In a complex system like the atmosphere anything and everything can have an effect. But some categories of input can have a greater magnitude of effect than ot

In a complex system like the atmosphere anything and everything can have an effect. But some categories of input can have a greater magnitude of effect than others. In one year volcanism may have a massive effect and then have little effect for decades. In recent years humans have had a high magnitude of effect. Based on that you could attribute some responsibility to humans for any and all weather events like this.