COP26 might limit global warming to 1.8 degrees if everyone honours their promises to stop forest clearances and if numerous, untried technologies deliver economic growth without environmental damage, which is optimistic, but unlikely. Unless mass public protests turn the situation around, we are still heading for 2-3 degrees of warming and the result could be that rising sea levels from melting ice sheets make Sizewell C a toxic island in a hundred years' time.
First, a reality check. I know the current science says that sea level rises are relatively slow and incremental. Some estimates state that even at six degrees, Greenland only loses 10 per cent of its ice over 400 years. It sounds like a slow-burner kind of problem. The problem is the difference between the average global temperature and what is happening in the Arctic.
Earlier this year, a report by the Arctic Monitoring and Assessment Programme (AMAP), showed that the Arctic had warmed three times as fast as the rest of the planet. The average one degree of warming that we have experienced so far has translated into three degrees near the north pole, with forest fires and thawing tundra. There is a localised feedback loop with the loss of the reflective ice increasing temperatures at sea, while methane released from the melting permafrost accelerates the greenhouse effect for this region.
According to forecasts in the report, by the end of the century, average temperatures in the Arctic are expected to rise 3.3 to 10 degrees. You have probably noticed that is a far higher range than the COP26 negotiators were haggling over for average world temperatures, and one of the worrying features of the climate emergency is the way it will hit some regions far harder and quicker than others. In 2007, the Intergovernmental Panel on Climate Change (IPCC) didn’t even include ice melt as a contributory factor in its estimates of sea-level rises. Science is still catching up with how fast things change.
On average, the Greenland ice melt is currently only raising sea levels about a millimetre a year for the entire world, but that rate has accelerated. The rise is erratic, but in 2019 it was nearer 2mm. This is still a long way off the potential 7m rise (enough to flood the Houses of Parliament) if Greenland lost all its ice, but why risk building new nuclear facilities on a shifting coastline?
The last time there was as much carbon in the atmosphere as we have today, the planet wasn't 1.2 or 1.3 degrees C warmer, it was about 3. The Arctic was thick with forest and sea levels weren't centimetres higher but 70 feet. That is a truly different world and would make Sizewell C a drowning and toxic legacy.