Wetlands play an ambivalent role in climate protection. On the one hand, they are of outstanding ecological importance as a habitat for numerous animals, as groundwater filters, flood protection and important carbon sinks. They can thus contribute to reducing the greenhouse effect. On the other hand, however, wetlands emit the highly climate-affecting gas methane-(CH4), which is produced, among other things, when microorganisms metabolize organic material in the absence of oxygen. This effect intensifies with rising temperatures. A vicious circle. In the journal Nature Climate Change, an international team now reports that methane emissions from wetlands have risen sharply over the period of . This highlights the need for continuous monitoring of global CH4 flows from wetlands to document new trends, fluctuations and underlying factors.
Methane heats the atmosphere over a period of 20 84 times more than carbon dioxide (CO2).Due to the relatively short lifetime of the greenhouse gas of only about 10 For years, reducing methane emissions from anthropogenic sources such as livestock, natural gas extraction and landfills is an important lever for limiting global warming to well below 1.5 or 2 Degree. The rapid increase in atmospheric methane concentrations in recent decades, as well as record-breaking growth rates in recent years; However, according to the team led by Zhen Zhang of the Chinese Academy of Sciences, there is cause for concern that climate change is increasing CH4 emissions from natural sources such as bogs and swamps.
For their simulation, the researchers used a wetland methane model that was developed to represent tropical and permafrost wetlands. It is based on two data sets – on the one hand, data from meteorological ground stations are evaluated and on the other hand, the scientists used a reanalysis based on satellite observations and atmospheric flow models.The climate projections suggested that emissions from wetlands worldwide by 2050 will increase by 30 to 50 million tonnes of CH4 per year compared to 2010 levels, they write.
The feedback between methane emissions from wetlands and global warming is mainly attributed to two causes: the effects of rising temperatures on microbial activities and thawing of permafrost soils, and the Expansion of wetlands in the tropics due to increased total precipitation. Recent observational studies suggest that the tropical water cycle has already intensified. Whether rising temperatures or increased precipitation play the more important role in the increase in CH4 from wetlands, however, is still unclear. Nevertheless, it must now be a high priority to take into account rapidly changing biospherical processes when calculating the remaining carbon budgets.
Source — https://www.spektrum.de/news/feuchtgebiete-setzen-verstaerkt-methan-frei/2122824