The world's population is graying at rate that few foresaw -- and the implications are terrifying. And as Phillip Longman details in his article "Think Again: Global Aging," this dramatic pace is going to change the world as we know it -- politically, economically, militarily -- in ways you might not expect.

CARL DE SOUZA/AFP/Getty Images

Two women cross the tracks of the Gara de Nord railway station, Bucharest's main train station, on Feb. 1, 2008. Romania's economic crisis has prompted the country's government to impose austerity measures, including pension cuts of 15 percent for government workers. As many as 50,000 demonstrators took to the streets of Bucharest in May to protest the plans, which the government says must be enacted if Romania is to receive IMF loans.

ANDREI PUNGOVSCHI/AFP/Getty Images

Wrecked by war and underdevelopment for the last 30 years, Afghanistan faces myriad demographic problems. On the one hand, it is an extremely young society: 50 percent of Afghans are under age 15, pointing to a dangerous youth bulge in a country without formal institutions or any paths to decent futures (at least 40 percent of the workforce is unemployed). Life expectancy as of 2008, however, was only 44 years. This imbalance has created a dramatic dependency ratio: There are 113 people under 15 or over 60 for every 100 between ages 15 and 59. Here, an elderly Afghan man walks along the street in the city of Bamiyan on Nov. 9, 2009.

SHAH MARAI/AFP/Getty Images

An elderly Indian smokes on a street in Kolkata on Aug. 4. India is a relatively young country, but the percentage of its population over 60 is expected to double from 1991 to 2016. Worse yet, with approximately 90 percent of the workforce in the unorganized sector -- farm laborers, construction workers, domestic servants, and others -- barely 10 percent of workers have any sort of pension plan. The rest are forced to rely instead on family members, who are often unable to help.

DESHAKALYAN CHOWDHURY/AFP/Getty Images

Elderly Belarusians exercise in a frosty forest on the outskirts of Minsk on Dec. 10, 2009. Belarus was one of few Eastern European countries not to raise its retirement age after the Cold War -- it is still 55 years for women and 60 for men. President Aleksandr Lukashenko recently affirmed that the retirement age will not be raised anytime soon -- though he did suggest that if workers desired to keep working after they reach retirement age, "It is a good addition to a pension, and we should support it."

VIKTOR DRACHEV/AFP/Getty Images

Yemeni society is youthful but getting older -- life expectancy jumped from 46 years in 1980 to 63 in 2008, a rare sign of stabilization in a country plagued by Islamist extremism and intense poverty. Still, there are few social services available to the elderly, who are often grouped in with the poor and disabled. Of the 3,569 charities and unions working in Yemeni social care in 2005, none specifically targeted the elderly.

AFP/Getty Images

A Palestinian man prays at the Ibrahimi Mosque, also known as the Tomb of the Patriarchs, in the West Bank town of Hebron on Feb. 25. The Palestinian Authority is in the process of cutting government spending following a decline in outside funding from the Arab world. The Palestinian territories have young median ages, 17.5 years in Gaza and 20.9 years in the West Bank, but high unemployment -- 40 and 20 percent, respectively -- and are thus unable to take advantage of their large working-age populations to fund pension plans. Instead Palestinians rely on outside sources to cover their pension costs; the European Union is a major contributor to the incomes of the 84,000 public employees and pensioners in the territories.

HAZEM BADER/AFP/Getty Images

With the Baby Boomers rapidly approaching retirement age, the culture they have helped define has matured along with them. In 2011, the first boomers will turn 65, and as that generation ages it will put significant strains on Medicare and Social Security in the United States. The federal budget deficit has emerged as a key issue in U.S. politics, but the rise in health care and welfare costs as the population grows older means it is unlikely to get smaller in the near future. Here, a mostly Boomer audience attends a concert celebrating the 40th anniversary of Woodstock -- the apex of the Boomer moment -- on Aug. 15, 2009. 

Photo by Mario Tama/Getty Images

Two elderly women wait for their martial arts class to begin in a slum in Nairobi, Kenya, in January. By some counts, one in five adult rape victims in Kenya is older than 60 -- one survivor is 105. Intercourse with the elderly is believed by many would-be attackers to bring good luck, purify one's sins, and even cure AIDS. Starting in 2007, a program called I'm Worth Defending has empowered women to fight back by teaching self-defense classes in Nairobi slums.

TONY KARUMBA/AFP/Getty Images

Chinese women sit together in Chongqing on March 16, 2008. China may be booming economically, but it faces a looming disaster as its massive working-age population gets old. By 2050, there are projected to be almost 440 million Chinese over age 60 and more than 100 million over 80. Less than one-third of workers have a pension, and though the government is working feverishly to create a safety net for the elderly, Chinese leaders are worried about the possibility of social upheaval due to the aging crisis.

Tim Graham/Getty Images

An elderly Indian couple visits the eighth-century Gwalior Fort on Feb. 22. India's rapidly transforming economy is bringing societal change with it, and new social norms have left the elderly -- traditionally cared for by their children and grandchildren at home -- often neglected. The problem is only going to get worse: A quarter of the Indian population will be over 60 in 2050.

MANAN VATSYAYANA/AFP/Getty Images

China is experimenting with ways to cope with its coming pension crisis, including allowing some private-sector employees in Shanghai to work an additional five years past the mandated retirement age of 60 for men and 55 for women. The government is also trying to enroll rural workers, frequently ignored by state schemes, in pension funds at a young age. An elderly couple talks on a street in Beijing on July 15.

PETER PARKS/AFP/Getty Images

Iran may be young today, but it won't be tomorrow -- it's the fastest-aging country on the planet. Between 2010 and 2050, the share of Iran's population age 60 and older is expected to increase from 7.1 percent to 28.1 percent.

BEHROUZ MEHRI/AFP/Getty Images

With this year's census likely to find more old people than ever in the United States, there has been something of a backlash against the elderly. Recently, old people -- with their ballooning consumption of health care and Social Security benefits -- have been accused of bankrupting the United States. "Far from serving the young, the old are now taking from them," New York Times columnist David Brooks recently lamented. Here, an elderly woman sits along the shore in Brooklyn, a notoriously difficult area for census workers to canvas.

Spencer Platt/Getty Images

With the average citizen expecting to live well into his or her 80s, Japan is home to some of the world's oldest people. By 2030, one in three Japanese will be a senior citizen. The importance placed on "acting one's age" in Japanese culture means that older people relax more than their peers elsewhere in the world, spending 2 percentage points more than the national average on entertainment and cultural activities. Japanese elders are also unusually technology-savvy: With more time and money on their hands, they have embraced social networking and technology like the iPad.

YOSHIKAZU TSUNO/AFP/Getty Images

Mexico is a young country and, as is the case for the rest of Latin America, most media coverage of demographic problems focuses on the lack of job opportunities for youth. But Mexico will face the problems of a much older country soon enough. Today, there are nine youth for every Mexican over age 65. But by 2050 there are projected to be as many elderly as there are young people. Mexico is not prepared for this demographic shift: The country has few old-age assistance policies in place, and the elderly have to rely on their families -- or become taxi drivers: One-third of Mexicans studying to become a cabbie are now over age 50.

Brent Stirton/Getty Images

Brazil's economic miracle has made it the envy of Latin America and has lifted millions out of poverty. Its growth shows no signs of slowing down in the near future -- but the boom will not last forever. Brazil's current trends point to an aged society by midcentury, as more effective social service keep the elderly alive longer, and as fertility rates continue to fall (they're now below the replacement level of 2.1 children per woman). By 2050, there will be more Brazilians over 60 than under 20, and almost as many people over 80 as under 5. Here, an elderly woman walks past a graffiti-marked wall in the Japanese neighborhood of Liberdade, Sao Paulo, on June 11, 2008.

MARC BURLEIGH/AFP/Getty Images

British pensioners, adorning oak sprigs to commemorate Charles II's restoration to the throne, attend the Founder's Day parade at the Royal Hospital Chelsea on June 10 in London. A pension review report commissioned by Britain's coalition government was released Oct. 7, which recommended raising the retirement age to 65 and cutting public-sector pay. Prime Minister David Cameron has advocated for austerity, saying last week, "There is no other responsible way" to get Britain's budget deficit -- currently at 11 percent of GDP -- under control.

Oli Scarff/Getty Images

Known as gran moun in Haitian Creole, the elderly make up only 3.4 percent of Haiti's population. While all of Port-au-Prince suffered after the earthquake, the old had it especially rough: Forgotten and hungry, many who survived took to begging for food and medicine. Older Haitians play an important role in this struggling country -- with many middle-age Haitians lost to AIDS or working abroad, grandparents are often responsible for much of the child care in Haitian families. Above, an elderly woman walks through a tent village in Pandiassou, Haiti, in January.

JEAN-PHILIPPE KSIAZEK/AFP/Getty Images

A man feeds seagulls in front of the Royal Palace in downtown Stockholm, Sweden, on Jan. 26. With 18 percent of its population over age 65 and the first country to have more than 5 percent over 80, Sweden is one of the oldest countries in the world -- and a model in eldercare. Older people in Sweden are especially independent, thanks to government-funded services such as visiting homemakers and meal deliveries.

OLIVIER MORIN/AFP/Getty Images

Bolivia, unlike many of its Latin American counterparts, is still a young country: Only 4 percent of Bolivians are over 65, and the fertility rate is still well above replacement level at 3.5 children per woman. Here, a woman leaves a polling booth in Tarabuco, during the Dec. 6, 2009, presidential election.

ERNESTO BENAVIDES/AFP/Getty Images

An elderly Russian woman walks through the wildfire-gutted town of Voronezh in August. The archetype of the Russian babushka is well known, for good reason: While male life expectancy in Russia hovers around 60, women -- who are less prone to rampant societal ills such as alcoholism -- live to an average age of 73. This has led to an interesting phenomenon: communities populated entirely by old women. According to the Guardian, there are at least 34,000 Russian villages inhabited by 10 people or fewer, almost all of them old women.

Alexey SAZONOV/AFP/Getty Images

Thirty-six percent of Colombians live on less than $2 a day, and pensions are nowhere near sufficient to cope with the coming glut of seniors. The Colombian government is tackling its aging problem head-on -- the government under former President Álvaro Uribe bumped the retirement age from 60 to 62 for men, and 55 to 60 for women, starting in 2014 -- but it might not be enough to forestall a crisis. Here, an elderly strolls along in Bogotá on May 12.

RODRIGO ARANGUA/AFP/Getty Images

France is famously known for its 35-hour work week and early retirement, but successive governments have tried to cut these benefits. French President Nicolas Sarkozy's plan to hike the retirement age to 62 has been met with massive street resistance, as union leaders have called successive national strikes in attempts to avert the change. Above, elderly women wait for a bus in Paris on June 26.

Antoine Antoniol/Bloomberg via Getty Images

Elderly Pakistanis had plenty of problems -- limited rural access to health care, terrorists attacking senior citizens -- even before this summer's terrible floods. Now, with an eighth of the Pakistani population significantly affected by the disaster, the disease- and disability-prone elderly are particularly vulnerable. Here, flood victims queue for aid in Sanawan, Punjab province, on Sept. 5.

CARL DE SOUZA/AFP/Getty Images

A family of Penan, a people indigenous to the Malaysian peninsula, spends an afternoon at home in Long Bubui, Sarawak state, on July 21. Experts say that Malaysia's current demographic window, in which it has a large working-age population relative to its under-15 and over-65 population, must not be wasted. Malaysians retire well before their working years are spent -- public servants only work until they're 55. Tengku Aizan Hamid of the Institute of Gerontology at University Putra Malaysia in Serdang told the Star, "Just because I am an old rambutan tree doesn't mean I produce old rambutans. In fact, the fruit of old trees is often sweeter."

ROSLAN RAHMAN/AFP/Getty Images

Romanian women sell vegetables along the road to Baleni village on June 7, 2009. On Oct. 6, Romania's Constitutional Court upheld the government's planned austerity programs, which include reducing state salaries by 25 percent, upping the retirement age to 65, and tying pensions to inflation.

DANIEL MIHAILESCU/AFP/Getty Images

Taiwan's society is aging so rapidly -- 10 percent of the population is over 65 and rising -- that its president, Ma Ying-jeou, recently had to reassure citizens, "The problem of an aging population is not that serious." One perk of being old in Taiwan: more exercise. Twenty-five percent of elderly people regularly participate in sports, a much greater frequency than younger Taiwanese.

PATRICK LIN/AFP/Getty Images

Two Ukrainian women cast their ballots in the village of Orane during the presidential election on Jan. 17. Ukraine's pension system is in crisis and nearing bankruptcy. The disbursements, which average around $140 a month per pensioner, constitute 18 percent of GDP. There are nine pensioners for every ten workers paying into the system -- and that ratio is going in the wrong way, fast. Over the last 20 years, Ukraine has avoided cutting its social-welfare programs, but the country seems to be paying for that decision now.

VIKTOR DRACHEV/AFP/Getty Images

Singapore has one of the world's fastest-aging populations, with over-65-year-olds estimated to be 23 percent of the population by 2030. Singapore also has one of the world's lowest fertility rates, at only 1.22 children per woman, for which blame can be placed on the country's "Stop at Two" plan: a wildly successful population control campaign launched in the 1960s. Half a century later, the Singaporean health-care system faces a wave of elderly demand for services, which will prompt a bigger state investment in social-welfare spending.

ROSLAN RAHMAN/AFP/Getty Images

Two elderly men walk along a street in Berlin on Sept. 22. While Germany fared better in the recession than many of its neighbors, the country's pensioners showed signs of hardship -- one group of four pensioners, dubbed the "Geritol Gang," took their discontent to a horrible extreme last year, kidnapping and torturing their financial advisor after losing about $3.5 million in investments.

Patrick Sinkel/AFP/Getty Images