The US is back in the Paris Agreement. Now the big question is what 2030 emission reduction target President Biden will bring to the table ahead of COP26 in Glasgow. His election campaign pledge to target net zero emissions by 2050 is encouraging, but now the world wants to know about US near-term action.
While the EU and UK both agreed strengthened targets for the next decade at the end of last year, most of the world’s major emitters have yet to pledge to significantly increase their near-term cuts. The US offer is likely to set the bar for the next round of offers. This one number will go a long way to determining whether governments keep the Paris Agreement’s goal of limiting global heating to 1.5C alive.
So what should it be?
Most of the Washington DC insiders are floating numbers in the range of 45–50% below 2005 levels. That’s based largely on the estimates from the Accelerating America’s Pledge study championed by former New York Mayor Bloomberg and former California Governor Brown.
That report analysed what could be achieved through bottom-up actions by US States, cities and businesses combined with federal measures. The authors cautiously claim it to be “compatible with the United States doing its fair share to limit global warming to 1.5C” and say it would “put the United States into a renewed position of global leadership”.
But on closer inspection, that claim rests on the assumption that US emissions should decline linearly from today to net zero emissions in 2050. Given that global heating is driven by the total cumulative emissions over time, the emissions pathway to net zero is critical. Others have suggested much deeper near-term emissions cuts are required, based on more principled considerations of the US responsibility for emissions and economic capacity to act.
- Climate Action Tracker suggest a US 2030 target of at least 52% below 2005 levels would be the minimum that could be considered a fair share consistent with limiting global heating below 2C, and a target of at least 75% would be the minimum consistent with the 1.5C goal.
- Climate scientist Kevin Anderson estimates annual mitigation rates of 10–12% are required of all developed countries based on the Paris Agreement’s equity principles, which for the US would equate to something like 72–78% below 2005 levels by 2030.
- Meanwhile the US Climate Action Network (CAN) is calling for a total US fair share of 195% below 2005 levels, consisting of emissions cuts in the US of at least 70% below 2005 levels and the remainder achieved through financial support to lower income countries. (If you think a number in excess of 100% sounds out of the realm of political feasibility, it’s worth checking the Bernie Sanders climate plan which took the analysis very seriously.)
I was involved with developing the approach used by US CAN as part of a global group of civil society actors ahead of the Paris COP. It’s the most comprehensive approach to determining the total fair share of national mitigation efforts, including the provision of international climate finance. But I’ll be the first to admit it isn’t easy to explain the method.
Here’s another approach to assessing a US fair share that has the virtue of simplicity.
In 2030, global average per capita emissions must be approximately 2.1 tCO2/year if the world is to get on track to limiting heating to 1.5C. As my work for Oxfam with colleagues at the Stockholm Environment Institute last year showed, currently the poorest half of the global population have carbon footprints some 2–3 times lower than that level, while the richest 10% — including most citizens in the US — have footprints that are ten times as high.
If US average per capita CO2 emissions are to converge to that level in 2030, based on US population projections, they would have to be reduced by some 87% below 2005 levels. Anything less than this implies greater efforts must be made in other parts of the world, and no increase in the per capita emissions of the world’s poorest people would be possible.
By contrast even the top end of the beltway insiders’ 45–50% below 2005 levels proposal would only amount to a reduction in US per capita emissions to some 8 tCO2/capita — still higher than the EU average today.
If we are to avert more than 1.5C of global heating, and if we take principles of climate justice seriously, then it seems that a US 2030 target in the region of 75–85% below 2005 levels is needed. Even if that feels politically unrealistic today, we should never lose sight of what science and ethics require. After all, the Paris Agreement is based on a ratchet mechanism that means countries should progressively strengthen their emissions reduction targets over time. And as President Biden’s election shows, political realities can shift rapidly.