Reacción a "Climate change is increasing sudden temperature changes"

It is an interesting study, methodologically correct and well developed by a group of researchers who in some cases have worked extensively in the field of global climate dynamics and simulation. The techniques are consistent and the data used adequate, with clear and robust results and which constitute a notable advance, since this approach to abrupt changes is novel. 

More than changes in mean temperature and variable trends, the most relevant information because of its immediacy and potential effect in terms of impacts on ecosystems and human health are those changes that are related to the behavior of climatic extremes, i.e., phases of droughts, floods, heat waves or cold drops, for example.  

This study clearly shows with high resolution observational data how, both globally and regionally, more than 60% of all regions studied have experienced clear and drastic changes in terms of increased frequency in the transition of these weather extremes within a few days. That is, cold phases transition from warm days more often and with greater intensity, and with less time between extremes. This fact can have clear and more pronounced effects on the survival of ecosystems, for example (think, for example, of the successive droughts in regions of Brazil in recent years, which caused greater tree mortality than much more intense individual events). It seems clear that vegetation, for example, is less adapted to withstand repeated dry or wet events than a single more intense one, because vegetation has less time to recover. 

Similarly, negative effects on human health are expected, although the study makes only rough inferences about this, but clearly this is an area that will deserve more attention in the future. 

The limitations of the study basically relate to simulations of extremes in future scenarios, for which climate models are not as well prepared as they are to simulate the average behavior of the climate. In this sense, using CMIP6 simulations to infer daily changes on decadal scales seems to me to entail considerable uncertainties that perhaps should have been highlighted in this study. Direct effects on human health are also not studied with the detail and approximation that would be required, although I understand that they are left for later studies.  

In summary, an interesting study that provides clear information on an apparent discrepancy with respect to the effects of global warming, since this increase in frequency may be accompanied by a greater impact not only in warm phases (to be expected), but also associated with cold extremes, which is new.