These posts include a brief mention of a number of news items relating to climate change. They don’t preclude treating any of these topics at more length in a separate post.
They can also serve as an open thread so that we can keep each other informed on important climate news.
Hansen and Sato say that limiting human-made warming to 2°C and CO2 to 450 ppm is a prescription for disaster
They say we could be looking at sea level rise of up to 5 metres by 2100.
Perhaps the most striking characteristic of Pliocene climate reconstructions is that low latitude ocean temperatures were very similar to temperatures today. High latitudes were much warmer than today, the ice sheets smaller, and sea level about 25 m higher (Dowsett et al., 2009 and references therein). Atmospheric CO2 amount in the Pliocene is poorly known, but a typical assumption, based on a variety of imprecise proxies, is 380 ppm (Raymo et al., 1996).
We conclude that Pliocene temperatures probably were no more than 1-2°C warmer on global average than peak Holocene temperature.
But it was considerably warmer at the poles, with consequent loss of ice sheets bulk. The effect is sometimes known as polar amplification. This involves a strong albedo feedback which could produce a doubling of ice loss every 10 years. The cumulative effect is shown in this graph: Continue reading Climate clippings 13