But this flat period has now gone on for about the same time as the 1980 – 1996 warming.” The models exhibit large variations in the rate of warming from year to year and over a decade, owing to climate variations such as ENSO, the Atlantic Multi-Decadal Oscillation and Pacific Decadal Oscillation. It is not uncommon in the simulations for these periods to last up to 15 years, but longer periods are unlikely.
Q.3 “Finally, do these data suggest that factors other than CO2 – such as multi-decadal oceanic cycles – may exert a greater influence on climate than previously realised?
Q.1 “First, please confirm that they do indeed reveal no warming trend since 1997.” The linear trend from August 1997 (in the middle of an exceptionally strong El Nino) to August 2012 (coming at the tail end of a double-dip La Nina) is about 0.03°C/decade, amounting to a temperature increase of 0.05°C over that period, but equally we could calculate the linear trend from 1999, during the subsequent La Nina, and show a more substantial warming.
As we’ve stressed before, choosing a starting or end point on short-term scales can be very misleading.
We announced that this work was going on in March and it was finished this week. Secondly, Mr Rose says the Met Office made no comment about its decadal climate predictions.
In addition, we also know that changes in the surface temperature occur not just due to internal variability, but are also influenced by “external forcings”, such as changes in solar activity, volcanic eruptions or aerosol emissions.To address some of the points in the article published today: Firstly, the Met Office has not issued a report on this issue.We can only assume the article is referring to the completion of work to update the Had CRUT4 global temperature dataset compiled by ourselves and the University of East Anglia’s Climate Research Unit.Climate change can only be detected from multi-decadal timescales due to the inherent variability in the climate system.If you use a longer period from Had CRUT4 the trend looks very different.· The reality is the Met Sine Thesis helmet does allow the air to flow nicely which ...My only concern with the Met Sine Thesis is the silicone gel pads on ...Eight of the top ten warmest years have occurred in the last decade.Over the last 140 years global surface temperatures have risen by about 0.8ºC.Q.2 “Second, tell me what this says about the models used by the IPCC and others which have predicted a rise of 0.2 degrees celsius per decade for the 21st century.I accept that there will always be periods when a rising gradient may be interrupted.