The prime minister will attend the United Nations general assembly's summit on the movements of refugees and migrants on 19 September, billed by the UN as "an historic opportunity to come up with a blueprint for a better international response".
On Saturday he will deliver his maiden address to the UN general assembly at the summit in New York, where he intends to repeat the warning that other countries must act or else.
In 2015, the pope will issue a lengthy message on the subject to the world's 1.2 billion Catholics, give an address to the UN general assembly and call a summit of the world's main religions.
The world's international community is gathering for the UN general assembly, which is hosting a summit on refugees and migrants, and for a leaders' summit on the global refugee crisis, hosted by Barack Obama.
United Nations general assembly and a key migration summit hosted by the United States president, Barack Obama, will be held next week.
The meeting in Costa Rica came ahead of a planned summit on migrants and refugees on the sidelines of the UN general assembly on 19 September and a separate summit called by Barack Obama on refugees 20 September.
However, the goals and targets will be adopted at a special summit at the UN general assembly in September and will come into force on 1 January 2016.
The day after the summit, May told the UN general assembly: "We will continue to champion the rights of women and girls, making sure that all girls get the education they deserve, and tackling horrific abuses such as female genital mutilation and the use of sexual violence in conflict".
So as two refugee summits convene at the UN general assembly, we propose that by the end of 2017, every Syrian child refugee should have a place in school as a first step to ensuring schooling for every displaced child.
Her speeches included one to Royal Society on 27 September 1988 and to the UN general assembly in November 1989, She did not visit the Earth Summit 1992 and later became sceptical about climate change policy.
