Thursday, July 3, 2014

Kudzu can release soil carbon, accelerate global warming

A press release from Clemson University: Clemson University scientists are shedding new light on how invasion by exotic plant species affects the ability of soil to store greenhouse gases. The research could have far-reaching implications for how we manage agricultural land and native ecosystems.

In a paper published in the scientific journal New Phytologist, plant ecologist Nishanth Tharayil and graduate student Mioko Tamura show that invasive plants can accelerate the greenhouse effect by releasing carbon stored in soil into the atmosphere.

Since soil stores more carbon than both the atmosphere and terrestrial vegetation combined, the repercussions for how we manage agricultural land and ecosystems to facilitate the storage of carbon could be dramatic.

In their study, Tamura and Tharayil examined the impact of encroachment of Japanese knotweed and kudzu, two of North America’s most widespread invasive plants, on the soil carbon storage in native ecosystems.

They found that kudzu invasion released carbon that was stored in native soils, while the carbon amassed in soils invaded by knotweed is more prone to oxidation and is subsequently lost to the atmosphere. The key seems to be how plant litter chemistry regulates the soil biological activity that facilitates the buildup, composition and stability of carbon-trapping organic matter in soil.

“Our findings highlight the capacity of invasive plants to effect climate change by destabilizing the carbon pool in soil and shows that invasive plants can have profound influence on our understanding to manage land in a way that mitigates carbon emissions,” Tharayil said....

Kudzu engulfing trees in Atlanta, Georgia, shot by Scott Ehardt, public domain

1 comment:

Dan Pangburn said...

Discovering that CO2 change and therefore human activity does not cause global warming is a start. But this leaves the question of what actually does drive average global temperature change.

Two primary drivers of average global temperature have been identified. They very accurately explain the reported up and down measurements since before 1900 with R2>0.9 (correlation coefficient = 0.95) and provide credible estimates back to the low temperatures of the Little Ice Age (1610).

The influence of CO2 change is insignificant.
Coefficient of determination, R2 = 0.9049 considering only sunspots and ocean cycles.
R2 = 0.9061 considering sunspots, ocean cycles and CO2 change.

The calculations use data since before 1900 which are publicly available.

The coefficients of determination are a measure of how accurately the calculated average global temperatures compare with measured.

Everything not explicitly considered (such as the 0.09 K s.d. random uncertainty in reported annual measured temperature anomalies, aerosols, CO2, other non-condensing ghg, volcanoes, ice change, etc.) must find room in the unexplained 9.51%.

The tiny difference in R2, whether considering CO2 or not, demonstrates that CO2 change has no significant effect on climate.

The method, equation and data sources are provided at and references.