Chemistry 2011.org
Chemistry2011.org
All About Chemistry... 2011 and beyond

Related Stories

Greenhouse gases unbalanced: How human intervention changes wetlands

Natural wetlands usually emit methane and sequester carbon dioxide. Anthropogenic interventions, in particular the conversion of wetlands for agriculture, result in a significant increase in CO2 emissions, which overcompensate potential decreases in methane emission. A large international research team now calculated that the conversion of arctic and boreal wetlands into agricultural land would result in an additional cumulative radiative forcing of about 0,1 mJ per square meter for the next 100 years. The conversion of temperate wetlands into agricultural land would even result in a cumulative radiative forcing of 0.15 mJ per square meter. Converting forested wetlands into managed forests also contributes to increased warming, albeit much less than the conversion of non-forested wetlands.

Wetlands are unique ecosystems, which -- under natural conditions -- are the single largest natural source of the greenhouse gas methane (CH4) but at the same time an important sink for the greenhouse gas carbon dioxide (CO2). The climate footprint of these ecosystems depends on the balance of these two important greenhouse gases. Despite methane being 28 times more potent as a greenhouse gas than carbon dioxide (in a 100 year time span), the conversion of natural wetlands into agricultural or forested ecosystems and its associated decrease in methane emissions still leads to an overall warming effect. "The human impact on wetlands, such as drainage, results in a shift of the climate footprint of that wetland" says Torsten Sachs at the GFZ German Research Centre for Geosciences, co-author of the study. "The overall balance of these two differently active greenhouse gases and thus the climate footprint of a wetland over different time spans depend on the relative sign and magnitude of these ecosystem-atmosphere fluxes."

The global impact is still rather uncertain due to large temporal and spatial variability and a lack of data on the complex interactions between environmental drivers such as temperatures of land, water, and sediment, water levels, vegetation, nutrient availability, among others, and the additional anthropogenic impacts such as land use change.

To calculate the net ecosystem carbon balance of wetland ecosystems, the more than 40 member research team synthesized data from almost 30 differently affected arctic, boreal, and temperate study sites across the globe. Simultaneous measurements of the ecosystem-atmosphere CO2 and CH4 fluxes in continental North America, Greenland, Europe, and Russia were used for analyses and modeling. For sites with a full annual dataset of CO2 and CH4 fluxes, natural and converted sites were paired in all possible combinations within similar ecosystem types. "To determine the climate impact of the conversion, we used the difference of the net ecosystem carbon balance between the site pairs as series of consecutive annual mass pulses and integrated their effect on tropospheric greenhouse gas concentrations," explains GFZ researcher Sachs. The different radiative efficiencies and atmospheric residence times of the greenhouse gases were accounted for when the radiative forcing was calculated for the period from 2000 -- 2100.

Story Source:

The above story is based on materials provided by Helmholtz Centre Potsdam - GFZ German Research Centre for Geosciences. Note: Materials may be edited for content and length.

Share this story with your friends!

Social Networking

Please recommend us on Facebook, Twitter and more:

Other social media tools

Global Partners
Feedback

Tell us what you think of Chemistry 2011 -- we welcome both positive and negative comments. Have any problems using the site? Questions?

About us

Chemistry2011 is an informational resource for students, educators and the self-taught in the field of chemistry. We offer resources such as course materials, chemistry department listings, activities, events, projects and more along with current news releases.

Events & Activities

Are you interested in listing an event or sharing an activity or idea? Perhaps you are coordinating an event and are in need of additional resources? Within our site you will find a variety of activities and projects your peers have previously submitted or which have been freely shared through creative commons licenses. Here are some highlights: Featured Idea 1, Featured Idea 2.

About you

Ready to get involved? The first step is to sign up by following the link: Join Here. Also don’t forget to fill out your profile including any professional designations.

Global Partners