Why jonathan conceded to buhari

I think there may be some confusion here.

To clarify, Jonathan was the President of Nigeria from 2010 to 2015, while Buhari is the current President of Nigeria, serving from 2015 to present.

In the 2015 presidential election, Muhammadu Buhari, the candidate of the All Progressives Congress (APC), defeated Goodluck Jonathan, the incumbent President and candidate of the People's Democratic Party (PDP). Buhari won the election with 15,424,921 votes, while Jonathan received 11,576,467 votes.

So, to answer your question, Jonathan did not "concede" to Buhari because he lost the election and accepted the outcome. In fact, Jonathan conceded defeat in a speech on April 1, 2015, saying: "I accept the result and I congratulate President-elect Muhammadu Buhari."

It's worth noting that Jonathan's concession was seen as a significant moment in Nigerian politics, as it marked a peaceful transfer of power from one democratically elected government to another.