If President-elect Joe Biden goes ahead with his net-zero emissions pledge by 2050 for the US, this could shave 0.1˚C off global warming by 2100, according to the Climate Action Tracker. Coupled with China’s pledge to bring emissions to net-zero before 2060, and the EU, Japan and South Korea’s commitments to reach net-zero by 2050, a tipping point is being approached that puts the Paris Agreement’s 1.5˚C limit within reach.
The Biden plan of net-zero emissions by 2050 and related policies results in cumulative emissions reductions between 2020 and 2050 of around 75 Gt CO2eq. These emission reductions would lead to a decrease in end-of-century warming of around 0.1°C compared to the CAT’s Pledges & Targets estimate of 2.7°C above pre-industrial levels (1).
The CAT earlier estimated the effect of China's net-zero goal as reducing end-of-century warming by 0.2-0.3°C.
“Taken together, the US and China going to net zero emissions would reduce our estimate of end-of-century warming to 2.3-2.4°C, taking the world 25-40% of the way towards limiting warming to the Paris Agreement’s 1.5oC limit,” said Niklas Höhne of NewClimate Institute, a Climate Action Tracker partner organisation.
“This could be an historic tipping point: with Biden’s election China, the USA , EU, Japan South Korea - two thirds of the world economy and over 50% of global GHG emissions – would have net-zero greenhouse gas emissions by mid-century commitments,” said Bill Hare of Climate Analytics, the other CAT partner organisation.
“These commitments are very close, if not within, 1.5oC-consistent pathways for this set of countries and for the first time ever puts the Paris Agreement’s 1.5˚C limit within striking distance.”
Across the globe, the wave of countries supporting net-zero greenhouse gas emissions by mid-century is now overwhelming. Adding the USA to the 126 countries that have made similar announcements on net zero emissions, would cover 63% of global emissions.
“What can other countries now do other than follow this overwhelming trend to net zero greenhouse gas emissions?” said Höhne.
“The US has formally left the Paris Agreement, but this will be a short hiatus,” said Hare. “President-elect Joe Biden has a lot of catching up to do: first to reverse the Trump Administration’s anti-climate moves, then begin to move the country in the right direction, but he will be surfing a new wave of global ambition.”
Of course whether President-elect Biden will be able to implement his full net-zero plan depends on the majority in the Senate. However, there are workarounds with executive orders, and the “We’re Still In” coalition of states and cities led by California are already showing they are taking strong action at state level.
(1) The CAT considers the uncertainty of the climate modelling using a likely range of 66% probability around the central temperature estimate. For these bounds, the avoided warming by the Biden plan could be up to 0.14°C for the upper bound and down to 0.08°C for the lower temperature bound.
Noting there is considerable uncertainty surrounding these estimates, including the possibility spill-over effects (i.e., other countries following suit) and where GHGs are included in the pledges (e.g., CO2 or all Kyoto gases). We assume the more conservative aspects of both in our estimates.