Nature's Journal Club

Rusty Feagin

Texas A&M University, College Station, Texas

A coastal ecologist sees the hidden effects of hurricanes.

As part of my job, I often drive around looking at the impacts of hurricanes in coastal areas. The one thing that stands out from such trips is that the devastation always looks the same, regardless of where I am — the boats perched on the streets, the newly house-less stilts near the beach, the furniture on a lawn covered in mould.

I realized though, after reading a recent article by Hongcheng Zeng of Tulane University in New Orleans, Louisiana and his colleagues (H. Zeng et al. Proc. Natl Acad. Sci. USA 106, 7888–7892; 2009), that I need to be concerned with the damage that I cannot see — the bleeding of carbon from the landscape, and the loss of future carbon stores.

Using field, satellite and modelled data, Zeng and his colleagues detail how damaging winds over the past 150 years have greatly reduced forest biomass through tree mortality, subsequent wood decay and carbon release. They estimate that between 1980 and 1990, 9–18% of the amount of carbon stored yearly by US forests was lost due to destruction caused by tropical cyclones. The carbon dioxide loss is cumulative because once a tree is lost, it cannot sequester CO2 in the future. Thus, an extreme event such as Hurricane Katrina in 2005 or the Indian Ocean tsunami in 2004 could radically reduce carbon sequestration in the areas affected for several decades.

These findings force me to consider more than just the visible effects of hurricanes; I realize that tree loss is in effect altering the global carbon cycle. This paper also makes me wonder about the cumulative impact of cyclones on CO2 in other ecosystems, such as grasslands that have been damaged by salt-water inundation, or even possible forest growth due to storm-induced rainfall inland.

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