By Theresa Duque
Limiting global warming to 1.5 degrees Celsius above pre-industrial levels will require severely cutting greenhouse gas emissions in half by 2030. Doing so calls for the immediate, large-scale adoption of renewable energy like solar and wind, electrified transportation, energy-efficient systems, alternative fuels, and carbon capture and storage technologies across all sectors globally.
This is one of the key messages in the "Synthesis Report of the Sixth Assessment Report" released this week (March 22) by the United Nations' Intergovernmental Panel on Climate Change (IPCC).
The synthesis report provides policymakers with the most up-to-date knowledge on climate change, including impacts and future risks along with strategies to mitigate those risks. It is based on the content of the Sixth Assessment Report, which includes three working group assessment reports and three special reports published between 2018 and 2022, with most of the work completed during the height of the pandemic.
Seven Lawrence Berkeley National Laboratory (Berkeley Lab) scientists contributed significantly to the Sixth Assessment Report's "Working Group 1 - Physical Science Basis," "Working Group 3 - Mitigation of Climate Change," and the special report "Global Warming of 1.5°C." They were among hundreds of researchers from 65 countries who together assessed tens of thousands of scientific publications and reviewed comments while writing the reports.
"In order to reach a temperature target of 1.5 degrees Celsius, emissions need to peak before 2025 and be reduced by around 43% by 2030."
- Nan Zhou, Berkeley Lab senior staff scientist, Energy Technologies Area
"We found that globally, greenhouse gas emissions are still on the rise. In order to reach a temperature target of 1.5 degrees Celsius, emissions need to peak before 2025 and be reduced by around 43% by 2030," said Nan Zhou, a senior staff scientist in Berkeley Lab's Energy Technologies Area.
Zhou is a lead author of the "Mitigation and Development Pathways in the Near- to Mid-Term" chapter of the Sixth Assessment Report. It shows how taking action now can slow down global warming and move societies toward a more equitable, livable world. "But it will be challenging to limit global warming to 1.5 degrees Celsius without drastically changing how we consume energy across all sectors and switching to renewable or cleaner low-carbon technologies soon," Zhou said.
Decarbonizing industry
Under the 2015 Paris climate agreement, nearly every nation agreed to hold global warming to 1.5 degrees Celsius. The world is already 1.1 degrees Celsius above pre-industrial levels as a consequence of "more than a century of burning fossil fuels," resulting in "more frequent and more intense extreme weather events," the IPCC said in a recent news release.
One major solution to prevent further warming involves decarbonization strategies for industry.
"We know that close to 50% of greenhouse gas emissions come from the production of chemicals, iron and steel, and cement," said Stephane de la Rue du Can, a lead author of the Sixth Assessment Report's industry chapter. "To reduce greenhouse gas emissions from these sectors, we will need to completely change the way we produce materials and consume goods by using less cement and steel, developing different compositions of low-emissions cement, and enabling a circular economy by recycling more steel and developing recyclable plastics."
Decarbonizing the industrial sector will also necessitate incentives on top of mitigation measures. "Benefits and opportunities will need to be transparent for workers who will be affected by the transition to a renewable industry, and decision makers will need to implement new policy regulations that would allow consumers to buy green steel or green concrete, and help us choose the lower carbon products," added de la Rue du Can.
"We know that close to 50% of greenhouse gas emissions come from the production of chemicals, iron and steel, and cement."
- Stephane de la Rue du Can, Berkeley Lab researcher, Energy Technologies Area
The Sixth Assessment Report also describes how our societies' other sectors - including energy, transportation, urban planning, buildings, and land use - can cut their emissions in half by 2030.
For example, electric vehicles offer the greatest potential to globally reduce greenhouse gas emissions, as long as they are combined with low- or zero-carbon electricity sources, the Sixth Assessment says. Advances in battery technologies could assist in the electrification of trucks and enhance electric rail systems. Alternative fuels such as low-emission hydrogen and biofuels could also help to decarbonize the aviation and shipping industries.
Another Berkeley Lab researcher who contributed to the Sixth Assessment report is Nina Khanna, a principal scientific engineering associate in the Energy Technologies Area. Contributions by Zhou, de la Rue du Can, and Khanna are part of the "Working Group 3 - Mitigation of Climate Change" report for the Sixth Assessment released in 2022.
Last year, Zhou became the technical program manager and de la Rue du Can became the South Africa coordinator for the U.S. Department of Energy's Net Zero World Action Center, which provides strategies to accelerate global energy decarbonization in support of the Net Zero World Initiative (NZWI). The center brings together 10 DOE national laboratories, nine U.S. government agencies, and a myriad of philanthropic organizations to promote net zero-emission energy systems around the world that are inclusive, equitable, and resilient.
