A new report states that it could take as little as 31 years before a majority of humankind is destroyed by climate change. The report, What Lies Beneath – The Understatement of Existential Climate Risk, is by Breakthrough National Centre for Climate Restoration (BNCCR), an independent think-tank working on climate emergency in Australia. This report is based on existing data such as the UN’s IPCC report and uses and collates such peer-reviewed material to understand the limitations and realities of current climate-change discourse. It does not produce new research but focuses on translating existing science into action and risk assessments.

The report states that the target pursued by the Paris Agreement of limiting global temperature increase to below 2 °C is inadequate and even if such voluntary emission reductions are implemented, it will result in a temperature increase of 3.4 °C by 2100, and this is without taking into account the long-term carbon-cycle feedbacks. When such feedback is considered, warming may go up to 5 °C – deadly for the entire planet and sure to wipe out most humans, at a minimum. Even 3 °C of warming already constitutes an existential risk to life on Earth.

If the planet were to warm up by 3 °C, most of Bangladesh and Florida would drown and major coastal cities such as Mumbai, Shanghai and Lagos would be swamped. This would create a refugee crisis of a scale the world has never witnessed. Food production would decrease dramatically and the number of extreme weather events will increase.

The report quotes studies by prominent scientists that the predictions made by organisations such as IPCC are ‘erring on the side of least drama’ and downplaying the worst possible outcomes. The conservative prediction of climate-change effects may make sense from a reticent, scientific point of view, but fail to accurately communicate the risks and dangers of global warming which, to date, continue unchecked.

It also finds that current climate-change reports have failed to make risks assessments in a balanced manner, often underplaying high-end possibilities and even underestimating their likelihood. These are the scenarios whose consequences will be catastrophic for humans and human civilisation, not to mention the damaging effects on other living beings and the planet’s entire ecosystem. The report asserts that it is important to understand the potential of the worst scenario and plan for it. One of the reasons for this oversight is that reports like the ones produced by IPCC are driven by consensus.

BNCCR’s findings assert that IPCC estimates of climate sensitivity (the amount by which the global average temperature will rise due to a doubling of the atmospheric GHG level, at equilibrium) in climate models do not adequately consider long-term feedbacks, resulting in flawed reporting. Over century time-scales, amplifying feedbacks may ultimately contribute 28–68 per cent of total warming when they are 1–7 per cent of current warming.

As the report states, today the world emits 50 per cent more CO2 for its energy needs than it did 25 years ago. Humanity now requires the biophysical capacity of 1.7 Earths annually as it keeps consuming natural capital. As the authors put it, ‘A fast, emergency-scale transition to a post-fossil fuel world is absolutely necessary to address climate change. But this is excluded from consideration by policymakers because it is considered to be too disruptive.’