The biggest challenge to limiting climate change to 2°C, the upper target of the 2015 Paris agreement, is this: methane emissions are rising very fast.
Methane is a greenhouse gas that, molecule for molecule, traps heat in the atmosphere more effectively than carbon dioxide, though over a much shorter timescale (decades versus centuries). Reducing emissions of methane to the atmosphere could drastically slow the rate at which Earth’s climate is warming.
