Three climate scientists examine recent slowdown (or ‘pause’) and online science communication

The recent slowdown (or ‘pause’) in global surface temperature rise is a hot topic for climate scientists and the wider public. We discuss how climate scientists have tried to communicate the pause and suggest that ‘many-to-many’ communication offers a key opportunity to directly engage with the public.

I recommend “Pause for thought” in Nature Climate Change. This very short essay by Ed Hawkins, Tamsin Edwards and Doug McNeall is ungated, after free registration. You can get a preview of the technical overview by studying the two following charts carefully. You’ll need to pay attention to the chart key underneath – there is a lot of information compressed into the two panels.

 

Observed global mean surface air temperatures (HadCRUT433, solid black line) and recent 1998–2012 trend (dashed black line), compared with ten simulations of the CSIRO Mk3.6 global climate model, which all use the RCP6.0 forcing pathway (grey lines). The grey shading represents the 16–84% ensemble spread (quantiles smoothed with a 7-year running mean for clarity); the ensemble mean trend is around 0.20 °C per decade. Two different realizations are highlighted (blue), and linear trends for specific interesting periods are shown (red, green, purple lines). a, The highlighted realization shows a strong warming in the 1998–2012 period, but a 15-year period of no warming around the 2030s. b, The highlighted realization is more similar to the observations for 1998–2012, but undergoes a more rapid warming around the 2020s. Note also that this realization appears outside the ensemble spread for 9 out of 10 consecutive years from 2003–2012.

The charts and discussion illustrate a central truth of climate science – the results are often only understood in a framework of statistics. The pretty, clean projected temperature curves that we see in the media are heavily smoothed over many runs of multiple models. That presentation conceals the natural variability that is part of the challenge of understanding, then testing hypotheses against observations. It is similar to the agonizing process at the Large Hadron Collidor (LHC) as the teams tried to develop enough data to tease out a sufficiently confident identification of an anomaly corresponding to the Higgs.

If you have a specific question about the authors’ presentation, you can ask the scientists directly on twitter. It is uncommon for authors to reveal their twitter handles in a paper, so please don’t make them regret the open door!

I recommend two other articles in this Nature Climate Change series:

1. Heat hide and seek [PDF] Natural variability can explain fluctuations in surface temperatures but can it account for the current slowdown in warming? The authors offer an excellent summary of the more promising current research, including particularly the variability in heat distribution such as

  • El Niño/Southern Oscillation
  • Pacific Decadal Oscillation
  • Atlantic Multi-decadal Oscillation

2. Media discourse on the climate slowdown where I learned among other things that the biggest recent media spike seems to be in Oceania – where we are presently (cruising). Australia has been suffering from a severe drought – that no doubt generates increased interest in climate.

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