Thursday, March 30, 2006

Farming vs Forestry a perspective in climate reality

The worlds climate is changing,save the forests ,save the planet,protect the forests is the perspective from the purveyors of a stoneage climate.

The perspective is that our national parks and the mature plantation forests are sequestoring carbon and are productive carbon sinks is already accepted as a nonsense,Once the forests reach maturity the sequestion of carbon turns slightly negative,and with heterotrophic respiration of various microflora it has a further negative effect on the GHG emmission budget.

The models assume that croplands and managed farming conversion have a negative balance on the carbon budget,This is not the case plant growth from various arable crops actually outperform forests by 2-6 times due to enhanced growth rates,now further benefits have been identified.

Climate scientists from the Lawrence Livermore National Laboratory found that models that included recent changes in agricultural practices, such as more irrigation, higher yielding crops, and less tillage, predicted lower temperatures than models that ignored these factors.

Nearly all models used to predict climate changes either ignore agriculture altogether or assume that farmers behave the same way through time," said David Lobell, the lead author on a paper appearing in the March 23 issue of the journal Geophysical Research Letters. "In reality, farmers are changing rapidly in response to new technologies, growth in demand and other factors. This study suggests that these changes may have important cooling effects, especially at local scales."

Human activities are widely recognized as contributing to climate change through the burning of fossil fuel and land use activities. Previous studies had considered the effects of converting natural ecosystems such as forests into croplands. Croplands generally reflect more sunlight than other land covers, and therefore tend to cool local temperatures.

"In our earlier study, we found that historical conversion of forests to croplands had cooled the planet by 0.5 degrees Fahrenheit, and locally by as much as 4 degrees Fahrenheit" said Govindasamy Bala, co-author.
Secondly, the study indicates that climate mitigation policies, which often include incentives to farmers, may be too simplistic. Most proposed climate policies focus only on the ability of farmers to sequester carbon in soils or reduce on-farm energy use.

"This study illustrates that carbon is not the only important way that agriculture affects climate, and so focusing only on carbon may lead to an under- or over-evaluation of agriculture's role," Lobell said.

For example, the study estimated that the increased albedo from reduced tillage had roughly as much of a cooling effect on global climate as the increased soil carbon sequestration.


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