A0623
Title: Long-term climate forecasts: A future heterogenous warming
Authors: Jesus Gonzalo - Universidad Carlos III de Madrid (Spain) [presenting]
Lola Gadea - University of Zaragoza (Spain)
Abstract: Climate is a long-term issue and therefore climate forecasts should be long-run forecasts. They are crucial in order to design the mitigation policies required to fulfil one of the main objectives of the Paris Climate Agreement (PCA): to limit the long-term mean temperature increase to well below 1.5-2C above the pre-industrial period levels (1850-1900). Using a realized quantile methodology where quantiles are converted into time series objects, a simple method is proposed to produce long-term temperature density forecasts from observational data. Analyzing the observational data from global cross-section stations CRU 1880-2018 we obtain three sets of important results: (i) In 10-25 years the mean global temperature will be above the 2C degrees upper bound set by the PCA and by the end of the 21st century the increment will be of 3.5C-4C degrees above pre-industrial levels; (ii) this increase is larger in the lower quantiles (e.g. q05 will go from the 0.07C pre-industrial level to 2.07C in 25 years and to 4.06C in 100 years) than in the upper quantiles (e.g. q95 from 25.6C to 27.05C in 25 years and to 27.66C in 100 years) producing a decrease in the variance of the temperature distribution (more serious consequences than the standard increase in the mean), and (iii) there is a clear accelerating warming heterogeneous process.
