1.5°C

Here's a quick reminder of what an average global temperature is. An average temperature is the sum of all the temperatures divided by the number of readings. That means some temperatures are lower, some are higher. At the current 1.1°C, 1.5°C  has already been reached, not constantly yet, not everywhere yet.

1.5°C and 2°C or other numbers are not magic numbers, they are checkpoints of climate models. Reaching any average temperature implies that some places are far above that level, so there are places in the world already where we can see what the effects of more heat are. These places are more or less at the poles, the North Pole the most,  and working their way down the latitudes. 

The poles are effectively linked to other climate zones in our ecosystem. We are already experiencing the effect of more energy in the air and water through the higher absorption of water vapor, itself a greenhouse gas, which adds mass to air masses, and adds chaos to the flow of circumpolar jet streams. 

It doesn't have to be a disaster everywhere for unrecoverable catastrophic weather events to happen right now in some places. The usual story we associate with a disaster is: despite some planning and preparation, a disaster occurs, destroying human and animal lives, infrastructure, and in some cases, the shape of land, seas or rivers. As these are rare events, there's period of recovery where the knowledge that that kind of disaster is possible informs the rebuilding efforts. In our new situation, we won't have time to rebuild and the assumptions for designing civil engineering are now unclear.

 This week (March 20, 2023), there will be a 40-50°F shift in temperature in North Carolina, from 29 to 80+ degrees. This stresses animal and plant life, but  also stresses steel and concrete. Cracks in roads and buildings lets in water and plant roots, two powerful corrosive and destructive  forces. This destruction is not proceeding at the pace of centuries.

Ecological system components influence each other. More water squeezed out of the air means more water on land, more fresh water in the ocean. The higher mass of water in the air means the air moves more slowly and powerfully, and the contrast between the weight of dry and wet air means more powerful winds. The parched earth has less capacity to absorb that water, creating new arroyos in what used to be stable formations.