Image caption The Darfur conflict in Sudan was linked to shifts in the climate The Darfur conflict in Sudan was linked to climate shifts Climate 'drives African conflict'

Climate change is not responsible for civil wars in Africa, a study suggests.

It challenges previous assumptions that environmental disasters, such as drought and prolonged heat waves, had played a part in triggering unrest.

Instead, it says, traditional factors - such as poverty and social tensions - were often the main factors behind the outbreak of conflicts.

The findings have been published in the Proceedings of the National Academy of Sciences (PNAS) in the United States.

"Climate variability in Africa does not seem to have a significant impact on the risk of civil war," said author Halvard Buhaug, senior researcher at the Peace Research Institute Oslo's (Prio) Centre for the Study of Civil War.

"If you apply a number of different definitions of conflict and various different ways to measure climate variability, most of these measurements will turn out not to be associated with each other.

He added that it was not too hard to find examples of where politicians were publicly making the link between the projected impact of climate change and the associated security risks.

Margaret Beckett, when she held the post of British Foreign Secretary, tabled a debate on climate change at the UN Security Council in 2007.

Ahead of the gathering, the British delegation circulated a document that warned of "major changes to the world's physical landmass during this century", which would trigger border and maritime disputes.

In his paper, Dr Buhaug questioned the findings of research that appeared in PNAS in November last year.

The 2009 paper suggested that climate had been a major driver of armed conflict in Africa, and that future warming was likely to increase the number of deaths from war.

US researchers found that across the continent, conflict was about 50% more likely in unusually warm years.

'Lack of research'

Dr Buhaug said it was too early to make such assertions.

Politicians and policymakers have often linked the threat of climate change to security Security Council takes on global warming

"It is not a misunderstanding as such, more a case of the research still being in its infancy - we still don't know enough yet," he told BBC News.

"My article points to the fact that there has been too much emphasis on single definitions of conflict and single definitions of climate.

"Even if you found that conflict, defined in a particular way, appeared to be associated with climate, if you applied a number of complementary measures - which you should do in order to determine the robustness of the apparent connection - then you would find, in almost all cases, the two were actually unrelated."

Dr Buhaug explained that there were a variety of ways to define what constituted a civil war.

One methods requires the conflict to claim 1,000 lives overall. Another method says unrest can only be categorised as a civil war if it results in 1,000 deaths each year.

Other definitions have much lower thresholds, ranging between one casualty and 25 casualties per year.

"I tried quite a few different and complementary definitions of conflict," said Dr Buhaug.

He found that that there was a strong correlation between civil wars and traditional factors, such as economic disparity, ethnic tensions, and historic political and economic instability.

"These factors seemed to matter, not so when it came to climate variability," he observed.

He says that it will take a while yet, even taking into account his own paper, for academic research to converge on an agreed position.

'Action still needed'

When it came to politicians and policymakers, many of the adopted positions were "speculative", he added.

"It is partly a result of a lack of solid evidence in the first place," the researcher explained.

"If you do not have any solid scientific evidence to base your assumptions, then you are going to have to speculate."

He also said that the end of the Cold War also seemed to have had a impact on civil unrest in African nations.

"You did see a shift in the focus of quite a few conflicts during the 1990s, when the ending of the supply of arms saw some groups lay down their arms, while others sought alternative forms of funding, such as diamonds."

However, he concluded, the uncertainty about the link between conflict and climate did not mean that global climate mitigation and adaptation measures did not matter.

"Targeted climate adaptation initiatives, such as those outlined in various UN (strategies), can have significant positive implications for social well-being and human security.

"But these initiatives should not be considered a replacement for traditional peace-building strategies.

"The challenges imposed by future global warming are too daunting to let the debate... be sidetracked by atypical, non-robust scientific findings and actors with vested interests."