Fast forward through last week’s methane news:

1. Wetland methane is probably bigger GHG source than previously thought
2. That one big BP methane burp never made it to the surface

We thank the second bit of methane news to the weight of deep ocean water and the unexpected appetite of local microbes (it’s mostly CO2 now – and that’s relatively good news).

Although ‘more methane’ is in itself a clear message, we have more difficulty quantifying the news on the world’s wetlands.

If you would for the moment ignore large-scale disturbances like deforestation it’s easy to theorize net carbon uptake of the terrestrial biosphere would be close to zero, as biomass growth and degradation go hand in hand – same for methane formation and breakdown. We do however live on a planet that is quickly loosing equilibria so now we have to count all the different parts of the equation. That’s when Swedish scientists of Linköping University [nothing about methane on the website last time we checked] discovered (measuring at 474 freshwater locations worldwide) the combined methane emissions of all wetlands (including ponds, rivers and big marshes) would be higher than previously estimated – ‘equivalent to 25 percent of forest CO2 uptake,’ citing media sources like Reuters.

That’s a very vague way of not mentioning the actual megatonnes – as we are still unaware to what extent forests are [if at all?] net CO2 sinks. The researchers have their publication upcoming in Science, so we hope to learn more in a week’s time.

© Rolf Schuttenhelm | www.bitsofscience.org