A study by Brazilian and American scientists just published in the Geophysical Research Letters magazine shows that the Amazon Forest is releasing way too much methane, a gas that is considered the second worst agent responsible for global warming.
Methane is believed to be responsible for almost as much global warming as all other non-CO² gases put together. Scientists call methane 20 times more harmful than carbon dioxide. The Amazon alone contributes with about 23% of the planet's annual world emissions of the gas.
Typically, methane is formed in and released from places that have little oxygen like swamps. During the flood season 20% of the Amazon forest is inundated and it would be natural to expect that the gases would be high at that time. Scientists, however, have found out that methane emissions are higher than expected not only during the rainy season but also during the dry one.
The study was done between 2000 and 2006. The Brazilian researchers from Ipen (Energy and Nuclear Research Institute), who coordinated the work, and their American colleagues from NOAA (National Weather Service) collected air samples from several altitudes starting at 150 meters (500 feet) and going up to 4 km (2.5 miles) using small planes. This study is known as LBA, its acronym in English (Large-Scale Biosphere – Atmosphere Experiment in Amazonia.
The Brazilian data were compared to measurements obtained in other global stations located across the globe. The study revealed that while the whole world releases 155 parts per billion (ppb) of methane into the atmosphere a year, the Amazon forest alone gives out 35 ppb of the product.
"We need to discover where all this methane is coming from," Ipen's researcher Luciana Vani Gatti, who was involved in the study, told the website G1."It might be coming from other sources, that we still ignore or the sources that we know emit more gas than we imagined. This is worrisome and we need to investigate more," said the Brazilian scientist.
A second phase of the study with new data should be released later. Researchers are still computing and writing about how important is the Amazon in regards to the release of carbon dioxide in the atmosphere.
Gatti anticipates, however, that the levels of CO² are higher than expected and are present the whole year around. "We are used to think that we only need to worry about the fires to prevent carbon emission in the forest, but this is not true. We have high rates of emission even during the time there are no fires."
For Gatti, the study shows that the world needs to pay more attention to all sources of gases that are causing global warming. "We cannot limit our thinking to CO². We need a global reorganization on how to live our lives if we want to fight the climatic change," she concludes.
