Instead of scaling up renewable energy, researchers promote unproved ideas
These models present pathways to carbon reductions that may permit us to keep climate change below two degrees Celsius.
They rely heavily on technologies that don't yet exist, such as ways to store carbon in the ground safely, permanently and affordably.
The IPCC models depend heavily on carbon capture and storage, also called carbon capture and sequestration.
Including companies such as ExxonMobil, say CCS is a proven, mature technology because for years industry has pumped carbon dioxide or other substances into oil fields to flush more fossil fuel out of the ground.
Carbon dioxide doesn't necessarily stay in the rocks and soil.
Keeping pumped carbon in the ground-in other words, achieving net negative emissions-is much harder.
Air-captured carbon dioxide is mixed with water and pumped into the ground, where it reacts with the basaltic rock to form stable carbonate minerals.
By comparison, just one company, tech giant Microsoft, produced nearly 14 million tons of carbon in 2021.
Or look at carbon capture at the Archer Daniels Midland ethanol plant in Illinois, which, since 2017, has been containing carbon at a cost to the American taxpayer of $281 million; at the same time, overall emissions from the plant have increased.
In 2016 the Massachusetts Institute of Technology closed its Carbon Capture and Sequestration Technologies program because the 43 projects it was involved with had all been canceled, put on hold or converted to other things.