[crandles (OP)]

I have produced the following from NOAA data. I don't really know what is the proper way to test for acceleration so I just had a go picking Dec 2000 as a nice round date to use as the break point.



It would be nice to think that the oscilations have just become bigger and longer but I fear that the above makes it a lot more likely that we are seeing less in the way of oscilations and the decline is accelerating.

Can anyone tell me the proper way to test/measure confidence interval for acceleration is such a data set?

Can an

[VAlibrarian]

I see no need to prove the idea that arctic ice melt will accelerate. It simply stands to reason based on what we know of the behavior of CO2 in the atmosphere. Human activities are steadily building the concentration of CO2, and CO2 acts to trap warmth in the atmosphere.Therefore melt is bound to accelerate. What possible reason is there to believe in any other outcome? Santa Claus will intervene by using magic to save his toy-making village?

I become impatient with critics of global warming who fail to believe in it primarily because they do not wish to believe in it. At a certain point, it becomes inappropriate to offer more proof when it is never accepted.

chris wiegard

[crandles (OP)]

Well I firmly believe not only in GW but also in AGW. However, I still want to know how to measure the confidence level appropriately.

quote:Human activities are steadily building the concentration of CO2, and CO2 acts to trap warmth in the atmosphere.Therefore melt is bound to accelerate.

True and true but likely not 'bound to'. The fundamental relationship is that the rate of warming will decrease with a steady rate of increase in CO2. It is quite possible than an exponential rise in CO2 would only lead to a steady rise in temperature. The IPCC make quite clear that the rate of warming is expected to be between .1 an .2 C per decade for the next 3 or so decades. After that it depends on our emissions in the meantime. The current rate of warming is .17C per decade and this is above the average expected.

Does a steady rate of warming necessarily mean an accelerating rate of melting? I don't think that is absolutely obvious and even if it is obvious, why can't you see it in the data from 1980 to 2000?

There are also a lot of ocean oscillations and our understanding of these is poor.

However, I do believe an acceleration is likely. This is because of the ice albedo effect where ice no longer covers the water more radiation will be absorbed by water instead of being reflected by ice. Secondly as the ice has been retreating it may well have become thinner than it used to be.

The 'we don't understand ocean oscillations' seems a valid sceptic point to me. But how far can that be taken if you can show a high level of confidence in acceleration?

(BTW surely it is more evidence not more proof - only maths deals with proofs.)

[another_someone]

quote:Originally posted by VAlibrarian
I see no need to prove the idea that arctic ice melt will accelerate. It simply stands to reason based on what we know of the behavior of CO2 in the atmosphere.

This shows the underlying problem with the whole issue about human driven climate change – people make gross assumption, and then make statements like there is 'no need to prove ...' - it then becomes a matter of faith and religion rather than science.

That you have a provisional conclusion in lieu of supporting research is perfectly reasonable, just as it is reasonable that I might have a contrary provisional conclusion – but to say there is no need to use proper scientific method to validate one hypothesis or another is very worrying.

George