Two-thirds of Earths surface is ocean. That is where global heat is accumulating. When Arctic Ocean Summers become completely ice free, likely next 5–10 years, we will be living on a different and worse weather planet. Best summarised as “Hot-House” Earth.

Dire functions of our complex climate systems have something of a carbon concentration hysteresis. We needed to stay below threshold of around 350 ppm to keep ice-caps around longer term. But once ice free, the systems dynamics change, and atmosphere CO2 concentrations may need to go below 280 ppm, the top of normal ice age periodicity, to get the ice caps and the stable “cooler earth” back again.

Once the Arctic is summer ice free, it is as if we added as much as 100 ppm to our atmosphere carbon, and subtracted large amounts of fossil fuel burning from our illusionary carbon budgets. With techno-empowered humans around, Holocene Earth will be never coming back.

We will likely stick around until long term feedbacks from all of our multiple system disturbances wipe us out. We either get with the systems or we get ejected from them. That is the broader purpose of evolution, finding a stable system balance. It often goes astray, then goes to another dynamic balance. The likelihood of ever turning wise enough to make a stable earth for ourselves seems very slim. The Holocene was a fluke.

James Hansen warned us well enough in “Storms of My Grandchildren”, and you have reminded us more ferocious weather systems are already on their way. This is all too much for cognitive denial systems that we, and possibly all animals possess, in order to maintain our short term survival mode functions.