CAIRO (BLOOMBERG) - Every child comes with its blessing, the Egyptian saying goes. With the country's population now soaring beyond 100 million, that adage is being put to the test like never before.

In the past three decades, the number of Egyptians has quadrupled and, if unchecked, could nearly double again by 2050, threatening to tip the host of this year's global climate summit into a future where ever-scarcer resources thwart ambitious development efforts.

Ms Omnia Abu Zaid's husband invokes the saying repeatedly as they struggle to care for their four children.

"We're making ends meet, but barely," said Ms Abu Zaid, who manages her husband's Cairo beauty salon and blames failed birth control for her larger-than-expected family.

"It was God's will," she said with a small laugh.

While family size has been in decline for decades, it remains dangerously high in a country where half of the people live around or below the poverty line. The nation is already the Arab world's most populous, and perennially struggling to create jobs for a population that skews young: Even now, about half of all Egyptians are under 25.

Compounding Egypt's concerns is a looming water crisis that may be exacerbated by a dam that Ethiopia is building on the Nile.

Government moves to cut state subsidies that provide a lifeline to many dovetail with the population-control campaign in a way that could prove combustible in a country with a historical potential for popular unrest.

"There is an entrenched culture unique to our country that one can buy things and receive services for less than they cost, and have children and expect someone else to feed them," President Abdel Fattah al-Sisi said in December. "This has held the country back in recent years."

Previous attempts to tackle the problem have had mixed success. Officials are aiming higher this time with a plan that provides cash incentives - possibly in the form of deferred savings certificates, Planning Minister Hala El-Said said in an interview.

The blueprint also includes family planning awareness projects, penalties to curb the incidence of unregistered births, more women's clinics and better access to contraception.

Another key element is boosting current efforts to empower women and help them finance small enterprises.

Egypt's current birth rate is 3.4 children per woman. Under the government's most optimistic scenario, the target rate is 2.11 by 2032 and 1.65 by 2052. The worst-case projection shows 2.1 by 2052, which would bring the nation's population to 191.3 million - a surge equal to the populations of Canada, Saudi Arabia and Portugal combined.

Some 98 per cent of the population live on just 3 per cent of the country's territory, either on the banks of the Nile or in the fertile northern delta. Cities are choked and chaotically developed, with metropolitan Cairo already Africa's largest city.

While Egypt is favouring incentives over penalties, taming birth rates will not necessarily be easy because of what officials see as citizens' cavalier approach to bearing children they cannot afford.

The government of ousted former president Hosni Mubarak opened thousands of clinics, provided family planning support and sought the help of religious scholars at Al-Azhar, the Sunni Muslim world's pre-eminent institution.

The success of those efforts was compromised in part by state subsidies covering core items like bread and a bloated civil service that effectively ensured employment for life for millions of workers.

Mr al-Sisi recently said his government has spent US$400 billion (S$538 billion) over the past few years combating poverty, even as state subsidies have been trimmed.

But these programmes will have little effect if the fertility rate does not drop.

A year ago, the President said the government would need US$1 trillion to fully provide for the needs of the current population. It would also need more than US$5.6 billion for the 900,000 people entering the workforce each year.

Sums of that magnitude would require economic growth rates far higher than projected expansions of 6 per cent in the 2024-2025 fiscal year. The government has bowed to cut subsidies that already consume around 17.5 per cent of Egypt's annual spending, possibly in the next budget.

Those changes will not sit well with Egyptians, who have toppled two leaders in popular uprisings in recent years.

Mr Mohamed Selim, a father of four who earns 1,150 Egyptian pounds (S$98) a month, says there is no fat left to trim after the government cut subsidies and raised the prices of public transport, electricity, gas and water.

The authorities are working against the people, and they will not stand for that, he said, citing another old proverb: "Bee, don't sting me and I won't take your honey."