While I worked to allay the student's fears (I very much remember having similar fears when I was that age, but it my case, it was fear of nuclear annihilation), I was also hesitant to downplay the seriousness of climate change. I believe that the world isn't about to end and that humanity will continue to exist for millenia to come; however, the many people are going to be facing greater hardships in the coming decades and centuries due to the haphazard ways that humans--especially human businesses--have been disposing of their waste (solid, liquid, and gas). More frightening to me is that climate change deniers are not only spreading misinformation, but are actively taking steps to make polluting and destructive exploitation of our environment easier and more common.
There is no question that the world is warmer now than at any point in humanity's history; anyone who tells you otherwise is selling something. There is no question that many people, especially in poorer nations, will be negatively impacted by the changes which are rapidly (from a historical, let alone a geological, perspective) occurring. The issue is how to we deal with these growing problems without bankrupting everyone. We should be spending our energy in that direction rather than sticking our heads in the sand and hoping it will all sort itself out.
I believe that crisis begets innovation. We are starting to see some remarkable, and practical, ideas being brought forth by a growing group of people. With the progress humanity has made in so many areas, I am certain we can make the world better in this regard as well.