Britain and Norway announced Thursday they would donate an additional $2.9 billion in relief for Syrian refugees by 2020, ahead of a conference seeking billions to help those displaced by the war. Leaders and diplomats from 70 countries will convene in London for one day to raise money and outline an international response to help the 4.6 million Syrians who are seeking refuge in countries like Jordan, Lebanon, and Turkey. The conference will also discuss plans to send more humanitarian aid to Syria. The United Nations has said it needs $9 billion in assistance for 2016 alone. The civil war has left an estimated 250,000 people dead.