The report, which involved leading climate scientists from the University of Bristol, found that between 2010 to 2019 average annual global greenhouse gas emissions were at their highest levels in human history, but the rate of growth has slowed. Without immediate and deep emissions reductions across all sectors, limiting global warming to 1.5°C by the end of this century is beyond reach.
However, since 2010 there have been sustained decreases of up to 85% in the costs of solar and wind energy, and batteries. The report also highlights that a growing range of policies and laws have improved energy efficiency, lowered rates of deforestation, and accelerated the deployment of renewable energy.
Dr Hoesung Lee, Chair of the Intergovernmental Panel on Climate Change (IPCC), said: “We are at a crossroads. The decisions we make now can secure a liveable future. 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.”
The Summary for Policymakers of the IPCC Working Group III report entitled Climate Change 2022: Mitigation of Climate Change was approved today by all 195 member governments.
It reported that limiting global warming will require major transitions in the energy sector, involving a substantial reduction in fossil fuel use, widespread electrification, improved energy efficiency, and use of alternative fuels, such as hydrogen.
Cities and other urban areas also offer significant opportunities for emissions reductions. These can be achieved through lower energy consumption, electrification of transport combined with low-emission energy sources, and enhanced carbon uptake and storage using nature.
Dr Jo House, Reader in Environmental Science and Policy at the university’s world-renowned Cabot Institute for the Environment, was lead author of the report chapter called Agriculture, forestry and other land use, and Viola Heinrich, a Physical Geography PhD student, was a contributing author of the same chapter.
Dr House said: “Agriculture, forestry, and other land use can provide significant emissions reductions, as well as remove and store carbon dioxide at scale. However, land cannot compensate for delayed emissions reductions in other sectors. Response options can benefit biodiversity, help us adapt to climate change, and secure livelihoods, food and water, and wood supplies.”
Reducing emissions in industry will involve using materials more efficiently, reusing and recycling products and minimising waste. For basic materials, including steel, building materials and chemicals, low- to -zero-greenhouse gas production processes are at pilot to near-commercial stage.
As industry accounts for about a quarter of global emissions, achieving net zero will be challenging and will require new productions processes, low and zero emissions electricity, hydrogen, and where necessary, carbon capture and storage.
In the scenarios assessed by the report, limiting warming to around 1.5°C 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.
“It’s now or never, if we want to limit global warming to 1.5°C. Without immediate and deep emissions reductions across all sectors, it will be impossible,” Dr House said.
“The global temperature will stabilise when carbon dioxide emissions reach net zero. For 1.5°C, this means achieving net zero carbon dioxide emissions globally in the early 2050s; for 2°C, it is in the early 2070s. This assessment shows limiting warming to around 2°C still requires global greenhouse gas emissions to peak before 2025 at the latest, and be reduced by a quarter by 2030.”
Professor Matt Rigby, Professor of Atmospheric Chemistry, was a contributing author for the Emissions trends and drivers chapter, where he provided updates on emissions of fluorinated greenhouse gases.
The report also looked at how the mitigation work could be financed and found that although this was a factor of three to six times lower than the levels needed by 2030 to limit warming to below 2°C there was sufficient global capital and liquidity to close investment gaps. This however relies on clear signalling from governments and the international community, including a stronger alignment of public sector finance and policy.
Mitigating and adapting to climate change must be equitable can help further sustainable development goals. Some response options can absorb and store carbon capture, while also helping communities limit the impacts of climate change. For instance, in cities networks of parks and open spaces, wetlands and urban agriculture can lower flood risk and reduce heat-island effects.
Mitigation in industry can reduce environmental effects and boost employment and business opportunities. Electrification with renewables and shifts in public transport can improve health, employment, and equity.
Dr House said: “Climate change is the result of more than a century of unsustainable energy and land use, lifestyles and patterns of consumption and production. The report underscores how taking immediate action can help move us towards a fairer, more sustainable world.”