The Lemon Fool

As we approach COP26 I am seeing numbers being quoted, like 50 Giga-tonnes per year of global CO2 emissions need to be reduced to say 15 Giga-tonnes in order to prevent a temperature rise of more than 2 Deg C globally.

I hear lots of talk, mainly from politicians on this theory but I have yet to see a simple model and computational proof that I can understand.

The principles of Gravity, Thermodynamics, Hydraulics etc all have rigorous proofs that most reasonably intelligent people can comprehend and accept.

Yet, we seem to be blindly accepting the premise of warming and these "hard" numbers, without a simple, understandable and rigorous proof being published for us to understand.

Especially when our way of life is about to be fundamentally altered.

scotview wrote:I hear lots of talk, mainly from politicians on this theory but I have yet to see a simple model and computational proof that I can understand.

I doubt there's a simple model. At a correlation level, the amount of Carbon Dioxide by hemisphere is lower in summer when it's warmer and higher in winter when it's colder. That's respectively down to the growth of plants and trees and the consumption of fossil fuels to provide heat and light.

The Unified Model I helped to write for the Met Office and used for their climate predictions is about 1 million lines of code. There is no simple equation I could point the layman at.

The models used in forecasts are the sort of things that require supercomputers to calculate for days on end, dividing the surface of the earth into cubes, and calculating temperatures, wind speeds & directions, cloud cover, evaporation, deep ocean temperatures.
We're often told about the temperature change by 2100. Remember too that's an arbitrary marker; things will go on changing for much much longer after that too.

There are lots of interesting graphs here:
https://ourworldindata.org/co2-and-othe ... -emissions
https://ourworldindata.org/explorers/co ... Per+capita

There's lots on Wikipedia, eg:
https://en.wikipedia.org/wiki/Climate_c ... bon_budget

I expect there is useful information in the IPCC report, but it's a lot to read.

Although, as other posters have explained, it's very complicated I can't help wondering if it might just be possible to come up with some kind of relatively simple equation. We surely know the average rate of increase in atmospheric CO2 over time, we presumably know the current average rate of increase in global temperature over an extended period so...

Obviously I realise they do not go together, day by day! There will be tremendous long term inertia behind any such simple relationship. But could it not be done? It would of course not be 'true', reliable over an extended period, or even based on any proper physical model. But might be of interest in getting a rough 'feel' of things? Though it wouldn't help the OP (nor me!) get a handle on the (complex) physical dynamics of climate change .

Climate Change: Global Temperature

https://www.climate.gov/news-features/understanding-climate/climate-change-global-temperature