Climate sensitivity characterises the response of the climate to changes in radiative forcing and can be measured in many different ways. However, estimates derived from observations of historical global temperatures have tended to be lower than those suggested by state-of-the-art climate simulators. Are the models too sensitive?
A new study largely explains the difference – it is because the comparison has not been done ‘like-with-like’.
The implications for understanding historical global temperature change are also significant. It is suggested that changes in global air temperature are actually ~24% larger than measured by the HadCRUT4 global temperature dataset. Continue reading Reconciling estimates of climate sensitivity
An update to the NOAA global temperature estimates has generated a lot of media excitement, based on a paper by Karl et al. in Science. How do the new estimates compare with other global temperature timeseries? Continue reading Global temperature comparisons
“In the last few years the warming trend of the earth has stopped” is a common type of remark these days. Is that indeed the case, and can we conclude that the projections for the rest of the century are being overestimated? And if so, how come that large parts of Europe are expected to have the warmest year recorded in 2014? There is a chance that the global mean temperature will also be the highest in the series.
Guest post by Geert Jan van Oldenborgh, KNMI Continue reading Hiatuses in the rise of temperature
The Earth is a complex system of interacting components, such as the atmosphere and ocean, which produce a wide variety of natural variability. This natural variability ensures that the evolution of a particular region’s climate, e.g. that of Western Europe, could be completely different to another region, or indeed the global mean climate. Such variability can impact on many areas of society; for example winter energy usage, or agriculture in sensitive regions. Continue reading Predicting changes in North Atlantic temperatures
A rather surprising question perhaps, but the answer is, ‘it depends’. There is no climatic reason to define a year from January to December, but that is what is generally done. But, is this the best definition? Continue reading What is a year?
After attending a recent workshop on Arctic predictability, I thought a brief discussion on sea-ice variability and potential predictability might be of interest. Continue reading Arctic predictability
Observations of Atlantic SSTs show significant multi-decadal variability since 1870 (see red line in figure 2 below), often termed the Atlantic Multi-Decadal Oscillation (AMO), though there is no clear evidence that it is really an ‘oscillation’. Continue reading Atlantic multi-decadal variability