Is this an example of "natural variation"?

Question

http://earthobservatory.nasa.gov/Newsroom/NewImages/images.php3?img_id=17800

Answer 1

No.  That particular data is an example of receding sea ice.  One would have to look at longer term trends in sea ice minimums in relation to human activity and other phenomena to determine whether it is the result of natural variation or can be linked to human activity.

If you do this, you'll find that there are strong linked between human activity and the factors determining sea ice extent.

To be fair, even if such a relationship existed, it would only indicate a “correlation,” not causation, which is impossible to determine by simple statistical observation.  To suggest causation (and in the end that’s all we can do), one would need to have an overwhelming data from various sources and on various factors to suggest a causal relationship between human activity and global warming, rather than simple natural variation.

As it happens, we do have that overwhelming amount of data and are therefore able, to the extent allowed by prudent science, to suggest a strong causal relationship between human activity and changes in global climate as manifested in sea ice minimums.

Answer 2

Theoretically it could be.  Millions of years in the past when atmospheric CO2 levels were very high and the planet was even warmer than today, I'm sure there was even less sea ice than there is now.

Of course, that's because CO2 levels were naturally high.  Unless you count humans burning fossil fuels as 'natural', the current warming cannot be explained by natural causes, which makes the rapid melting of sea ice unnatural.

So the short answer to your question is 'no.'

Answer 3

Its an example of something very depressing.....