Trump is most certainly a threat to mankind. We don't know the extent of it. The greatest challenge to ever face us is climate change, the end result of which, if things keep going the way they are, is disastrous for how many living near sea level? But worse, we don't know that the impact on ocean currents could not lead us to oceans deprived of oxygen in the water such that our atmosphere ends up massively poisoned by sulphur compounds as is believed to be the cause of a number of mass extinctions the planet has previously experienced.  Look up Canfield Oceans. If it happens, it isn't inconceivable we'll rename them Trump Oceans. When the world's historically greatest emitter walks away from any concern about GHG emissions, the consequences are certainly going to be grave.