SOME processes of cause and effect are relatively easy to get your head around.
For example, if I smash the end of my thumb with a hammer then the effect will be extreme sharp pain, followed by a short burst of f****** swearing and then probably one of those under-the-nail bruises that stick around for months.
An equally simple process to understand is that burning fossil fuels like oil, coal and gas releases extra carbon dioxide into the atmosphere, which causes temperatures to rise. The extra CO2 sticks around for a century or so, perhaps longer.
Now this is of course a hugely oversimplified version of the greenhouse effect. There's lots of “noise” in the climate system, but the fundamentals are there. This brings us to the Arctic. No honestly, it really does.
Earlier this week, the US Government's National Snow and Ice Data Center declared that more sea ice melted away this year than at any other time since records began in 1979.