By Steven Goddard
No matter what happens with the summer Arctic ice minimum, NSIDC will report that the long-term trend is downwards.
Why? Because of mathematics. In order to reverse the 30 year downwards linear trend, this summer’s minimum would have to be nearly 20,000,000 km². More ice than has ever been directly measured.
In other words, we could have a “Day After Tomorrow” scenario, and the mathematical trend would still be downwards.
Conclusion: You can count on NSIDC to continue reporting a downwards trend, regardless of what happens over the next few years. For now, it will be fun seeing what happens over the next eight weeks.
No matter what the long term trend of Arctic ice shows, denialists will say it’s recovering.
Enonym says:
June 25, 2010 at 6:09 am
Ian W:
Correct me if I’m wrong (the figure doesn’t have a label on the y-axis), but to the best of my knowledge one doesn’t need a baseline to make a linear regression. If you were to calculate anomalies, that would change things. So what do you really mean by your statement?
Ahh homonyms and synonyms.
What I meant was taking a short period and then claiming a trend – means that you have chosen a period as the ‘average’ or ‘normal’ from which the trend is running.
So imagine a graph that _started_ just after the *beginning* of the last Glacial period and ran to now. What is the overall trend in Arctic ice? Oh – its UP isn’t it. It may even be that the overall trend from the start of the Holocene to now is up also. But choose a suitable high point and it is down. As you get closer to the noise being displayed then the movements about the mean for the Holocene may be stochastic, they may move as in a Levy Flight, with a certain inertia to the changes. Drawing a ‘trend’ line through such noisy stochastic data is meaningless.
Math’s a bitch, aint it? Reality has a decidedly liberal bias.