Conflicts in Syria, Democratic Republic of the Congo and Mali push number of displaced people to more than 45 million

The world is in the throes of its most serious refugee crisis for almost 20 years, as conflicts in Syria, Democratic Republic of the Congo and Mali have forced tens of thousands of people to flee their homes, the UN's refugee agency has said.

In its global trends report (pdf), UNHCR said more than 45.2 million people were displaced by the end of last year, the largest number since 1994. This includes 15.4 million refugees [see footnote], 937,000 asylum seekers, and 28.8 million internally displaced people (IDPs) – those forced to find refuge within the borders of their own countries.

"These truly are alarming numbers. They reflect individual suffering on a huge scale and they reflect the difficulties of the international community in preventing conflicts and promoting timely solutions for them," said António Guterres, UN high commissioner for refugees and head of UNHCR.

The number of 28.8 million IDPs is the highest level in more than two decades, mainly because of the war in Syria. The three-year conflict, which has claimed 90,000 lives, has led to 4.25 million Syrians being internally displaced and more than 1.6 million refugees, concentrated in Jordan, Lebanon and Turkey. Last week the UN launched its biggest appeal – $5bn (£3.2bn) – as it warned that half of Syria's population will need humanitarian aid by the end of the year.

Somalia was the second-largest source of refugees in 2012. Photograph: Rebecca Blackwell/AP

Globally, 7.6 million people fled their homes last year, of whom 1.1 million were refugees and 6.5 million internally displaced. This is equivalent to a new refugee or internally displaced person every 4.1 seconds.

African countries have emerged as pioneers in addressing the problem of IDPs. In December, the Kampala convention, the world's first legally binding instrument to outline the obligations of governments to protect and assist IDPs, came into force.

Signed, although not necessarily ratified, by 37 of the 53 members of the African Union, the convention binds governments to provide legal protection for the rights and wellbeing of those forced to flee within their countries because of conflict, violence, natural disasters or development projects.

Under the convention, governments must gather data and identify IDPs to understand where they are and what they need, provide personal identification documents, trace families and help reunite them, and consult IDPs in decisions on their needs.

Children under 18 comprise 46% of refugees. A record 21,300 asylum applications submitted during 2012 were from children unaccompanied or separated from their parents.

Countries bearing the biggest burden of refugees tend to be in the developing world. Pakistan last year continued to host more refugees than any other country (1.6 million), followed by Iran (868,200) and Germany (589,700). Developing countries host 8.5 million refugees (81% of the world's total compared with 70% a decade ago).

Refugees from the town of Anderamboukane, northern Mali, in the Sinegodar camp. Photograph: Helene Caux/UNHCR

Afghanistan remains the largest source of refugees, a position it has held for 32 years. One in four refugees worldwide is Afghan, with 95% located in Pakistan or Iran. Somalia, another war-ravaged country, was the second-largest source of refugees in 2012, although the rate of outflow has slowed as the country has stabilised. Iraqis were the third-largest refugee group (746,700), followed by Syrians (471,400).

As for solutions, voluntary repatriation provides the most durable response, followed by local integration and resettlement to a third country, although this option is open to few refugees.

According to the report: "Voluntary repatriation is the durable solution for the largest number or refugees. It requires the commitment of the country of origin to protect and to reintegrate its own citizens back into their home communities."

Over the past 10 years, 7.2 million refugees were repatriated, but only 836,500 were resettled. Last year, more than 500,000 were able to return home. The main countries of return were Afghanistan, Iraq, Ivory Coast and Syria. Most of the Afghans and Iraqis had been in exile for many years before their return. Of the repatriating Syrian and Ivorian refugees, most returned after only one or two years in exile, but with the prospects for continued violence in Syria and DRC, returns to these countries are likely to be poor.

The world's four largest refugee camps are in Kenya, known collectively as Dadaab, home to about 500,000 refugees. Nyaragusu camp in Tanzania is the world's fifth-largest camp, home to 68,100 refugees, mainly from DRC.

• This footnote was appended on 23 July 2013 to clarify that of 15.4 million refugees 4.9 million are Palestinians, who don't appear in UNHCR statistics because they are registered with the United Nations Relief and Works Agency in the Near East (UNWRA). In addition the original said that 45.2 million people were displaced "last year". This has been corrected.