Uncharted Territory

April 8, 2010

Ice Sickle

I continue to fret about the emphasis on the Arctic sea-ice extent as an indicator of global warming (GW).

I have to chop down (got to justify my blog entry title somehow!) a Guardian story, “Arctic sea ice still low despite winter recovery” (p.20 in today’s print edition), the online version titled incoherently “Arctic winter ice recovers slightly despite record year low, scientists say” and cryptically subtitled “Figures from the National Snow and Ice Data Centre [the NSIDC] indicate six or seven-year low over past three decades”. (They mean 2010 has had the 6th or 7th lowest maximum ice extent – which occurs in March – on record, i.e. of the last 32 years).

The story itself is garbled as well:

“Last night [NSIDC] released the data for the winter of 2009-10 showing the maximum extent reached on 31 March was 5.89m square miles (15.25m sq km). This was 250,000 square miles (650,000 sq km) below the 1979 to 2000 average for March…”

What the NSIDC actually said was that the average for March (15.10m km2 or 5.83m square miles – btw, wouldn’t it be simpler if we all standardised on km2?) was 250,000 square miles below the 1979-2000 March average. In fact, NSIDC’s news posting was titled “Cold snap causes late-season growth spurt” and noted that the maximum sea-ice extent occurred later than usual at the end of March, when the ice extent was only marginally below the 1979-2000 average for that date, as can be seen in the graph illustrating this BBC story about the launch of a satellite to monitor the situation.

I would have thought the real story was the recovery in the maximum Arctic sea ice extent compared to the last few years. “Arctic sea ice still low” is arguably a little misleading.

It is really not helpful to keep spinning Arctic sea ice shrinkage as an indicator of GW. There will be a vicious backlash should nature conspire to undermine the Arctic ice melt narrative. It will then become even more difficult to muster the political will to deal with GW.

The Guardian story goes on to note that:

“Last month, Japanese scientists reported in the journal Geophysical Research Letters that winds rather than climate change had been responsible for around one-third of the steep downward trend in sea ice extent in the region since 1979. The study did not question global warming is also melting ice in the Arctic, but it could raise doubts about high-profile claims that the region has passed a climate “tipping point” that could see ice loss sharply accelerate in coming years.”

Maybe this is what the researchers did actually say – I may have to go the library to check – but, as I pointed out before, it makes no sense to try to distinguish “winds” from “climate change”. Winds are not caused by some arbitrary external force, they are determined by differences in temperature, albedo (reflectivity), moisture content and so on between different areas of the planet. Winds are part of the climate system that is changing, so it is simply meaningless to separate the cause of ice melt into “winds” and “climate change”.

Solving the GW problem is difficult enough without the constant drip-feed of confusing reporting of the issue.

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2 Comments »

  1. […] under: FT, Global warming, Media, Science, Science and the media — Tim Joslin @ 5:54 pm I wrote earlier, in relation to a story in today’s Guardian, that: “Solving the GW problem is difficult […]

    Pingback by Cold FT « Uncharted Territory — April 8, 2010 @ 5:54 pm

  2. […] other posts Ice Pie and Ice Sickle explore aspects of the […]

    Pingback by On Climate, and Causes in Complex Systems « Uncharted Territory — April 27, 2010 @ 6:24 pm


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