Lake Chad is a hydrological miracle – a life-giving, freshwater lake in the Sahara desert. But the region around the lake has been engulfed in a violent crisis for more than a decade, which has left nearly 10 million people in urgent need of humanitarian assistance.

Military crackdowns on insurgent groups such as Boko Haram have failed to end the violence. Bringing durable peace to the region requires unpicking a Gordian knot of many interlinked factors: poverty, sectarian mistrust, political marginalisation and corruption. The risks posed by the climate crisis to the rainfall-dependent livelihoods of the people of Lake Chad are an important strand of this challenge.

For years, the prevailing narrative about Lake Chad is that it has been in inexorable decline as a result of the over-extraction of water and climate crisis. A much-repeated factoid is that the lake shrunk by 90% between the 1960s and the 1990s. This statistic is employed to back up a compelling series of causal links to explain the many problems that the region faces. The story goes as follows: the declining lake has done farmers and fishermen out of their jobs, who have been recruited into armed groups such as Boko Haram and Islamic State, fuelling the ongoing violence that blights the region.

Under this logic, refilling the lake might seem a step worth taking – to reverse the decline of both lake and region. And the Inter Basin Water Transfer project proposes to do just that.

A woman pumps water into jerrycans in the far north of Cameroon next to a civilian vigilante. Photograph: Joe Penney/Reuters

It calls on international donors to bankroll the 2,400km (1,500 mile) Transaqua canal from the Ubangi river in the Democratic Republic of the Congo to Lake Chad, through war-torn Central African Republic, at an estimated cost of $50bn (£39bn) – roughly a third of the annual global aid budget. A feasibility study is already under way. Nigeria, with the support of the African Development Bank, is actively looking to raise the money needed for the project.

Our two-year study of climate change and security risks in the Lake Chad region charts the hydrological health of the lake over the last 30 years.

The conclusion – uncomfortably for the pipeline’s proponents – is that the lake is not actually shrinking. True, the size of the lake did fall steeply between the 1960s and the 1990s. True, the lake fluctuates dramatically over the course of each year and across decades. However, since the 1990s Lake Chad’s size has, on average, been stable. By some measures, it has even been growing.

The story of an ever-shrinking lake has been built on snapshots of data – the extremes of lake size in the 1960s and 1990s – taken out of their wider context. It has proved to be a doubly convenient narrative for leaders in the region: it takes the spotlight off serious governance failures, which set the stage for the conflict in the first place, and it also makes the case for a highly lucrative, technical fix as the solution. The danger is that the canal will not address the various problems facing the region and instead, at best, provide multiple opportunities for corruption and personal enrichment for those involved and, at worst, exacerbate the region’s environmental and conflict challenges.

Let’s be crystal clear here: we are not suggesting that the Lake Chad region is immune to the effects of the climate crisis, quite the opposite. Temperatures in the region are rising one and a half times faster than the global average. The unpredictability brought by climate change is worsening the political and economic conditions that gave rise to the violence in the first place. But, so far at least, it is not happening due to a shrinking lake.

Lake Chad is caught in a conflict trap that undermines people’s ability to deal with the changes that an increasingly variable climate is bringing.

A thorough, fact-based understanding of the interlinked climate and conflict risks facing Lake Chad is fundamental to appropriate solutions to ensure that hugely costly responses do not actually make things worse.