Climate action: Extreme steps needed to avert disaster - IPCC

Radical emission cuts combined with some atmospheric carbon removal are the only hope to limit global warming to 1.5°, scientists warn.

Greenhouse gases (photo credit: REUTERS)
Greenhouse gases
(photo credit: REUTERS)

From 2010 to 2019, the average annual global greenhouse gas emissions were at their highest levels in human history, though the rate of growth has slowed, according to the UN's latest climate report. Without immediate and deep emissions reductions across all sectors, limiting global warming to 1.5° is beyond reach.

“We are at a crossroads. The decisions we make now can secure a livable future. We have the tools and know-how required to limit warming,” said Intergovernmental Panel on Climate Change (IPCC) Chair Hoesung Lee.  

“I am encouraged by climate action being taken in many countries. There are policies, regulations and market instruments that are proving effective.  If these are scaled up and applied more widely and equitably, they can support deep emissions reductions and stimulate innovation,” he added. 

"We have options in all sectors to at least halve emissions by 2030," the IPCC stated. Limiting global warming will require major reconfigurations in the energy sector. This will involve a substantial reduction in fossil fuel use, widespread electrification, improved energy efficiency, and the use of alternative fuels (such as hydrogen).

“Having the right policies, infrastructure, and the right technology in place to enable changes in our lifestyles and behavior can result in a 40-70% reduction in greenhouse gas emissions by 2050. This offers significant untapped potential,” said IPCC Working Group III Co-Chair Priyadarshi Shukla. “The evidence also shows that these lifestyle changes can improve our health and wellbeing.”

Renewable energy wind turbines as seen next to the snowy peaks of Mount Hermon on January 3, 2021. Northern Golan Heights. (credit: MICHAEL GILADI/FLASH90)Renewable energy wind turbines as seen next to the snowy peaks of Mount Hermon on January 3, 2021. Northern Golan Heights. (credit: MICHAEL GILADI/FLASH90)

Cities and other urban areas also offer significant opportunities for emissions reductions. These can be achieved through lower energy consumption (such as by creating compact, walkable cities), electrification of transport in combination with low-emission energy sources, and enhanced carbon uptake and storage using nature. There are options for established, rapidly growing and new cities.

“We see examples of zero energy or zero-carbon buildings in almost all climates,” said IPCC Working Group III Co-Chair Jim Skea. “Action in this decade is critical to capture the mitigation potential of buildings.”

The next few years are critical

In scenarios assessed by the IPCC, limiting warming to around 1.5°C (2.7°F) requires global greenhouse gas emissions to peak before 2025 at the latest, and be reduced by 43% by 2030; at the same time, methane would also need to be reduced by about a third. Even if we do this, it is almost inevitable that we will temporarily exceed this temperature threshold but could return to below it by the end of the century.

“It’s now or never if we want to limit global warming to 1.5°C (2.7°F),” said Skea. “Without immediate and deep emissions reductions across all sectors, it will be impossible.”

The global temperature will stabilize when carbon dioxide emissions reach net zero. For 1.5°C (2.7°F), this means achieving net-zero carbon dioxide emissions globally in the early 2050s; for 2°C (3.6°F), it is in the early 2070s.  

This assessment shows that limiting warming to around 2°C (3.6°F) still requires global greenhouse gas emissions to peak before 2025 at the latest, and be reduced by a quarter by 2030.