On Sunday, international donors will meet in Cairo to consider a $4 billion (Dh14.7bn) request from the Palestinian Authority for emergency reconstruction aid for Gaza to repair the devastation wrought by Israel over 50 days in the summer.

The fact that this conference is being held at all ought to be seen as a positive step to address a humanitarian disaster. Some significant promises of reconstruction aid will be pledged, even if past experience shows that much of this money may never materialise. This is a permanent feature of donor conferences but made more significant in the case of Gaza by two concerns.

The first is whether construction can take place without Israel easing its blockade to allow the import of cement, steel and other building materials. The other is the question of how long before what is rebuilt is levelled again. The latest onslaught, Operation Protective Edge, was the third since Hamas seized control of the Gaza Strip from the Palestinian Authority in 2007.

Without political progress there will inevitably be a return to what one United Nations official has called “the unsustainable pattern of blockade, rockets and destruction”.

With 60,000 homes destroyed and more than 100,000 people homeless, this is a real emergency as winter draws closer. On the political front, two surprising elements are falling into place. The Palestinian national unity government, bringing together technocrats from the West Bank and Gaza under the Palestinian president, Mahmoud Abbas – which previously existed only on paper – has been reaffirmed.

West Bank ministers travelled to Gaza yesterday to hold their first cabinet meeting there, symbolically ending Hamas’s absolute control of the territory. Hamas still controls the security forces in Gaza, however, and the unity agreement is lacking significant content.

Israel agreed to allow the ministers to travel to Gaza, reversing its previous rejection of the unity government, in accordance with its long-standing policy of isolating Hamas. The formation of the unity government, following the collapse of efforts by the US secretary of state, John Kerry, to revive Israeli-Palestinian peace talks, was one of the markers on the path of war in June.

On the premise that Mr Abbas is now in control of Gaza – more of a pious hope than a reality – the Israelis have reached agreement with the UN and the Palestinian Authority on a system that would allow building materials in to Gaza. There is a further surprise here: the Israelis who have been so suspicious of the UN are now putting their trust in it to ensure that building materials are used for civilian reconstruction.

Having been blamed by senior US figures for the collapse of the peace talks, the Israeli government now apparently wants to be seen as not standing in the way of reconstruction.

The key to understanding these surprises is in the text of the UN-sponsored agreement. According to The Guardian, which has seen the agreement, this puts the UN in charge of a monitoring regime that effectively enforces the Israeli blockade. Building materials are considered “dual use” items which have a potential military application for constructing the tunnels used by Hamas. Major projects have to be approved by Israel, while the details of every home being rebuilt, including names and ID numbers of the residents, must be entered into a database that can be seen by Israel. Concrete mixing plants have to be constantly monitored.

Establishing such a database and recording the journey of every bag of cement would stretch the capacity of most developedcountries. In Gaza, in circumstances of a humanitarian disaster with limited electricity, this is almost certain to break down.

The UN envoy, Robert Serry, has been put in a difficult position. Since Egypt is enforcing the blockade of Gaza at the southern end, the only way to import building materials is through Israel. Washington and Israel are agreed that what the US State Department calls “Israel’s security needs” are paramount in the reconstruction effort. The UN has had to swallow that.

Aid agencies, big and small, are keenly aware that the vital work they do in Gaza and the West Bank can be seen as reducing the burden of occupation on Israel. Since Israel primarily controls access to Gaza by land, air and sea, it should be responsible for the welfare of the Gazans. Yet this burden is borne by US and European taxpayers and other international donors.

It is a short leap of logic for the people of Gaza to see the UN and other aid agencies as complicit in the occupation. The UN is keenly aware of this, but on the positive side, there is at least the possibility of a significant easing of the blockade to enable desperately needed construction to go ahead. If it can make the system work, then life for the people of Gaza could improve.

As the talk turns to money this weekend, the major participants will be setting out stalls that bear little relation to reality. The Israelis can claim to have made an effort to come up with a plan that allows some easing of the blockade, while ensuring that nothing will change the envelope of control it dominates around Gaza. In fact, the monitoring regime will actually increase its control.

As for the PA, it can claim to be in control of Gaza, but everyone knows Hamas is still firmly entrenched. And as for Hamas, it is making a tactical retreat over the unity government, but it believes that its rhetoric and record of resistance gives it a higher standing in Palestinian opinion than Mr Abbas, who is obliged to carry out security coordination with the Israeli military on a daily basis.

From the donors, it can be expected that the headline amounts offered will contain a lot of money previously pledged and repackaged for the event. They would argue that they cannot afford to pour money into such an uncertain situation. The people of Gaza, however, cannot spend the winter without homes.

Alan Philps is a commentator on global affairs

On Twitter: @aphilps