Just to limit the global warming already well underway to 1.5 degrees Celsius would require “rapid and far-reaching transitions in land, energy, industry, buildings, transport and cities,” the report said.
"Limiting warming to 1.5 degrees Celsius is possible within the laws of chemistry and physics, but doing so would require unprecedented changes," Jim Skea, co-chair of IPCC Working Group III said.
“Global net human-caused emissions of carbon dioxide (CO2) would need to fall by about 45 percent from 2010 levels by 2030, reaching 'net zero' around 2050. This means that any remaining emissions would need to be balanced by removing CO2 from the air,” according to the report.
Techniques for removing CO2 from the air to try and reduce the global temperature by 1.5 degrees Celsius are unproven, though. It's not even clear that it could be done on a mass scale.
The IPCC report is the first in a series assessing the impact of a 1.5 and 2-degree Celsius temperature increase. The next reports will focus on the impact of global warming on the ocean and cryosphere followed by one on the impact of land use.