Prince Charles has made headlines and faced criticism for claiming that climate change is one of the reasons for the Syrian conflict and ensuing refugee crisis.
Speaking to Sky News, the Prince said: "We're seeing a classic case of not dealing with the problem because, it sounds awful to say, but some of us were saying 20-something years ago that if we didn't tackle these issues you would see ever greater conflict over scarce resources and ever greater difficulties over drought, and the accumulating effect of climate change, which means that people have to move."
"And there's very good evidence indeed that one of the major reasons for this horror in Syria, funnily enough, was a drought that lasted for about five or six years, which meant that huge numbers of people in the end had to leave the land."
Singer turned political activist Charlotte Church made a similar point during an episode of Question Time in October, telling the audience: “Lots of people don’t know about this, but there is evidence to suggest that climate change was a big factor in how the Syrian conflict came about."
She added: "I think we also need to look at what we are doing to the planet and how that might cause more conflict in the world."
Both Church and Prince Charles faced criticism and mockery for their claims - Charles, for getting involved in in politics and pushing his personal interests, and Church, for making a slightly implausible-sounding claim in an unclear way.
However, their theories aren't entirely without merit.
Refugee crisis - in pictures
Refugee crisis - in pictures
A child looks through the fence at the Moria detention camp for migrants and refugees at the island of Lesbos on May 24, 2016.
Ahmad Zarour, 32, from Syria, reacts after his rescue by MOAS (Migrant Offshore Aid Station) while attempting to reach the Greek island of Agathonisi, Dodecanese, southeastern Agean Sea
Syrian migrants holding life vests gather onto a pebble beach in the Yesil liman district of Canakkale, northwestern Turkey, after being stopped by Turkish police in their attempt to reach the Greek island of Lesbos on 29 January 2016.
Refugees flash the 'V for victory' sign during a demonstration as they block the Greek-Macedonian border
Migrants have been braving sub zero temperatures as they cross the border from Macedonia into Serbia.
A sinking boat is seen behind a Turkish gendarme off the coast of Canakkale's Bademli district on January 30, 2016. At least 33 migrants drowned on January 30 when their boat sank in the Aegean Sea while trying to cross from Turkey to Greece.
A general view of a shelter for migrants inside a hangar of the former Tempelhof airport in Berlin, Germany
Refugees protest behind a fence against restrictions limiting passage at the Greek-Macedonian border, near Gevgelija. Since last week, Macedonia has restricted passage to northern Europe to only Syrians, Iraqis and Afghans who are considered war refugees. All other nationalities are deemed economic migrants and told to turn back. Macedonia has finished building a fence on its frontier with Greece becoming the latest country in Europe to build a border barrier aimed at checking the flow of refugees
A father and his child wait after being caught by Turkish gendarme on 27 January 2016 at Canakkale's Kucukkuyu district
Migrants make hand signals as they arrive into the southern Spanish port of Malaga on 27 January, 2016 after an inflatable boat carrying 55 Africans, seven of them women and six chidren, was rescued by the Spanish coast guard off the Spanish coast.
A refugee holds two children as dozens arrive on an overcrowded boat on the Greek island of Lesbos
A child, covered by emergency blankets, reacts as she arrives, with other refugees and migrants, on the Greek island of Lesbos, At least five migrants including three children, died after four boats sank between Turkey and Greece, as rescue workers searched the sea for dozens more, the Greek coastguard said
Migrants wait under outside the Moria registration camp on the Lesbos. Over 400,000 people have landed on Greek islands from neighbouring Turkey since the beginning of the year
The bodies of Christian refugees are buried separately from Muslim refugees at the Agios Panteleimonas cemetery in Mytilene, Lesbos
Macedonian police officers control a crowd of refugees as they prepare to enter a camp after crossing the Greek border into Macedonia near Gevgelija
A refugee tries to force the entry to a camp as Macedonian police officers control a crowd after crossing the Greek border into Macedonia near Gevgelija
Refugees are seen aboard a Turkish fishing boat as they arrive on the Greek island of Lesbos after crossing a part of the Aegean Sea from the Turkish coast to Lesbos
An elderly woman sings a lullaby to baby on a beach after arriving with other refugees on the Greek island of Lesbos after crossing the Aegean sea from Turkey
A man collapses as refugees make land from an overloaded rubber dinghy after crossing the Aegean see from Turkey, at the island of Lesbos
A girl reacts as refugees arrive by boat on the Greek island of Lesbos after crossing the Aegean sea from Turkey
Refugees make a show of hands as they queue after crossing the Greek border into Macedonia near Gevgelija
People help a wheelchair user board a train with others, heading towards Serbia, at the transit camp for refugees near the southern Macedonian town of Gevgelija
Refugees board a train, after crossing the Greek-Macedonian border, near Gevgelija. Macedonia is a key transit country in the Balkans migration route into the EU, with thousands of asylum seekers - many of them from Syria, Afghanistan, Iraq and Somalia - entering the country every day
An aerial picture shows the "New Jungle" refugee camp where some 3,500 people live while they attempt to enter Britain, near the port of Calais, northern France
A Syrian girl reacts as she helped by a volunteer upon her arrival from Turkey on the Greek island of Lesbos, after having crossed the Aegean Sea
Refugees arrive by boat on the Greek island of Lesbos after crossing the Aegean sea from Turkey
Beds ready for use for migrants and refugees are prepared at a processing center on January 27, 2016 in Passau, Germany. The flow of migrants arriving in Passau has dropped to between 500 and 1,000 per day, down significantly from last November, when in the same region up to 6,000 migrants were arriving daily.
It's well-documented that from 2006-2010, the 'Fertile Crescent', the agricultural area that covers parts of northern Syria as well as Iraq, Lebanon and Israel, experienced the worst drought on record.
The drought, coupled with poor irrigation techniques and government mismanagement, resulted in an agricultural collapse.
This collapse caused tens of thousands of people from farming communities in the rural north to migrate en masse to southern cities in order to earn a living - the theory goes that this mass migration caused overcrowding, poverty and youth unemployment, which occurred as food prices roses due to the scarcity of grain.
In turn, this poor quality of life led to dissatisfaction with the government, and the protests and resulting government violence kicked off the insurgency and multi-faction clashes that eventually developed into the Syrian civil war.
There have been links between major ecosystem change and violence made before - a 2007 study, published by an international team of Chinese, British and American scientists in the Proceedings of the National Academy of Sciences journal, involved the study of historic climate data from around the world and the frequency of wars and population changes in the affected countries.
Their findings suggested that a changing climate, in their case global cooling, resulted in changes in food production, food prices and associated social problems, which then led to war and famine.
Although their study suggested a correlation between cooling temperatures and war, they admitted that their findings could relate to our modern warming climate - they wrote that any major ecosystem change that would have a negative effect on agriculture could intensify social unrest, as it has done in the past.
Inspired by studies like these, governments around the world have looked into the possibility of social unrest caused by climate change, with the US Department of Defence launching a scheme in 2008 that has given funding to universities to look into these aspects of the climate threat.
It is widely accepted that the drought was one of many factors that sparked the unrest in Syria, but the disagreement is on how imprtant it was.
Scientists from the University of California in Santa Barbara found at the start of this year that greenhouse gas emissions exacerbated the drought, in a study that is often cited by those trying to use the drought as the main explanation for the Syrian conflict.
However, Colin Kelley, one of the study's authors, told The Guardian at the time: "We're not arguing that the drought, or even human-induced climate change caused the uprising."
"What we are saying is that the long term trend, of less rainfall and warmer temperatures in the region, was a contributing factor, because it made the drought so much more severe."
Others have pointed out that many other countries in the Middle East, such as eastern parts of Turkey, Iraq and Iran also suffered terrible droughts without descending into civil war.
The drought, although possibly made worse by climate change, could have happened without global warming - and many believe that it was the lack of assistance that the Assad government provided to the affected farmers that made it particularly disruptive.
Others, such as David Butter, a Middle East and North Africa expert at Chatham House, say the conflict could have occurred anyway in Syria, "irrespective of the drought."
Speaking to The Guardian in September, he said: "The fact that [the conflict] did escalate nationally is all to do with the structure of the regime as a brutalising kleptocracy that has for years and years taken people off to jails and tortured them."
There's no single cause for any major conflict, and the climate change theory, although it is neat and simply explains the complex issue in a scientific-sounding way, is not the sole reason.
However, it would be just as inaccurate to suggest that the drought and its possible links to climate change had no effect - it contributed to the dissatisfaction and poverty that went on to spark protests and uprisings.
Prince Charles isn't entirely wrong to suggest links between climate change and social unrest, but the problems facing Syria are too complex to pin to one single factor.