Thread by @AndrewLFanning

With countries unveiling their latest climate pledges for #COP26, I wanted to see how they stack up against national fair shares of the 1.5C carbon budget that take historical responsibility into account. A 🧵(with charts!🤓)

Here’s a global picture of cumulative CO2 emissions since 1850. Humanity passed the ‘safe’ 350 ppm CO2 boundary in 1988, and the 1.5C boundary is fast-approaching. The net zero curve by 2050 is equivalent to global emission cuts around 8% PER YEAR. Globally. 😱

But ‘humanity’ is misleading – Global North countries are more responsible for climate breakdown than the rest of the world. Lots of Global South countries are within fair shares of the climate boundary adjusted for population size, like Kenya.

India is in a similar situation. And virtually all low-income countries. These countries would have plenty of space to transition towards low-carbon infrastructure over the coming decades if high-emitting countries hadn’t appropriated more than their fair share.

The United States is known for excess, but it’s shocking to see the scale of it. Net zero by 2050 would still be more than 4 times over its fair share of the 1.5C boundary. The only fair path is via non-existent negative emissions (and/or reparations).

The UK and other wealthy countries have a very similar picture, with a Net Zero pathway overshooting fair shares of the 1.5C boundary by 3-4 times. I believe this is an important point to be raised at #COP26.

China, Brazil, and other middle-income countries would also tend to have space to decarbonise their economies over the coming decades while staying within fair shares of the 1.5C boundary. Or they would have if the climate crisis wasn’t already here.

So there you have it, my little contribution to #COP26. Net zero by 2050 may sound ambitious, but a look at historical responsibilities tells a different story. And since cumulative impacts are what drive climate breakdown, this story needs telling.

I haven’t written up this analysis yet (negative time technologies, pls!). It replicates this study by @jasonhickel: doi.org/10.1016/S2542-… and the projections are guided by @robjhyndman’s work: otexts.com/fpp2/. Questions and comments are welcome.