I seriously believe it. Climate change will almost certainly lead to food insecurity and political upheavals, leading mass migration and war, not to mention potential knock-on effects where, for example, photosynthesis reductions due to extreme heat at the equator, rapid rates of methane release as permafrost melts, mass death in a heating and acidifying sea... . really there are just so many things that could go wrong, much more wrong. So yes, we should be very serious, and very scared.