Resplandy et al. correction and response

Guest commentary from Ralph Keeling (UCSD) I, with the other co-authors of Resplandy et al (2018), want to address two problems that came to our attention since publication of our paper in Nature last week. These problems do not invalidate the methodology or the new insights into ocean biogeochemistry on which it is based, but they do influence the mean rate of warming we infer, and more importantly, the uncertainties of that calculation. We would like to thank Nicholas Lewis for first bringing an apparent anomaly in the trend calculation to our attention. We quickly realized that our calculations incorrectly

O Say Can You CO2…

Guest Commentary by Scott Denning The Orbiting Carbon Observatory (OCO-2) was launched in 2014 to make fine-scale measurements of the total column concentration of CO2 in the atmosphere. As luck would have it, the initial couple of years of data from OCO-2 documented a period with the fastest rate of CO2 increase ever measured, more than 3 ppm per year (Jacobson et al, 2016;Wang

1.5ºC: Geophysically impossible or not?

Guest commentary by Ben Sanderson Millar et al’s recent paper in Nature Geoscience has provoked a lot of lively discussion, with the authors of the original paper releasing a statement to clarify that there paper did not suggest that “action to reduce greenhouse gas emissions is no longer urgent“, rather that 1.5ºC (above the pre-industrial) is not “geophysically impossible”. The range of post-2014 allowable emissions for a 66% chance of not passing 1.5ºC in Millar et al of 200-240GtC implies that the planet would exceed the threshold