The melt of the summer sea ice in the Arctic is dramatic. Each September, when the ice reaches its annual minimum, there used to be around 7.5 million sq km of ice. It is now regularly below 5 million sq km, and hit a record low of 3.6 million sq km in 2012. This downward trend is projected to continue as global temperatures increase, but somewhat erratically.
If you watched the opening ceremony of the Olympics, you would have noticed a segment discussing climate change, accompanied by graphics of CO2 emissions, Arctic sea ice melting, sea level rise and a somewhat familiar spiral representation of rising global temperatures (above), a version of which you may have seen somewhere before.
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’.
What was the last truly ‘amazing’, ‘novel’ or ‘spectacular’ science paper that you read? According to a recent bibliographic analysis the chance of encountering such ‘ground-breaking’ research has increased almost nine-fold since the 1970s.
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→
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→