* Nutrients that feed the world damage the environment
* More efficient use would offer multiple benefits
* Report calls for inter-governmental cooperation
By Nina Chestney
LONDON, Feb 18 More efficient use of nitrogen
fertilisers could cut annual consumption by 20 million tonnes,
help the environment and save $170 million a year by the end of
the decade, scientists said in a report on Monday.
Nitrogen, phosphorous and other nutrients essential for
plant growth have long been used in fertilisers to meet world
food and energy demand.
It is estimated that nitrogen and other mineral fertilisers
help to feed about half the world's population, which is set to
rise to 9 billion people by 2050 from the 7 billion today.
However, the excessive use or misuse of fertilisers can also
release harmful greenhouse gases into the atmosphere and nitrate
and phosphate compounds into water, contributing to soil erosion
and damage to ecosystems.
The global annual cost of damage from nitrogen pollution
alone is about $800 billion. But improving the efficiency of
nutrient use by 20 percent by 2020 would not only save money,
the report commissioned by the United Nations Environment
Programme (UNEP) said.
"Our analysis shows that by improving the management of the
flow of nutrients we can help protect the environment, climate
and human health, while addressing food and energy security
concerns," said Mark Sutton, lead author of the report and
professor at Britain's Centre for Ecology and Hydrology.
While many sub-Saharan African farmers struggle to access
enough nutrients to produce good-quality crops, excessive use of
nutrients by rich and rapidly developing countries is
threatening the climate and biodiversity.
Current nutrient use is not very efficient. On average, more
than 80 percent of nitrogen and 25-75 percent of phosphorous are
lost to the environment and the energy used to prepare them is
The UNEP report's co-author Oene Oenema, of Wageningen
University in the Netherlands, says that 4-12kg of both nitrogen
and phosphorous are needed to produce 1kg each of the two
nutrients in the food on a consumer's plate.
The study, carried out by nearly 50 experts in 14 countries,
calls for an inter-governmental framework to tackle inefficient
Lead author Sutton said that the motivation to take action
would be much stronger if governments joined forces to meet the
multiple global challenges for food, climate, health and energy,
water and air pollution.
One option could be to include rules on nutrient use in the
1995 UNEP agreement to prevent the degradation of marine
environments from land-based activities.
Improvements should be made to the management of soil,
crops, livestock and manure, the report said. Nutrient loss from
industry and waste water treatment could also be reduced and the
rate of nutrient recycling increased.
The study also said that individuals and governments should
consider ways of lowering the amount of meat and dairy eaten
where there are high rates of consumption and waste.
"With rapidly increasing meat and dairy consumption, as Asia
and Latin America aspire to European and North American norms,
our diet choices have a huge potential to influence future
levels of global nutrient pollution," it said.
(Editing by David Goodman)