We deniers frequently claim that the world's ice is increasing and hence there is no global warming. The world's ice is located around the poles, in the Arctic and Antarctic. While the ice in the Arctic is entirely sea ice, we distinguish land and sea ice in the Antarctic. Let's discuss the Antarctic first.
Antarctic land and sea ice: volume and extent
A study by Zhang (2007) finds that the Antarctic sea ice is increasing in extent (2-D) while the regional temperatures are increasing (see Fig. to the left). So, global cooling cannot be the cause. John Cook over at Skeptical Science treats this in more detail and discusses possibly mechanisms. Work by Velicogna (2009) indicates that the land ice volume (3-D) is decreasing. This is shown in the two Figs below. West Antarctica ice sheet is red and East Antarctica ice sheet is green. The recent ice loss in East Antarctica was quantified by satellite gravity measurements Chen et al. (2009). So yes, we deniers cherry pick the Antarctic sea ice, and only in 2-D, and we ignore the increasing land ice volumes, but hey...Thickness * Extent = Volume (3-D)
Arctic sea ice: volume and extent
Now let's have a look at the Arctic sea ice, where the intermediate and long term trends are rather clear. To the right are the March 2010 northern sea ice extent anomalies by the National Snow and Ice Data Center. The sea ice has been decreasing both in extent and mass inrecent decades.
Lorne Gunter, opinion writer of the National Post, our preferred global warming denial organ, recently harped on a drastic 2-year microtrend of arctic-sea-ice-extent recovery (red line by the cherry in sea ice extent anomalies diagram). Now he claims, the new ice age is coming (see here or here). This gives us a good opportunity to apply what we have learnt in previous sections:
1. A microtrend is not representative of the larger trend
2. Regional is not global
3. 2-D is not 3-D
It comes as no surprise that Lorne Gunter's upcoming ice age is not compatible with Roy Spencer's long and intermediate satellite temperature anomalies, the current absolute global record temperatures (January and March 2010 warmest on record), and the decreasing arctic ice volumes according to NASA's ICEsat. Congratulations Lorne, you will have to debate Roy Spencer or Lord Monckton, to be moderated by Douglas Leahey.
NASA's Goddard Space Flight Center visualisation of declining arctic sea ice thickness. Dear fellow deniers:
Thickness * Extent = Volume (3-D)
The Denier's Pictorial Review of 2-D vs 3-D
Pecuniae Obediunt Omnia!