Wait a minute: If a glacier melts this year, how do we know that the cause is CO2 emitted this year? Why isn't it a delayed response to natural warming that occurred decades or centuries ago?

BBC News - World's glaciers 'out of balance'

Earth's glaciers are seriously out of balance with the global climate and are already on their way to losing almost 40% of their volume.

That is the assessment of scientists after studying a representative group of 144 small and large glaciers around the world.

Their figure assumes no further warming of the climate.