Climate change is helping to make the world less peaceful by causing conflicts or making them worse by affecting livelihoods, security and resources, a study has said.
Nearly one billion people worldwide live in areas with high or very high exposure to climate hazards and 400m of them are in countries with already low levels of peacefulness, the Global Peace Index (GPI) found.
The link between climate change and conflict is illustrated by eight of the 25 least peaceful countries having 10% or more of their population in areas of high climate hazard.
More than 100 million people across those countries - South Sudan, Iraq, Libya, the Democratic Republic of the Congo, Sudan, North Korea, Nigeria and Mexico - are at risk.
Even more people - 122 million - are considered vulnerable in sub-Saharan Africa, the region least able to cope with climate hazards, which could exacerbate climate-related violent conflicts.
More peaceful countries are better-placed to cope with climate-induced shocks and tend to have higher environmental performance than less peaceful nations, for whom climate shocks are harder to manage, the report found.
"The impacts of fluctuating climate conditions on societal stability and its potential to lead to violent conflict is of growing importance," the report said.
"Research is clear that changes in the natural environment impose stress on human societies."
While admitting "long-term" evidence on the link between climate change and peace is "scarce", the report states that what there is, "suggests that climate has played a role in triggering or exacerbating conflict through its effects on livelihood security and resource availability."
The annual report, produced by the Institute for Economics and Peace (IEP) and in its 13th edition, ranks 163 independent states and territories according to their level of peacefulness.
This year it classed more than a quarter (45) of the countries as low or very low.
Scientists will have more chance to explore the link between climate change and conflict in the future.
The Intergovernmental Panel on Climate Change (IPCC) predicts Earth's surface temperature could rise by a further 1.5 degrees Celsius between 2030 and 2052.
Over the decade the report has been issued, the average level of global peacefulness has decreased by nearly 4%, with the Middle East and North Africa (MENA) region the least peaceful for the fifth year in a row.
:: Most peaceful countries
2. New Zealand
:: Least peaceful countries
3. South Sudan