I keep thinking that I should maybe take a break and write fewer posts. Then I make the mistake of having one final look at Watts Up With That (WUWT). Today they have a guest essay by Kevin Marshall called NOAA exaggerates 2012 Greenland ice-mass loss by 10x.
The post includes the figure below which is from the NOAA Arctic report card.
So, what does the WUWT post actually say? It says,
A graph on NOAA’s 2012 “Greenland Ice Sheet” report uses a 2006 modelled projected ice melt for 2012 that is over ten times that in the latest published paper and equivalent to 250% of the long-term sea-level rise of 3.2mm per annum.
I take this to mean that the author of this post is assuming that the right-hand axis of the above graph is the sea-level rise per year. The author of the post is assuming that this figure is claiming that Greenland ice sheets have contributed to an increase in sea-level in 2012 of 8mm. This is 10x greater than that suggested in other papers and 250% greater than the long-term trend of 3.2mm per year. Shall we see what the actual report says about this graph? It says.
The data show that the ice sheet continues to lose mass and has contributed +8.0 mm to globally-averaged sea level rise since 2002.
The right-hand axis is not the annual rise, it is the total change since 2002. In other words, since 2002, the Greenland ice sheet has contributed – on average – 0.8mm per year to the sea-level rise, well below the annual trend and consistent with the suggestions from other papers. Maybe this is simply a silly mistake that will be corrected in due course. I wait with bated breath. I will say, however, that often when you think a group of well-qualified, experienced scientists have made some kind of mistake, the best course of action is often to take a step back and consider if it isn’t you who has made the mistake.