Category Archives: observations

Slowdown discussion

The temporary slowdown in global temperatures in the early-2000s is still prompting significant scientific discussion. A recent Commentary on the topic by Fyfe et al. was summarised in an earlier post. In response, a recent post by Rahmstorf et al. reiterates some of the statistical arguments that we discussed briefly in our Commentary1, but misses the main point. Continue reading Slowdown discussion

Observing long-term climatic changes with unusual sources

We are all familiar with the usual metrics used to highlight that the climate is changing: surface air temperatures, sea level, sea surface temperatures and ocean heat content all rising, glaciers retreating, Arctic sea ice declining etc. But, there are also many other less well known sources of information about how our climate is changing, and many involve ‘citizen scientists’, who often didn’t realise the potential long-term benefits of the data they were collecting. Continue reading Observing long-term climatic changes with unusual sources

What have global temperatures ever done for us?

Much attention is rightly given to changes in global mean surface temperature – it is the key metric for assessing how our climate is changing and evaluating mitigation strategies. However, no-one directly experiences changes in global mean temperature – it is only through local variations that changes in climate are felt.

So, what have global temperatures ever done for us? Continue reading What have global temperatures ever done for us?

Was there ever a 'pause'?

The importance of the ‘pause’ in global temperatures has never been about whether some particular trend is just below or just above zero, or about whether a specific period shows a statistically significant trend (whatever that actually means), or even about whether the trend has changed. The ‘pause’ has always been about understanding whether Earth’s climate is evolving in line with our expectations. Continue reading Was there ever a 'pause'?

An apples to apples comparison of global temperatures

When comparing global temperatures estimated from observations with climate model simulations it is necessary to compare ‘apples with apples’. Previous posts have discussed the issues of incomplete observational data, but a new paper by Cowtan et al. quantifies the influence of different observational data types. Continue reading An apples to apples comparison of global temperatures