"I don't understand you," Sem's mother says. "Since you've got that car, you've been using it to go to school more and more often. And you even study environmental science. If anyone should know that the earth is warming up because too much CO2 is being emitted, it's you. When I used to go to university, I used to ride my bike. I loved cycling the twenty two kilometres through all kinds of weather.

Sem looks outside. He knows that his mother is a bit right, he has indeed been taking the car more and more often lately. But what does she want? His studies are much harder than he had expected, he works on them day and night. He realises that time is valuable and he gets to school much quicker by car. "Look at the weather," Sem grumbles to his mother. "It's raining cats and dogs. I worked until late at night to finish my report. I really don't have time to cycle for forty-five minutes and back."

Sem walks grumpily out of the house and slams the door behind him. His mother feels pitiful and stares at the closed door. Recently Sem has been retreating more and more to his room. His studies are indeed very tough, but the ease with which he takes the car every time, is actually no longer acceptable. And that's not all. He also plays more and more video games and she has seen on the power bill how much extra consumption they have since he installed the new video card. It uses up to 150 Watts at peak times.

Sem's mother is worried about global warming. And it is precisely these kinds of things that you can do something about yourself. Lately she has been arguing more often with Sem about this. How nice it would be if Sem would care about it even a little bit ...