Arctic Sea Ice Extent is an interesting climate variable because it is relatively simple to measure.
Each year sea-ice retreats in the Arctic summer, reaching a minimum in the middle of September, and then grows back through the Arctic winter.
The data for September sea-ice extent are plotted in the graph at the head of the page. They clearly show a ‘melting’ trend: currently there are around 2.5 million square kilometres less sea ice in September than in the 1980s and 1990s.
Last year (2012) September sea-Ice extent reached a new minimum of 3.63 million square kilometres. This can be understood as partly resulting from the melting trend, and partly from year-to variability of around ±0.5 million square kilometres.
This year (2013) September sea ice extent ‘recovered’ to 5.35 million square kilometres, so 1.72 million square kilometres of sea ice was frozen this September that was unfrozen last September.
Looking at the data above, could anyone seriously conclude that this ‘recovery’ was evidence that the melting trend had halted and that we were embarked on a new phase of Global Cooling? Only an idiot would think so.
Well the Daily Mail thinks this so, and covers this story with the headline:
And now it’s global COOLING! Return of Arctic ice cap as it grows by 29% in a year
The article is pernicious: lacking in any understanding of the science, and full of attacks on the BBC and IPCC. It mocks any rational concern over Climate Change. Presumably the author is aware of how stupid the article makes him appear, but he just doesn’t seem to care.
I have written this article, but frankly, I am now lost for words and actually reduced to tears. I think this is actually the worst and most depressing piece of journalism I have ever read.
The data I have plotted comes from the Data Archives of the Arctic Sea Ice Section of the National Snow and Ice Data Centre in the USA. If you intend to re-plot some of these graphs then you need to be careful with the data – it comes in many forms and some files and folders are extremely large. But understanding the formats will help you to understand how the data is acquired and recorded.