates of economic growth. "Fortunately for the sparing of
cropland," it said of world trends, "Meat consumption is rising
only half as fast as affluence."