Five Expert Takes on the IPCC 1.5C Report

This week, top climate scientists from around the globe came together to publish the IPCC Special Report on Global Warming of 1.5C. The report explores pathways to limit warming to below 1.5C, a critical goal to protect the world’s most vulnerable populations and ecosystems. (For more information on what 1.5C of warming means for the planet, we recommend Carbon Brief’s interactive webpage.)

We’ve seen article upon article telling us the punchline of the report: the climate is in a dire state and we need to take action now. And while the report serves as a strong motivator for action, there are some interesting findings buried within the report that explore the role carbon removal plays in meeting this ambitious goal. So we set out to make sense of them — we asked five experts what they thought this new report meant for carbon removal. Read what they had to say below.


Dr. Jonah Busch — Chief Economist, Earth Innovation Institute

The new IPCC report is every bit as grim and technical as previous IPCC reports but it’s also new in some important ways. The report shows what it would take to stabilize the climate: lots more solar, wind, and nuclear and lots less fossil fuels; lots more forests and lots less pasture and non-agricultural land. This report also places a much larger emphasis on carbon dioxide removal. Most options for taking CO2 out of the air still only exist on paper or in the lab; forests are the big exception. (For Jonah’s full summary, read his Twitter thread here.)

Dr. Sabine Fuss — Mercator Research Institute on Global Commons and Climate Change (MCC) and Humboldt University of Berlin

In the report, a broad range of pathways that keep global warming below 1.5°C with limited or no overshoot has been assessed. Even though all of them feature carbon removal (in the form of bioenergy with carbon capture and storage (BECCS) and/or afforestation), the dependence on carbon removal can be greatly reduced by considerable changes in lifestyle and behavior and a rapid decrease in emissions before 2030. Still, at least 100 billion tons of CO2 are removed even under the most stringent assumptions. More likely, carbon removal will be on the order of magnitude of a few hundred billion tons of CO2. Trying to achieve this with only BECCS can result in risks for sustainability, which could be reduced if a portfolio of the removal options deployed at lower scales was considered.

Dr. Kate Marvel — NASA Goddard Institute for Space Studies and Columbia Engineering’s Department of Applied Physics and Mathematics

The report says that a world that is 1.5 degrees warmer than it was before the Industrial Revolution is less dangerous than a world that’s 2 degrees warmer. That extra half degree makes a huge difference to extreme weather risk, sea level rise, and agriculture, but it will take a massive, civilization-wide effort to reduce CO2 emissions in order to get there. Even then, we’re not “safe” at 1.5 degrees — climate change will still happen, and still be catastrophic for some. But that’s no reason not to try.

Dr. Joana Portugal Pereira — Senior Scientist at the IPCC Working Group III and Faculty of Natural Sciences at Imperial College

  1. Global warming above pre-industrial levels is already happening and requires immediate actions to avoid irreversible losses.
  2. To limit global warming to below 2°C, CO2 emissions need to reach net zero around 2075. This required global, large-scale and rapid transitions in energy, land, urban and infrastructure. This implies increasing share of renewable energy in the energy sector, fast electrification of energy end-use, increase energy efficiency and behavioral change to reduce energy demand (mobility and diet shifts). Carbon dioxide removal technologies, including fossil fuel CCS and BECCS, would be used to compensate residual emissions in the industrial sector, aviation, and maritime transport sectors.
  3. Avoided impacts of climate change will bring significant synergies in other Sustainable Development Goals (SDGs) dimensions, mainly on human health, access to clean energy, responsible consumption and production, and protection of ocean biodiversity. Some conflicts may exist between climate mitigation efforts and water access, land biodiversity, poverty, and hunger SDGs. Policy makers need to enhance strategies to promote diversification of the economic activities and capacity programs for civil societies to address the associated challenges.

Dr. Heidi Steltzer — Associate Professor of Biology at Fort Lewis College

We are on our way to a 1.5C warmer planet. We don’t need a report to tell us this. Many are experiencing the impacts of a hotter, drier world where storms have greater consequences. The report aims to help us assess, do we want to be headed to a 1.5C warmer planet? Many do not…If this question is difficult to answer, then the 1.5C report is a new opportunity, a chance to figure out ‘why not’ and be open to changing one’s mind — not one’s values, but one’s perspective.

It’s hard to know what it will be like and why 1.5C should be the new target. It’s a line on a stick in order to manage risk. The chances are greater that 1.5C is too much warming, rather than not a problem.