Examining the recent "Pause" in global warming

Global surface temperatures have warmed more slowly over the past decade than previously expected. The media has seized this warming pause in recent weeks, and the UK's Met Office released a three-part series of white papers looking at the causes and implications. While there is still no definitive cause identified, some researchers point to a combination of more heat going into the deep oceans and downturns in multi-decadal cycles in global temperature as the primary drivers of the pause. Others argue that a plethora of recent small volcanoes, changes in stratospheric water vapor, and a downturn in solar energy reaching the earth may also be contributing to the plateau. While few expect the pause to persist much longer, it has raised some questions about the growing divergence between observed temperatures and those predicted by climate models."

"Vær opmærksom på , at man tidligere har set perioder, hvor temperaturen er vokset lidt mindre end forventet, men hvor man efterfølgende at set en tilvækst."

Conclusions
The 'hiatus' in the global mean temperature rise of the earth over the last 10 years is not a very sensible way to study global warming. Trends over such a short period are influenced heavily by (winter) weather over North America and Siberia, and by El Niño and La Niña. Over land the trend has not gone down to zero and 10-year trends are compatible with the long-term trend within the large uncertainty margins. Over sea there is also strong persistence from year to year, making the probability to obtain 10-year trends that are very different from the long-term trend very large. The best measure of whether global warming continues is the ocean heat content below the surface. This measure shows a very consistent rise, which is also expressed in sea level rise.

On top of the rising trend of the land temperature, much of Europe had warm weather for large periods this year. These two factors together, the long-term trend and a short positive fluctuation, caused the record-high temperatures that are expected this year.

With thanks to Andreas Sterl and Robert Mureau for very useful comments.

The best measure of whether global warming continues is the ocean heat content below the surface. This measure shows a very consistent rise, which is also expressed in sea level rise.

N A Nielsen skrev:

Havniveaustigningen er i øvrigt decellereret i det seneste tiår, indikerende et lavere varmeoptag i perioden.

Synes du ikke det er mere korrekt at benytte en accelererende langtidstrend til en prediktiv prognose, fremfor at drage konklusioner på korttidsdata?

It is found that the GMSL rises with the rate of 3.2 ± 0.4 mm/yr during 1993–2003 and started decelerating since 2004 to a rate of 1.8 ± 0.9 mm/yr in 2012. This deceleration is mainly due to the slowdown of ocean thermal expansion in the Pacific during the last decade, as a part of the Pacific decadal-scale variability

Periods of sea level rise acceleration are detected at different times throughout the last 200 years and are to some extent related to air pressure variations. The recent rates of sea level rise (i.e. over the last two to three decades) are high compared to the long-term average, but are comparable to those which have been observed at other times in the late 19th and 20th century.