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We address the hypothetical question of whether an increasing total solar irradiance (TSI) trend, without anthropogenic contributions, could be sufficient to explain the ongoing global warming. To this end, the intermediate-complexity climate model PlaSim is used. To consider the total internal variability, we present a set of ensemble simulations, with different forcing histories in TSI and CO2 concentration, that have converged sufficiently tightly to the relevant probability distributions to provide a satisfactory bound on any spurious trend possibly arising from a sampling bias; similar bounds on any other unforced contributions to ensemble mean trends are also estimated. A key point is the consideration, among the forcing histories, the steepest increasing trend in TSI that is still consistent with observations according to a recent study; thereby, we essentially revisit corresponding TSI reconstructions, more than 20 years after their last modeling-based evaluation, by improving the analysis through taking care of all possible sources of error or uncertainty and incorporating data that have become available since then. Without any change in CO2 concentration, our TSI trend (i.e., and upper bound on actual TSI trends) is found to be insufficient to produce outcomes compatible with the observational record in global mean surface temperature (GMST) with a nonnegligible probability. We formalize our statement for quantifiers of GMST trends through evaluating their distributions over the ensemble, and we speculate that the hypothesis about the exclusive role of an increasing TSI remains implausible even beyond our particular model setup. At the same time, if we consider a constant TSI, and the observational record in CO2 concentration is applied as forcing, the simulation results and the recorded GMST match well. While we currently need to leave the question of a precise attribution open, we conclude by pointing out that an attribution of the ongoing global warming to an increasing TSI alone could be made plausible only if a bias in the set of land-based instrumental temperature measurements were increasing more rapidly than commonly estimated; an assessment of the latter possibility is out of the scope of our study, as well as addressing solar forcing mechanisms beyond the effect of TSI. [ABSTRACT FROM AUTHOR]

In Southern Africa, precipitation is a crucial variable linked to agriculture and water supply. In addition, extreme precipitation causes devastating flooding, and heavy rainfall events are a significant threat to the population in this region. We analyse here the spatial patterns of extreme precipitation and its projected changes in the future. We also investigate whether the Agulhas Current, a major regional oceanic current system, influences those events. For this purpose, we analyse simulations with the regional atmospheric model CCLM covering the last decades and the 21st century. The simulations are driven by atmospheric reanalysis and by two global simulations. The regional simulations display the strongest precipitation over Madagascar, the Mozambique channel, and the adjacent mainland. Extreme rainfall events are most intense over the mountainous regions of Madagascar and Drakensberg and the African Great Lakes. In general, extremes are stronger in the Summer Rainfall Zone than in the Winter Rainfall Zone. Extremes are projected to become more intense over the South African coast in the future. For the KwaZulu-Natal Province, the heaviest rainfall event in the future is twice as strong as the strongest extreme simulated in the historical period and the recently observed disastrous extreme event in April 2022. The impact of the Agulhas Current System on strong rainfall events over the South African coast does not clearly appear in the simulations. [ABSTRACT FROM AUTHOR]