What is the difference between "is beginning" and "has begun"?
is beginning => (in present progressive tense: action still in progress, at this very moment) means we are still at the very early stage of an action. We are starting an action but haven't completely comprehended what this means.
has begun => (in present perfect tense: actions began in the past, time unspecified, and completed in the recent past or have an effect in the present.) means we are over the very early stage of an action and have started an action. The action has an impact in the present and we have somewhat comprehended what this means.