Thread by @rishpardikar

In recent #IPCC report, developing countries insisted a disclaimer be highlighted in a separate box. That models "do not make explicit assumptions about global equity, environmental justice or intra-regional income distribution." 🧵

For @carboncopyinfo carboncopy.info/ipccs-climate-…

So what does this disclaimer mean? What are the assumptions underlying modelled emission reduction pathways & why are they not driven by equity-based considerations like burden of energy transition on poorer countries?

Let's start with how models call for a rapid & drastic decline in only one fossil fuel which is primarily used in the developing world i.e. coal. A recent study by @FuelOnTheFire questioned the socio-political feasibility of such pathways & the leeway they provide for oil & gas

Now coming to integrated assessment models (IAMs) that are used to draw up IPCC pathways. IAMs are complex models that account for both human & earth systems. They examine possible futures of climate & energy systems & also the economy. But IAMs have serious limitations.

IAMs also do not consider historical emissions & instead choose to distribute burdens cost-effectively as a "practical solution". Reason? Truly equitable emission reduction pathways would mean high-income countries would have to reach net-zero immediately

Models also project an unequal future.

A study of 556 of 700 IPCC scenarios by @KanitkarT & @tjayaraman found global inequities are projected to continue even upto 2050. With far less per capita energy & GDP in developing world compared to developed half osf.io/p46ty/

Two other striking findings from this study: in some scenarios, Sub-Saharan Africa reduces emissions at rates faster in near term compared to developed countries. Burden of carbon removal via land-based carbon sinks & tech like CCS is also squarely placed on developing countries

Coming back to this disclaimer box in the recent IPCC Synthesis Report. One could argue it’s not that models used to construct these scenarios don't make explicit assumptions about global equity, but that they in fact assume perpetuation of existing inequities for decades to come

There's a lot more critique of modelling processes in the report. + some insightful & intricate comments from @DrTongia & @the_yushi. There's also a reference to another study that showed how IPCC mitigation scenarios "perpetuate colonial inequalities"
sciencedirect.com/science/articl…

A major implication of such critique is they make IPCC reports less useful as policy guides. Like to point to required emission cuts in developed world. As #IPCC's Sixth Assessment cycle #AR6 draws to a close, a Q that remains is whether #AR7 will reckon with such critique & how