Good climate policy depends on good climate science. And good climate science has depended on the Intergovernmental Panel on Climate Change (IPCC) since it was set up by governments in 1988.

The IPCC is made up of tens of thousands of scientists in dozens of countries, covering multiple facets of “why” and “how” the climate is changing. It lays down the consensus-based line in great doorstopper reports every five or six years. So well was it judged to have carried out that remit that in 2007 it was awarded the Nobel Peace Prize alongside former Vice President Al Gore.

Critics of the IPCC see it as being far too slow, always several years behind the reality of what's happening on the front line of our changing climate, and far too susceptible to brutish political pressure from petrostates and the fossil fuel industry. However, if you're looking for an institutional manifestation of what good science looks like in practice, then the IPCC is seen by many as providing that gold standard.

Over the years, it's become very familiar with attacks from climate deniers (serried ranks of pointy-headed flat-earthers have been summarily seen off by the IPCC over the years), more radical, independent scientists (with whom it's maintained a polite “agree to disagree” position), and climate activists, who it rather patronizingly ignores.

But the IPCC is now in real trouble, with a much more problematic opponent: the world's elite actuaries! The driest, dustiest, most unimpeachably authoritative of global professions has chosen to turn its full firepower on the IPCC—and the fallout could (and should!) transform the world of climate science.

In January 2025, without any huge fanfare, the Institute of Faculty and Actuaries published its “Planetary Solvency: Finding our Balance in Nature” report, in partnership with scientists at the University of Exeter. It robustly critiques orthodox economic predictions, which estimate that the impact of an average temperature increase of 3°C by the end of the century would be around 2% of annual GDP. “These estimates are precisely wrong, rather than being roughly right, and do not recognize there is a risk of ruin.” The institute's risk management experts diligently reassessed risks associated with impacts such as fires, flooding, droughts, temperature increases, and rising sea levels through 2050 and on to the end of the century.

There is now a very strong likelihood that we'll experience an average temperature increase of at least 2°C by 2050—an outcome described by the report's authors as “catastrophic.” Take a deep breath and get your head around the projected impacts associated with that 2°C rise:

  • Economic contraction; GDP loss of over 25%.

  • Mass human mortality events resulting in over 2 billion deaths.

  • Warming of 2°C or more triggers a high number of climate tipping points.

  • Breakdown of some critical ecosystem services and Earth systems.

  • Major extinction events in multiple geographies.

  • Ocean circulation was severely impacted.

  • Severe socio-political fragmentation in many regions; low-lying regions lost.

  • Heat and water stress are driving the mass migration of billions.

  • Catastrophic mortality events from disease, malnutrition, thirst, and conflict.

Two billion prospective deaths by 2050. That's just 25 years away. And for the final kicker, bearing in mind that we're currently on a business-as-usual trajectory towards at least a 3.7°C temperature increase by 2100, the contraction in GDP then rises to 50% and the number of projected deaths rises to 4 billion.

The institute's definition of “planetary solvency” is fascinating:

Planetary Solvency” assesses the ongoing ability of the Earth system to support our human society and economy. In the same way that a solvent pension scheme is one that continues to be able to provide pensions, a solvent Earth system is one that continues to provide the natural services we rely on, support ongoing prosperity, and a safe and just future.

The problem is that the IPCC, on behalf of citizens of Planet Earth, does not assess risk in the same way that the managers of pension schemes assess risk for their clients.

Unmitigated climate change and nature-driven risks have been hugely underestimated. Global risk management practices for policy makers are inadequate, and we've accepted much higher levels of risk than is broadly understood.

I'm not sure that the IPCC will welcome being called “precisely wrong rather than roughly right”, especially when it dives down into the details of this devastating critique. It basically stands accused of:

  1. Relying on excessively narrow, reductionist science, based on retrospective “proof points,” without any capacity to cope with uncertainty and more sophisticated risk analysis.

  2. Failing to take into account the science of critical tipping points: “waiting for certainty” on whether these critical ecosystems will or won't tip, risks ruin.

  3. Slow-moving, static methodologies, which means that its risk assessments are infrequent and seemingly incapable of taking into account irrefutable evidence that the climate is changing far faster than its assessments indicate.

  4. Providing false (and therefore very dangerous) reassurance to governments that the scale of the damage done to the global economy by an average temperature increase of 2°C before the end of the century will be “manageable” at around 1.5% of global GDP. This is where the institute accuses the IPCC of being “wholly wrong”.

In due course, I'm sure the IPCC will provide some kind of riposte. When it does, it will need to take into account another equally devastating report from scientists at the Institute for Climate Risk at the University of New South Wales, confirming the actuaries’ hypothesis of underestimated financial risks—simply because the IPCC's Integrated Assessment Models on which it has depended for decades are incapable of capturing major risks—what actuaries describe as risks with “low probability but catastrophic impact.”

As Professor Andy Pitman, one of the co-authors of this report, put it:

It's in the extremes when the rubber hits the road. It isn't about average temperatures. In a hotter future, we can expect cascading supply chain disruptions triggered by extreme weather events worldwide.

Which is, of course, what's already happening, in front of our very eyes, in real time, country after country.

So does some arcane standoff between climate geeks and number-crunching actuaries have any bearing on the real world? It absolutely does! If the IPCC continues to provide governments with seriously flawed assessments of climate risk, furnishing them with every conceivable variety of comfort blanket that protects us from the “whole truth” about accelerating climate change, then there is literally no way governments will ever come up with timely, proportionate responses to the crisis.

And we'll all pay the price for that.

In the meantime, the resurgence of climate denialism in the USA, turbocharged by the Trump Administration's determination to kill off America's burgeoning green industries, is already having predictable consequences.

Amongst others, the big US banks feel liberated from their previous wishy-washy efforts to contribute to Net Zero decarbonization targets—only too keen to extricate themselves from the Net Zero Banking Alliance and other greenwashing exercises of this kind. Reading the political runes, Morgan Stanley recently declared, “We now expect a 3°C world”, without so much as a passing reference to the economic consequences of a 3°C world, not least as there are stupendously rich pickings to be made along the road to the apocalypse.

A recent article in Politico commented on a “mundane Morgan Stanley research report on the future of air conditioning stocks.” The global “cooling market” is already worth $235 billion, and Morgan Stanley analysts now expect this to grow at 7% per annum rather than 3% per annum as the world goes on getting hotter! As climate campaigner Bill McKibben put it, “Confronted with the probability of hell, they're figuring out a way of selling air conditioners to the devil”.

We can expect a lot more of this, with guidance from endless morally bankrupt asset managers and banks about “how to operate profitably as temperatures soar and climate impacts worsen”—how the rich can go on making themselves richer off the end of life on Earth.

And just in case you've already relegated to the back of your mind that analysis from the Institute and Faculty of Actuaries, let me remind you that in a 2°C warmer world, GDP will contract by more than 25%, with “mass human mortality events resulting in over 2 billion deaths.”

I wonder what the IPCC will have to say about the Morgan Stanley 3°C warmer world?