"Maybe it'll just -waves hands- magically happen" is "no reason". Saying "climate has changed in the past and therefore there is reason to believe that it will

"Maybe it'll just -waves hands- magically happen" is "no reason". Saying "climate has changed in the past and therefore there is reason to believe that it will change in this particular way, in the future" does not logically follow. Climate has changed repeatedly throughout history. Every time a temperature increase has changed to a temperature decrease, this must be preceded by the rate of temperature increase decreasing. We observe the rate of temperature increase, continuing to increase. Thus there is reason to believe that it will get hotter for some time, before it again gets colder.