Over the past 15 years air temperatures at the Earth's surface have not increased. This news has caused great celebration among climate change deniers, and they use it to assure us that climate change is a grand fraud. However, average global surface temperatures have not decreased, and greenhouse gas emissions have continued to rise, which, theoretically, should have caused warming. This mismatch between rising green-house gas emissions and not-rising temperatures is a big puzzle for climate scientists.
The Economist, in the Science and Technology section of the March 30, 2013 issue, has an article on this question. It is well worth a read, no matter which side of the line you are on.
They summarise several avenues of research with possible answers to this question. There may be a lag in climate response to CO2 levels, or the rapid warming in the 1990s was anomalous, or, as an increasing body of research shows, the climate is responding to rising carbon levels in totally new ways.
This is important and alarming.
As suspected, there are numerous interactions between the global temperature and many other factors, such as clouds, aerosols (soot and other pollutants) and varying infra-red levels. Most of these affect the global temperature both positively and negatively, which makes interpretation extremely difficult. These factors have been modelled before, but now there is a lot more data, which should make for more accurate predictions.
The planet's oceans are a major component in all this. Surface temperatures and apparently those down to 700m also seem to have stalled. However, new data from Kevin Trenberth of America's National Centre for Atmospheric Research and others, indicates that 30 per cent of ocean warming in the past decade has taken place in the deep ocean (below 700m). This is unprecedented. It seems reasonable that at least some of the missing heat is going here.
Finally we come to the elephant bookends on the planet, the ice caps. According to Nasa, both are still melting at an extraordinary pace. There are many possible factors in this - most, apparently, man-made. This takes a lot of heat, and probably is not being caused by the devil with his hairdryer. This is another place for the extra heat to be going.
To summarise, it is almost certain that the Earth is still warming up by virtue of extensive deep-sea warming and numerous other factors as yet not fully understood.
This is all cutting-edge science, and, as usual, scientists are working on probabilities, not certainties. The smart money is still on climate change, with uneven and unexplained variations.
Conflicts of interest? None. I'm retired, have never worked for any climate-associated body and live 100m above sea level.