Global Challenges

Global Challenges are a feature added to Scrap Clicker 2 on the 8.0 update (July 11), after being suggested for several times by several people. They last for 24 hours, and reward the player with Combine tokens (a popular suggestion by Schrottii) based on the barrels merged (up to 7.5k for 5x reward) at the end of the time. A new Global Challenge comes after 24 hours.

How many tokens?
There are two things that define the amount of tokens a player can get:
 * The total merges. Up to 5 Tokens.
 * The requirement of the amount of merges will go up by 1M per one 100% completed challenge,or go down by the same amount per one <90% completed challenge.
 * The own merges. Up to x5 Multiplier (7,500 Merges) from the above point. The player needs to have at least x1 Multiplier (1,500 Merges) to claim tokens.

The maximum Combine Tokens from a Global Challenge are 25.

Combine tokens
Combine tokens can be used to combine two Ad Events (costs at the table presented), with bad combinations like More Bricks + More Scrap being cheap(1) and the good ones, like Faster Barrels + Auto Merge being very expensive(12) to keep the balance.

Combining Faster Barrels with any other event will reduce x10 boost to x5.

the pic on the right is very outdated btw

Speculation

 * It's not known yet if the goal will always be merges.
 * Before it was speculated that Global Challenges would last a week, but repeated suggestions of making it daily instead made this false.