: The amount of methane in Earth’s atmosphere shot up in 2007. This brings to an end a decade in which levels of the potent greenhouse gas were relatively stable says a report in the journal Geophysical Review Letters. Methane levels in the atmosphere have more than tripled since pre-industrial times. Though much less methane is generated than carbon dioxide, it is more effective at trapping heat from the Sun, meaning that it accounts for around 20 per cent of the human contribution to …