World may get a little greener but then will wilt due to warming
Pastor Dale Morgan
Thursday March 15, 6:53 PM Reuters
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World may get a little greener but then will wilt due to warming*
By Alister Doyle, Environment Correspondent
OSLO (Reuters) - Global warming is expected to turn the planet a bit
greener by spurring plant growth but crops and forests may wilt beyond
mid-century if temperatures keep rising, according to a draft U.N. report.
Scientists have long disputed about how far higher temperatures might
help or hamper plants -- and farmers -- overall. Plants absorb carbon
dioxide, the main greenhouse gas, as they grow and release it when they rot.
"Global agricultural production potential is likely to increase with
increases in global average temperature up to about 3 Celsius, but above
this it is very likely to decrease," the draft said.
Plants in tropical and dry regions from Africa to Asia are set to suffer
from even a small rise in temperatures, threatening more hunger linked
to other threats such as desertification, drought and floods.
But some plants in temperate regions, such as parts of Europe or North
and South America, could grow more in a slightly warmer world, according
to the draft.
A 79-page technical summary, a copy of which was obtained by Reuters,
will be released in Brussels on April 6 after a final review as part of
a report based on the work of 2,500 scientists to guide governments in
combating warming.
The first part of the report, by the Intergovernmental Panel on Climate
Change (IPCC), projected as a "best estimate" that temperatures, stoked
by human emissions led by burning fossil fuels, would rise 1.8-4.0
Celsius this century.
SOAK UP CARBON
Plants now absorb more carbon than they release, "but this is likely to
peak before mid-century and then tend towards a net carbon source before
2100" without accounting for other effects such as deforestation, it said.
"In temperate regions, moderate warming benefits cereal crops and
pasture yields, but even slight warming decreases yields in seasonally
dry and tropical regions," it said.
"Further warming has increasingly negative impacts in all regions," it
said. In South America, for instance, rice yields are expected to fall
by the 2020s while soybean yields could rise in temperate zones.
The report warns warming could worsen water and food shortages in some
regions, especially in developing nations least able to cope. And rising
sea levels could threaten coasts.
There are also risks that projected changes in extreme climate events
could have "significant consequences on food and forestry production,
and food insecurity," it said.
"Growth will probably increase a little bit," said Anders Portin, senior
vice president of the Finnish Forestry Industry Federation. But he said
climate change was harmful overall.
He said southerly insect pests could invade Nordic pine forests, recent
storms in Sweden have been the most destructive on record and heavy
trucks are often unable to travel in winter on normally frozen forest
tracks because the ground is boggy.