The expectations are partly based on the reframing of the aid debate over the past year, following the chaotic migration of hundreds of thousands of desperate Syrians to Europe.
Donor countries trying to slow the influx would arguably serve their own interests as much as lofty principles of international solidarity if they give more and spend in smarter ways to improve refugees' lives and ease the burden on Middle Eastern host countries.
The stark reality of a drawn-out conflict requiring more ambitious long-term aid plans has also sunk in.
Fighting between Syrian President Bashar Assad's forces and those trying to topple him has only intensified over the past year, and the latest long-shot attempt at UN-brokered peace talks got off to an acrimonious start in Geneva over the weekend.
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Tomorrow's donor conference, to be held in London, is co-hosted by Britain, Germany, Norway, Kuwait and the United Nations. World leaders and representatives of dozens of countries have been invited, along with officials from international organisations, aid agencies and civic groups.
The total aid requirement to be presented in London amounts to nearly USD 9 billion, including a UN-coordinated appeal by dozens of aid agencies for USD 7.73 billion and a USD 1.23 billion request by regional host governments.