The white t-shirt law

Here's new law to save the planet:  Only white t-shirts are allowed, all others are banned - until the climate agreements are met.  Enforced with fines, and swapping the offending t-shirt for a white one by police.

Why?

1.  Surely world governments can agree on this trivial thing
2.  Helps young people to focus on finding a solution to climate problems rather than worrying about whether their t-shirt makes the grade with their peer group / gang
3.  A constant visible reminder to everyone
4.  Very easy to enforce.