Paper suggests warming will end up closer to double the IPCC estimates
nature.com> This paper, released two weeks ago, used new modeling techniques to examine cores taken off the coast of California. Their findings show a much higher sensitivity between CO2 concentrations in the atmosphere and temperatures. The main conclusion is that with the doubling of CO2 we have experienced since the Industrial Revolution took off, we should expect a rise of 5-7C by the end of the century, instead of the 2-3C suggested by the IPCC.
As the paper notes in its closing discussion (quoted below), it seems to support the theory that there is much more warming to come. This paper also reinforces the conclusions of Hansen et al.'s Global Warming in the Pipeline (linked below) and a growing (but admittedly controversial) body of academic literature which finds that we may indeed be heading to a "hothouse Earth" future.
When we again weigh each sensitivity by the percent-area for the Earth, our global average ECS is 7.2 °C per doubling of CO2, much higher than the most recent IPCC estimates of 2.3 to 4.5 °C and consistent with some of the latest state-of-the-art models which suggest ca. 5.2 °C
> Our reconstructed pCO2 [atmospheric CO2] values across the past 15 million years suggest Earth system sensitivity averages 13.9 °C per doubling of pCO2 and equilibrium climate sensitivity averages 7.2 °C per doubling of pCO2. Although these values are significantly higher than IPCC global warming estimations, they are consistent or higher than some recent state-of-the-art climate models and consistent with other proxy-based estimates.